Polyhydroxybutyrate Composites with Random Mats of Sisal and Coconut Fibers

Meire Noriko Hosokawa,Andressa Bella Darros,Virgínia Aparecida Da Silva Moris,Jane Maria Faulstich De Paiva

doi:10.1590/1980-5373-mr-2016-0254

Meire Noriko Hosokawa, Andressa Bella Darros + Show 2 more

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https://doi.org/10.1590/1980-5373-mr-2016-0254

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Journal: Materials Research	Publication Date: Dec 22, 2016
Citations: 37	License type: cc-by

Affiliation: Universidade Federal de São Carlos

Abstract

Biodegradable polymeric composites using natural fibers have been investigated aiming to mitigate environmental impacts. In this paper, polyhydroxybutyrate (PHB) composites obtained using random mats of sisal and coconut fibers by compression molding in a hydraulic press, and the fiber content varied between 10% and 15% relative to the weight of the polymer. Thermal analyses were performed such as Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Flexural and tensile tests were performed before and after conditioning in climate chamber with temperature and moisture. The results of thermal analysis show that the thermal stability of the materials remained, both PHB without fiber as for composites with natural fibers mats. The results of mechanical tests indicated that the PHB without fibers and composites showed similar flexural strength values, while the results of the tensile test PHB without fibers showed resistance to higher tensile composite.

Highlights

A few years ago, researchers have focused on the development of polymer composites using natural raw material replacing those synthetically produced aiming at reducing environmental impacts[1,2,3]
Despite having low processing temperatures, high sensitivity to environmental effects, mechanical properties variable and modest when compared to the high-performance fibers[29,30], natural fibers provide low-density materials, less abrasion and wear of equipment and molds when procesed . 29,31,32 Among the natural fibers can include fibers extracted from the sisal plant and coconut husk
The Differential Scanning Calorimetry (DSC) curves of the coconut fibers and sisal fibers in Figure 1, showed similar profiles. In both analyzes it was possible to see a curve around 100 °C which is related to the elimination of water due to the hydrophilic character of the fibers. It is noted in those same curves (Figure 1), two degradation peaks at around 290°C and 360°C, which temperatures cause the decomposition of cellulose and hemicellulose

Summary

Introduction

A few years ago, researchers have focused on the development of polymer composites using natural raw material replacing those synthetically produced aiming at reducing environmental impacts[1,2,3]. PHB can be produced under aerobic conditions[11] and other carbon sources, e.g, sugars such as glucose and xylose[12], carbohydrates sources as sugarbeet juice[13], agricultural residues[14] and even fatty acids[15]. It is a polymer having hydrophobic and highly crystalline feature[16], with mechanical properties comparable to a conventional thermoplastic[17,18]. Despite having low processing temperatures, high sensitivity to environmental effects, mechanical properties variable and modest when compared to the high-performance fibers (glass, carbon and aramid)[29,30], natural fibers provide low-density materials, less abrasion and wear of equipment and molds when procesed . 29,31,32 Among the natural fibers can include fibers extracted from the sisal plant and coconut husk

Objectives

Results

Conclusion