Journal articles: 'Polypropylene liner'

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INOUE, Atsushi, Toshiki SASAYAMA, Yoshitoku INOUE, and Yoshiteru AOYAGI. "114 Effect of Microstructure on Non-Liner Elastic Behavior of Polypropylene." Proceedings of Autumn Conference of Tohoku Branch 2014.50 (2014): 7–8. http://dx.doi.org/10.1299/jsmetohoku.2014.50.7.

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Wei, Zhang, Feng, Xie, Wu, and Cao. "Influence of Polypropylene Fiber on Tensile Property of a Cement-Polymer Based Thin Spray-On Liner." Applied Sciences 9, no. 14 (July 18, 2019): 2876. http://dx.doi.org/10.3390/app9142876.

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The influence of a polypropylene fiber on the tensile properties of a cement-polymer based thin spray-on liner (TSL) was investigated in this study. Two different contents of fiber were added to the liner, yielding two TSL groups. Tensile tests were performed (in accordance with the ASTM D638 standard) on the two groups of specimens as well as the control group at 1, 7, 14, and 28-day curing. The test result verified the large plasticity and low elastic modulus of the TSL compared with the fiber. SEM examination revealed that fibers lying parallel to the load direction ruptured or were pulled out from the matrix, which was beneficial to the tensile strength, but detrimental to the elongation because of their high stiffness. Other fibers lying perpendicular with the load direction were detrimental to both tensile strength and elongation through aggravating the propagation of the cracks. The tensile strength was improved by fiber incorporation, while the elongation was reduced at all curing. The influence of fibers on tensile toughness was uncertain since tensile toughness depended on strength as well as deformity.

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Reynaldo, Alvin, Hari Sidik Pramono, Sigit Puji Santosa, and Muhammad Aziz. "Finite Element Analysis of Liquefied Ammonia Tank for Mobility Vehicles Employing Polymers and Composites." Energies 13, no. 20 (October 13, 2020): 5312. http://dx.doi.org/10.3390/en13205312.

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Hydrogen has attracted global attention as a clean secondary energy source and has numerous possible applications, including fuel for vehicles. To store the hydrogen effectively, ammonia is considered promising due to high hydrogen density, stability, and total energy efficiency. Adopting ammonia as a fuel in vehicles requires a proper fuel tank design to fulfill the required volumetric content and safety standards, without neglecting the economic objectives. In general, a type-IV pressure vessel is utilized as a fuel tank because it is the lightest one, compared to other types of pressure vessel. This paper focuses on the effort to develop a lightweight type-IV ammonia pressure vessel designed for mobility vehicles. The material combination (liner and composite) and composite stacking sequence are analyzed for both burst and impact tests by using a finite element method. Two polymer materials of polyethylene terephthalate (PET) and polypropylene (PP) are evaluated as the liner considering their ultimate tensile strength, density, cost, and compatibility with ammonia, while carbon-fiber-reinforced polymer (CFRP) and glass-fiber-reinforced polymer (GFRP) are adopted as composite skins. In addition, five composite stacking sequences are analyzed in this study. Von Mises stress and Hashin’s damage initiation criteria are used to evaluate the performance of liner and composite, respectively. As the results, PP-based pressure vessels generate lower stress in the liner compared to PET-based vessels. In addition, CFRP-based pressure vessels have a higher safety margin and are able to generate lower stress in the liner and lower damage initiation criteria in the composite skin. The material combination of PP-CFRP with a stacking sequence of [90/±30/90]3s gives the lowest maximum stress in the liner during the burst test, while, for the impact test, the stacking sequence of [90/±θ/90]3s is considered the most appropriate option to realize a lower stress at the liner, although this tendency is relatively small for vessels with PP liner.

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Lee, Joo-Ha, Hwang-Hee Kim, Sung-Ki Park, Ri-On Oh, Hae-Do Kim, and Chan-Gi Park. "Mechanical Properties and Durability of Latex-Modified Fiber-Reinforced Concrete: A Tunnel Liner Application." Advances in Materials Science and Engineering 2018 (2018): 1–14. http://dx.doi.org/10.1155/2018/2134873.

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This study assessed the mechanical properties and durability of latex-modified fiber-reinforced segment concrete (polyolefin-based macrosynthetic fibers and hybrid fiber-macrosynthetic fiber and polypropylene fiber) for a tunnel liner application. The tested macrosynthetic fiber-reinforced concrete has a better strength than steel fiber-reinforced concrete. The tested concrete with blast furnace slag has a higher chloride ion penetration resistance (less permeable), but its compressive and flexural strengths can be reduced with blast furnace slag content increase. Also, the hybrid fiber-reinforced concrete has higher compressive strength, flexural strength, chloride ion water permeability resistance, impact resistance, and abrasion resistance than the macrosynthetic fiber-reinforced concrete. The modified fiber improved the performance of concrete, and the hybrid fiber was found to control the formation of micro- and macrocracks more effectively. Therefore, overall performance of the hybrid fiber-reinforced concrete was found superior to the other fiber-reinforced concrete mixes tested for this study. The test results also indicated that macrosynthetic fiber could replace the steel fiber as a concrete reinforcement.

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Lyakhevich, G. D., V. A. Grechukhin, A. G. Lyakhevich, and S. Yu Rozhantsev. "Theoretical Aspects, Experimental Investigations and Efficiency in Concrete Reinforcement by Organic Fibres." Science & Technique 19, no. 3 (June 5, 2020): 215–23. http://dx.doi.org/10.21122/2227-1031-2020-19-3-215-223.

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Fibre concrete is a composite material reinforced by fibres. Construction of facilities while using concrete reinforced by organic fibres has rather long history. An analytical review of national and international investigations have shown that application of fibre concrete for bridge and tunnel structures significantly improves their physical and mechanical indices and, firstly, their service life. 3D strengthening of fibre concrete fundamentally changes properties of cement stone while ensuring high crack resistance of structures, increasing their resistance to impact and dynamic loads. Changes in volume ratio of various fibres in concrete make it possible to regulate material properties. It permits to increase its tensile strength, corrosion resistance, weather resistance and resistance to periodical moistening-drying and freezing-defrosting processes, and other indices are improved as well. The paper presents the developed technologies and fibre concrete compositions and contains description of manufactured and tested experimental specimens of non-pressure pipes reinforced by polypropylene fibres. The executed investigations have shown that the polypropylene fibres reduce probability of crack initiation and prevent their enlargement and when they are operated they depress growth of cracks and concentration of stresses in the field of macrodefects. Due to introduction of the fibre re-distribution of stresses caused by the process of structure formation has occurred from places of their concentration for the whole concrete volume. The fibre increases concrete resistance to compression and also improves service life of concrete at low temperatures and aggressive reagent action. The polypropylene fibres is expediently to apply for disperse reinforcement of structures working in bending, for example, being used for tunnel liner, bridge structures, concrete non-pressure pipes etc.

