| Traditional plastics have developed rapidly in recent years,and have become an indispensable part of people’s lives with their practical applications in various fields.As time goes by,the hazards brought by traditional plastics are gradually revealed,and the problems of "white pollution" and "microplastics" caused by the unsound recycling mechanism are becoming more and more serious,and the threats to the environment and human health are increasing.Therefore,biodegradable plastics have gained more attention from researchers and scholars,and people are committed to developing biodegradable materials that are nontoxic to the environment.Polypropylene carbonate(PPC)is synthesized from carbon dioxide,which helps to solve the problem of "greenhouse effect" and is completely biodegradable,but its molecular chain is flexible,easy to rotate,and has poor mechanical properties,which makes it difficult to be used alone.In this paper,PPC is modified under the premise of degradability,and the research is as follows:1.In the first part,PPC was first grafted with glycidyl methacrylate(GMA)to obtain the graft product PPC-g-GMA,and then the PPC/PBAT(PCP)and PPC-g-GMA/PBAT(PGP)composites were prepared by blending with poly(adipic acid-butylene terephthalate)(PBAT),respectively,and the properties were tested and characterized.The results are as follows: the compatibility between the two phases of PPC and PBAT was poor,and the introduction of GMA improved the compatibility of the two phases significantly,while the energy storage modulus,loss modulus and complex viscosity of the composites were further improved;with the increase of PBAT content in the system,the toughness and initial thermal decomposition temperature of the composites were gradually increased,and when the PBAT content was 50wt%,the impact strength increased by 185.7% and the elongation at break increased by 612.1%;SEM showed that the interfacial bond between the two phases was enhanced and the material changed from brittle to ductile.2.In the second part,rice husk(RH)was first treated with alkali and γ-glycidyl ether oxypropyl trimethoxysilane(KH560)to obtain modified rice husk(MRH).MRH and RH were melt blended with a fixed ratio of PPC-g-GMA/PBAT to obtain PPC-g-GMA/PBAT/MRH(PPM)and PPC-g-GMA/PBAT/RH(PPR)composites,respectively,the performance tests were conducted and the following results were obtained: the introduction of rice husk significantly improved the impact strength of the blended system,and when the content of RH was 20wt%,the impact strength of the composites was increased by 85.7% compared with pure PPC,and the modification of rice husk enhanced the interfacial bonding between the phases and further improved the toughness of the composites,and when MRH was 20wt%in the system is 20wt%,the impact strength of the composites is improved by 185.7%compared to pure PPC.3.In the third part,in order to improve the toughness of PPC,the fourth generation PHA product P34 HB,which is also fully biodegradable,was added to the PPC matrix,and the effect of the content of P34 HB on the properties of the blends was investigated,with the following results: the introduction of P34 HB improved the toughness of the material,and its impact strength and elongation at break increased by 271.4% and 310.1%,respectively,at30% mass ratio in the system;The energy storage,loss and viscosity of the blended system increased with the increase of the mass of P34 HB in the system,the melt strength of the material increased and the processing properties improved;the initial decomposition temperature of the blends gradually increased;SEM shows that when the P34 HB content is10wt%,the section shows "terraces" with a lot of stress whitening,and after the P34 HB content increases to 25wt%,the section changes to "island" structure,which indicates that the compatibility of the material gradually deteriorates.At the same time,the impact section of the material gradually becomes rougher and changes to ductile fracture. |
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