Relevant bibliographies by topics / Polymer ageing

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Polymer ageing'

Author: Grafiati
Published: 10 February 2023

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Journal articles on the topic "Polymer ageing"

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Krauklis, Andrey E., Christian W. Karl, Iuri B. C. M. Rocha, Juris Burlakovs, Ruta Ozola-Davidane, Abedin I. Gagani, and Olesja Starkova. "Modelling of Environmental Ageing of Polymers and Polymer Composites—Modular and Multiscale Methods." Polymers 14, no. 1 (January 5, 2022): 216. http://dx.doi.org/10.3390/polym14010216.

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Service lifetimes of polymers and polymer composites are impacted by environmental ageing. The validation of new composites and their environmental durability involves costly testing programs, thus calling for more affordable and safe alternatives, and modelling is seen as such an alternative. The state-of-the-art models are systematized in this work. The review offers a comprehensive overview of the modular and multiscale modelling approaches. These approaches provide means to predict the environmental ageing and degradation of polymers and polymer composites. Furthermore, the systematization of methods and models presented herein leads to a deeper and reliable understanding of the physical and chemical principles of environmental ageing. As a result, it provides better confidence in the modelling methods for predicting the environmental durability of polymeric materials and fibre-reinforced composites.
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Bors, Adriana-Mariana, Marius-Eduard Lungulescu, Nicoleta Oana Nicula (Butoi), Alina-Ruxandra Caramitu, and Iosif Lingvay. "Ageing of Some Lacquers Due to Microbiological Stress." Materiale Plastice 56, no. 2 (June 30, 2019): 330–36. http://dx.doi.org/10.37358/mp.19.2.5181.

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This paper shows the ageing study of some coatings and / or impregnation lacquers due to microbiological stress through fungal attack. Dielectric spectroscopy has shown that the dielectric losses of the investigated materials increase as result of microbiological ageing. The mean recorded increases are about 4 times for the alkyl-epoxy-melamine copolymer, 2 times for epoxy polymer and 1.5 times for urethane polymer in agreement with the mould coverage degree of about 20 %, 10 %, and 3 %, respectively. The fungal attack of the investigated polymers led to a decrease in volume resistivity of about 65 % for the alkyl-epoxy-melamine copolymer, 45 % for the epoxy polymer, and 14 % for polyurethane, in agreement with the increase of dielectric losses and degree of mold coverage of the samples. FTIR determinations have shown that fungal attack significantly increased the number of aliphatic -OH and C-H bonds and decreased the number of C-O bonds, respectively of C-O-C oxiran groups and C-C aromatic bonds. DSC thermograms recorded at different temperature ranges and the activation energies calculation for first major oxidation process indicate that after the fungal attack the thermooxidative reactivity of the investigated polymers increases.
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Lamnii, Hamza, Moussa Nait-Abdelaziz, Georges Ayoub, Jean-Michel Gloaguen, Ulrich Maschke, and Bilal Mansoor. "Effect of UV Ageing on the fatigue life of bulk polyethylene." MATEC Web of Conferences 165 (2018): 08002. http://dx.doi.org/10.1051/matecconf/201816508002.

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Polymers operating in various weathering conditions must be assessed for lifetime performance. Particularly, ultraviolet (UV) radiations alters the chemical structure and therefore affect the mechanical and fatigue properties. The UV irradiation alters the polymer chemical structure, which results into a degradation of the mechanical and fatigue behavior of the polymer. The polymer properties degradation due to UV irradiation is the result of a competitive process of chain scission versus post-crosslinking. Although few studied investigated the effect of UV irradiation on the mechanical behaviour of thermoplastics, fewer examined the UV irradiation effect on the fatigue life of polymers. This study focuses on investigating the effect of UV irradiation on the fatigue properties of bulk semi-crystalline polymer; the low density Polyethylene (LDPE). Tensile specimens were exposed to different dose values of UV irradiation then subjected to fatigue loading. The fatigue tests were achieved under constant stress amplitude at a frequency of 1Hz. The results show an important decrease of the fatigue limit with increasing absorbed UV irradiation dose.
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Glaskova-Kuzmina, Tatjana, Olesja Starkova, Sergejs Gaidukovs, Oskars Platnieks, and Gerda Gaidukova. "Durability of Biodegradable Polymer Nanocomposites." Polymers 13, no. 19 (September 30, 2021): 3375. http://dx.doi.org/10.3390/polym13193375.

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Biodegradable polymers (BP) are often regarded as the materials of the future, which address the rising environmental concerns. The advancement of biorefineries and sustainable technologies has yielded various BP with excellent properties comparable to commodity plastics. Water resistance, high dimensional stability, processability and excellent physicochemical properties limit the reviewed materials to biodegradable polyesters and modified compositions of starch and cellulose, both known for their abundance and relatively low price. The addition of different nanofillers and preparation of polymer nanocomposites can effectively improve BP with controlled functional properties and change the rate of degradation. The lack of data on the durability of biodegradable polymer nanocomposites (BPN) has been the motivation for the current review that summarizes recent literature data on environmental ageing of BPN and the role of nanofillers, their basic engineering properties and potential applications. Various durability tests discussed thermal ageing, photo-oxidative ageing, water absorption, hygrothermal ageing and creep testing. It was discussed that incorporating nanofillers into BP could attenuate the loss of mechanical properties and improve durability. Although, in the case of poor dispersion, the addition of the nanofillers can lead to even faster degradation, depending on the structural integrity and the state of interfacial adhesion. Selected models that describe the durability performance of BPN were considered in the review. These can be applied as a practical tool to design BPN with tailored property degradationand durability.
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Starkova, Olesja, Abedin I. Gagani, Christian W. Karl, Iuri B. C. M. Rocha, Juris Burlakovs, and Andrey E. Krauklis. "Modelling of Environmental Ageing of Polymers and Polymer Composites—Durability Prediction Methods." Polymers 14, no. 5 (February 24, 2022): 907. http://dx.doi.org/10.3390/polym14050907.

