Water Absorption and Thermomechanical Characterization of Extruded Starch/Poly(lactic acid)/Agave Bagasse Fiber Bioplastic Composites

F J Aranda-García,E Mendizábal,R González-Núñez,C F Jasso-Gastinel

doi:10.1155/2015/343294

F J Aranda-García, E Mendizábal + Show 2 more

Open Access

https://doi.org/10.1155/2015/343294

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Abstract

Water absorption and thermomechanical behavior of composites based on thermoplastic starch (TPS) are presented in this work, wherein the concentration of agave bagasse fibers (ABF, 0–15 wt%) and poly(lactic acid) (PLA, 0–30 wt%) is varied. Glycerol (G) is used as starch (S) plasticizer to form TPS. Starch stands as the polymer matrix (70/30 wt/wt, S/G). The results show that TPS hygroscopicity decreases as PLA and fiber content increase. Storage, stress-strain, and flexural moduli increase with PLA and/or agave bagasse fibers (ABF) content while impact resistance decreases. The TPS glass transition temperature increases with ABF content and decreases with PLA content. Micrographs of the studied biocomposites show a stratified brittle surface with a rigid fiber fracture.

Highlights

Nowadays, the interest in bioplastics is growing for market niches such as packaging, agriculture, or automotive parts among others
Such figure illustrates that the rate of moisture absorption decreases as the agave bagasse fibers (ABF) content increases and that equilibrium is reached in approximately two weeks
It can be noticed that an increase in ABF content reduces the equilibrium moisture value (Figure 2); that behavior can be explained in terms of the lower hydrophilic character of the fiber comparing with the thermoplastic starch (TPS)

Summary

Introduction

The interest in bioplastics is growing for market niches such as packaging, agriculture, or automotive parts among others. Dufresne and Vignon in an early work on starch/fiber composites reported that thermomechanical properties of potato starch films were improved when they were mixed with cellulose nanofibers, showing a decrease in moisture sensitivity, while maintaining biodegradability. They found that increasing the glycerol content the equilibrium moisture increased and that such parameter decreased when the fiber content was augmented [5]. There are several works that follow the effect of PLA or natural fibers on moisture absorption and mechanical properties of TPS, there are very few reports on the effect of the simultaneous addition of both materials to the TPS. TPS/PLA blends, which are discarded fibers from industrial processes

Experimental

Results

Conclusions