Thermal and morphological analysis of novel composites made with fibers from invasive wetland plants and poly-(3-hydroxybutyrate-co-3-hydroxyvalerate).
There has been growing interest in biocomposites in recent years due to the adverse environmental impact of petroleum-based thermoplastics. This work focuses on manufacturing novel green composites using a bacterial polyester, poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), with fibers of invasive plants, namely, common reed (Phragmites australis), reed canary grass (Phalaris arundinacea), and wild or water celery (Vallisneria americana). Fabrication of the biocomposites, with a range of fiber loadings, was carried out by extrusion compounding followed by injection molding of ASTM type I parts, and the effects of the fibers on the morphological and thermal properties of PHBV were characterized. Thermal analysis indicated miscibility between the fibers and PHBV for various blends, while the midpoint glass transition shifted to 5°C from 0°C for pure PHBV. Water celery fibers, specifically, were finely dispersed in the PHBV matrices as visualized by SEM, indicating good compatibility. The finely ground water celery fibers increased the fiber-matrix interactions without the use of additives or compatibilizers, reducing the production cost of the composites. This new use for invasive species can provide a dual benefit of contributing to a novel composite and reducing environmental impact.