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Polymers and polymer composites are negatively impacted by environmental ageing, reducing their service lifetimes. The uncertainty of the material interaction with the environment compromises their superior strength and stiffness. Validation of new composite materials and structures often involves lengthy and expensive testing programs. Therefore, modelling is an affordable alternative that can partly replace extensive testing and thus reduce validation costs. Durability prediction models are often subject to conflicting requirements of versatility and minimum experimental efforts required for their validation. Based on physical observations of composite macroproperties, engineering and phenomenological models provide manageable representations of complex mechanistic models. This review offers a systematised overview of the state-of-the-art models and accelerated testing methodologies for predicting the long-term mechanical performance of polymers and polymer composites. Accelerated testing methods for predicting static, creep, and fatig ue lifetime of various polymers and polymer composites under environmental factors’ single or coupled influence are overviewed. Service lifetimes are predicted by means of degradation rate models, superposition principles, and parametrisation techniques. This review is a continuation of the authors’ work on modelling environmental ageing of polymer composites: the first part of the review covered multiscale and modular modelling methods of environmental degradation. The present work is focused on modelling engineering mechanical properties.
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Akinyemi, Banjo A., and Temidayo E. Omoniyi. "Effect of experimental wet and dry cycles on bamboo fibre reinforced acrylic polymer modified cement composites." Journal of the Mechanical Behavior of Materials 29, no. 1 (September 22, 2020): 86–93. http://dx.doi.org/10.1515/jmbm-2020-0009.

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AbstractThis study experimentally evaluated the effect of accelerated wet/dry cycles on the dimensional stability and some selected mechanical properties of polymer modified vegetable fibre cement composites. The bamboo fibres were pre-treated with 10% conc. of sodium hydroxide and varied from 0 – 2.0% while acrylic polymer admixture of 10% w/w of cement was added to improve the properties. The modified fibre-cement composites were subjected to 50 cycles of wet/dry processes to simulate natural weathering process of the environment. The samples were subjected to water absorption, thickness swelling, modulus of rupture (MOR) and modulus of elasticity (MOE) after 28 days of curing and aging cycles respectively using 5 replicates. One way ANOVA at p<0.05 was used to analyse the results. Scanning electron microscope (SEM) and Fourier Transformer Infrared Spectroscopy (FTIR) analyses were conducted on the samples. The results showed improvement of 33.3, 64, 71 and 57% in MOR and 135, 85, 101 and 188% in MOE for samples with 0.5, 1, 1.5 and 2% fibre inclusion after ageing tests. Significantly improved dimensional stability values were observed in this study in comparison with data from similar ageing tests conducted on unmodified vegetable fibre-cement matrix. SEM micrographs showed marginal increase in the size of the pores before and after ageing tests. FTIR analysis indicated increase in intensities during the ageing tests especially for spectra bands located at 3384 – 3520cm−1 which are denoted for OH vibration stretching as well as 1676, 1726 and 1794 cm−1 which depict the presence of carbonyl groups because of absorption of polymers to the fibre surface during the ageing cycles. The study has shown thatwet/dry ageing cycles showed less harmful effect on vegetable fibre cement composites provided the cement matrix is modified with polymer admixtures.
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Lear, G., S. D. M. Maday, V. Gambarini, G. Northcott, R. Abbel, J. M. Kingsbury, L. Weaver, J. A. Wallbank, and O. Pantos. "Microbial abilities to degrade global environmental plastic polymer waste are overstated." Environmental Research Letters 17, no. 4 (March 15, 2022): 043002. http://dx.doi.org/10.1088/1748-9326/ac59a7.

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Abstract Internationally, the environmental damage caused by the improper disposal of approximately 100 Mt of plastic waste per annum is of growing concern. Attempts to address this issue have generated many hundreds of scientific studies announcing the discovery of novel plastic-degrading microorganisms and their respective enzymes. On closer inspection, however, evidence remains sparse for the microbial degradation of most of the plastic polymers produced globally. We systematically surveyed the international literature to confirm how many microorganisms proposed to degrade plastics (n = 664) cause substantial (i.e. ⩾20% mass) losses of virgin polymer, rather than losses of plastic additives, filler, and/or shedding of polymer micro-fragments. We noted where degradation was only demonstrated for artificially aged polymer since physicochemical ageing procedures increase the abundance of monomers and oligomers such that they may be degraded by microbial activity. Additionally, artificial ageing may introduce functional groups to the polymer backbone, creating more locations susceptible to microbial degradation than would otherwise occur in the environment. We identified multiple studies demonstrating the effective microbial degradation of heterochain plastic polymers such as polylactic acid, polycaprolactone and polyethylene terephthalate (i.e. polymers containing elements other than carbon in the backbone structure). However, in the literature, we find no evidence for the substantial degradation of unadulterated polyethylene, polypropylene, polystyrene or polyvinyl chloride, homochain polymers which represent the overwhelming majority of global plastics production. Current research demonstrates that the pre-treatment of plastics with elevated temperature or UV-light may speed physicochemical plastic degradation, with valuable applications for downstream microbial processing. However, evidence for the microbial degradation of most plastic polymers in current circulation is lacking. We outline simple criteria that should be met before announcing the microbial degradation of plastic polymers. We hope this may help to address largely unsubstantiated expectations that microorganisms can degrade many plastic polymers in situ.
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Hall, Finn, and Greg White. "The Effect of Waste Plastics on the Ageing Phenomenon of Bituminous Binders and Asphalt Mixtures." Materials 14, no. 20 (October 18, 2021): 6176. http://dx.doi.org/10.3390/ma14206176.

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The push for environmental sustainability in the civil engineering industry has resulted in an increased interest in the use of recycled construction materials, with one example being the use of waste plastic for the modification of bituminous binder in asphalt mixtures. Existing research has associated waste plastics with various binder and asphalt mixture performance enhancing properties. However, there is a lack of research on the age-related durability of waste plastic-modified roads. This research compared the effect of commercially available waste plastic binder modifiers on the ageing phenomenon of bituminous binders and asphalt mixtures, to the effect of conventional polymers SBS and EVA, through artificial bituminous binder and asphalt mixture ageing performed in a laboratory. The addition of polymers (both waste and virgin) resulted in an increase in binder stiffness after short-term ageing as the polymer content increased. The effect of the waste plastic on ageing was comparable to the effects associated with the conventional polymers, and it was concluded that the waste plastic binder modified products should be considered sustainable alternatives to standard polymers for bituminous binder and asphalt mixture modification.
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Nakonieczny, Damian S., Magdalena Antonowicz, Gražyna SimhaMartynkova, Frank Kern, Lenka Pazourková, Karol Erfurt, and Michał Hüpsch. "PA-12-Zirconia-Alumina-Cenospheres 3D Printed Composites: Accelerated Ageing and Role of the Sterilisation Process for Physicochemical Properties." Polymers 14, no. 15 (August 2, 2022): 3152. http://dx.doi.org/10.3390/polym14153152.

