Journal articles: 'Propylene polymer'

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Тверитникова, Изабелла, Izabella Tveritnikova, Ирина Кирш, Irina Kirsh, Дарья Помогова, Darya Pomogova, Ольга Банникова, et al. "Polyolefin-Based Multilayer Packaging Material Modified by Ethylene Propylene Copolymer in Food Storage." Food Processing: Techniques and Technology 49, no. 1 (June 26, 2019): 135–43. http://dx.doi.org/10.21603/2074-9414-2019-1-135-143.

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The research features a comprehensive study aimed at increasing the technological compatibility of multilayer packaging materials. The paper describes a recycling technology with the prospect of returning the resulting secondary raw materials to the production cycle. The research included the following tasks: to conduct a comprehensive study of polyolefin mixtures modified by ethylene propylene copolymer; to study the effect of the copolymer on the rheological and physicomechanical properties of polymer compositions; to propose a technology for the recycling of secondary polyolefin mixtures. The research involved the following methods: the capillary viscometry method was used to determine the rheological properties of polymer compositions; the tensile test method was employed to define the physicomechanical properties of the compositions; the pycnometric method was used to assess the density of the mixtures. The study featured such polymers as polyethylene, polypropylene, and ethylene-propylene copolymer, which was chosen as a link between the polymers. The authors obtained polymer compositions in various ratios of polyethylene, polypropylene, and ethylene-propylene copolymer: 70:30:0; 68.5:28.5:3; 65:25:10; 30:70:0; 28.5: 68.5: 3; 25:65:10. The article describes the process of modifying polyolefin compositions based on polyethylene and polypropylene by ethylene-propylene copolymer on a single-screw extruder. The authors defined the rheological properties and the deformation-strength characteristics of the polymer mixtures. Repeated processing proved to lead to a decrease in the physicomechanical properties of polyolefin mixtures, with the exception of compositions based on polyethylene and polypropylene in the ratio of 30:70, where the breaking stress increased. The number of processing cycles increased the melt flow rate of the mixtures. The proposed technology is meant for producing multilayer packaging materials using packaging waste in the middle layer for contact with food.

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Trianto, Azis, Yazid Bindar, and Noezran Noezran. "Propane Dehydrogenation in a Modified Porous Membrane Reactor for Producing Propylene with Chemical and Polymer Grades." ASEAN Journal of Chemical Engineering 5, no. 2 (December 1, 2005): 176. http://dx.doi.org/10.22146/ajche.50187.

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Propane dehydrogenation is a promising route for producing propylene to replace traditional cracking methods. A membrane reactor offers a possibility to produce not only chemical grade but also polymer grade of propylene. The purpose of the present study is to evaluate the performance of a Modified Porous Membrane Reactor (MPMR) in producing these two propylene grades simultaneously. The study involves evaluations based on thermodynamics and process flow sheeting. The performance of this reactor is compared to that of conventional reactor. At first, the thermodynamics is conducted using minimum Gibb's Energy approach. Then the process flow sheeting evaluation is built using the HYSYS simulator. The effect of inert gas (steam) concentration in both sweep and feed sides is investigated. The thermodynamics study results optimum temperature and inert gas concentration to obtain these two grades of propylene simultaneously. The propylene with polymer grade above 99% is produced from the sweep side outlet. The propylene with chemical grade is produced from the feed side outlet. The simultaneous production of these two grades of propylene has benefit in vanishing propane-propylene splitter. Keywords: Membrane reactor, porous membrane, propane dehydrogenation, propylene production, and process simulation.

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NOMURA, Takao, Takeyoshi NISHIO, Hideaki TANAKA, and Kenji MORI. "Ordered Structures of High-Performance Propylene/Ethylene-Propylene Rubber Polymer Blends." KOBUNSHI RONBUNSHU 52, no. 2 (1995): 90–96. http://dx.doi.org/10.1295/koron.52.90.

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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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GREEK, BRUCE. "Propylene price outlook hinges on polymer use." Chemical & Engineering News 68, no. 18 (April 30, 1990): 21–22. http://dx.doi.org/10.1021/cen-v068n018.p021.

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Longo, Julie M., Angela M. DiCiccio, and Geoffrey W. Coates. "Poly(propylene succinate): A New Polymer Stereocomplex." Journal of the American Chemical Society 136, no. 45 (November 4, 2014): 15897–900. http://dx.doi.org/10.1021/ja509440g.

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Smith, Barton A., Edward T. Samulski, Li Ping Yu, and Mitchell A. Winnik. "Polymer diffusion in molten poly(propylene oxide)." Macromolecules 18, no. 10 (October 1985): 1901–5. http://dx.doi.org/10.1021/ma00152a017.

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Williams, Rhys J., Luke Fox, and Candice Majewski. "The effect of powder age in high speed sintering of poly(propylene)." Rapid Prototyping Journal 27, no. 4 (May 10, 2021): 707–19. http://dx.doi.org/10.1108/rpj-05-2020-0090.

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Purpose This study aims to demonstrate for the first time that the cheap, commodity polymer, poly(propylene), can be successfully processed using high speed sintering, and that it can be recycled several times through the process, with little to no detriment to either the polymer itself or the parts obtained. This is significant as a step towards the realisation of high speed sintering as a technology for high-volume manufacturing. Design/methodology/approach A poly(propylene) powder designed for laser sintering was used to build parts on a high speed sintering machine. The unsintered powder was then collected and reused. Repeating this process allowed creation of seven generations of aged powder. A variety of characterisation techniques were then used to measure polymer, powder and part properties for each generation to discern any effects arising from ageing in the machine. Findings It was found that poly(propylene) could be used successfully in high speed sintering, albeit with a low build success rate. Increased powder age was found to correlate to an increase in the build success rate, changes in microscopic and bulk powder properties and improvement to the dimensional accuracy of the parts obtained. By contrast, no discernible correlations were seen between powder age and polymer molecular weight, or between powder age and the tensile properties of parts. Originality/value This is the first report of the use of poly(propylene) in high speed sintering. It is also first study regarding powder recyclability in high speed sintering, both in general and using poly(propylene) specifically.

