Academic literature on the topic 'Self-Reinforced Polyethylene (SRPE)'

The presented research focused on the evaluation of the novel concept of the overmolding technique using self-reinforced composite prepregs and recycled polymer blends. In order to evaluate the effectiveness of the proposed manufacturing technique, several series of materials based on polycarbonate/polyethylene terephthalate (PC/PET) and polycarbonate/polyethylene terephthalate glycol (PC/PETG) blends were prepared. The reinforcing component in the form of overmolded prepreg was made from polyester-based self-reinforced composite (srPET). The prepared materials were compared in terms of mechanical properties and heat resistance; the study was supplemented by thermal analysis measurements. Considering the mechanical characteristics, the overmolding technique turns out to be an effective method of improving the properties of composites, and the increase in impact strength turns out to be particularly beneficial. The increase of the impact strength for the overmolded PC/PET blend reached 430% for PC/PETG sample 330%, while for the PC-based composite, only 100%. The expected improvement in thermomechanical properties turned out to be difficult to achieve due to the rapid softening of the srPET prepreg at around 70 °C. However, technological tests and properties analysis indicated that the use of PC-based blends makes it possible to create a permanent connection with reinforcement based on srPET prepregs, which can significantly expand the potential of applications of this type of material. The presented research confirmed that the self-reinforced composites can be successfully used as reinforcement for recycled polymer blends.

Interfacial properties of composite materials play an important role in overall efficiency and reliability of these materials in structural applications. The objective of this study is to develop a multiple fiber microbond pull-out test to determine the interfacial properties of self-reinforced polymer composites (SRPC) and compare it with single fiber multiple fiber pull-out tests. SRPC possess better interfacial adhesion due to their similarity in chemical structure. The system used in this study is LDPE sheet reinforced with plain weave ultra-high molecular weight polyethylene (LDPE/ UHMWPE). The optimal operating temperature was estimated with DSC and TGA analysis. The micromechanical and meso-mechanical approaches were compared to validate the results. A fractographic study was performed to correlate lamina and meso-mechanical properties found in this study. It was observed that the multiple fiber pullout test explained in this study is on par with or better than the other conventional methods to evaluate interface properties.