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Plé, Olivier, Thi Ngoc Hà Lê, and Murad S. AbuAisha. "Landfill Clay Barrier: Fibre Reinforcement Technique." Advanced Materials Research 378-379 (October 2011): 780–84. http://dx.doi.org/10.4028/www.scientific.net/amr.378-379.780.

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Landfills come with a cover barrier which includes a compacted silty clay liner essential to safety on site. However this barrier encounters problems, especially those related to the differential settlement, which may cause stress in the clay layer leading to the development of cracks. Generally speaking, tensile stress damage and shearing are observed on the cap cover. Due to the weak mechanical performance of the clay layer it was proposed to add polypropylene fibre reinforcement. Direct tensile tests and compression tests under low confinement were carried out on unreinforced and reinforced soils. An improvement in soil resistance and in the brittleness index of fibre-reinforced clay was characterised. The proposed solution, technically feasible, enabled an optimization of the thickness of the mineral barrier.

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Z. Rosman, M., and C.-M. Chan. "The Influence of Water Content on the Settlement Behaviour of Polypropylene Fibre-Reinforced Dredged Marine Soil (DMS)." International Journal of Engineering & Technology 7, no. 4.14 (December 24, 2019): 434. http://dx.doi.org/10.14419/ijet.v7i4.14.27712.

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The use of fiber as soil reinforcement is not new in civil engineering field. In the earlier times, rice straw was mixed together with mud or clay to produce construction materials such as brick and concrete. Conventional concrete mix without fiber tends to exhibit brittleness behaviour. Hence, there is a growing attention on using current reinforcement materials such as steel, polypropylene and glass fibers. It is reported that fiber in concrete provide bridging effect, which transfer and distribute load evenly, thus increasing ductility. Now, similar concept of fiber inclusion in concrete can be applied to the case of problematic soil. The addition of chemical additives such as cement in soil resulted with stiffness and brittleness. As solution, numerous studies have shown that the fiber inclusion in soil have increased strength, permeability and ductility. Due to the many studies of fibre-reinforced soil related to its shear strength, the present study will investigate the compressibility behaviour of the fibre-reinforced soil through oedometer test. In this study, the dredged marine soil (DMS) was mixed together with 0.25, 0.5, 0.75 and 1 % of polypropylene (PP) fiber. Two conditions of soil, namely high water content (1.40LL) and low water content (0.90LL) were tested. Samples with 0.90LL water content show great reduction of settlement than samples with 1.40LL water content. The outcome of this study will suggest the beneficial reuse of DMS for engineering application such as backfill material, land reclamation or clay liner for landfills.

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Jeon, Han Yong, Y. H. Lee, Jung Min Seo, Beong Bok Hwang, and H. S. Koo. "A Study on the Chemical Resistance of GT Composites." Materials Science Forum 539-543 (March 2007): 988–91. http://dx.doi.org/10.4028/www.scientific.net/msf.539-543.988.

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This paper is concerned with the performance of geo-textile (GT) against chemical condition. GT is generally adopted for the upper part of geo-membrane (GM) for waste landfills and thus it is very important to consider the performance of GT against certain chemical environments until landfill is completed. In this study, PVA geo-textile/HDPE geo-membrane was prepared to investigate the waste landfill related properties in terms of long-term performance against chemical conditions imposed. GT composites of PVA GT/HDPE GM, PVA GT and HDPE GM were produced in thermal bonding process. Polyester and polypropylene GT were also manufactured in needle punching process. The experiments have been conducted under a modified version of EPA 9090 test method which is very similar to the method of evaluating chemical resistance of flexible membrane liner by the US Environmental Protection Agency (EPA). In this testing method, samples immersed in chemical of different solutions up to 150 days at 30 day interval were obtained to find tensile strength holding rate and chemical resistance. The analysis in this paper is focused to evaluate the effect of different pH conditions and temperature environments on geo-synthetics weights strength retention. It was concluded from the experiments that tensile strength of GT composites against leachate were reduced by 10 to 20% in both polypropylene and polyester non-woven GT. The reduction was more significant at temperatures of 50 °C than that at 25 °C. The experiments conducted in this study demonstrated that PVA GT is excellent in terms of chemical resistance.

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Hosney, M. S., and R. Kerry Rowe. "Changes in geosynthetic clay liner (GCL) properties after 2 years in a cover over arsenic-rich tailings." Canadian Geotechnical Journal 50, no. 3 (March 2013): 326–42. http://dx.doi.org/10.1139/cgj-2012-0367.

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A test cover comprised of three different needle-punched geosynthetic clay liner (GCL) products and covered with up to 1 m of cover soil (gravelly sand) was built over arsenic-rich tailings at a former gold mine in Nova Scotia, Canada, to evaluate the performance of the GCLs under local climatic conditions. Of the GCLs examined, one had untreated and two had polymer-enhanced natural sodium bentonite. The three GCLs each had different carriers: one with a woven geotextile, one with a scrim-reinforced nonwoven geotextile, and one with a woven geotextile laminated with a polypropylene film. At some locations, each type of GCL was placed in direct contact with the tailings. At other locations, each GCL was separated from the tailings by 0.15 m of cover soil. Samples of each GCL, tailings, and cover soil were recovered 1 and 2 years after construction. Tests show that the GCL with untreated bentonite maintained a low hydraulic conductivity (≤5 × 10−11 m/s) at locations where there was ≥0.7 m of cover soil above the GCL even though there was significant cation exchange of the sodium in the GCL with divalent cations in the tailings-soil porewater (the mole fraction of sodium (exchangeable sodium percentage (ESP)) decreased from 65% to 10%–17%). The GCL with polymer-enhanced bentonite had a lower hydraulic conductivity (≤3 × 10−11 m/s under ≥0.7 m of cover soil above the GCL) and experienced less cation exchange (ESP decreased to 19%–28%) than the standard GCL. The other GCL with polymer-enhanced bentonite and a carrier geotextile coated with a geofilm demonstrated the best hydraulic performance regardless of the thickness of cover soil or presence of an initially uncontaminated foundation layer. The presence of a foundation layer between the GCL and tailings impeded the migration of arsenic from the tailings into the GCLs. All GCLs were serving as an effective barrier to arsenic migration.

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Pekhotikov, A. V., B. B. Kolchev, P. A. Visloguzov, and D. V. Belyaev. "Practice of Using Fire-safety Sleeve for Free Flow Conduits of the Engineering Systems Made of Polymer Materials." Occupational Safety in Industry, no. 7 (July 2021): 66–72. http://dx.doi.org/10.24000/0409-2961-2021-7-66-72.