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Kresge, Edward N. "SCIENCE AND SERENDIPITY IN POLYOLEFIN ELASTOMER DEVELOPMENT." Rubber Chemistry and Technology 83, no. 3 (September 1, 2010): 227–34. http://dx.doi.org/10.5254/1.3525682.

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Abstract Polyolefin elastomers based on ethylene, propylene, and isobutylene plus other monomers are now widely used in many diverse applications. Major research and development efforts have led to thermoplastic polyolefin soft automobile bumpers, modifiers for lubricating oils, and fast extrusion grades of ethylene–propylene–diene terpolymers. These and other successful commercial innovations depend on the tools of the basic science of structure–property relationships, proper needs assessments, sound engineering, and good management. These tools have been largely provided by my colleagues at ExxonMobil Chemical, customers, and universities and I thank them profoundly. Several historical commercial developments are discussed, including thermoplastic polyolefin elastomers based on ethylene–propylene copolymer–isotactic–polypropylene blends, shear stable viscosity modifiers based on ethylene–propylene copolymers, bimodal molecular weight and compositional distribution EPDM to control rheological characteristics, and diene structure and interchain distribution. In addition, the ongoing research on nanocomposites for tire innerliners based on isobutylene polymers and clay is reviewed. The roles of polymer science, serendipity, and lost opportunity costs on innovation are also discussed.

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Skálová, Tereza, Jarmila Dušková, Jindřich Hašek, Petr Kolenko, Andrea Štěpánková, and Jan Dohnálek. "Alternative polymer precipitants for protein crystallization." Journal of Applied Crystallography 43, no. 4 (May 22, 2010): 737–42. http://dx.doi.org/10.1107/s0021889810014317.

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A set of 16 inexpensive and commercially available polymer precipitants were tested for protein crystallization. Eight of them were found suitable: polyethylene glycol dimethyl ether of molecular weight (MW) 500, 1000 and 2000; di[poly(ethylene glycol)] adipate, MW 900; poly(ethylene glycol-ran-propylene glycol), MW 2500 and 12000; poly(acrylic acid) sodium salt, MW 2100; and polyethylene glycol methyl ether methacrylate, MW 1100. Two new crystallization screens, PolyA and PolyB, were formulated using these eight polymers, each containing 96 solutions – four polymers in combination with 24 common salts and buffers, covering pH values from 4.5 to 9.0. The screens were tested on 29 proteins, 21 of which were crystallized. The tests confirmed the applicability of the eight polymers as precipitants for protein crystallization.

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Sethi, Bhawana, and Rupa Mazumder. "COMPARATIVE EVALUATION OF SELECTED POLYMERS AND PLASTICIZER ON TRANSDERMAL DRUG DELIVERY SYSTEM." International Journal of Applied Pharmaceutics 10, no. 1 (January 6, 2018): 67. http://dx.doi.org/10.22159/ijap.2018v10i1.21960.

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Objective: The present work was aimed at preparation of transdermal patches by a solvent casting method using a varying concentration of polymers i.e. methocel (K15 and K100), ethocel (4 and 10), gelatin, chitosan, eudragit (RL and RS) grade using plasticizer (glycerin and propylene glycol).Methods: The ratio of drug to polymers and plasticizer was varied and the effect of formulation variables was studied. Prepared transdermal patches were evaluated for physicochemical properties, in-vitro permeation studies, content uniformity, primary skin irritation studies and FT-IR studies.Results: The formulated transdermal patch by using Methocel K 100 M showed good physical properties. The average weight of patches prepared using glycerin as a plasticizer were ranged from 42.33-67.00 mg and propylene glycol as a plasticizer were ranged from 40.67-67.67 mg. The percentage moisture absorption varies from 1.76 to 10.73 for patches formulated using glycerin and 2.28 to 7.97 for propylene glycol patches. The percentage moisture loss from patches prepared using glycerin was ranged from 2.75 to 11.54 and 2.87 to 12.02 from propylene glycol. The water vapour transmission rate from patches prepared using glycerin was ranged from 0.25 to 0.92 and 0.41 to 1.76. The formulated patch showed the acceptable quantity of medicament ranged from (100.20-101.05%). This result met the test content uniformity as per BP (85% to 115%). According to that, the drug was consistent throughout the patches. The formulation PGD is considered as the best formulation, since it shows a maximum in vitro drug release as 43.75 % at 24 h. The drug release kinetics studied showed that the majority of formulations was following zero order.Conclusion: In conclusion, controlled release transdermal drug delivery system patches of aliskiren can be prepared using polymer combinations, with a different plasticizer. The release rate of drug depends upon the polymer. However, release kinetics followed zero order.

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Chowdhury, Faisal I., Jahidul Islam, A. K. Arof, M. U. Khandaker, Hossain M. Zabed, Ibrahim Khalil, M. Rezaur Rahman, Shahidul M. Islam, M. Razaul Karim, and Jamal Uddin. "Electrocatalytic and structural properties and computational calculation of PAN-EC-PC-TPAI-I2 gel polymer electrolytes for dye sensitized solar cell application." RSC Advances 11, no. 37 (2021): 22937–50. http://dx.doi.org/10.1039/d1ra01983j.

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In this study, gel polymer electrolytes (GPEs) were prepared using polyacrylonitrile (PAN) polymer, ethylene carbonate (EC), propylene carbonate (PC) plasticizers and different compositions of tetrapropylammonium iodide (TPAI) salt.

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Toft, Jostein, Olav M. Kvalheim, Terje V. Karstang, Alfred A. Christy, Karstein Kleveland, and Arne Henriksen. "Analysis of Nontransparent Polymers: Mixture Design, Second-Derivative Attenuated Total Internal Reflectance FT-IR, and Multivariate Calibration." Applied Spectroscopy 46, no. 6 (June 1992): 1002–8. http://dx.doi.org/10.1366/0003702924124457.