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The aim of this study was to conduct artificial ageing tests on polymer-ceramic composites prepared from polyamide PA-12 polymer matrix for medical applications and three different variants of ceramic fillers: zirconia, alumina and cenospheres. Before ageing, the samples were subjected to ethyl oxide sterilization. The composite variants were prepared for 3D printing using the fused deposition modeling method. The control group consisted of unsterilized samples. Samples were subjected to artificial ageing in a high-pressure autoclave. Ageing conditions were calculated from the modified Hammerlich Arrhenius kinetic equation. Ageing was carried out in artificial saliva. After ageing the composites were subjected to mechanical (tensile strength, hardness, surface roughness) testing, chemical and structural (MS, FTIR) analysis, electron microscopy observations (SEM/EDS) and absorbability measurements.
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Młyniec, A., and T. Uhl. "Modelling and testing of ageing of short fibre reinforced polymer composites." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 226, no. 1 (September 19, 2011): 16–31. http://dx.doi.org/10.1177/0954406211411552.

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A study in accelerated humidity–temperature ageing and it is numerical modelling for short fibre reinforced polymer composites (SFRPC) based on poly(butylene terephthalate) (PBT) is reported. Authors described experimental results of humidity–temperature ageing of PBT reinforced with glass fibres and proposed a novel computation method of strength and durability analysis for SFRPC parts. Experimental results showed different ageing behaviours, which depend on fibre alignment, e.g. a decrease of Young’s modulus in longitudinal fibre alignment in tension after ageing, an increase of Young’s modulus in transverse direction in tension after ageing, and the increase of the shear modulus and decrease of shear strength after ageing in both directions. Proposed modelling procedure takes the fibre orientation from mould filling analysis as an independent material orientation, using a developed ageing dependent material model, based on tensile, compressive, and shear properties for longitudinal and transverse fibre alignments, and calculates failure criteria as a function of the ageing time and fibre alignment. An innovative approach is to create a fibre alignment dependent material ageing model which takes into account changes of material properties depending on the direction of the reinforcement. This methodology was extended to arbitrary models and validated on real parts made of SFRPC.
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Dissertations / Theses on the topic "Polymer ageing"

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Bose, Sonia Manjusri. "Computer simulation modelling of polymer ageing." Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/843495/.

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Detailed information of the underlying mechanisms of macromolecular disintegration processes is not always fully available from lab-based experiments and GPC. A powerful computer simulation technique was thus indispensable in this respect whilst saving time, labour and expense. This project aims to develop an interactive computer program to capture the behaviour of a complex reactor and offer the following functionality: mathematical calculations, graph/chart generation, processing simulation-experiment pertaining to user-given scission and environmental characteristics, data saving and re-loading etc, Windows-style menu-driven interfaces provide templates for easy implementation of complex mathematical algorithms -a new simulation technique (Slider interfaces) presented in the thesis, based on cellulose-ageing study in electrical transformers (Heywood, 2000). A novel statistical concept was introduced to significantly improve real-tune performance of mathematical calculations to simulate polymer chain fragmentation phenomena, enabling transformation of the simple iterative to a semi-iterative and instant calculation algorithm. Three new mathematical functions were constructed - (a) Monte Carlo Dynamic (Slider), (b) Algebraic Exact, (c) Markov Statistical models, initially using an arbitrary time scale for degradation. Real-time simulation was developed using three time model variants that included the interpretation of deviations in the order reaction rate from linearity to an exponential type function. The above transformation enhanced reproducibility and accuracy of degraded MWD curve sampling whilst then- graphical display & clarity via 'Cubic B-Spline' smoothing-algorithm. Complex models were created from a ranking ensemble of single scission mechanisms, structured with levels of probability constructs to effectively simulate GPC-like curve-deformities and side-shifts. The simulation results provided new information in the following key areas: the temporal shift patterns of MWD/PCLD under different ageing conditions graphical comparisons between simulated and observed Idnetic and scission parameters. the dominant types of scission strategy at different reactor conditions, the dependence of reaction behaviour on the polymer structural order. An alternative way of predicting life expectancy of an ageing polymer via relating time- temperature to the magnitude of intermediate MWD curve shifts that is independent on DP. The latter is an average value and subjected to errors. An equation was derived for this. Introduction of a binary tree "death time" algorithm for calculation of the life expectancy of different categories of polymer chain species. Non-iterative techniques developed here opens up new avenues of further research. The developed algorithms and computer program may provide ample scope for investigating the ageing of other industrially important polymers and can be utilised in other areas of polymer research with little modification where probability distribution is sought.
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Elliott, Susan. "The physical ageing of homopolymers and blends." Thesis, Heriot-Watt University, 1990. http://hdl.handle.net/10399/888.

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Lee, Yuen-Pen. "Electrically and thermally activated ageing mechanisms in metallised polymer film capacitors." Thesis, Loughborough University, 2001. https://dspace.lboro.ac.uk/2134/33870.

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This dissertation describes a combined computational and experimental study to understand the fundamental electrostatic, thermal, electromagnetic, and discharge related processes during the ageing of metallised polymer film capacitors. In the event of internal breakdowns, these capacitors are capable of "self-healing" through a controlled isolation of defects on the electrode surfaces by mosaic patterning the electrode. The objective of this project is to develop viable computer models to unravel electrothermally activated ageing processes in capacitors. To provide the necessary validation to any capacitor models developed, our work is supported by comprehensive experiments including industrial standard accelerated life tests and associated breakdown damage analyses of tested capacitors.
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Liu, Ning. "Space charge characteristics in polymer materials and their relation with ageing." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/417276/.