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To exclude the possibility of fire spreading through the utility lines of buildings and structures, various technical means are used that meet the normative established characteristics. As part of the intersection nodes of the enclosing building structures of sewage and water disposal systems, fire-safety sleeves are used, which ensure the limit of fire spreading to adjacent rooms through the node crossed by the pipeline. The use of fire-safety sleeves for these utility lines is only possible for free flow conduits of the systems made of polymer materials (polypropylene, polyethylene, polyvinyl chloride, etc.). For different types of the pipelines, other technical solutions are used to limit the spread of fire. The principle of fire-safety sleeves operation is to completely cover the intersecting mounting opening of the building structure in the shortest possible time and prevent the transfer of flame and combustion products to adjacent rooms. The efficiency of the operation of fire-safety sleeve and the preservation of its fire-technical characteristics for a given time depends on the following factors: correct installation carried out in accordance with the established instructions; design of fire-safety sleeves; physical and chemical properties of the material used for thermally expanding sleeve liner; material of a polymer pipeline. Statistics of the conducted tests show that the maximum fire resistance limits are typical for intersection nodes with polymer pipelines having diameter from 32 to 110 mm. For the pipelines with a diameter of 160 mm and more, it is very difficult to achieve similar fire-technical characteristics due to the large area of the overlapping mounting openings and the increased inertia of a fire-safety sleeve actuation.

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Bahreini, Ebrahim, Seyed Foad Aghamiri, Manfred Wilhelm, and Mahdi Abbasi. "Influence of molecular structure on the foamability of polypropylene: Linear and extensional rheological fingerprint." Journal of Cellular Plastics 54, no. 3 (March 23, 2017): 515–43. http://dx.doi.org/10.1177/0021955x17700097.

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The foaming structure and rheological properties of four different isotactic homo-polypropylenes with various molecular weights and an isotactic long chain branched polypropylene were investigated to find a suitable rheological fingerprint for PP foams. The molecular weight distribution and thermal properties were measured using GPC-MALLS and differential scanning calorimetry, respectively. Small amplitude oscillatory shear data and uniaxial extensional experiments were analyzed using the frameworks of van Gurp-Palmen plot (δ vs. | G*|) and the molecular stress function model, respectively. These analyses were used to find a correlation between the molecular structure, rheological properties and foaming structures of linear and long chain branching polypropylenes. Two linear viscoelastic characteristics, | G*| at δ = 60° and | η*| at ω = 5 rad/s were used as criteria for foamability of these polymers, where decreasing of both parameters by increasing the long chain branching content results in smaller cell size and higher cell density. The molecular stress function model was able to quantify the strain hardening properties of long chain branching blends using small amplitude oscillatory shear data and two nonlinear material parameters, 1 ≤ β ≤ 2.2 and 1 ≤ [Formula: see text] ≤ 600, where the minimum and maximum values of these parameters belong to the linear and long chain branched polypropylene, respectively. Increasing the long chain branched polypropylene content of the PP blends increased strain hardening, and therefore improved the foaming characteristics significantly by suppressing the coalescence of cells. Dilution of linear PP with only 10 wt% of long chain branched polypropylene enhanced the cell density from 5.7 × 106 to 2.7 × 107 cell/cm3 and reduced the average cell diameter from 58 to 26 µm, respectively, while their volume expansion ratio remained in the same range of 2–3. Increasing of long chain branching to 50 and 100 wt% enhanced the V.E.R. to 6.2 and 7.8, respectively.

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Munuera, Pedro V., and Rocio Mazoteras-Pardo. "Benefits of custom-made foot orthoses in treating patellofemoral pain." Prosthetics and Orthotics International 35, no. 4 (September 26, 2011): 342–49. http://dx.doi.org/10.1177/0309364611420201.

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Background: Patellofemoral pain is one of the most common disorders affecting the knee. Forefoot varus and excessive subtalar pronation can be associated with patellofemoral pain. Foot orthotics may produce an improvement in symptoms. Objectives: The aim of this study was to test whether patellofemoral pain is improved after four weeks of using custom-made foot orthoses. Study Design: Clinical trial without control group. Methods: Twenty-one subjects with patellofemoral pain were given custom-made foot orthoses (2-mm thick polypropylene and 4-mm thick polyethylene foam liner of 45 shore A hardness). Patellofemoral pain was evaluated with a visual analogue scale before applying the treatment, and at two weeks and four weeks follow-up. At the two-week check-up, a forefoot varus posting was added to the orthoses. Results: Improvements in patellofemoral pain was significant in all comparisons: initial pain with pain at the two-week check-up ( P<0.001), initial pain with pain at four weeks ( P<0.001), and pain at two weeks with pain at four weeks ( P<0.001). The effect size was large in all comparisons. Conclusion: For the participants in this study, the custom-made foot orthoses were found to be an effective conservative treatment to reduce the symptoms of patellofemoral pain.

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Dharmarajan, N., and L. G. Kaufman. "High Flow TPO Compounds Containing Branched EPDM Modifiers." Rubber Chemistry and Technology 71, no. 4 (September 1, 1998): 778–94. http://dx.doi.org/10.5254/1.3538504.

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Abstract Polymer blends of ethylene-propylene elastomers and polypropylene plastics, referred to as thermoplastic olefins, are finding increasing use in automotive applications. The combination of attractive mechanical properties, low raw material cost and recyclability make these materials ideal substitutes for expensive engineering thermoplastics (polycarbonate/polybutylene terephthalate alloys) and nonrecyclable polyurethane systems. The primary application is in automotive bumper fascia. This paper describes the addition of long chain branched ethylene-propylene elastomers in thermoplastic olefin compounds containing a high flow polypropylene resin matrix. In such compounds, the modifier molecular architecture plays an important role in impact toughening. The results clearly indicate that linear modifiers such as traditional ethylene-propylene copolymers are ineffective in impact toughening, while long chain branched polymers provide enhanced impact resistance with a ductile failure mode in high flow polypropylenes.

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SIVARAMAKRISHNA, VIJAYKRISHNA, ANISH MEHTA, GERHARD SCHRAMM, and MELVIN A. PASCALL. "Leak Detection in Polyethylene Terephthalate Bottles Filled with Water and Pulped and Unpulped Orange Juice Using a Vacuum Decay System." Journal of Food Protection 70, no. 10 (October 1, 2007): 2365–72. http://dx.doi.org/10.4315/0362-028x-70.10.2365.