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The composition of nontransparent polymers has been predicted from the fingerprint region in the mid-IR. The polymers were analyzed by the Horizontal Attenuated Total internal Reflection (HATR) FT-IR technique. The polymers were blends of three different master batches: (1) a polymer of ethylene with carbon black, (2) a co-polymer of ethylene and propylene monomers, and (3) an ethylene-propylene-diene elastomer. A calibration set was defined by use of mixture design. Partial least-squares (PIS) regression was used to calculate models for prediction of the relative concentrations of each master batch (one at a time). Second-derivated IR profiles normalized to 100% were used as predictive variables. Two alternative criteria were compared for optimizing the predictive ability of the calibration models: (1) squared prediction error of all the calibration samples, and (2) prediction error of replicated calibration samples of the centerpoint in the design only. The latter criterion turned out to be the more useful for the purpose of this study. This is because the centerpoint represents the target sample of the blending process. The one-component PLS models, suggested by the latter optimization criterion, gave predictions within 1% of the stated relative concentrations and with standard deviations from 0.5 to 1.3% for all three master batches.

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Anada, Yui Chi. "Study of Motion of Impurity Ions Making Influence on Electrical Properties of Polymer Solids in Low Frequency Range." Advanced Materials Research 740 (August 2013): 630–35. http://dx.doi.org/10.4028/www.scientific.net/amr.740.630.

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The motion of impurity ions affects the electrical properties of polymer solid. The ions move through free spaces which exist in the non-crystalline part between polymer crystallites. The free spaces have inhomogeneous size distribution depending on a property of polymers or crystallization conditions. The homogeneity or inhomogeneity of the size of the free space affects the ionic motion, and consequently it also affects the electrical properties of polymer solids. In order to study the electrical properties of polymer solids in relation with such motion of impurity ions, the conductivity relaxation time was calculated for isotactic poly (propylene) (iPP), low density poly (ethylene) (LDPE) and plasticized poly (vinyl chloride) with dioctyl phthalate (p-PVC) from the electric modulus as a function of frequency which was observed by means of the Broadband Dielectric Spectroscopy (BDS). The value of the conductivity relaxation time reflects the non-crystalline structure of these polymers.

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Sallam, Sahar, Yuanyuan Luo, Matthew L. Becker, and Chrys Wesdemiotis. "Multidimensional mass spectrometry characterization of isomeric biodegradable polyesters." European Journal of Mass Spectrometry 23, no. 6 (June 6, 2017): 402–10. http://dx.doi.org/10.1177/1469066717711401.

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The biodegradable polyester copolymer poly(propylene fumarate) (PPF) is increasingly utilized in bone tissue engineering studies due to its suitability as inert cross-linkable scaffold material. The well-defined poly(propylene fumarate) oligomers needed for this purpose are synthesized by post-polymerization isomerization of poly(propylene maleate), which is prepared by ring opening polymerization of maleic anhydride and propylene oxide. In this study, multidimensional mass spectrometry methodologies, interfacing matrix-assisted laser desorption ionization and electrospray ionization with mass analysis, tandem mass spectrometry fragmentation and/or ion mobility mass spectrometry, have been employed to characterize the composition, end groups, chain connectivity and isomeric purity of the isomeric copolyesters poly(propylene maleate)and poly(propylene fumarate). It is demonstrated that the polymerization catalyst is incorporated into the polymer chain (as the initiating chain end) and that the poly(propylene maleate) to poly(propylene fumarate) isomerization using an amine base proceeds with quantitative yield. Hydrolytic degradation is shown not to alter the double bond geometry of the poly(propylene fumarate) or poly(propylene maleate) chains.

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Alfihed, Salman, Mark Bergen, Antonia Ciocoiu, Jonathan Holzman, and Ian Foulds. "Characterization and Integration of Terahertz Technology within Microfluidic Platforms." Micromachines 9, no. 9 (September 11, 2018): 453. http://dx.doi.org/10.3390/mi9090453.

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In this work, the prospects of integrating terahertz (THz) time-domain spectroscopy (TDS) within polymer-based microfluidic platforms are investigated. The work considers platforms based upon the polar polymers polyethylene terephthalate (PET), polycarbonate (PC), polymethyl-methacrylate (PMMA), polydimethylsiloxane (PDMS), and the nonpolar polymers fluorinated ethylene propylene (FEP), polystyrene (PS), high-density polyethylene (HDPE), and ultra-high-molecular-weight polyethylene (UHMWPE). The THz absorption coefficients for these polymers are measured. Two microfluidic platforms are then designed, fabricated, and tested, with one being based upon PET, as a representative high-loss polar polymer, and one being based upon UHMWPE, as a representative low-loss nonpolar polymer. It is shown that the UHMWPE microfluidic platform yields reliable measurements of THz absorption coefficients up to a frequency of 1.75 THz, in contrast to the PET microfluidic platform, which functions only up to 1.38 THz. The distinction seen here is attributed to the differing levels of THz absorption and the manifestation of differing f for the systems. Such findings can play an important role in the future integration of THz technology and polymer-based microfluidic systems.

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Ko, Dongkyun, Jong Hak Kim, Sang Wook Kang, Dong Hoon Lee, Jongok Won, and Yong Soo Kang. "Propylene-induced plasticization in silver polymer electrolyte membranes." Journal of Industrial and Engineering Chemistry 15, no. 1 (January 2009): 8–11. http://dx.doi.org/10.1016/j.jiec.2008.08.009.

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Ikezaki, Kazuo, and Yuji Murata. "Electret properties of ethylene–propylene random co-polymer." Journal of Electrostatics 67, no. 2-3 (May 2009): 407–11. http://dx.doi.org/10.1016/j.elstat.2009.01.006.

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NOMURA, Takao, Takeyoshi NISHIO, Masaya AKIYAMA, Eiichi SUGIHARA, and Kozoh TANAKA. "Polymer-Polymer Interaction in the Blends of Polypropylene and Ethylene-Propylene Rubber." KOBUNSHI RONBUNSHU 52, no. 2 (1995): 83–89. http://dx.doi.org/10.1295/koron.52.83.

