Fabrication of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) biocomposite reinforced wood fiber modified with mixed coupling agents CS-201 and KH550

To improve the interfacial adhesion and mechanical performance of biocomposite, titanate coupling agent CS-201 and silane coupling agent KH550 as the mixed coupling agents, poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) biocomposite reinforced wood fibers modified with mixed coupling agents were prepared via hot pressing process. The mixed coupling agents showed a good synergistic effect on improving the interfacial compatibility of of biocomposite. From SEM, it could be seen that the interfacial compatibility between wood fibers and P34HB were effectively enhanced by the mixed coupling agents. By FTIR spectroscopy, new chemical bonds could be observed between P34HB and wood fibers as a result of adding the mixed coupling agents. The thermal stability of the biocomposite was increased by adding the mixed coupling agents. DMA indicated that the temperature was negatively correlated with the storage modulus E' of the biocomposite. Compared to untreated biocomposite, the biocomposite treated with the mixed coupling agents displayed excellent mechanical properties (a 56 % and 200 % improvement in tensile strength and elastic modulus respectively). In addition, the synergistic enhancement effect was most significant when the content of the mixed coupling agent was 1%.