Modelling of Environmental Ageing of Polymers and Polymer Composites—Modular and Multiscale Methods

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.

Investigation of Jute and Glass Fibre Reinforced Hybrid Composites Manufactured through Compression Molding Process

Expensive and non-biodegradable synthetic fibres are commonly utilized as reinforcement in composites for better mechanical properties. The eco-friendly and low-cost properties of natural fibres are promising alternative reinforcement for composites. In this study epoxy-based glass and jute fibres reinforced hybrid composites are fabricated varying fibre stacking sequences, 1jute-1glass alternatively (j-g-j-) and 4glass-9jute-4glass (4g-9j-4g). Hybridization of jute and glass fibre results better tensile, flexural and water absorption properties than only jute fibre reinforced composites but inferior to only glass fibre reinforced composites. The 4g-9j-4g stacking sequence resulted in better mechanical and water absorption properties than j-g-j-- stacking sequence. The effect of chemical treatment and glass microfiber infusion are also investigated. Chemically treated jute fibre and 2 wt.% microfiber infused hybrid composite shows about 42% improvements in flexural strength as compared to untreated and without microfiber infused composites. However, fibre chemical treatment and microfiber do not have a positive impact on tensile strength.

Micromechanical Tests on Natural Fibre Composites with Enzymatically Enhanced Fibre–Matrix Adhesion

Natural fibre–reinforced composites are more sustainable than other composites with respect to the raw materials. Their properties are attractive due to high specific properties, and especially so wherever high damping is valued. As the interphase between fibre and matrix is the region of highest stresses, a strong bond between fibre and matrix is essential for any composites’ properties. The present study compares two methods of determining the interfacial shear stress in natural fibre–reinforced composites: the single fibre fragmentation test and the single fibre pullout test. The studied composites are flax fibre reinforced epoxy. For a variety of fibre–matrix interaction, the fibres are treated with a laccase enzyme and dopamine, which is known to improve the fibre–matrix shear strength. In the observed samples, single fibre fragmentation test data, i.e. of fracture mode and fragment length, scatter when compared to pullout data. In single fibre pullout tests, the local interfacial shear strength showed a 30% increase in the laccase-treated samples, compared to the control samples. The method also permitted an evaluation of the frictional stress occurring after surface failure.

Effects of compressing parameters and Mg(OH)2 content on mechanical properties and flame retardancy of rice straw-fibre reinforced composites

Rice straw fibre was utilized for unidirectional (UD) composites. In this study, the effects of compression temperature, duration, pressure, and fibre volume fraction on the mechanical properties of composites were investigated, respectively. The composite with optimal mechanical properties was prepared at a temperature of 180oC, pressure of 125 kg.cm-2 for 10 min, and at a fibre volume fraction of 40%. Mg(OH)2 was found to be an appropriate additive to enhance the flame retardancy of the composite. Interestingly, this agent also improved the mechanical and thermal insulation properties of the obtained composite.

A Rheological Study of Fibre Reinforced Composites and The Factors That Affect Rheological Behaviour During Impregnation Process: A Review

Rheological behaviour is an important factor affecting the flow behaviour of a fluid and many aspects related to this, mainly in the manufacturing process of fiber reinforced composites, either for Newtonian fluids or non-Newtonian fluids. During impregnation process, the viscosity changes with temperatures and their strain rate, has influenced the resin flow behaviour during curing process. In this paper, a review on the rheological studies of fiber reinforced composites for both, synthetic and natural based fibers, respectively, are presented. In addition to that, this review paper highlighting a few research studies conducted in literature on the main factors that affecting the rheological quality and performance of the composites. The aims of this review, mainly to capture the trend ranging from the recent five years back and summarize the various studies via experimental, theoretical or modelling works. Furthermore, also aiming to provide an ideal baseline information in the selection of the methods regarding rheological study to ensure better quality of pre-preg product and fibre reinforced composites can be produced in the author’s future work.

Exploration of Tensile, Flexural and Chemical Inertness Properties of Sisal Fibre Reinforced Polymer Composites-Surface Analysis

Our Experimentation finds, reaction of fibre external analysis on tensile, flexural and chemical resistance properties were studied for sisal fibre reinforced composites. Fibre surface analysis has done to produce link between fibre and the matrix to improve the mechanical properties. Fibre surface analysis were done by boiled the sisal fibres in different % of NaOH and treated the fibres in different % of NaOH, treated in acetic acid and methanol. Polyester resin have used as the matrix for preparing the composites and these properties for Natural sisal fibre reinforced composites were also studied. From the results it was observed that 25% NaOH boiled sisal fibre reinforced composites have higher tensile, flexural properties than other composites. Natural sisal fibre composites show fewer properties than treated composites. Chemical inertness properties indicate that all sisal fibre reinforced composites are resistance to all chemical agents except carbon tetra chloride.