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Bakather, Omer Yahya, and Mamdouh A. Al-Harthi. "Effect of titanium nanofiller on the productivity and crystallinity of ethylene and propylene copolymer." Journal of Polymer Engineering 34, no. 9 (December 1, 2014): 829–37. http://dx.doi.org/10.1515/polyeng-2014-0044.

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Abstract Bis(cyclopentadienyl) zirconium (IV) dichloride of empirical formula C10 H10 Cl2 Zr was used as a catalyst. Doped titania with iron (TiO2/Fe) nanofillers were used to study the effect of nanofillers on ethylene homopolymer and ethylene/propylene copolymer properties. Using titanium dioxide doped with iron (TiO2/Fe) resulted in the increase in the molecular weight (Mw) of polyethylene and ethylene/propylene copolymer nanocomposites of up to 80% when compared to the neat polymer. The catalyst activity was increased by using TiO2/Fe nanofiller for both ethylene polymerization and ethylene/propylene copolymerization. Besides the investigation of the catalyst activity and the molecular weight (Mw) of the obtained polymer, molecular weight distribution, copolymer composition, crystallinity and thermal characteristics of polyethylene and polyethylene/polypropylene nanocomposites were also studied. Non-isothermal crystallization kinetics of polyethylene and polyethylene/polypropylene nanocomposites fits well with the Avrami-Erofeev model.

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Lin, Rijia, Lei Ge, Hui Diao, Victor Rudolph, and Zhonghua Zhu. "Propylene/propane selective mixed matrix membranes with grape-branched MOF/CNT filler." Journal of Materials Chemistry A 4, no. 16 (2016): 6084–90. http://dx.doi.org/10.1039/c5ta10553f.

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Tomlinson, Richard W., and Daniel F. Sheridan. "Pulsed NMR for Molecular Structure Analysis of EPDM." Rubber Chemistry and Technology 62, no. 4 (September 1, 1989): 643–55. http://dx.doi.org/10.5254/1.3536266.

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Abstract The use of pulsed NMR analysis under proper operating conditions has proven to be useful for controlling various polymer compositions in the manufacture of EPDM. It can be used in determining the amount of oil incorporated into oil-extended EPDMs. At higher oil contents, the differences in EPDM properties will affect this test method, which will require a separate calibration curve for each type of polymer. It can be used to measure the propylene content of EPDM. Comparison data have shown that this technique is more accurate in predicting crystallinity or propylene content than the standard IR method within the propylene range of 22 to 41%. Pulsed NMR can also be used to predict uncured EPDM compound tensile strength and EPDM/PP compression-molded tensile strength. Since these properties are affected by the crystallinity of EPDM, of which percent ethylene is the major contributor, then tensile strength can be determined indirectly. Based on the tensile and SER correlation, it seems obvious that this technique is measuring the spin-spin relaxation times of the crystalline phase, whereas the ir method is only measuring propylene content.

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Ahmed Mahmoud, Ahmed Mohamed, and Kenji Miyatake. "Optimization of the pendant chain length in partially fluorinated aromatic anion exchange membranes for alkaline fuel cells." Journal of Materials Chemistry A 6, no. 29 (2018): 14400–14409. http://dx.doi.org/10.1039/c8ta04310h.

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Bohdanecký, Miloslav, Antonín Sikora, Jiří Horský, and Vladimír Petrus. "Properties of Dilute Solutions of Ethylene-Propylene-Diene Terpolymers in Benzene and Toluene." Collection of Czechoslovak Chemical Communications 60, no. 11 (1995): 1950–70. http://dx.doi.org/10.1135/cccc19951950.

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Commercial samples of ethylene-propylene-diene terpolymers (EPDM) and their fractions were characterized by osmometry (number-average molecular weight, second virial coefficient), viscometry (intrisic viscosity) and 1H NMR spectrometry (mole fraction of propylene monomeric units). The results were analyzed in terms of the two-parameter theory of polymer solutions. Theta temperatures and polymer-solvent interaction parameters were estimated and correlated with composition. Existence of organized structures is indicated by high values of the reduced partial molar entropy parameter y. The increase in y with increasing content of ethylene units is assigned to their association. The results lend support to the previous study on the Huggins viscosity coefficient of EPDM.

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Chen, Shaoyun, Min Xiao, Luyi Sun, and Yuezhong Meng. "Study on Thermal Decomposition Behaviors of Terpolymers of Carbon Dioxide, Propylene Oxide, and Cyclohexene Oxide." International Journal of Molecular Sciences 19, no. 12 (November 23, 2018): 3723. http://dx.doi.org/10.3390/ijms19123723.

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The terpolymerization of carbon dioxide (CO2), propylene oxide (PO), and cyclohexene oxide (CHO) were performed by both random polymerization and block polymerization to synthesize the random poly (propylene cyclohexene carbonate) (PPCHC), di-block polymers of poly (propylene carbonate–cyclohexyl carbonate) (PPC-PCHC), and tri-block polymers of poly (cyclohexyl carbonate–propylene carbonate–cyclohexyl carbonate) (PCHC-PPC-PCHC). The kinetics of the thermal degradation of the terpolymers was investigated by the multiple heating rate method (Kissinger-Akahira-Sunose (KAS) method), the single heating rate method (Coats-Redfern method), and the Isoconversional kinetic analysis method proposed by Vyazovkin with the data from thermogravimetric analysis under dynamic conditions. The values of ln k vs. T−1 for the thermal decomposition of four polymers demonstrate the thermal stability of PPC and PPC-PCHC are poorer than PPCHC and PCHC-PPC-PCHC. In addition, for PPCHC and PCHC-PPC-PCHC, there is an intersection between the two rate constant lines, which means that, for thermal stability of PPCHC, it is more stable than PCHC-PPC-PCHC at the temperature less than 309 °C and less stable when the decomposed temperature is more than 309 °C. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetric analysis/infrared spectrometry (TG/FTIR) techniques were applied to investigate the thermal degradation behavior of the polymers. The results showed that unzipping was the main degradation mechanism of all polymers so the final pyrolysates were cyclic propylene carbonate and cyclic cyclohexene carbonate. For the block copolymers, the main chain scission reaction first occurs at PC-PC linkages initiating an unzipping reaction of PPC chain and then, at CHC–CHC linkages, initiating an unzipping reaction of the PCHC chain. That is why the T−5% of di-block and tri-block polymers were not much higher than that of PPC while two maximum decomposition temperatures were observed for both the block copolymer and the second one were much higher than that of PPC. For PPCHC, the random arranged bulky cyclohexane groups in the polymer chain can effectively suppress the backbiting process and retard the unzipping reaction. Thus, it exhibited much higher T−5% than that of PPC and block copolymers.

