Study On The Preparation And Properties Of Basalt Fiber Reinforced PHBV/PBS Composites

Poly(3-hydroxybutyrate-co-4-hydroxyvalerate)(PHBV)has developed rapidly in recent years due to its excellent biocompatibility,good mechanical properties,and complete degradability.More and more research scholars attach much importance to PHBV,it has gradually became a research hotspot in the polymer field.However,PHBV has high brittleness,poor thermal stability,insufficient strength and high cost,which limit its application range.In order to solve the problem of high brittleness and expand the application field of PHBV,this paper adopts the method of melt blending modification to prepare PHBV-based blending and composite materials.The structure and properties of each component material were systematically studied.Besides,the recyclability of PHBV-based blends and composites were fully evaluated through multiple extrusion.Based on this,the paper has done the following three aspects of research:(1)PHBV/PBS blends were prepared by melt blending and injection molding,and the compatibilizer dicumyl peroxide(DCP)was added to the blended materials for improving compatibility of the two phases.The structure and properties of PHBV/PBS blends and PHBV/PBS/DCP compatibilization system was studied.The results showed that the addition of PBS hindered the crystallization of PHBV.The crystallinity of PHBV was further reduced after the addition of DCP.With the increase of PBS content,the thermal stability of PHBVwas not improved,but the initial decomposition temperature and maximum weight loss temperature of PHBV has been upgraded after adding DCP,the thermal stability of PHBV was improved.The PHBV phase is incompatible with PBS,and the PBS phase is unevenly distributed.After adding DCP,the dispersion of PBS nodules is significantly improved,and the two phases form a typical sea-island structure with obvious compatibility improvement.The addition of PBS improved the elongation at break and impact strength of the system,but the strength and modulus decreased.After the introduction of DCP,the mechanical properties of the system increased uniformly,and the tensile mechanical properties improved significantly at 37? The compatibilization effect of PHBV/PBS/DCP(50/50/0.5)was the most obviousin all components.(2)The effect of chopped basalt fiber(BF)content treated by coupling agent(KH550)on the structure and properties of PHBV/PBS/BF composites was researched.The results showed that the crystallinity of PHBV in the composite material was improved while the fiber content was less,but when the fiber content was more than 10%,the PHBV crystal was inhibited and the crystallinity was reduced.The addition of fiber reduced the maximum weight loss rate of the material.The material had a positive effect on the thermal stability,but it had little effect on the initial decomposition temperature of PHBV and PBS.When the fiber content came to 5%,the single fiber was completely infiltrated by the matrix,and the bonding effect was better.As the fiber content continued to increase,the combination between matrix and fiber was deteriorated,the fiber was debonded and formed some pore structure.After the fiber was added,the strength and modulus of the composite were improved,but the elongation at break and toughness were lowered.PHBV/PBS/BF(50/50/15)composite had better comprehensive mechanical properties,the tensile strength and Young's modulus were increased by 53%and 74%respectively,while the elongation at break was 12.6%,with a loss of only 2.95%.(3)By executing five times thermal cycle history,the effect of different thermal cycles on structure and properties were studied among the PHBV/PBS,PHBV/PBS/DCP,PHBV/PBS/DCP/BF components,and it provided data for assessing their repeated use.The results showed that multiple heat cycles reduced the crystallinity of PHBV in PHBV/PBS(50/50)and PHBV/PBS/DCP(50/50/0.5)components,while in PHBV/PBS/DCP/BF(50/50/0.5/15)components,the crystallinity of PHBV was improved.After three to five cycles,the initial decomposition temperature of each component was significantly improved,the maximum weight loss rate became larger,and the thermal stability of the material had some enhancement;After thermal cycling,the uniformity of phase distribution of PHBV/PBS(50/50),PHBV/PBS/DCP(50/50/0.5)had obviously improvement,and the fiber content of PHBV/PBS/DCP/BF(50/50/0.5/15)was less.The increase of thermal cycles reduced the tensile strength,modulus,and elongation at break of the components,but the average performance loss was less than 10%in per cycle.