Study On Modified Bagasse/PHBV/PBAT Packaging Materials

With the shortage of petroleum resources and the increasingly serious environmental problems,the development of bio-based degradable polymer materials has become a hot research topic.In this project,poly(3-hydroxybutyrate–co-3-hydroxyvalerate)(PHBV),poly(butylene adipate-co-terephthalate)(PBAT)and bagasse were used as raw materials,and alkali treatment,silane coupling agent treatment and alkali and silane coupling agent compound treatment were selected to modify bagasse.The modified bagasse/PHBV/PBAT composites were prepared by powder blending and hot pressing process.The structure and properties of the composites were analyzed by Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM),differential scanning calorimetry(DSC),thermogravimetric analysis(TGA),mechanical properties and water absorption properties and other characterization methods.The optimum blending ratio of raw material,and the optimum modification method and treatment concentration of bagasse were determined.(1)PHBV/PBAT composites were prepared with different mass ratios of PHBV and PBAT.The results showed that PHBV and PBAT were physically blended,and the two materials had a certain compatibility;The mechanical properties showed that the mechanical strength and modulus of the composites decreased and the flexibility increased with the increase of PBAT content.The addition of PBAT reduced the crystallinity,improved the thermal stability,and improved the water absorption performance of the composites.(2)On the basis of the PHBV/PBAT mass ratio of 60/40,different contents of bagasse were added to obtain the bagasse/PHBV/PBAT composites.The research results showed that the modulus and rigidity of the composites increased greatly with the addition of bagasse;DSC data showed that bagasse could improve the crystallization properties of the composites;With the increase of bagasse content,the thermal stability of the composites decreased gradually,the UV barrier effect increased gradually,and the water absorption capacity increased greatly.When the content of bagasse was 20%,the composites had the best comprehensive properties.(3)The bagasse was treated with different concentrations of NaOH,and the composites were prepared according to the optimal blending ratio determined above.The results showed that NaOH effectively removed hemicellulose and lignin in bagasse,and the DTG curve changed from two thermal decomposition peaks to one thermal decomposition peak.Alkali treatment improved the interfacial compatibility of the composites,thus improving the mechanical properties,crystallization properties and hydrophobic properties of the composites.When the concentration of NaOH treatment was 4%,the composite material had the best comprehensive properties.(4)The bagasse was treated with different concentrations of silane coupling agent KH570,and the two methods of direct coupling agent treatment and alkali and coupling agent compound treatment were compared.Infrared analysis showed that KH570 was successfully grafted to the surface of bagasse fibers.The polarity of the fiber surface was reduced,and the interfacial compatibility of the composites was well improved,and the modification effect of alkali and coupling agent was the best.With the increase of the concentration of KH570,the mechanical properties of the composites first increased and then decreased,the thermal stability was improved,and the hydrophobic properties were improved.When the concentration of KH570 was 8%,the composite material had the best comprehensive properties.