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This research evaluated an offline vacuum decay leak detection system for 1,775-ml polyethylene terephthalate (PET) bottles. These bottles were filled with water and pulped and unpulped orange juice and induction sealed with an aluminum liner and an outer 38-mm continuous thread polypropylene cap. The objectives of this study were to evaluate (i) minimum leak size sensitivity of the instrument; (ii) ability to identify weak but nonleaking seals; (iii) effect of varying fill heights on the equipment's sensitivity; and (iv) percentage of false-positive and negative results likely to be obtained during a normal test run. To meet these objectives, leaks 5, 10, 15, 20, 30, 40, and 50 μm were created in the PET bottles. A second set of bottles was induction sealed at high voltage and 1, 1.5, 2, 2.5, 3, 3.5, and4sof dwell time. A third set of bottles with good seals was filled with differing headspace measurements of brimful, 1, 2, 3, 4, and 5 cm. After optimizing the equipment, leak tests on random sets of leaking and nonleaking bottles showed 0.0% false-positive and 0.0% negative identifications. Results showed 5-μm minimum leak size detection for bottles filled with all products. Optimum seal conditions were >2 but <3s at high voltage. Product fill heights >2to ≤3 cm did not affect the efficiency of the equipment. These results show that this vacuum decay system has potential for use in identifying leaks in PET bottles used for food packaging.

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Vallejo, Fernando, and Randolph Beaudry. "Absorption of 1-MCP by Nontarget Materials during Storage." HortScience 40, no. 4 (July 2005): 1131D—1131. http://dx.doi.org/10.21273/hortsci.40.4.1131d.

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We tested the sorptive capacity of a number of nontarget materials found in apple storage rooms on their capacity to remove 1-MCP from the storage atmosphere and thereby compete with the fruit for the active compound. Furthermore, we evaluated the impact of temperature and moisture. Nontarget materials included bin construction materials [high density polyethylene (HDPE), polypropylene (PP), weathered oak, nonweathered oak, plywood, and cardboard] and wall construction materials (polyurethane foam and cellulose-based fire retardant). Each piece had an external surface area of 76.9 cm2. We placed our “nontarget” materials in 1-L mason jars and added 1-MCP gas to the headspace at an initial concentration of ≈30 μL·L-1. Gas concentrations were measured after 2, 4, 6, 8, 10, and 24 hours. The concentration of 1-MCP in empty jars was stable for the 24-hour holding period. Little to no sorption was detected in jars containing dry samples of HDPE, PP, cardboard, polyurethane foam, or fire retardant. Inclusion of plywood, nonweathered oak, and weathered oak lead to a loss of 10%, 55%, and 75% of the 1-MCP after 24 hours, respectively. Using dampened materials, no sorption resulted from the inclusion of HDPE, PP, polyurethane foam, or the fire retardant. However, the rate of sorption of 1-MCP by dampened cardboard, plywood, weathered oak, and nonweathered oak increased markedly, resulting in a depletion of ≈98%, 70%, 98%, and 98%, respectively. The data suggest that there are situations where 1-MCP levels can be compromised by wooden and cardboard bin and bin liner materials, but not by plastic bin materials or typical wall construction materials.

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Tabatabaei, Seyed H., Pierre J. Carreau, and Abdellah Ajji. "Rheological and thermal properties of blends of a long-chain branched polypropylene and different linear polypropylenes." Chemical Engineering Science 64, no. 22 (November 2009): 4719–31. http://dx.doi.org/10.1016/j.ces.2009.04.009.

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Drozdov, A. D. "Linear thermo-viscoelasticity of polypropylene." Mechanics Research Communications 37, no. 8 (December 2010): 690–95. http://dx.doi.org/10.1016/j.mechrescom.2010.10.004.

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Theodorou, Doros N., and Ulrich W. Suter. "Shape of unperturbed linear polymers: polypropylene." Macromolecules 18, no. 6 (November 1985): 1206–14. http://dx.doi.org/10.1021/ma00148a028.

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Drozdov, A. D., S. Agarwal, and R. K. Gupta. "Linear thermo-viscoelasticity of isotactic polypropylene." Computational Materials Science 29, no. 2 (February 2004): 195–213. http://dx.doi.org/10.1016/j.commatsci.2003.09.003.

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Cai, Yan Da, Jing Song Wang, Yun Feng Luo, Wen Wu Long, Xiao Feng Yang, and Feng Zhu. "Different Performance of Foam Concrete Caused by Two Types of Fiber." Advanced Materials Research 842 (November 2013): 156–59. http://dx.doi.org/10.4028/www.scientific.net/amr.842.156.

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400kg/m3 apparent density foam concrete consists of protein foaming agent, ordinary Portland cement and two types of polypropylene fibers is made in this study. The effects of two types of fibers (polypropylene linear fiber and polypropylene mesh fiber) on the compressive strength, flexural strength and water absorption of the foam concrete were investigated. The results showed the difference of the water absorption of the foam concrete with addition of the two types of fibers is not significant, but the difference of the compressive strength and flexural strength is clear. Moderate addition of fibers could improve the strength of the foam concrete. As compared with control, the compressive strength and flexural strength increased by as high as 60.7% and 71.2%, respectively. From the experimental results, it is clear that polypropylene linear fiber has advantage of compressive strength and flexural strength over polypropylene mesh fiber when mixed with foam concrete.

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Barkoula, Nektaria M., Ben Alcock, Tim B. van Erp, Leon E. Govaert, and Ton Peijs. "Nonlinear creep response of oriented polypropylene tapes." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 232, no. 12 (July 6, 2016): 987–92. http://dx.doi.org/10.1177/1464420716659093.

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The creep response of a highly oriented polypropylene tape used for the manufacture of self-reinforced polypropylene or all-polypropylene composites was studied over a range of stresses and temperatures. Similar to oriented polyethylene, the creep compliance is linear viscoelastic at short loading times, whereas pronounced stress dependence is observed at longer loading times. A mathematical model is proposed, where the total deformation of the fibre is regarded as being composed of a stress-linear delayed elastic component and a nonlinear plastic flow contribution. Model predictions are in good agreement with the experimental data.

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Merhej, Tammam, Xin Kai Li, and De Cheng Feng. "Polypropylene Fiber Reinforced Concrete for Airport Rigid Pavements: Compressive and Flexural Strength." Advanced Materials Research 219-220 (March 2011): 1601–7. http://dx.doi.org/10.4028/www.scientific.net/amr.219-220.1601.

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This paper presents the experimental investigation carried out to study the behavior of polypropylene fiber reinforced concrete (PPFRC) under compression and flexure. Crimped polypropylene fibers and twisted polypropylene fiber were used with 0.0%, 0.2%, 0.4% and 0.6% volume fractions. The influence of the volume fraction of each shape of polypropylene fiber on the compressive strength and flexural strength is presented. Empirical equations to predict the effect of polypropylene fiber on compressive and flexural strength of concrete were proposed using linear regression analysis. An increase of 27% in flexural strength was obtained when 0.6% volume fraction of twisted polypropylene fiber was added. It was also found that the contribution of fiber in flexural strength is more effective when twisted fibers were used. The compressive strength was found to be less affected by polypropylene fiber addition.

