Mechanical Properties and Weathering Behavior of Polypropylene‐Hemp Shives Composites

Abstract

This paper presents the obtaining and the characterization of composites with polypropylene matrix and hemp shives as filler in different ratios and containing poly(propylene)-co maleic anhydride (MAH-PP) 3% wt as compatibility agent. The weathering behavior of the composite enclosing 60% hemp shives, performed after the exposure to UV radiations at different exposure times, was evaluated. The changes in the chemical and morphological structures were investigated by FT-IR and RAMAN spectroscopies and AFM microscopy. The mechanical characteristics of the composites were determined before and after an artificial aging process, and they are within the limits of the values reported for polyolefin-based composites and materials with natural fillers. During the accelerated weathering process, the correlation between the chemical degradation of the main components of the composite and the modification of the mechanical properties after the process of aging has been observed.

Environmental Degradation of Plastic Composites with Natural Fillers—A Review

“…Organic solvents (e.g., petroleum-based liquids, vegetable oils) can enter the surface voids of composites, weakening the interface and swelling the hydrophobic matrix, resulting in decreased tensile strength of the material. Water exposure generates fiber pull-out from composites; hydrolysis reactions degrading the biomass material generate high amounts of active species that can initiate the degradation of the polyolefin matrix (e.g., PP), leading to decreased molecular mass [142,143]. Fiber pull-out leading to material failure was reported during weathering in various conditions of bagasse fibers reinforced polymer composites [144].…”

Influence of weathering on visual and surface aspect of wood plastic composites: Correlation approach with mechanical properties and microstructure

“…The polymer matrix and wood flour are mainly deteriorated on composites surface during weathering which results in a reduction of the molecular weight of the polymer [5] and an evolution of surface roughness [6], [15]. Peng et al measured the surface roughness of WPC before and after accelerated weathering by AFM analysis [6].…”

Production and Characterization of Laminates of Paper and Cellulose Nanofibrils

“…In the past few decades, a growing environmental awareness toward “green” materials together with depletion of fossil fuels, have led to various attempts to produce alternative biobased products. − The automotive industry, in particular, has a primary motivation in the advancement of green composites, as these nature-based products can provide alternative solutions to various disadvantages of conventional materials currently used in the industry. , Biobased composites can offer mechanical strength, lower weight and cost, ecological sustainability, low energy requirements for production, safe end of life disposal and carbon dioxide neutrality that have made them particularly attractive to many industries. ,, Therefore, several studies have focused on introducing renewable materials into automotive parts, , mostly by incorporating natural fibers into the formulation of commodity nondegradable polymers like polypropylene, either as a filler or as reinforcement. − …”