Study On Modification And Performance Of PBAT/TPS By Fillers Filling

Biodegradable polymer materials are considered to be the most effective solution to the environmental problems caused by traditional plastics.PTAT/TPS（polybutanediol adipic acid terephthalate/thermoplastic starch）composites are the research focus of biodegradable polymer materials.It combines the good heat resistance of PBAT,toughness and the easy processing of thermoplastic starch,low cost,is expected to replace the traditional packaging,film bag plastic in the future.In order to further reduce the cost of composite materials,many researchers will add fillers to modify the composite materials.The study of the effects of fillers on the properties and regeneration of composites is of great significance to the application of PBAT/TPS composites.In this thesis,calcium carbonate（CaCO₃）,calcium gluconate（CG）,talcum powder（T-2）as fillers were used to melt and blend with PBAT/TPS composites by means of torque rheometer,prepared three different composite materials:PBAT/TPS/CaCO₃,PBAT/TPS/CG,and PBAT/TPS/T-2.The structure,crystallization properties,mechanical properties,hydrophilicity and microstructure of the modified composite are analyzed.At the same time,the composite materials are placed in the room for 180 days and in a constant temperature and humidity box for 28 days respectively for regeneration study.The effects of calcium carbonate（CaCO₃）on the properties and regeneration of PBAT/TPS composites are investigated.According to the study of PBAT/TPS/CaCO₃,adding a small amount of CaCO₃can improve the crystallinity of the composites,and make the T_mof the composites slightly increase to 120.45℃.The addition of 11%calcium carbonate can effectively improve the thermal stability of the composites,and T_m1and T_m2are 325.49℃and 409.12℃,respectively.When the content of calcium carbonate is 3%,the mechanical properties of the composites are the highest,the elongation at break is 837.12MPa,the tensile strength is 15.53 MPa,and the tensile modulus increases with the increase of the content of calcium carbonate.After 180 days of indoor regeneration,it was found that the addition of a small amount of calcium carbonate had little effect on the regeneration of the composite material,and it had certain inhibitory effect on the regeneration of the composite material when the content of calcium carbonate increased to 7%.After 28 days of regeneration in a constant temperature and humidity chamber,it was found that calcium carbonate had certain inhibitory effect on the regeneration of the composite.The effects of calcium gluconate（CG）on the properties and regeneration of PBAT/TPS composites are studied.The results show that adding a small amount of calcium gluconate can increase the melting temperature of the composite,which can rise to 124.28℃.Meanwhile,with the increase of calcium gluconate,the thermal stability of the composites also gradually improved,T_m1and T_m2increased to 327.02℃and 404.67℃,respectively.When the content of calcium gluconate was added to 4%,the elongation at break and tensile strength were close to those of PBAT/TPS composites,which were 938.14%and 12.53MPa,respectively.With the increase of calcium gluconate content,the contact Angle of PBAT/TPS/CG decreased gradually,indicating that the hydrophilicity increased,while the compatibility of the composite decreased gradually.In indoor regeneration,4%calcium gluconate had little effect on the short-term regeneration of the composite,but had inhibitory effect on the long-term regeneration of the composite.In the study of regeneration in constant temperature and humidity box,adding a small amount of calcium gluconate has little effect on regeneration,and when the content of calcium gluconate rises to 8%,it can effectively inhibit its regeneration.The effects of talcum powder（T-2）on the properties and regeneration of PBAT/TPS composites were studied.The results of PTAT/TPS/T-2 shows that the Tm of the composite is slightly increased to about 121℃when the talc content is increased to 7%.Moreover,the temperature of the maximum decomposition rate of the composite is also significantly increased,with T_m1and T_m2being 324.67℃and 405.84℃,respectively,indicating that the thermal stability of the composite is significantly improved.When the talc content increases to 3%,the tensile strength increases to 14.18 MPa and the maximum tensile modulus is206.46MPa when the talc content is 13%.In the process of indoor regeneration,the addition of 3%talcum powder significantly inhibited the short-term and long-term regeneration of the composites.In the constant temperature and humidity box,when the talc content rose to7%,the starch regeneration in the composite material could be inhibited.