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Stanic, Sascha, Thomas Koch, Klaus Schmid, Simone Knaus, and Vasiliki-Maria Archodoulaki. "Improving Rheological and Mechanical Properties of Various Virgin and Recycled Polypropylenes by Blending with Long-Chain Branched Polypropylene." Polymers 13, no. 7 (April 2, 2021): 1137. http://dx.doi.org/10.3390/polym13071137.

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Blends of two long-chain branched polypropylenes (LCB-PP) and five linear polypropylenes (L-PP) were prepared in a single screw extruder at 240 °C. The two LCB-PPs were self-created via reactive extrusion at 180 °C by using dimyristyl peroxydicarbonate (PODIC C126) and dilauroyl peroxide (LP) as peroxides. For blending two virgin and three recycled PPs like coffee caps, yoghurt cups and buckets with different melt flow rate (MFR) values were used. The influence of using blends was assessed by investigating the rheological (dynamic and extensional rheology) and mechanical properties (tensile test and impact tensile test). The dynamic rheology indicated that the molecular weight as well as the molecular weight distribution could be increased or broadened. Also the melt strength behavior could be improved by using the two peroxide modified LCB-PP blends on the basis of PODIC C126 or PEROXAN LP (dilauroyl peroxide). In addition, the mechanical properties were consistently enhanced or at least kept constant compared to the original material. In particular, the impact tensile strength but also the elongation at break could be increased considerably. This study showed that the blending of LCB-PP can increase the investigated properties and represents a promising option, especially when using recycled PP, which demonstrates a real “up-cycling” process.

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Chaudhary, Amit Kumar, and Krishnamurthy Jayaraman. "Extrusion of linear polypropylene-clay nanocomposite foams." Polymer Engineering & Science 51, no. 9 (March 23, 2011): 1749–56. http://dx.doi.org/10.1002/pen.21961.

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Silva, Marcelo Seixo de Brito e., Renato Miranda de Melo, Liliana Borges de Menezes, Sonia Maria Malmonge, Leandro Guimarães Franco, and Neusa Margarida Paulo. "2-hydroxyethyl methacrylate composite - polypropylene mesh for preventing peritoneal adhesions in female dogs." Acta Cirurgica Brasileira 25, no. 4 (August 2010): 342–46. http://dx.doi.org/10.1590/s0102-86502010000400008.

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PURPOSE: To evaluate whether the lining facing the visceral side of polypropylene mesh made with 2-hydroxyethyl methacrylate (p(HEMA)) hydrogel could avoid peritoneal adhesion in female dogs. METHODS: Eight animals (group PP) had a polypropylene mesh implanted to correct a defect in the rectal abdominal muscle, whereas in the other group (group PH) the polypropylene mesh was coated with p(HEMA) composite on the surface facing the peritoneal area. RESULTS: Adhesions were observed on the mesh in 62.5% of the PP group. In the PH group adhesions were present only on the suture lines. CONCLUSION: p(HEMA) hydrogel was well tolerated and effective in avoiding visceral and omental adhesions on the surface of the polypropylene mesh.

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Hiziroglu, Huseyin, and Iosif Shkolnik. "Electrical Characteristics of Polypropylene Mixed with Natural Nanoclay." Polymers 10, no. 9 (August 24, 2018): 942. http://dx.doi.org/10.3390/polym10090942.

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Polypropylene has been used in radio-frequency capacitors and has also started to be employed in cables as insulation. The objective of this study was to evaluate the electrical properties of polypropylene filled with natural clay as a nano-material. Polypropylene samples having 0%, 2% and 6% natural clay by weight were exposed to 60-Hz sinusoidal voltages at two different rates of rise. The breakdown voltage of each sample was recorded at these different ramp rates. Also, the Root-mean-squared (rms) current was measured as the voltage was increased across the test samples. The important findings of this study were (a) the breakdown strength of the natural nanoclay-filled polypropylene was higher than the unfilled polypropylene, and the optimum concentration of nanoclay appeared to be 2% by weight; (b) the current density as a function of the electric-field intensity indicated a non-linear behavior with saturation, and the saturation onset took place at a higher electric-field intensity in nanoclay-filled polypropylene, wherein 2% nanoclay seemed to be the optimum concentration as well for the onset electric field of saturation.

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Huang, Jintao, Guangjian He, Xia Liao, Yajiang Huang, and Qi Yang. "The rheological property and foam morphology of linear polypropylene and long chain branching polypropylene." Journal of Wuhan University of Technology-Mater. Sci. Ed. 28, no. 4 (July 13, 2013): 798–803. http://dx.doi.org/10.1007/s11595-013-0771-9.

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Rohlmann, C. O., M. D. Failla, and L. M. Quinzani. "Linear viscoelasticity and structure of polypropylene–montmorillonite nanocomposites." Polymer 47, no. 22 (October 2006): 7795–804. http://dx.doi.org/10.1016/j.polymer.2006.08.044.

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Drozdov, A. D., and R. K. Gupta. "Non-linear viscoelasticity and viscoplasticity of isotactic polypropylene." International Journal of Engineering Science 41, no. 20 (December 2003): 2335–61. http://dx.doi.org/10.1016/s0020-7225(03)00239-8.

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Ingemey, R. A., G. Strohe, and W. S. Veeman. "Dynamic Infrared Linear Dichroic Spectra of Prestretched Polypropylene." Applied Spectroscopy 50, no. 11 (November 1996): 1360–65. http://dx.doi.org/10.1366/0003702963904746.

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DIRLD (dynamic infrared linear dichroic) spectra of prestretched isotactic polypropylene have been recorded. The line shape features in the in-phase spectra are described on the basis of frequency shifts and absorption amplitude variations during the stretching cycle. Details such as the dichroism of the bands, direction of the shift, and changes in the absorption intensities must be considered to explain signs and shapes of the DIRLD bands. Evidence for chain reorientations under stress has not been found. The general principle of frequency shifts and changes in absorption intensities as the origin of DIRLD bands is demonstrated by spectral simulations.

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Dean, G. D., and W. Broughton. "A model for non-linear creep in polypropylene." Polymer Testing 26, no. 8 (December 2007): 1068–81. http://dx.doi.org/10.1016/j.polymertesting.2007.07.011.

