| The development of new biodegradablematerials instead of plastics has become one of themainstream approaches to solving environmental problems.Polylactide(PLA)is a natural polymer formed by bio-based polymerization.It is made from starch as a raw material and iscompletely independent of petroleum.Fossil energy eventually generates carbon dioxde and water unedr the degradation of microorganisms.The poor strength and toughness of PLA has.greatly limited its application.Polyhydroxybutyrate pentanoate copolyester(PHBV)has many advantages,such as good biocompatibility,fast degradation rate,optical activity,piezoelectricity,non-toxic and harmless to the buman body and it has been widely used.However,PHBV also has a lack of filling,such as narrow processing eemperature,easy to decompose during processing.As,a kind of high-strength,high-modulus material has been widely used in the reinrorcement and toughening of composite materials,the bimass fiber has both reproducible and recyclable properties,and becomes the main reinforcing matcrial of the degradable biological material.In this paper,waste paper fiber(WF)was introduced for the lack of mechanical properties of PHBV and PLA.Waste paper fiber/PHBV blends with different mass ratios and waste paper fiber/PLA/PHBV ternary blends were prepared by injection molding.The mechsanical properties,thermal properties,crystallization properties,water absorption properties and phase structures of the blended materials were studied.Research indicates:1.When the waste paper fiber content was 15wt%,the mechanical p0roperties of the waste paper fiber/PHBV composites prepared had the best reinforcing effect,and the impact strength and flixural strength increased by 12.7%and 39%,respectively.The analysis shows that the addition of waste paper fiber can act as a nucleating agent in lthe matrix and improve thecrystallization performance of PHBV.The thermal stability of the conent increases,the thermal composite material has been improved.When the waste paper fiber contert increases,the thermal stability of the composite material decreases.Comparing the water absorbency of the matcrial,the addition of the fiber can increase the water absorption of the composite material.The higher the fiber content,the more obvious the increase of the water absorption rate.2.PLA was used as the enhancer to enhance the PHBV matrix.The mechanical properties of PLA/PHBV blends were improved compared with PHBV,and the PLA30/PHBV70 group had the most obvious enhancement effect.The addition of PLA could promote the crystallization of PHBV,along with the blend system PLA.When the content of PLA increases,the particle size of PLA becomes larger and the uniformity decreases.The initial decomposition temperature of PLA30/PHBV70 is 27? higher than that of PHBV,and the thermal stability is improved.The FT-IR diagram shows that PLA and PHBV are completely incompatible systems.3.For the PLA30/PHBV70 group with the best mechanical properties,adding waste paper fiber,the mechanical strength of PLA30/PHBV70/WF composites has been reduced,and the toughness has been improved.When the waste paper fiber content is 15wt%,PLA30/PHBV70/WF The composites show the best mechanical properties.The addition of WF can increase the initial decomposition temperature of PLA30/PHBV70 blends,improve the thermal stability,and increase the crystallinity of PHBV in the composites.4.The KH550 modifier was used to modify the waste paper fiber.The KH550 modified waste paper fiber had a better mechanical reinforcement effect on the waste paper fiber/PHBV.When the waste paper fiber content was 15wt%,the tensile strength was lower than that of the waste paper fiber.Modifications increase by 25%and impact strength increases by 5%compared to unmodified.Comparing the thermal stability of the two,the KH550 modification has a certain reduction in the thermal stability of the material,and there is also a small decrease in the crystallinity of the composite material.KH550 modified waste paper fiber can reduce the water absorption of waste paper fiber/PHBV composites.5.With KH550 modifier,WF enhances the thermal stability of PLA30/PHBV70,PLA30/PHBV70/WF/KH550 blends;when the WF content is 15%,the tensile strength increases by 10.9%,and the impact strength increases.17.1%;The crystallinity of PHBV in the modified composites decreased from 47.78%to 28.67%;after the KH550 modified WF,the interface between WF and PLA30/PHBV70 is well compatible,the interface is blurred,and they can be well combined together.KH550 modified waste paper fiber can reduce the water absorption of PLA30/PHBV70/WVF/KH550 composites. |
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