Réduire la consommation énergétique est un enjeu essentiel pour la société actuelle. Pour opérer une transition énergétique durable, en particulier dans le domaine des transports, de nouvelles réglementations plus exigeantes sont mises en place. Augmenter la proportion de matériaux recyclés et recyclables ainsi qu'alléger les pièces de structures sont les maitres-mots.L'emploi de polymères peut être une solution mais pour garantir une bonne tenue mécanique, le recours à des composites auto-renforcés (SRP : Self-Reinforced Polymer) constitue un levier d'action. Ils sont composés d'un polymère ou d'une famille de polymères sous deux états physiques, un pour former la matrice et le second pour le renfort. Ils présentent alors une faible densité,une tenue mécanique intéressante et une recyclabilité accrue. Pour appréhender le comportement d'un polyéthylène auto-renforcé,et pouvoir ainsi envisager l'utilisation de ce matériau pour une application donnée, comprendre le comportement de chacun des éléments qui le constitue est primordial.Si le comportement de composites plus conventionnels, comme des composites à matrice thermoplastique renforcée de fibres de verre ou de carbone est bien maitrisé, exploiter des renforts thermoplastiques tels que l'UHMWPE (Ultra-High Molecular Weight PolyEthylene) au sein de composite, complexifie la compréhension du comportement des SRP. L'impact de la température et du temps sur la réponse mécanique des renforts est alors examiné dans un premier temps, et les observations sont reliées à des considérations microstructurales. Un protocole d'essai a été proposé et validé au préalable. Une transition de phase solide est mise en évidence autour de 49°C et engendre un changement abrupt de comportement.Ces renforts UHMWPE sont intégrés au sein de composites et un procédé de moulage par compression est suggéré pour les mettre en œuvre en une seule étape à partir d'une matrice sous forme de granulés. L'effet des différents paramètres du procédé est évalué pour pouvoir proposer une combinaison optimale. La réponse mécanique en traction et en fluage à court et long termes est ensuite analysée et l'intérêt des SRPE ainsi conçus est mis en évidence. En effet, le bénéfice de son utilisation est clair, notamment à basse température.Par ailleurs, la présence de renforts thermoplastiques semble introduire des paramètres supplémentaires qui affectent le comportement des composites et en particulier en fluage. La caractérisation précise et la connaissance des températures de transition de ces derniers sont alors apparues déterminantes, à plus forte raison étant donné que les transitions dépendent de la microstructure du renfort et donc du type d'étirage et des conditions appliquées. Enfin, la recyclabilité des composites mis en œuvre est étudiée puisqu'elle constitue un moteur pour le développement des SRP sur le marché
Reducing energy consumption is an essential issue for today's society. In order to achieve a sustainable energy transition, especially in the field of transportation, new and more demanding regulations are being implemented. The keywords are to increase the proportion of recycled and recyclable materials and lightening structural parts.The use of polymers can be a solution. However, to guarantee good mechanical resistance, the use of self-reinforced composites(SRP) is a lever for action. They are composed of a polymer or a family of polymers in two physical states, one to form the matrix and the second for the reinforcement. They present a low density, interesting mechanical behavior, and increased recyclability. To understand the behavior of a self-reinforced polyethylene and to be able to consider the use of this material for a given application,it is essential to understand the behavior of each of its components. If the behavior of more conventional composites, such as glass or carbon fiber reinforced thermoplastic matrix composites, is well understood, using thermoplastic reinforcements such as UHMWPE (Ultra-High Molecular Weight PolyEthylene) within the composite makes the understanding of the behavior of SRP more complex. The impact of temperature and time on the mechanical response of the reinforcements is then examined in a first step, and the observations are related to microstructural considerations. A test protocol has been proposed and validated before hand. A solid-phase transition is highlighted around 49°C and generates an abrupt behavior change.These UHMWPE reinforcements are integrated into composites. A compression molding process is suggested to process them in a single step from a matrix in granular form. The effect of different process parameters is evaluated to propose an optimal combination.The short and long-term mechanical response in tension and creep is then analyzed, and the interest of the SRPE thus designed is highlighted. Indeed, the benefit of its use is evident, especially at low temperatures. Moreover, the presence of thermoplastic reinforcements seems to introduce additional parameters that affect the behavior of the composites and, in particular, in creep. The precise characterization and the knowledge of the transition temperatures of the latter appeared then determining, mainly since the transitions depend on the microstructure of the reinforcement and thus on the type of stretching and the applied conditions. Finally, the recyclability of the implemented composites is studied since it constitutes a driving force for the development of SRP on the market

Abstract Composite materials such as carbon-fiber-reinforced plastics (CFRP) and glass-fiber-reinforced plastics (GFRP) have been attracting much attention from the viewpoint of lightweight solution of automobiles and airplanes. However, the recyclability of these composite materials is not sufficient and the environmental load is large. Recently, self-reinforced polymer (SRP), in which similar polymer is used for reinforcing fibers and matrix, has been proposed. High-density polyethylene (HDPE) reinforced with ultra-high-molecular-weight polyethylene (UHMWPE) fibers, so-called self-reinforced PE (SRPE), is one of the promising thermoplastic composites. In this study, SRPE plates were made and the tensile tests were carried out. After the effect of reinforcement of UHMWPE fibers was evaluated on the basis of the tensile strength, the relationship between the distribution of UHMWPE fibers and the location of the final fracture line was examined. It was found from these experimental results that the fracture tends to occur along the regions with low area fraction of fibers or along those with low area fraction of fiber/matrix boundaries. This fact suggests that the fracture location of SRPs is predictable from the distribution of reinforcing fibers.