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Qi, Xiaodong, Guanghui Yang, Mengfan Jing, Qiang Fu, and Fang-Chyou Chiu. "Microfibrillated cellulose-reinforced bio-based poly(propylene carbonate) with dual shape memory and self-healing properties." J. Mater. Chem. A 2, no. 47 (2014): 20393–401. http://dx.doi.org/10.1039/c4ta04954c.

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Alsewailem, Fares D., and Yazeed A. Binkhder. "Effect of Coupling Agent on the Properties of Polymer/Date Pits Composites." Journal of Composites 2014 (January 9, 2014): 1–7. http://dx.doi.org/10.1155/2014/412432.

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The morphology of the fracture surfaces of polymer/date pits composites was investigated. Polymers used in this study were high density polyethylene (HDPE) and polystyrene (PS). Date pits in the form of granules were two types of date pits: khlaas (K) and sekari (S). Two coupling agents, diphenylmethane-4 4′-diisocyanate (DPMI) and ethylene propylene grafted with malice anhydride (EP-g-MA), were used to ease the incorporation of date pit particles into polymer matrix. The SEM micrographs of the neat composites, that is, with no coupling agents, showed coarse morphology with bad dispersion, adhesion, and distribution of date pit particles within the polymer matrix. On the other hand, PS100/K composites coupled with DPMI and EP-g-MA had reasonable dispersed phase size with good distribution and adhesion to the composite matrix which in turn improve the mechanical properties of the resulted polymer/date pits composites.

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Qi, Xiaodong, Mengfan Jing, Zhenwei Liu, Peng Dong, Tianyu Liu, and Qiang Fu. "Microfibrillated cellulose reinforced bio-based poly(propylene carbonate) with dual-responsive shape memory properties." RSC Advances 6, no. 9 (2016): 7560–67. http://dx.doi.org/10.1039/c5ra22215j.

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Dutta, Kingshuk, Suparna Das, and Patit P. Kundu. "Polyaniline nanowhiskers induced low methanol permeability and high membrane selectivity in partially sulfonated PVdF-co-HFP membranes." RSC Advances 6, no. 109 (2016): 107960–69. http://dx.doi.org/10.1039/c6ra24090a.

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Sulfonated poly(vinylidene fluoride-co-hexafluoro propylene)/polyaniline nanowhiskers polymer electrolyte membrane exhibited the best membrane properties in terms of methanol permeability and selectivity.

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Fischer, Michele R., and Gary M. Hieftje. "Near-IR Multiplex Bandpass Spectrometer Utilizing Polymer Filters." Applied Spectroscopy 50, no. 10 (October 1996): 1246–52. http://dx.doi.org/10.1366/0003702963904944.

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A simple near-infrared spectrometer is described that utilizes ordinary polymer sheets as near-IR spectral filters. Examples of filter materials include polymethyl methacrylate, polyvinyl chloride (PVC), and organic solutions immobilized in a PVC matrix. The polymers were prepared by using solvent-molding techniques as well as with a thermoforming process. Each filter substance passes multiple bands of near-IR radiation. The performance of the spectrometer is demonstrated in selected quantitative and qualitative near-IR analytical applications. The applicability of the designed multiplex bandpass spectrometer in determining trace levels of water in methanol, dimethyl sulfoxide, and propylene glycol is examined. Additionally, the utility of the spectrometer in the determination of glucose concentration in aqueous solutions is studied.

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van Reenen, Albert J., and Omar Sultan. "The Effect of Catalyst Isomerization on Polypropylene Properties." Zeitschrift für Naturforschung B 62, no. 3 (March 1, 2007): 362–66. http://dx.doi.org/10.1515/znb-2007-0309.

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Two C2-symmetric metallocene catalysts in solution were exposed to light, and the rac-meso conversion followed by NMR spectroscopy. Both exposed and unexposed catalyst solutions were used, in conjunction with a suitable cocatalyst, to polymerize propylene. The polymers were characterized with respect to their microstructure and fractionated according to crystallinity. The relationship between the catalyst isomerization and the polymer structure is illustrated. The effect of pre-activation of the catalyst before exposure to light was also studied and is reported on.

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Wang, Liang, Da-Gang Guo, Hui Zhu, and Lei Xie. "Light emitting diodes (LEDs) encapsulation of polymer composites based on poly(propylene fumarate) crosslinked with poly(propylene fumarate)-diacrylate." RSC Advances 5, no. 65 (2015): 52888–95. http://dx.doi.org/10.1039/c5ra01667c.

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Liu, Xifeng, A. Lee Miller II, Brian E. Waletzki, Michael J. Yaszemski, and Lichun Lu. "Novel biodegradable poly(propylene fumarate)-co-poly(l-lactic acid) porous scaffolds fabricated by phase separation for tissue engineering applications." RSC Advances 5, no. 27 (2015): 21301–9. http://dx.doi.org/10.1039/c5ra00508f.

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Bahramian, B., Y. Ma, R. Rohanizadeh, W. Chrzanowski, and F. Dehghani. "A new solution for removing metal-based catalyst residues from a biodegradable polymer." Green Chemistry 18, no. 13 (2016): 3740–48. http://dx.doi.org/10.1039/c5gc01687h.

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Stahl, Sarah-Franziska, and Gerrit A. Luinstra. "DMC-Mediated Copolymerization of CO2 and PO—Mechanistic Aspects Derived from Feed and Polymer Composition." Catalysts 10, no. 9 (September 16, 2020): 1066. http://dx.doi.org/10.3390/catal10091066.

