Study of the Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/Cellulose Whisker Nanocomposites

摘要

With a Young's modulus of over 100 GPa and a surface area of several hundredm~2/g, cellulose nano crystals (CNC) have the potential to significantly reinforcepolymers at low filler loadings while offering several environmental andperformance advantages over traditional nano-fillers such as nano clays and calciumcarbonate. As in many nano-fillers, CNC presents significant melt processingchallenges. The high surface area and polar nature of the material causes theparticles to agglomerate during melt blending. Our research hypothesis was thatsoluble polymers deposited on the surface of the CNC would facilitate dispersion inthermoplastic polymers. Towards this end, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a hydrophobic biopolymer, was selected as a candidatematrix material. A stable colloidal dispersion of the CNC was formed in differentsolutions of water-soluble polymers selected for their mutual solubility in water andPHB. The solutions were then freeze-dried, ground, and compounded with PHB in atwin-screw extruder. The resulting material was injection molded, mechanicallyevaluated, and characterized for filler dispersion.