Research Of Preparation And Properties Of Bamboo Flour Reinforced PHBV Composites

In the 21st century,the shortage of resources and environmental pollution problems faced by human beings have become increasingly serious.Poly(hydroxybutyrateco-valerate)(PHBV)not only has excellent mechanical properties,but also has excellent biocompatibility and degradability;However,its high cost,narrow processing performance and high brittleness limit its wide application.As a kind of plant fiber,bamboo(BF)is not only rich in resources,has good renewable and degradable properties,but also has excellent mechanical properties.In this paper,BF/PHBV green composites were prepared by melt blending injection molding.The effects of BF particle and content,coupling agent treatment,biological enzyme treatment and filler of inorganic talc on the mechanical properties,water absorption and thermal properties of the composites were investigated.The chemical structure of BF and fracture appearance of composites were investigated by Fourier spectroscopy(FTIR)and scanning electron microscopy(SEM).The results show that:1.The tensile strength and flexural properties of BF/PHBV composites increased first and then decreased with the increase of the fiber content.The introduction of BF reduced the impact strength of PHBV and increased the water absorption of the composites.The thermal stability of the composites decreased slightly.When the fiber content is low,the smaller the fiber particle size,the better the mechanical properties of the composites.With the increase of the fiber content,the large particle size fiber has better reinforcing effect on the composite.When the fiber content is 20wt%,the composites prepared with 60 mesh bamboo flour has the best overall properties.2.All the three coupling agents reduced the polarity of BF and improved the interfacial compatibility between fiber and matrix.As the content of the coupling agent increases,the mechanical properties of the composites first increase and then decrease.When the content of the coupling agent is 2wt%,Then tensile strength and impact strength of the composites increased by 8.4%and 11.2%,respectively,and the flexural strength and modulus were increased by 10.3%and 12.3%,respectively.The results of TG and DSC experiments show that coupling agent treatment had little effect on the thermal stability of the composites,but increased the crystallinity of the composites and reduced the water absorption of the composites.Composite treated with silane coupling agent KH50 has the best overall performance.3.The biological enzyme treatment improved the surface roughness of the BF,and the adhesion of the fiber to the matrix was improved.The tensile strength and impact strength of the composites after bio-enzyme treatment reached 33.73 MPa and 8.19 MPa,respectively,and the flexural strength and modulus reached 53.12 MPa and 4312 MPa.The biological enzyme treatment improved the mechanical properties and thermal stability of the composites,promoted the crystallization process of the composites,and improved the water resistance of the composites.Among them,the composites prepared by pectinase treatment has the best overall performance.4.Although the addition inorganic talc enhanced the water absorption of the composites,but the talc played a very good toughening role,and the impact strength of the composites were improved significantly.At the same time,the addition of the talc improved the thermal stability and decreased the crystallinity of the composites.When the talc content is 6wt%,the mechanical properties of the composites are the best.