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The influence of composition of liquid phase on composition of poly(propylene ether carbonates) in the copolymerization of CO2 with propylene oxide (PO), mediated by a zinc chloride cobalt double metal cyanide, was monitored by FT-IR/CO2 uptake/size exclusion chromatography in batch and semi-batch mode. The ratio of mol fractions of carbonate to ether linkages F (~0.15) was found virtually independent on the feed between 60 and 120 °C. The presence of CO2 lowers the catalytic activity but yields more narrowly distributed poly(propylene ether carbonates). Hints on diffusion and chemistry-related restrictions were found underlying, broadening the distribution. The incorporation of CO2 seems to proceed in a metal-based insertion chain process, ether linkages are generated stepwise after external nucleophilic attack. The presence of amines resulted in lower activities and no change in F. An exchange of chloride for nitrate in the catalyst led to a higher F of max. 0.45. The observations are interpreted in a mechanistic scheme, comprising surface-base-assisted nucleophilic attack of external weak nucleophiles and of mobile surface-bound carboxylato entities on activated PO in competition to protonation of surface-bound alkoxide intermediates by poly(propylene ether carbonate) glycols or by surface-bound protons. Basic entities on the catalyst may promote CO2 incorporation.

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Davletbaeva, Ilsiya M., Ilgiz M. Dzhabbarov, Askhat M. Gumerov, Ilnaz I. Zaripov, Ruslan S. Davletbaev, Artem A. Atlaskin, Tatyana S. Sazanova, and Ilya V. Vorotyntsev. "Amphiphilic Poly(dimethylsiloxane-ethylene-propylene oxide)-polyisocyanurate Cross-Linked Block Copolymers in a Membrane Gas Separation." Membranes 11, no. 2 (January 29, 2021): 94. http://dx.doi.org/10.3390/membranes11020094.

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Amphiphilic poly(dimethylsiloxane-ethylene-propylene oxide)-polyisocyanurate cross-linked block copolymers based on triblock copolymers of propylene and ethylene oxides with terminal potassium-alcoholate groups (PPEG), octamethylcyclotetrasiloxane (D4) and 2,4-toluene diisocyanate (TDI) were synthesized and investigated. In the first stage of the polymerization process, a multiblock copolymer (MBC) was previously synthesized by polyaddition of D4 to PPEG. The usage of the amphiphilic branched silica derivatives associated with oligomeric medium (ASiP) leads to the structuring of block copolymers via the transetherification reaction of the terminal silanol groups of MBC with ASiP. The molar ratio of PPEG, D4, and TDI, where the polymer chains are packed in the “core-shell” supramolecular structure with microphase separation of the polyoxyethylene, polyoxypropylene and polydimethylsiloxane segments as the shell, was established. Polyisocyanurates build the “core” of the described macromolecular structure. The obtained polymers were studied as membrane materials for the separation of gas mixtures CO2/CH4 and CO2/N2. It was found that obtained polymers are promising as highly selective and productive membrane materials for the separation of gas mixtures containing CO2, CH4 and N2.

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Ito, Akira, and Sun-Tak Hwang. "Permeation of propane and propylene thrugh cellulosic polymer membranes." Journal of Applied Polymer Science 38, no. 3 (August 5, 1989): 483–90. http://dx.doi.org/10.1002/app.1989.070380308.

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Grande, Carlos A., Frank Poplow, and Alírio E. Rodrigues. "Vacuum Pressure Swing Adsorption to Produce Polymer-Grade Propylene." Separation Science and Technology 45, no. 9 (May 28, 2010): 1252–59. http://dx.doi.org/10.1080/01496391003652767.

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Prasad, M., Smita Mohanty, and Sanjay K. Nayak. "Polymer electrolyte membranes from Cloisite 30B-based solid proton conductor and sulfonated polyether ether ketone/polyvinylidene fluoride-co-hexafluoro propylene blends for direct methanol fuel cells." RSC Adv. 4, no. 105 (2014): 61178–86. http://dx.doi.org/10.1039/c4ra07701f.

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The improved fuel cell performance of polymer electrolyte membranes from C 30B-filled sulfonated polyether ether ketone/polyvinylidene fluoride-co-hexafluoro propylene blends indicates their candidature for DMFC applications.

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Zuga, M. D., Lucretia Miu, M. Crudu, V. Bratulescu, H. Iovu, and E. Manaila. "Products of Ethylene-Propylene Terpolymer Rubber (EPDM) Obtained by an Environmentally Friendly Process." Advanced Materials Research 23 (October 2007): 333–36. http://dx.doi.org/10.4028/www.scientific.net/amr.23.333.

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In the research work some thermoplastic elastomers have been obtained by compounding the ethylene-propylene terpolymer (EPDM) rubber with melt platicized PVC. The influence of every constituent level on the polymer compound characteristics was measured. The two polymers are incompatible, for the improvement of the EPDM/ PVC blends two methods of compatibility improvement have been used: 1) using compatibilizing agents (CPE was the selected compatibilizing agent); 2) electron beam irradiation (the optimum irradiation dose determined was 5 Mrad). The resulted products showed specific elastomer characteristics and can be processed by commonly used techniques for thermoplastic materials like as injection and injection molding.

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El Mohtadi, Farah, Richard d’Arcy, Xiaoye Yang, Zulfiye Yesim Turhan, Aws Alshamsan, and Nicola Tirelli. "Main Chain Polysulfoxides as Active ‘Stealth’ Polymers with Additional Antioxidant and Anti-Inflammatory Behaviour." International Journal of Molecular Sciences 20, no. 18 (September 17, 2019): 4583. http://dx.doi.org/10.3390/ijms20184583.

