Fiber-matrix interface improvement via glycidyl methacrylate compatibilization for rotomolded poly(lactic acid)/agave fiber biocomposites

Abstract

The growing interest in research and development of eco-friendlier materials makes attractive the use of bio-based and biodegradable polymers such as polylactic acid (PLA). However, the higher cost of PLA compared to conventional polymers limits its applications. Moreover, raw materials for rotational molding must be in a powder form, which further increases their cost. So, the main objective of this study was to use agave fibers to produce lower-cost PLA based rotomolded biocomposites (BC) without compromising its bio-sourced origin and to compare with a standard rotomolding resin: linear medium density polyethylene (LMDPE). To improve the fiber-matrix interface, a chemical surface treatment of the fibers with glycidyl methacrylate grafted polylactic acid (GMA-g-PLA) in solution was evaluated. The results showed that a better biocomposites’ morphology was obtained, especially with the fibers treated twice. The surface treatment was also shown to substantially improve the flexural and tensile properties of treated fiber biocomposites at higher fiber content (25% wt.) compared to those with untreated fiber. The surface treatment also led to a substantial reduction of the biocomposites porosity and water absorption. Overall, the samples were shown to have better mechanical properties than neat LMDPE while being eco-friendlier due to their bio-nature.

Influence of agro-industrial wastes over the abiotic and composting degradation of polylactic acid biocomposites

“…This higher porosity allows easier access to humidity and oxygen, causing increments in the interfacial voids between fiber-matrix. 8,28 The color change of the materials is also presented in Figure 1 and Table 1. The most significant color parameter change corresponds to lightness (ΔL*); in other words, the samples became whiter with weathering.…”

“…Agave and coir fibers are two of those wastes, with costs around $0.10 USD per kg, making them excellent alternatives to be used as reinforcements for PLA. 7,8 The Tequila process in Mexico produced around 563,000 tons of residual Agave tequilana Weber var. Azul fibers only in 2020.…”

Crystallinity and impact strength improvement of wood-polylactic acid biocomposites produced by rotational and compression molding

“…Similar behavior was observed in flexural modulus results for both CM and RM samples. Even when it is well known that natural fibers possess high flexural modulus, the low wood/matrix compatibility, and the particle agglomeration can decrease this property in composites materials (Pérez-Fonseca et al 2015, Robledo-Ortíz et al 2021. The thermal annealing treatment did not significantly affect the tensile and flexural modulus since the biocomposites' values are similar to those of the untreated materials.…”

“…However, it is important to mention that even when it was found a significant decrease in flexural and tensile strength, the values are still competitive with those of polyethylene (flexural strength = 23 MPa, tensile strength 21 MPa), which is the most used polymer for rotomolding processes (95 % of the worldwide rotomolded parts) (Robledo-Ortíz et al 2021).…”

Influence of the blending method over the thermal and mechanical properties of biodegradable polylactic acid/polyhydroxybutyrate blends and their wood biocomposites

“…At the same time, the important biodegradable nature of these materials could be positively or negatively affected. It is important to mention that the mechanical properties of these biodegradable polymers and their biocomposites are very competitive or even higher than those of petroleum‐based polymers 25 …”