Mechanical properties of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)/wood flour composites: Effect of interface modifiers

Abstract

A fully biodegradable and biobased wood plastic composite based on a microbial biopolyester matrix, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and a lignocellulosic filler, pine wood flour (WF), was manufactured using extrusion at industrystandard level of wood content. The effects of three compatibilization techniques on the mechanical properties of the composites were investigated. Techniques include silicone fiber treatment using Sigmacote, maleic anhydride (MA) grafting of PHBV matrix, and the addition of polymethylene diphenyl-diisocyanate (pMDI). Results showed that Sigmacote treatment resulted in a 20 AE 5% decrease in tensile strength of the composite. The use of MA-grafted PHBV, independent of content, enhanced slightly the composites tensile strength (5 AE 3%) and impact strength (10 AE 4%). The addition of 2 wt % of pMDI improved the tensile strength of the composite by 25 AE 6%, but the strength level returned to the original state when 4 wt % was added. Processing conditions had a more significant effect on the composite properties giving a 40 AE 5% reduction in tensile strength and 45 AE 6% in impact strength when a higher shear extrusion configuration was used. The modeling of the mechanical data suggested that PHBV/WF composites have achieved better interfacial interactions without compatibilization when compared to other composite systems.

Effect of Diisocyanates as Compatibilizer on the Properties of BF/PBAT Composites by In Situ Reactive Compatibilization, Crosslinking and Chain Extension

“…Chan et al studied the compatibilizing system with PHBV (poly-hydroxybutyrate-co-hydroxyvalerate) and wood powder as the main substrates. It was found that when the content of 4, 4-methylenebis (phenyldiisocyanate) (MDI) was 2 wt %, the tensile strength of the composite increased by 256%, but when the content was 4 wt %, it returned to the original state [27].…”

Reactive Melt Mixing of Poly(3-Hydroxybutyrate)/Rice Husk Flour Composites with Purified Biosustainably Produced Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate)

“…Moreover, in the case of reactive compatibilizers, chemical bonds between the fillers and polymer matrix are formed and the overall performance of the composite can be remarkably improved [47]. For instance, the maleic anhydride (MA) grafting of PHBV matrix prior to extrusion has successfully increased the hydrophilicity of the biopolyester matrix making it more compatible with lignocellulosic fillers [48].…”

Bio-Polyethylene-Based Composites Reinforced with Alkali and Palmitoyl Chloride-Treated Coffee Silverskin

“…Improvement of interface adhesion in NFRP or WPC can be achieved by several strategies: on one hand, by lowering the hydrophilicity of the filler/reinforcement and on the other hand, by promoting chemical interactions between the filler/reinforcement and the polymer matrix. To achieve this objective several approaches can be used, such as selective surface modification of fillers, modification of the polymer matrix by additives and using compatibilizers to provide increased interactions among the polymer-particle interface [9]. A typical matrix modification is graft copolymerization of the base polymer with maleic anhydride (MA), which can be obtained by reactive extrusion [10,11,12,13].…”