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We present the evaluation of a sulfoxide-based polymer (poly(propylene sulfoxide), PPSO) as a potential ‘stealth’ macromolecule, and at the same time as a pharmacologically active (anti-inflammatory/anti-oxidant) material. The combination of these two concepts may at first seem peculiar since the gold standard polymer in biomaterials and drug delivery, poly(ethylene glycol) (PEG), is ‘stealth’ due to its chemical and biological inertness, which makes it hardly biologically active. Polysulfoxides, on the contrary, may couple a substantial inertness towards biomolecules under homeostatic conditions, with the possibility to scavenge reactive oxygen species (ROS) associated to inflammation. Polysulfoxides, therefore, are rather uniquely, ‘active’ ‘stealth’ polymers. Here, we describe the synthesis of PPSO through controlled oxidation of poly(propylene sulfide) (PPS), which on its turn was obtained via anionic ring-opening polymerization. In vitro, PPSO was characterized by a low toxicity (IC50 ~7 mg/mL at 24 h on human dermal fibroblasts) and a level of complement activation (in human plasma) and macrophage uptake slightly lower than PEG of a similar size. Importantly, and differently from PEG, on LPS-activated macrophages, PPSO showed a strong and dose-dependent ROS (hydrogen peroxide and hypochlorite)-scavenging activity, which resulted in a corresponding reduction of cytokine production.

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Ivannikova, A. V., G. M. Danilova-Volkovskaya, and M. Kh Ligidov. "The Development of a Functional Additive Based on a Nanosized Filler of Natural Origin for the Production of thin Multilayer Heat-Shrink Films." International Polymer Science and Technology 45, no. 6 (June 2018): 279–82. http://dx.doi.org/10.1177/0307174x1804500607.

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This paper sets out the results of developing a functional additive based on low-density polyethylene and a copolymer of ethylene with butene, hexene, and propylene to modify the properties of flexible polymer packing by mean of the controlled effect of a concentrate of nanosized filler introduced during polymer processing with the aim of replacing imported filler concentrates.

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Quirk, Roderic P., and Deanna L. Gomochak. "Recent Advances in Anionic Synthesis of Chain-End Functionalized Elastomers Using Epoxides and Related Compounds." Rubber Chemistry and Technology 76, no. 4 (September 1, 2003): 812–31. http://dx.doi.org/10.5254/1.3547774.

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Abstract Recent developments are reviewed for the applications of reactions of polymeric organolithium compounds with epoxides and oxetane to obtain the corresponding ω-hydroxy chain-end functionalized polymers. State-of-the-art characterization methods for ω-functionalized polymers are also reviewed. Investigations of the usefulness of functionalization reactions of polymeric organolithium compounds with ethylene oxide, propylene oxide, 1-butene oxide, styrene oxide, oxetane, 3,4-epoxy-1-butene, 3-glycidoxypropyltrimethoxysilane and other epoxides are described. In general, these functionalization reactions are very efficient (> 90% yields of ω-hydroxy-functionalized polymers). The use of substituted epoxides is shown to provide an efficient methodology for attachment of a variety of groups at the polymer chain end.

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Zhang, Zhen, Baiyu Jiang, Feng He, Zhisheng Fu, Junting Xu, and Zhiqiang Fan. "Comparative Study on Kinetics of Ethylene and Propylene Polymerizations with Supported Ziegler–Natta Catalyst: Catalyst Fragmentation Promoted by Polymer Crystalline Lamellae." Polymers 11, no. 2 (February 19, 2019): 358. http://dx.doi.org/10.3390/polym11020358.

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The kinetic behaviors of ethylene and propylene polymerizations with the same MgCl2-supported Ziegler–Natta (Z–N) catalyst containing an internal electron donor were compared. Changes of polymerization activity and active center concentration ([C*]) with time in the first 10 min were determined. Activity of ethylene polymerization was only 25% of that of propylene, and the polymerization rate (Rp) quickly decayed with time (tp) in the former system, in contrast to stable Rp in the latter. The ethylene system showed a very low [C*]/[Ti] ratio (<0.6%), in contrast to a much higher [C*]/[Ti] ratio (1.5%–4.9%) in propylene polymerization. The two systems showed noticeably different morphologies of the nascent polymer/catalyst particles, with the PP/catalyst particles being more compact and homogeneous than the PE/catalyst particles. The different kinetic behaviors of the two systems were explained by faster and more sufficient catalyst fragmentation in propylene polymerization than the ethylene system. The smaller lamellar thickness (<20 nm) in nascent polypropylene compared with the size of nanopores (15–25 nm) in the catalyst was considered the key factor for efficient catalyst fragmentation in propylene polymerization, as the PP lamellae may grow inside the nanopores and break up the catalyst particles.

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Sawada, Toshiki, Hiroki Fukuta, and Takeshi Serizawa. "Preparation of Biocomposite Soft Nanoparticles Composed of Poly(Propylene Oxide) and the Polymer-Binding Peptides." Processes 8, no. 7 (July 17, 2020): 859. http://dx.doi.org/10.3390/pr8070859.

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The molecular recognition capability of naturally occurring biomolecules is generally expressed against biomolecules in the biological milieu. Recently, it was demonstrated that the specific interactions of biomolecules such as short peptides were applicable to artificial materials. We have developed peptides with specific affinities for synthetic polymers toward functional biocomposite polymeric materials. In this study, we demonstrated the preparation of biocomposite nanoparticles composed of poly(propylene oxide) (PPO) and PPO-binding peptides. A simple injection of a concentrated PPO solution dissolved in an organic solvent into the peptide solution under sonication resulted in the formation of nanospherical structures. Morphological observation indicated characteristic softness and high applicability as a molecular carrier of the biocomposite nanoparticles. Structural characterization of PPO and the PPO-binding peptide revealed the structural conformability of these molecules to interact specifically with each other. Our findings expand the potential applicability of polymer-binding peptides for the future construction of biomedical materials composed of peptides and various polymers.

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Wang, Wen-Zhen, Kai-Yue Zhang, Xin-Gang Jia, Li Wang, Lei-Lei Li, Wei Fan, and Li Xia. "A New Dinuclear Cobalt Complex for Copolymerization of CO2 and Propylene Oxide: High Activity and Selectivity." Molecules 25, no. 18 (September 8, 2020): 4095. http://dx.doi.org/10.3390/molecules25184095.