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Space charge formation in polymeric materials can cause serious concerns for design engineers as the electric field may severely be distorted, leading to part of the material being overstressed. This may give rise to accelerated material degradation and possibly premature failure in the worst conditions. As space charge dynamics in polymeric materials can be directly related to the changes in their composition, structure and morphology, a quantitative model is highly desirable for a better understanding of charge injection, trapping and detrapping in the polymeric materials. This dissertation reviews some well-known ageing models of insulating materials and shows their related derivation procedures. Most of these models treated ageing phenomenon as a chemical kinetics process but explained it using different approaches microscopically. Moreover, these models hold different perspectives on space charge effect on ageing. According to Crine’s model and Lewis’ model, space charge is just one of the consequences of material degradation whereas in the model established by Dissado-Montanari-Mazzanti, it is intended to prove that space charge can also act as a cause of ageing. In the present research, the space charge characteristics of both normal and gamma-irradiated low density polyethylene (LDPE) films during voltage-off periods have been investigated by PEA technique. Irradiation treatment can alter the physical structures of materials and bring chemical changes into normal samples. By analyzing those parameters estimated by Chen’s trapping/detrapping model, it shows the increment in trap sites and changes in trap depths, indicating that chemical reactions brought by irradiation have some changes in trapping characteristics of LDPE. However, there are some drawbacks in the previous trapping/detrapping model. By considering Schottky injection process and a modified Pool-Frenkel conduction mechanism, an improved trapping/detrapping model is established based on Chen’s model. Such model can not only estimate the trapping parameters of polymeric materials like previous models but also evaluate some new parameters like mobile charge escape rate coefficient and injection barrier for both electrons and holes. By using such a model, trapping parameters of aged samples under nine different ageing conditions are estimated. Moreover, breakdown tests were performed on these samples. An increment in breakdown strength can be found for samples from the early stage of ageing. This can be explained by the surface oxidation process which concentrates the charges near the both electrodes and therefore reduce the field between metal-insulator interface. When the ageing condition reach certain circumstance (applied field and temperature sufficiently high), the breakdown strength begin to decrease due the generation of traps in the sample bulk. With the experimental data of dc breakdown tests for different aged samples, a new model to depict the relationship between breakdown strength and ageing conditions (electric field, temperature and ageing time) has been built based on Simoni’s model. Such a new model mimic the initial rise of the breakdown strength by introducing an inverse reaction rate during the ageing. Moreover, through the implementation of such a model, the electron trap density can be used to quantitatively reflect the stage of ageing. Several XLPE extruded cable sections (12, 11, 10 and 8-year) retired from HVAC service are peeled into films by using the microtome. Preliminary experimental works were done by using the 10-year cable section: the heterocharges accumulation near both electrodes can be observed. To see homocharge injection, degas treatment is thereby required to eliminate the byproducts, which can give rise to ionic dissociation process inside the sample. Thereafter, based on the improved trapping/detrapping model, trapping parameters of the XLPE peelings are found for 12, 11 and 8-year operated cable sections. The estimated injection barrier, trap density and overall trap depth can be clearly related to the dc breakdown performance of XLPE samples. Moreover, from the estimated trapping parameters and the breakdown tests, they both indicate that the inner layer is most seriously aged part across the radial direction of the cable section. The threshold field (dc) of charge injection can be evaluated through three approaches for LDPE materials. Subtraction method on voltage-on measurement data and direct measurement on charges with multiple voltage-off tests can both give values of the threshold field. And the subtraction method is more sensitive way to obtain a relatively lower threshold field at 8 kV/mm. Another method taking account of maximum peak heights at both electrodes is not suitable to measure threshold field for total charge injection but can give an inception field of injection respectively for positive or negative charges. Taking advantage of plasma technology using gas CF4, fluorination treatments are performed on LDPE samples to produce fluorinated samples at two different discharge voltage levels and two different exposure times. For both normal and fluorinated LDPE samples, the space charge measurements are performed. The results indicate that the injected homocharges can be effectively suppressed with fluorination process but the heterocharges which come from ionization of the lower molecular weight specifies become prominent in the sample. The sufficient fluorination on normal LDPE samples can lower the dc conductivity but when the fluorination is not enough, the heterocharges can lead to even higher dc conductivity than the original one.
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Zhang, Xin. "Etude du vieillissement thermique de revêtements de peinture sur plaque par réflectométrie ultrasonore." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20234.

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La recherche de critères de vieillissement des revêtements de protection sur le long terme est nécessaire dans de nombreuses configurations industrielles. Ce travail présente l'étude de l'évolution de l'élasticité de revêtements de peinture sur plaque métallique par réflectométrie ultrasonore pour détecter de façon non destructive l'endommagement induit lors de tests de vieillissement thermique accéléré. La modélisation du pouvoir réflecteur permet d'identifier, dans une certaine gamme de fréquence, un mode particulier dont la valeur de l'angle critique est préférentiellement sensible à la rigidité de la couche en bon accord avec les tests réalisés sur des revêtements de 100µm de peinture sur plaque d'acier. Cette méthode est appliquée sur des échantillons étuvés à 80°C et 110°C durant 4000 heures. En fonction de la température, la mesure quotidienne de la position de cet angle critique permet de suivre le temps nécessaire au séchage complet des revêtements suite à l'évaporation du solvant. Au-delà, les variations de cette position angulaire indiquent, pour les modules élastiques de la peinture, une légère augmentation de moins de 2%. L'altération de la structure chimique détectée par mesures de température de transition vitreuse et de concentration de certains marqueurs (FTIR) se traduit donc par des modifications faibles d'élasticité nécessitant une résolution angulaire inférieure à 0,1°. Pour mieux différencier la rigidité de ces échantillons suite au vieillissement thermique, la sensibilité nécessaire est obtenue en réalisant une excursion en température autour de l'ambiante de quelques °C durant les mesures de réflectométrie
The determination of paint coating's ageing criteria after long term service is necessary in many industrial configurations. In this work, we have studied by ultrasonic reflectometry the evolution of the elasticity of paint coated on a metallic plate in order to detect in a non destructive way the damage induced by thermal accelerated ageing tests. The simulation of the reflection coefficient identifies a particular mode whose critical angle is preferentially sensitive to the elasticity of the paint layer in a particular range of frequency. This result is in agreement with experimental tests performed on 100 µm thick paint coated on a steel plate. These samples are heated at 80°C and 110°C during 4000 hours. The everyday measurement of the evolution of the critical angle allows the identification of the time necessary to reach the complete drying of the paint coating. This parameter depends on the heating temperature. The total variations of these critical angular positions indicate a small increase less than 2% of the paint's elasticity moduli. In parallel, the change of the chemical structure is detected by the measurement of the glass transition temperature and the concentration of some markers identified by FTIR. This chemical change is linked to a small variation of elasticity implying an angular resolution less than 0.1°. For an easier differentiation of the rigidity of these thermally aged coatings, an enhanced sensibility is obtained by changing the temperature during the reflectometry measurements
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Pehlivan-Davis, Sebnem. "Polymer Electrolyte Membrane (PEM) fuel cell seals durability." Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/21749.