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Mo, Yi-xin, Jian-yong Pang, and Jin-kun Huang. "Dynamic Mechanical Properties and Fractal Characteristics of Polypropylene Fiber-Reinforced Cement Soil under Impact Loading." Advances in Materials Science and Engineering 2019 (July 30, 2019): 1–14. http://dx.doi.org/10.1155/2019/3735891.

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This paper aims to study the dynamic mechanical properties, failure patterns, fractal behaviors, and energy dissipation of polypropylene fiber-reinforced cement soil under impact loading. Dynamic compression tests for reinforced cement soil with different polypropylene fiber contents of 0%, 0.4%, 0.8%, and 1.2% were conducted using a 50 mm diameter split Hopkinson pressure bar (SHPB) device. The static and dynamic stress-strain curves, dynamic strength increase factor (DIF), fractal behaviors, and energy dissipation properties of polypropylene fiber-reinforced cement soil were investigated and analyzed. The experimental results indicated that the dynamic strength increase factor (DIF) of cement soil increases firstly and then decreases with the increase of polypropylene fiber content from 0% to 1.2%. The maximum dynamic compressive strength of cement soil was obtained with adding 0.8% polypropylene fiber. With the increase of polypropylene fiber content, the average particle size of cement soil fragments has an increasing trend, whereas the fractal dimension presents a decreasing trend. Besides, the fragmentation degree of cement soil decreases correspondingly with the increase of polypropylene fiber content. The fractal dimension value has a linear relationship with the polypropylene fiber content and a decreasing exponential relationship with the average particle size. The absorbed energy per unit volume of cement soil presents an increasing trend firstly and a decreasing trend subsequently as the polypropylene fiber content increases from 0% to 1.2%. When the fractal dimension of cement soil is kept in the range of 2.04 to 2.15, the absorbed energy per unit volume of cement soil increases first and then decreases. The absorbed energy per unit volume of cement soil has a quadratic parabola relationship with polypropylene fiber content and fractal dimension, respectively. At last, the relationship of the absorbed energy per unit volume, fractal dimension, and polypropylene fiber content can be established, which can be used in the studies of dynamic behaviors and fractal properties of the fiber-reinforced cement soil under impact loading.

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Qian, Yu Qiang, You Song Sun, Xiao Ting Xiao, and Guo Hua Yang. "Study on Influences of Injection Process Parameters on the Mechanical Properties of the Modified Polypropylene Products with Weld Lines." Advanced Materials Research 139-141 (October 2010): 698–701. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.698.

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Influence of weld lines is important to the mechanical properties of the modified polypropylene products. Orthogonal experiments are adopted to confirm injection process parameters for such mechanical properties as impact resistance and tensibility of the modified polypropylene injection-molded parts in weld lines. The factors which affect the mechanical properties at welding joints product vary, and how to select rational parameters is a difficult problem for production. The mechanical strength can be increased through higher temperature, lower injecting pressure, higher velocity of filling, higher packing pressure and longer packing time. The specifications of cross section in weld lines of the products are analyzed to illustrate the theory of fracture. In order to increase mechanical strength of the sample, the length of hot weld lines should be increased and the length of cold welding joints should be decreased through adjusting the process parameter.

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Muñoz-Pascual, Santiago, Cristina Saiz-Arroyo, Zina Vuluga, Mihai Cosmin Corobea, and Miguel Angel Rodriguez-Perez. "Foams with Enhanced Ductility and Impact Behavior Based on Polypropylene Composites." Polymers 12, no. 4 (April 18, 2020): 943. http://dx.doi.org/10.3390/polym12040943.

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In this work, formulations based on composites of a linear polypropylene (L-PP), a long-chain branched polypropylene (LCB-PP), a polypropylene–graft–maleic anhydride (PP-MA), a styrene-ethylene-butylene-styrene copolymer (SEBS), glass fibers (GF), and halloysite nanotubes (HNT-QM) have been foamed by using the improved compression molding route (ICM), obtaining relative densities of about 0.62. The combination of the inclusion of elastomer and rigid phases with the use of the LCB-PP led to foams with a better cellular structure, an improved ductility, and considerable values of the elastic modulus. Consequently, the produced foams presented simultaneously an excellent impact performance and a high stiffness with respect to their corresponding solid counterparts.

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Luciano, Ermanno, Francesco Della Monica, Antonio Buonerba, Alfonso Grassi, Carmine Capacchione, and Stefano Milione. "Polymerization of ethylene and propylene promoted by group 4 metal complexes bearing thioetherphenolate ligands." Polymer Chemistry 6, no. 25 (2015): 4657–68. http://dx.doi.org/10.1039/c5py00488h.

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Duan, Xue-lei, and Jing-shuang Zhang. "Mechanical Properties, Failure Mode, and Microstructure of Soil-Cement Modified with Fly Ash and Polypropylene Fiber." Advances in Materials Science and Engineering 2019 (May 6, 2019): 1–13. http://dx.doi.org/10.1155/2019/9561794.

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In order to investigate the effects of fly ash and polypropylene fiber on mechanical properties, failure mode, and microstructure of soil-cement, the unconfined compression test, splitting tension test, and scanning electron microscopy (SEM) test of soil-cement with different polypropylene fiber contents (0%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% by weight of dry soil) and fly ash contents (0%, 4%, 8%, and 12% by weight of dry soil) were carried out. The compressive and tensile strengths, deformation characteristics, failure mode, and microstructure of soil-cement modified with fly ash and polypropylene fiber were analyzed. The results show that the unconfined compressive strength and splitting tensile strength of soil-cement show a trend of increasing first and then decreasing with the increase of polypropylene fiber and fly ash content. Under the condition of 0.4% polypropylene fiber and 8% fly ash, the unconfined compressive strength and the splitting tensile strength are 4.90 MPa and 0.91 MPa, respectively, which increased by 32.79% and 51.67% as compared with the plain soil-cement, respectively. When 8% fly ash was used in the experiment, the unconfined compressive peak strain and the splitting tensile peak strain of the inclusion of 0.4% polypropylene fiber were 0.0410 and 0.0196, respectively. The corresponding peak strains were increased by 20.94% and 68.97% as compared with non-fiber-stabilized soil-cement, respectively. The stress-strain curve of fly ash soil-cement modified with polypropylene fiber can be divided into compaction phase, linear rise phase, nonlinear rise phase, and failure phase. Polypropylene fiber constrains the lateral deformation of fly ash soil-cement, which improves the peak strain and the failure mode of soil-cement.

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Zia, Asad, and Majid Ali. "Effectiveness of Polypropylene Fiber Reinforced Concrete in Enhancement of Long-Term Durability of Hydraulic Structures." Materials Science Forum 923 (May 2018): 125–29. http://dx.doi.org/10.4028/www.scientific.net/msf.923.125.