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Based on the ligand H4Salen-8tBu (salen-4), a new dinuclear cobalt complex (salen-4)[Co(III)TFA]2 (salen-4 = 3,5-di-tert-butylsalicylaldehyde-3,3′-diaminobiphenylamine; TFA = trifluoroacetic acid) has been firstly synthesized and characterized. It shows high catalytic activity for the copolymerization of propylene oxide (PO) and carbon dioxide (CO2), yielding regioregular poly(propylene carbonate) (PPC) with little generation of propylene carbonate (PC) by-product. It has been found that (salen-4)[Co(III)TFA]2 shows higher activity at milder conditions, generating a polymer with maximum Mn of 293 kg/mol and a narrow molecular weight distribution PDI of 1.35. The influences of reaction time, CO2 pressure, reaction temperature, nature of the cocatalyst, catalyst dosage and substrate concentration on the molecular weight, yield and selectivity of the polymer were explored in detail. The results showed that the (salen-4)[Co(III)TFA]2/[PPN]TFA catalyst system demonstrated a remarkable TOF as high as 735 h–1. In addition, a hypothetical catalytic reaction mechanism was proposed based on density functional theory (DFT) calculations and the catalytic reaction results of the (salen-4)[Co(III)TFA]2.

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Wheeler, L. M., and J. N. Willis. "Gel Permeation Chromatography/Fourier Transform Infrared Interface for Polymer Analysis." Applied Spectroscopy 47, no. 8 (August 1993): 1128–30. http://dx.doi.org/10.1366/0003702934067982.

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A new solvent elimination interface capable of operating at elevated temperatures, here 145°C, has been used to collect polymer molecular weight fractions eluting from a gel permeation chromatogram and to prepare them for IR analysis. The sample is deposited continuously onto a rotating germanium disk which can subsequently be scanned with the use of GC/FT-IR software, allowing direct access to the polymer or copolymer composition as a function of molecular weight. Data are presented here for an ethylene-propylene copolymer which has a distinct bimodal molecular weight distribution. Both the concentration profile and the “composition distribution” are examined. For the polymer concentration profile, comparison is made between the chromatogram obtained with a differential refractive index (DRI) detector and the IR detector (plotting the absorbance as a function of time using Gram-Schmidt vector orthogonalization). The copolymer composition is determined from the relative absorbance of methyl and methylene groups in the CH stretching region. The results show a small change in propylene content as a function of molecular weight, and there is good agreement between composition calculated with the use of the Gram-Schmidt and point-to-point methods.

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Kang, Sang Wook. "Enhanced Olefin Transport by SiO2 Particles for Polymer/Ag Metal/Electron Acceptor Composite Membranes." Polymers 12, no. 10 (October 10, 2020): 2316. http://dx.doi.org/10.3390/polym12102316.

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We showed the potential of poly(ethylene-co-propylene) (EPR)/silver metal/p-benzoquinone composite membranes for propylene/propane mixtures, i.e., a selectivity of 10 and a mixed gas permeance of 0.5 GPU (1 GPU = 1 × 10−6 cm3 (STP)/(cm2 s cmHg) in a previous study. In this study, we additionally found that the incorporation of fumed silica nanoparticles into EPR/silver metal/p-benzoquinone (p-BQ) composite membranes exhibited much higher permeance and selectivity for propylene/propane mixtures. The positive polarity of silver metal continuously increased with the increasing silica content up to the 0.1 weight ratio, as revealed by x-ray photoelectron spectroscopy (XPS). This increase in the polarity of silver metal was attributed to the enhanced interaction of p-BQ with the surface of Ag nanoparticles by the increased dispersion of p-BQ by fumed silica nanoparticles. Differential scanning calorimetry (DSC) also presented that the glass transition temperature (Tg) of the membranes was almost invariant. Therefore, the improvement of the permeance and selectivity with the silica nanoparticles was attributable to the increased polarity of the silver metal rather than the structural change.

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Causin, Valerio, Carla Marega, Antonio Marigo, Giuseppe Ferrara, Angelo Ferraro, and Roberta Selleri. "Structure-Property Relationships in Isotactic Poly(propylene)/Ethylene Propylene Rubber/Montmorillonite Nanocomposites." Journal of Nanoscience and Nanotechnology 8, no. 4 (April 1, 2008): 1823–34. http://dx.doi.org/10.1166/jnn.2008.0031823.

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Nanocomposites based on isotactic polypropylene/ethylene propylene rubber (iPP/EPR) were prepared adding different amounts of montmorillonite and maleated polypropylene. The structure and morphology of the samples were characterized by small angle X-ray scattering, wide angle X-ray diffraction, electronic and optical microscopy and differential scanning calorimetry. iPP showed a polymorphic behavior. Clay disrupted the ordered crystallization of iPP and had a key role in shaping the distribution of iPP and EPR phases: larger filler contents brought about smaller, less coalesced and more homogeneous rubber domains. Clay distributed itself only in the continuous phase and not in the rubber domains. Tactoids persisted on the surface of the sample, while delamination proceeded to a greater degree in the bulk of the materials. Melt flow rate, impact strength, flexural and tensile properties, were also measured and a structure-property correlation was sought. Clay produced its most significant effect on physical-mechanical properties by controlling the size of rubber domains in the heterophasic matrix. This allowed to obtain nanocomposites with increased stiffness and impact strength, a remarkable achievement for polymer layered-silica nanocomposites that usually suffer the drawback of being stiffer than the unfilled matrix, but at the same time with a lower resistance to impact. A beneficial effect of clay on thermal stability was also observed.

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Salakhov, Ildar, Elena Tkacheva, Valeriy Kozlov, Dmitriy Galanin, and Anas Sakhabutdinov. "A highly chlorinated xylene promoter for ethylene–propylene copolymerisation over a vanadium catalyst." RSC Advances 11, no. 34 (2021): 20916–25. http://dx.doi.org/10.1039/d0ra10583j.

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Hexachloro-p-xylene was found to be an effective promoter of olefin copolymerisation in the presence of vanadium catalyst, which increases the activity severalfold, enhances propylene incorporation in the copolymer, and results in a more homogeneous polymer.

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Journal articles on the topic 'Propylene polymer'

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