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Polymer electrolyte membrane fuel cell (PEMFC) stacks require sealing around the perimeter of the cells to prevent the gases inside the cell from leaking. Elastomeric materials are commonly used for this purpose. The overall performance and durability of the fuel cell is heavily dependent on the long-term stability of the gasket. In this study, the degradation of three elastomeric gasket materials (silicone rubber, commercial EPDM and a developed EPDM 2 compound) in an accelerated ageing environment was investigated. The change in properties and structure of a silicone rubber gasket caused by use in a real fuel cell was studied and compared to the changes in the same silicone rubber gasket material brought about by accelerated aging. The accelerated aging conditions were chosen to relate to the PEM fuel cell environment, but with more extreme conditions of elevated temperature (140°C) and greater acidity. Three accelerated ageing media were used. The first one was dilute sulphuric acid solution with the pH values of 1, 2 and 4. Secondly, Nafion® membrane suspended in water was used for accelerated ageing at a pH 3 to 4. Finally, diluted trifluoroacetic acid (TFA) solution of pH 3.3 was chosen. Weight change and the tensile properties of the aged gasket samples were measured. In addition, compression set behaviour of the elastomeric seal materials was investigated in order to evaluate their potential sealing performance in PEM fuel cells. The results showed that acid hydrolysis was the most likely mechanism of silicone rubber degradation and that similar degradation occurred under both real fuel cell and accelerated aging conditions. The effect of TFA solution on silicone rubber was more aggressive than sulphuric acid and Nafion® solutions with the same acidity (pH value) suggesting that TFA accelerated the acid hydrolysis of silicone rubber. In addition, acid ageing in all three acidic solutions caused visible surface damage and a significant decrease in tensile strength of the silicone rubber material, but did not significantly affect the EPDM materials. EPDM 2 compound had a desirable (low) compression set value which was similar to silicone rubber and much better than the commercial EPDM. It also showed a very good performance in the fuel cell test rig conforming that it a potential replacement for silicone rubber in PEMFCs.
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Fromageot, Camille. "Modification of biodegradable polymer films." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/131622/1/Camille_Fromageot_Thesis.pdf.

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This project aimed at tuning the photodegradability of a biodegradable polyester by employing a photosensitizing molecule, 2-oxepane-1,5-dione (OPD), as an additive mixed with commercial polymer and as a monomer to be copolymerized. Various processing techniques were employed, such as reactive extrusion, film blending or synthesis of polymers. The accelerated artificial ageing of modified polyesters revealed that OPD accelerated the rate of photodegradation of the polyester, with the differing mechanisms of degradation found for blends and copolymers providing scope for tuning the photodegradability of the polyester via alteration of the method of OPD incorporation.
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Cooper, Elizabeth Susan. "Application of polymer ageing models to cable geometry and time-to-failure distributions." Thesis, University of Leicester, 2002. http://hdl.handle.net/2381/9984.

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Polymer ageing models predict the working lifetime of polymeric insulation in terms of the electrical and thermal stresses to which it is subjected. Two such models are investigated in this thesis and are found to be mathematically similar even though they are based on different mechanisms for the way in which an electric field accelerates the ageing process. It is shown that both models can successfully fit characteristic time-to-failure data from ageing experiments involving thin films. A new method is developed to allow the ageing models to be applied to cable insulation, where the field and temperature are not spatially constant. This method is used to apply one of the models to characteristic lifetime data from experiments involving cables. The fits to data are found to be good, and resulting parameter values are used as the basis for a discussion of the possible effects of specimen volume on ageing. The distribution of failure times observed when thin films and cable insulation are aged at a given experimental condition has also been investigated. This has been carried out using distributions of the activation free energy of ageing within one of the ageing models. It is established that small changes in the minimum activation energy from specimen to specimen could be responsible for the observed failure statistics. Changes in the activation energy distributions with ageing condition suggest that ageing may involve conformational re-arrangements of chain segments in the crystalline-amorphous interface. This is in broad agreement with the conclusions of other workers.
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Jemmett, Peter A. "Investigation into the effects of ageing on the explosiveness of a polymer bonded explosive." Thesis, Cranfield University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421234.

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Zhao, Weijia. "Partial discharge ageing of polymer insulation under combined AC and DC stress at elevated temperatures." Thesis, University of Strathclyde, 2017. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=28507.

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Cable termination is the weakest part in any HV underground cable system, as defects may be left in the main insulation during the installation process. In HVDC systems, the converters produce the intended DC voltage for transmission but there may also be AC harmonics superimposed. The frequency of the AC harmonics could be in kHz range. The superimposed harmonics on the HVDC may have synergistic effects on cable insulation and may lead to further degradation in the cable insulation. In addition, for the sake of environmental protection, XLPE is no longer the suitable choice for underground cable insulation as it cannot be recycled. Thermoplastic material may be a candidate. There is little published information on the behaviour of thermoplastic materials under combined AC and DC voltages. In thermoplastic materials, HDPE film and PP film were selected as the target material to study in this project. As the properties of HDPE are similar to those of XLPE, the data obtained from HDPE was regarded as a bench-mark. It was decided to use the thermo-electrical stress to age the samples. For thermal stress, 90°C was chosen as the aging temperature for HDPE, while 90°C and 110°C were chosen for PP. For the electrical stress, AC & DC combined voltage was used to age the samples. DC voltage was 6 kV. The superimposed frequency of AC voltage was 1 kHz, 1.5 kHz, 2 kHz and 2.5 kHz. The AC/DC voltage ratio is from 10%, 30% and 50%. In this project, the effect of frequency and voltage ratio on HDPE and PP degradation under superimposed stresses was studied using the following approaches: Equivalent Phase Resolved Partial Discharge (PRPD) plots, Fourier Transform Infrared - Attenuated Total Reflection (FTIR-ATR) Spectroscopy and Dielectric Spectroscopy (DS) measurements were carried out. The performance of HDPE and PP were compared.
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Books on the topic "Polymer ageing"

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Verdu, Jacques. Oxidative Ageing of Polymers. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118562598.