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The long-term durability of concrete hydraulic structures can be improved by controlling their rate of water absorption and linear shrinkage. Incorporation of fibers in concrete composites has the potential to improve these properties of concrete. Artificial fibers are commonly used in concrete due to its durable nature for long serviceable life. So, the overall aim of this research program is to study the effectiveness of artificial fibers for improvement of long-term durability of concrete hydraulic structures. To start with, polypropylene fibers are considered. The polypropylene fibers (PPF) have the unique properties of chemically inertness and low cost raw materials. The pilot study presents the experimental evaluation of water absorption and linear shrinkage of polypropylene fiber reinforced concrete (PPFRC) in comparison to that of plain concrete (PC). The mix design proportion of 1:3:1.5:0.7 (cement:sand:aggregates:water) is used in preparation of PC and PPFRC. For PPFRC, the fiber length of 50 mm and content of 5% by mass of cement are added. All tests are performed as per ASTM standard. Discussions on the considered properties of PC and PPFRC are made. As per expected outcomes PPFRC showed less water absorption and less linear shrinkage as compared to that of PC. Because of this possible attribute, the PPFRC can be used in hydraulic structures.

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Aldosari, Haia. "Investigation the Phase Separation in Metallocene Linear Low Density Polyethylene/Polypropylene Blends." Advanced Materials Research 1159 (September 2020): 1–18. http://dx.doi.org/10.4028/www.scientific.net/amr.1159.1.

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The present study is aimed at investigated the miscibility in binary blend the Metallocene linear low density polyethylene (PE) and the Polypropylene homo (PP). Metallocene linear low density polyethylene is one of LLDPEs but with lower density higher melt flow index (MFI) than conventional LLDPE. The polyethylene and polypropylene blends (PB) were prepare by using o-xylene as solvent and polyethylene-co-glycidyl methacrylate (PE-co-GMA) as compatibilizer promote blending of immiscible homopolymers and the stability of the blend . The composites were characterized by wide angle X-ray diffraction (WAXD). Long period spacing was obtained using small angle X-ray scattering (SAXS).Crystallinity and melting behavior were studying by use the DSC and TGA, Metallocene linear low density polyethylene provide better behavior than the conventional LLDPE. The tensile test and DMA test were applied on the blends, which displayed improvement on the blend properties by using the PE-co-GMA and confirm the incompatible nature of the blends.

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39

Kressmann, Reiner. "Linear and nonlinear piezoelectric response of charged cellular polypropylene." Journal of Applied Physics 90, no. 7 (October 2001): 3489–96. http://dx.doi.org/10.1063/1.1398597.

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Tian, Jinghua, Wei Yu, and Chixing Zhou. "Crystallization Kinetics of Linear and Long‐Chain Branched Polypropylene." Journal of Macromolecular Science, Part B 45, no. 5 (October 2006): 969–85. http://dx.doi.org/10.1080/00222340600870507.

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41

Tian, Jinghua, Wei Yu, and Chixing Zhou. "Crystallization behaviors of linear and long chain branched polypropylene." Journal of Applied Polymer Science 104, no. 6 (2007): 3592–600. http://dx.doi.org/10.1002/app.26024.

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42

Jian, Li, Chixing Zhou, Wang Gang, Yu Wei, Tao Ying, and Liu Qing. "Preparation and linear rheological behavior of polypropylene/MMT nanocomposites." Polymer Composites 24, no. 3 (June 2003): 323–31. http://dx.doi.org/10.1002/pc.10032.

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Ibrahim, Elamin E., Dorina Magdalena Chipara, Ram Thapa, Karen Lozano, and Mircea Chipara. "Raman Spectroscopy of Isotactic Polypropylene-Halloysite Nanocomposites." Journal of Nanomaterials 2012 (2012): 1–8. http://dx.doi.org/10.1155/2012/793084.

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Raman spectroscopy investigations on nanocomposites obtained by dispersing halloysite within isotactic polypropylene are reported. A detailed analysis of the modifications of the regularity band associated to the polymeric matrix is presented. The Raman lines assigned to the polymeric matrix are broadened and weakened as the loading with halloysite is increased. The analysis of Raman lines indicates that the polymeric matrix becomes less crystalline upon the loading with halloysite and that the nanofiller is experiencing a weak dehydration upon dispersion within the polymeric matrix, probably due to the related thermal processing used to achieve the dispersion of halloysite.

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44

Boston, Daniel W., Steven R. Jefferies, and John P. Gaughan. "The Relative Location of the Dye Staining Endpoint Indicated With Polypropylene Glycol-Based Caries Dye versus Conventional Propylene Glycol-Based Caries Dye." European Journal of Dentistry 02, no. 01 (January 2008): 29–36. http://dx.doi.org/10.1055/s-0039-1697350.

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ABSTRACTObjectives: This study determined the difference in the location of the caries dye staining endpoint of 1% Acid Red dye in propylene glycol versus that of 1% Acid Red dye in polypropylene glycol.Methods: Freshly extracted permanent molar crowns with primary occlusal carious lesions were chisel-split axially to expose the lesion in cross-section on both halves. One half was stained with propylene glycol-based dye and the other with polypropylene glycol-based dye. For the control group, both halves were stained with propylene glycol-based dye. The dye staining front was marked on digital images of the stained split surfaces, and the images were aligned using reference notches. The distance between the marked staining front lines was measured in five locations, and the measurement protocol was repeated. Weighted averages and a 95% confidence interval for the distance between marked staining front lines were calculated for the control and experimental groups.Results: The weighted average distance for the experimental group (0.298 mm, 95% confidence interval 0.240 mm -0.357 mm) was about four times that of the control group (0.070 mm, 95% confidence interval 0.051 mm - 0.089 mm). Generally, the marked staining line for the polypropylene glycol-based dye specimens was located shallow (occlusal) to the propylene glycol-based staining line (range -0.12 mm to 0.66 mm).Conclusions: The staining endpoint of 1% Acid Red dye in polypropylene glycol is shallower than that of 1% Acid Red dye in propylene glycol. The method is useful for comparing staining endpoints of caries dye formulations. (Eur J Dent 2008;2:29-36)

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Wang, Wei, Xiaomin Guo, Liu Liu, Ruiyun Zhang, and Jianyong Yu. "Effect of Temperature and Strain Rate on the Flexural Behavior of Wood-Polypropylene Composites." Materials 12, no. 23 (December 2, 2019): 3987. http://dx.doi.org/10.3390/ma12233987.