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Oxydative ageing of polymers. London: ISTE, 2012.

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Alizai, A. K. Effect of corona impingement on hydrophobicity of various organic polymers with regard to ageing. Manchester: UMIST, 1996.

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Morgan, G. J. Correlation of chemical and physical test data for the environmental ageing of Tefzel (ETFE): International research project on the effects of chemical ageing of polymers on performance properties. Austin, Tex: [Texas Research Institute Austin, Inc., 1996.

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Innes, George L. Polymeric materials and flame retardants for wire, cable, and fiber optics. Norwalk, CT: Business Communications Co., 1993.

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Mulrooney, John Leonard. An investigation of a sorption apparatus to measure the solubility and diffusivity of a liquid blowing agent in a polymer at an elevated pressure. Ottawa: National Library of Canada, 1995.

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Henkel, Malte, Michel Pleimling, and Roland Sanctuary. Ageing and the Glass Transition. Springer London, Limited, 2007.

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Henkel, Malte, Various, Michel Pleimling, and Roland Sanctuary. Ageing and the Glass Transition. Springer, 2010.

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(Editor), Malte Henkel, Michel Pleimling (Editor), and Roland Sanctuary (Editor), eds. Ageing and the Glass Transition (Lecture Notes in Physics). Springer, 2007.

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Verdu, Jacques. Oxydative Ageing of Polymers. Wiley & Sons, Incorporated, John, 2012.

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Book chapters on the topic "Polymer ageing"

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Kuram, Emel. "Ageing of Mineral-Reinforced Polymer Composites." In Mineral-Filled Polymer Composites, 85–110. Boca Raton: CRC Press, 2021. http://dx.doi.org/10.1201/9781003220947-5.

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Piccarolo, Stefano, Elena Vassileva, and Zebene Kiflie. "Physical Cross Links in Amorphous PET, Influence of Cooling Rate and Ageing." In Polymer Crystallization, 325–42. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/3-540-45851-4_18.

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Colin, Xavier, Gilbert Teyssedre, and Magali Fois. "Ageing and Degradation of Multiphase Polymer Systems." In Handbook of Multiphase Polymer Systems, 797–841. Chichester, UK: John Wiley & Sons, Ltd, 2011. http://dx.doi.org/10.1002/9781119972020.ch21.

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Mazabraud, Philippe, Patrick Hourquebie, and Hakim Janah. "Ageing of Polyethylene and Conducting Polymer Blends." In Ageing Studies and Lifetime Extension of Materials, 63–69. Boston, MA: Springer US, 2001. http://dx.doi.org/10.1007/978-1-4615-1215-8_5.

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Billingham, Norman C., and Vincent Dudler. "Advanced Analytical Techniques for Studying Polymer Oxidation." In Ageing Studies and Lifetime Extension of Materials, 241–48. Boston, MA: Springer US, 2001. http://dx.doi.org/10.1007/978-1-4615-1215-8_26.

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Dear, John P., and Nick S. Mason. "Lifetime of Polymer Pipes in Water Distribution Systems." In Ageing Studies and Lifetime Extension of Materials, 553–61. Boston, MA: Springer US, 2001. http://dx.doi.org/10.1007/978-1-4615-1215-8_62.

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Blanco, Ignazio. "Decomposition and Ageing of Hybrid Materials with POSS." In Polymer/POSS Nanocomposites and Hybrid Materials, 415–62. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-02327-0_13.

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Tate, Philip C. Miller, Sina Talal, Christopher J. Page, and R. Keith Scarrow. "Accelerated Compression Set at Elevated Temperature in Rigid Polymer Foams." In Ageing Studies and Lifetime Extension of Materials, 81–86. Boston, MA: Springer US, 2001. http://dx.doi.org/10.1007/978-1-4615-1215-8_7.

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Guimarães Furtado, Cristina Russi, and Márcia Christina Amorim Moreira Leite. "CHAPTER 23. Life Cycle Analysis, Ageing and Degradation Behaviour of Natural Rubber Based Blends and IPNs." In Polymer Chemistry Series, 550–68. Cambridge: Royal Society of Chemistry, 2013. http://dx.doi.org/10.1039/9781849737647-00550.

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Goldrein, H. T., P. J. Rae, S. J. P. Palmer, and A. L. Lewis. "Ageing Effects on the Mechanical Properties of a Polymer Bonded Explosive." In Ageing Studies and Lifetime Extension of Materials, 129–36. Boston, MA: Springer US, 2001. http://dx.doi.org/10.1007/978-1-4615-1215-8_13.

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Conference papers on the topic "Polymer ageing"

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Shankar, Vivek, Shekhar Sunit, Robert Zagitov, Abhishek Kumar Gupta, Suresh Kumar, Ritesh Kumar, Kumarish Pahari, Rahul Agarwal, Petro Nakutnyy, and Santhosh Veerabhadrappa. "Evaluation of Alternative Polymers for Mangala Polymer Flood." In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211461-ms.

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Abstract Mangala field is under polymer-flood since 2015. The polymer-flood is very successful in accelerating recovery compared to waterflood. As the flood matured, field performance indicated that part of the injected polymer was degrading in the reservoir. Lab studies and polymer samples collected from the reservoir suggest that the most likely reason of degradation is increased hydrolysis due to thermal ageing. This degradation compels higher dosing of polymer to make up for the lost viscosity and increases operating costs. Polymer precipitation in the reservoir may also lead to loss of reservoir permeability. Literature survey and preliminary lab studies showed that polymers with Acrylamide-Tertiary-Butyl-Sulfonic acid monomer units (referred as ATBS polymers) could be a suitable option for Mangala. To evaluate the hypothesis, team did a series of lab and core flood studies. The studies include accelerated thermal ageing, rheology, dynamic adsorption, injectivity, water flood with fresh and degraded samples and compatibility studies with topside chemicals. Two HPAM polymers with different DOH and two ATBS polymers were evaluated. The selected ATBS polymer was then tested for compatibility with surface topside chemicals. The studies show that the classic 20-25% DOH HPAM suffers viscosity degradation and possible precipitation in Mangala reservoir conditions. ATBS polymers and a lower DOH HPAM provide superior results to the incumbent HPAM with an acrylamide (86)-ATBS (14) copolymer providing the best results. ATBS polymers were especially resistance to cloud point lowering and provide some superiority in shear degradation. ATBS monomer was resistant to hydrolysis in the period of testing. Contrary to published literature ATBS polymers showed higher adsorption and their propagation through cores required higher pressure drop. ATBS polymer seemed to plug a low permeability section of the core stack. All polymers reach their peak viscosity at 30-40% hydrolysis and decline sharply after 40%. However, viscosity and cloud points measured during accelerated ageing are possibly conservative. A large-scale pilot of ATBS injection in Mangala is underway to validate the laboratory test results. ATBS polymer can be a suitable polymer for some layers of Mangala with high residence time and permeability. The choice is driven by the economics of the incremental cost of ATBS for the benefits it offers. In some sands with shorter inter wells pacing, a lower DOH HPAM may work out to be a more cost-effective solution. The study results provide insights to operators to understand the reservoir performance of existing polymer-floods and plan for future polymer-floods.
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Zikmundová, Markéta, Klára V. Machalická, Martina Eliášová, and Miroslav Vokáč. "Artificial ageing of Silane Terminated Polymer adhesive for façade application." In The 13th international scientific conference “Modern Building Materials, Structures and Techniques”. Vilnius Gediminas Technical University, 2019. http://dx.doi.org/10.3846/mbmst.2019.048.

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Adhesive bonding is commonly used in the automotive and aerospace industry, where it has proved its advantages. Nowadays, the bonded joints are starting increasingly used in civil engineering, where they can be applied in façade structure. Traditionally used structural silicones are resistant to the external environment, but their low strength and elasticity do not meet the requirements of civil engineering. The greater spread of higher strength adhesives such as acrylates or polyurethanes is hampered by the lack of knowledge of their ageing resistance. The paper is focused on the experimental analysis of a double-lap shear joints of Silane Terminated Polymer (STP) adhesive applied in joints with aluminium and Zn-electroplated steel substrates with various surface treatments. The specimens were exposed to artificial ageing according to the technical regulations of the Timber Research and Development Institute in Prague. According to this regulation, specimens were exposed to changing of high and low temperatures, UV-radiation and humidity. This ageing should simulate 5 years in the climatic environment of Central Europe. Specimens exposed to laboratory ageing are compared with reference set of test specimens that were not artificially aged. STP demonstrated excellent resistance to laboratory ageing.
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Rault, Jacques. "Slow Dynamics and Mechanical Properties of Polymer Glasses : Ageing Properties." In SLOW DYNAMICS IN COMPLEX SYSTEMS: 3rd International Symposium on Slow Dynamics in Complex Systems. AIP, 2004. http://dx.doi.org/10.1063/1.1764112.

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Tanahashi, Taeko, Syoichi Ishikawa, Masahito Imai, Tomoyasu Sasaki, Hiroyuki Shinokubo, Ryosuke Matsuoka, Masayoshi Suzuki, and Masanori Isozaki. "Effect of insulator configuration on ageing deterioration of polymer insulators." In 2011 Electrical Insulation Conference (EIC) (Formerly EIC/EME). IEEE, 2011. http://dx.doi.org/10.1109/eic.2011.5996125.

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Benz, J., and C. Bonten. "Temperature induced ageing of PA12 powder during selective laser sintering process." In PROCEEDINGS OF THE EUROPE/AFRICA CONFERENCE DRESDEN 2017 – POLYMER PROCESSING SOCIETY PPS. Author(s), 2019. http://dx.doi.org/10.1063/1.5084904.

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Komatsu, L. G. H., W. L. Oliani, H. F. R. Ferreto, A. B. Lugao, and D. F. Parra. "Effects of environmental ageing on HMS-polypropylene/Cloisite nanocomposites." In PROCEEDINGS OF PPS-29: The 29th International Conference of the Polymer Processing Society - Conference Papers. American Institute of Physics, 2014. http://dx.doi.org/10.1063/1.4873776.

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Yoshikawa, M., T. Mizuno, A. Muto, T. Kawaguchi, and R. Matsuoka. "Effect of Internal Electrodes on Ageing Deterioration of Polymer Bushing Shells." In 2008 IEEE International Symposium on Electrical Insulation. IEEE, 2008. http://dx.doi.org/10.1109/elinsl.2008.4570281.

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Gardette, Jean-Luc, Agnès Rivaton, Sandrine Thérias, Sylvain Chambon, Matthieu Manceau, Julien Gaume, A. D’Amore, Domenico Acierno, and Luigi Grassia. "Predicting the ageing and the long-term durability of organic polymer solar cells." In V INTERNATIONAL CONFERENCE ON TIMES OF POLYMERS (TOP) AND COMPOSITES. AIP, 2010. http://dx.doi.org/10.1063/1.3455592.

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Dehbi, Abdelkader, Khaled Djakhdane, and Abdel-Hamid I. Mourad. "Impact of Degradation of Polyethylene Films Under Simulated Climatic Conditions on Their Mechanical Behaviour and Thermal Stability and Lifetime." In ASME 2012 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/pvp2012-78796.