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The mechanical properties of wood-polypropylene composites exhibit typical viscoelasticity. However, there is little information on the mechanical properties of wood-polypropylene composites related to temperature and time, which limits the use of wood-polypropylene composites as structural components. Here, the effect of time (strain rate) and temperature on the flexural properties and the master curve of the storage modulus used to predict the long-term performance of wood-polypropylene composites were investigated. The results showed that the flexural strength and modulus increased linearly with the increase of wood contend, which can increase by 134% and 257% respectively when the mass fraction of wood powder reached 45%. Moreover, there was a positive linear relationship between flexural strength and ln strain rate, while the flexural strength and modulus decreased as temperature elevated. The storage modulus as a function of frequency (time) and temperature confirmed this trend. To evaluate the long-term performance, the storage modulus master curve was constructed and the respective activation energy was calculated, which revealed that the long-term performance of the samples depended on the matrix and the addition of an appropriate amount of wood powder was beneficial to improve their durability.

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Sędłak, Paweł, Beata Białobrzeska, Tomasz Stawicki, and Piotr Kostencki. "Effect of Polypropylene Modification by Impregnation with Oil on Its Wear and Friction Coefficient at Variable Load and Various Friction Rates." International Journal of Polymer Science 2017 (2017): 1–19. http://dx.doi.org/10.1155/2017/9123586.

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Laboratorial two-body wear testing was carried out in order to assess effects of polypropylene modification by impregnating it with oils on friction coefficient and wear in comparison to those parameters of unmodified polypropylene, Teflon, and polyamide during operation under conditions of sliding friction without lubrication. Wear behaviour of the tested specimens was investigated using ASTM G77-98 standard wear test equipment. Recording program made it possible to visualise and record the following parameters: rotational speed and load, linear wear, friction coefficient, temperature of the specimen, and ambient temperature. In addition, wear mechanisms of the analysed materials were determined with use of scanning electron microscopy. In the case of the remaining tested polymers, the most important mechanism of wear was adhesion (PP, PTFE, PA 6.6, and PA MoS2), microcutting (PTFE, PA 6.6, and PA MoS2), fatigue wear (PTFE), forming “roll-shaped particles” combined with plastic deformation (PA 6.6 and PA MoS2), and thermal wear (PP). Impregnation of polypropylene with engine oil, gear oil, or RME results in significant reduction of friction coefficient and thus of friction torque, in relation to not only unmodified polypropylene but also the examined polyamide and Teflon.

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Dibaei, Asl, Majid Abdouss, Angaji Torabi, and Aminoddin Haji. "Surface and mechanical properties of polypropylene/clay nanocomposite." Chemical Industry and Chemical Engineering Quarterly 19, no. 3 (2013): 441–48. http://dx.doi.org/10.2298/ciceq120226079d.

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Huge consumption of polypropylene in the industries like automotive motivates academic and industrial R&Ds to find new and excellent approaches to improve the mechanical properties of this polymer, which has no degradation effect on other required performance properties like impact resistance, controlled crystallinity, toughness and shrinkage. Nowadays, nanoparticles play a key role in improving the mechanical and surface properties of polypropylene. In this study, three compositions of "Polypropylene/nanoclay", containing 0%, 2% and 5% of nanoclay were prepared in internal mixer. For characterizing the nanoclay dispersion in polymer bulk, TEM and XRD tests were used. For scratch resistance test, scratch lines were created on the load of 900 grain on sheets and SEM images were taken and compared with neat PP scratch image. Crystallinity and mechanical behavior were studied. The results showed that mechanical properties and scratch resistance of the composites have been improved.

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Koloskova, G. M., and V. Yu Koloskov. "Modelling of impact of temperature gradient on content of polymer ampoule during its forming." Journal of Achievements in Materials and Manufacturing Engineering 1, no. 100 (May 1, 2020): 12–19. http://dx.doi.org/10.5604/01.3001.0014.1958.

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Purpose: The aim of the represented study was to model the impact of temperature gradient on content of polymer ampoule during its forming. Design/methodology/approach: The model of polymer ampoules forming is built in SolidWorks software on the basis of finite element method. Using the developed model the study of temperature condition changes is carried out. Numerical modelling was carried out for two types of polymer packaging materials – polypropylene and polyvinylchloride – in similar conditions. Findings: During polymer ampoule forming the highest temperature of liquid is obtained at the bottom of it. The most effective packaging method is to form the ampoule from polypropylene by means of aluminium die. Investigation results have shown that the highest obtained liquid temperature has linear dependence from initial one. Linear coefficients of heating were evaluated for polypropylene (equal to 0.72) and polyvinylchloride (equal to 0.58). Practical implications: Decrease of initial liquid temperature value gives an opportunity to expand the range of products allowed to be packed in polymer ampoules in represented method. Safe conditions for packaging of liquid products in polymer ampoules are formulated, The results of the study may be used to improve the quality of liquid products packaging in polymer ampoules. Originality/value: For the first time the model was developed for determination of liquid heating degree during its packaging in polymer ampoules. The calculations of the temperature distribution are represented for polypropylene and polyvinylchloride ampoules forming by means of aluminium and ceramic dies. The results of the study may be of interest to specialists in the field of polymer packaging manufacturing for food or pharmaceutical industry.

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Pereira, Márcio Dias, Denise Cunha Fernandes dos Santos Dias, Eduardo Euclydes de Lima e. Borges, Sebastião Martins Filho, Luiz Antônio dos Santos Dias, and Paulo Emídio Soriano. "Physiological quality of physic nut (Jatropha curcas L.) seeds during storage." Journal of Seed Science 35, no. 1 (2013): 21–27. http://dx.doi.org/10.1590/s2317-15372013000100003.

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The physic nut has been considered as one of the oilseed plants species with the highest potential for biofuel production. Oleaginous seeds demand special care during storage to maintain their quality. This study aimed to establish the most adequate conditions for their storage. Freshly-harvested seeds were dried until 7.2 moisture content and stored along a year, under the following conditions: environmental laboratory and cold chamber ( ±5 ºC and 60% RH), into paper bag, polypropylene bag, and cardboard barrel. Physiological quality was then assessed by the tests: germination; first count; germination speed index; seedling length; accelerated aging; cold test; field emergence; and emergence speed index, after zero, three, six, nine, and 12 months. There was linear reduction of germination and vigor of the seeds after storage under environmental laboratory condition, into paper or polypropylene bags, and cardboard barrel. Physiological quality was higher after storage in cold chamber, into paper or polypropylene bags; and into cardboard barrel, at environmental laboratory condition.

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Fu, Dajiong, Feng Chen, Tairong Kuang, Dachao Li, Xiangfang Peng, Debbie Y. Chiu, Chiang Shiang Lin, and Ly James Lee. "Supercritical CO2 foaming of pressure-induced-flow processed linear polypropylene." Materials & Design 93 (March 2016): 509–13. http://dx.doi.org/10.1016/j.matdes.2016.01.012.

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Journal articles on the topic 'Polypropylene liner'

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