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Studying the impact of degradation of polyethylene tri-layer films under simulated climatic conditions, of North Africa, on their mechanical behaviour and thermal stability and lifetime is the main objective of this work. The films are produced by the co-extrusion technique which is used in several industrial applications such as the nuclear related applications. The climatic conditions such as temperature, solar radiation, wind, sand and humidity are crucial factors in the ageing process, degradation and lifetime of polymeric materials. At the molecular level, these conditions have severe structural modifications and oxidation in polymers which are the main mechanism of ageing. Polyethylene films have numerous industrial applications in which they are susceptible to such harsh environmental conditions. Samples in the form of polyethylene films of 180μm thickness are artificially aged at different conditions of temperature and humidity. Monitoring the degradation in physicochemical properties of polymer matrices used and their stabilizing additives is carried out by thermal analysis (DSC) and mechanical tests. The results revealed that the investigated climatic conditions have essential deteriorative effects on the performance of the film. The correlation between the modification in the material structure and the degradation in the film properties is discussed.
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Laffly, Elie, Marie-Cecile Pera, and Daniel Hissel. "Polymer Electrolyte Membrane Fuel Cell Modelling and Parameters Estimation for Ageing Consideration." In 2007 IEEE International Symposium on Industrial Electronics. IEEE, 2007. http://dx.doi.org/10.1109/isie.2007.4374595.

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Reports on the topic "Polymer ageing"

1

Altstein, Miriam, and Ronald J. Nachman. Rational Design of Insect Control Agent Prototypes Based on Pyrokinin/PBAN Neuropeptide Antagonists. United States Department of Agriculture, August 2013. http://dx.doi.org/10.32747/2013.7593398.bard.

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The general objective of this study was to develop rationally designed mimetic antagonists (and agonists) of the PK/PBAN Np class with enhanced bio-stability and bioavailability as prototypes for effective and environmentally friendly pest insect management agents. The PK/PBAN family is a multifunctional group of Nps that mediates key functions in insects (sex pheromone biosynthesis, cuticular melanization, myotropic activity, diapause and pupal development) and is, therefore, of high scientific and applied interest. The objectives of the current study were: (i) to identify an antagonist biophores (ii) to develop an arsenal of amphiphilic topically active PK/PBAN antagonists with an array of different time-release profiles based on the previously developed prototype analog; (iii) to develop rationally designed non-peptide SMLs based on the antagonist biophore determined in (i) and evaluate them in cloned receptor microplate binding assays and by pheromonotropic, melanotropic and pupariation in vivo assays. (iv) to clone PK/PBAN receptors (PK/PBAN-Rs) for further understanding of receptor-ligand interactions; (v) to develop microplate binding assays for screening the above SMLs. In the course of the granting period A series of amphiphilic PK/PBAN analogs based on a linear lead antagonist from the previous BARD grant was synthesized that incorporated a diverse array of hydrophobic groups (HR-Suc-A[dF]PRLa). Others were synthesized via the attachment of polyethylene glycol (PEG) polymers. A hydrophobic, biostablePK/PBAN/DH analog DH-2Abf-K prevented the onset of the protective state of diapause in H. zea pupae [EC50=7 pmol/larva] following injection into the preceding larval stage. It effectively induces the crop pest to commit a form of ‘ecological suicide’. Evaluation of a set of amphiphilic PK analogs with a diverse array of hydrophobic groups of the formula HR-Suc-FTPRLa led to the identification of analog T-63 (HR=Decyl) that increased the extent of diapause termination by a factor of 70% when applied topically to newly emerged pupae. Another biostablePK analog PK-Oic-1 featured anti-feedant and aphicidal properties that matched the potency of some commercial aphicides. Native PK showed no significant activity. The aphicidal effects were blocked by a new PEGylated PK antagonist analog PK-dF-PEG4, suggesting that the activity is mediated by a PK/PBAN receptor and therefore indicative of a novel and selective mode-of-action. Using a novel transPro mimetic motif (dihydroimidazole; ‘Jones’) developed in previous BARD-sponsored work, the first antagonist for the diapause hormone (DH), DH-Jo, was developed and shown to block over 50% of H. zea pupal diapause termination activity of native DH. This novel antagonist development strategy may be applicable to other invertebrate and vertebrate hormones that feature a transPro in the active core. The research identifies a critical component of the antagonist biophore for this PK/PBAN receptor subtype, i.e. a trans-oriented Pro. Additional work led to the molecular cloning and functional characterization of the DH receptor from H. zea, allowing for the discovery of three other DH antagonist analogs: Drosophila ETH, a β-AA analog, and a dF analog. The receptor experiments identified an agonist (DH-2Abf-dA) with a maximal response greater than native DH. ‘Deconvolution’ of a rationally-designed nonpeptide heterocyclic combinatorial library with a cyclic bis-guanidino (BG) scaffold led to discovery of several members that elicited activity in a pupariation acceleration assay, and one that also showed activity in an H. zea diapause termination assay, eliciting a maximal response of 90%. Molecular cloning and functional characterization of a CAP2b antidiuretic receptor from the kissing bug (R. prolixus) as well as the first CAP2b and PK receptors from a tick was also achieved. Notably, the PK/PBAN-like receptor from the cattle fever tick is unique among known PK/PBAN and CAP2b receptors in that it can interact with both ligand types, providing further evidence for an evolutionary relationship between these two NP families. In the course of the granting period we also managed to clone the PK/PBAN-R of H. peltigera, to express it and the S. littoralis-R Sf-9 cells and to evaluate their interaction with a variety of PK/PBAN ligands. In addition, three functional microplate assays in a HTS format have been developed: a cell-membrane competitive ligand binding assay; a Ca flux assay and a whole cell cAMP ELISA. The Ca flux assay has been used for receptor characterization due to its extremely high sensitivity. Computer homology studies were carried out to predict both receptor’s SAR and based on this analysis 8 mutants have been generated. The bioavailability of small linear antagonistic peptides has been evaluated and was found to be highly effective as sex pheromone biosynthesis inhibitors. The activity of 11 new amphiphilic analogs has also been evaluated. Unfortunately, due to a problem with the Heliothis moth colony we were unable to select those with pheromonotropic antagonistic activity and further check their bioavailability. Six peptides exhibited some melanotropic antagonistic activity but due to the low inhibitory effect the peptides were not further tested for bioavailability in S. littoralis larvae. Despite the fact that no new antagonistic peptides were discovered in the course of this granting period the results contribute to a better understanding of the interaction of the PK/PBAN family of Nps with their receptors, provided several HT assays for screening of libraries of various origin for presence of PK/PBAN-Ragonists and antagonists and provided important practical information for the further design of new, peptide-based insecticide prototypes aimed at the disruption of key neuroendocrine physiological functions in pest insects.
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