| CPVC(chlorinated polyvinyl chloride)and PVC(polyvinyl chloride)are common resin products,with excellent mechanical properties and flame retardant properties.There is still development space for the domestic application of high-performance CPVC and PVC prod-ucts.This paper focused on two application scenarios,CPVC flame-retardant plastics and PVC automobile under coating,and explored the influencing factors of system mechani-cal property,flame retardant property and rheological property.In the third chapter,CPVC flame retardant plastics system was enhanced by different flame retardant pretreatment meth-ods and multiple flame retardants compounding,then the influences of different flame retar-dant pretreatment methods and different amount of addition on the system performance were obtained.In the fourth chapter,the factors affecting the viscosity,thixotropy and gelation temperature of the resin paste were explored in the PVC automobile under coating system,and the feasible formula design was determined.In the fifth chapter,the pyrolysis mecha-nism of CPVC resin and the flame retardant mechanism of Sb2O3 were studied by the thermal decomposition kinetics model.And the thermal decomposition model of CPVC was imple-mented by establishing the concentration field equation coupled with the kinetic model of CPVC thermal decomposition reaction as the internal heat source.In the third chapter of this paper,it was found that the method of prefabricating master-batch could mostly improve the negative influence on the mechanical properties of the sys-tem by Sb2O3,and the ultra-fine method could also improve the tensile strength and impact strength of the system to a certain extent.so it was considered that the method of prefabricat-ing Masterbatch could improve the dispersion effect of the system most obviously.Mg(OH)2 and Al(OH)3 both had the degradation effect on the tensile strength and bending strength of the system,while had enhancement on the tensile modulus and bending modulus,which met the general rule of filler reinforcement.After ablation,the structure of the samples added with Mg(OH)2 and Al(OH)3 formed compact structure,but those added with Sb2O3 formed a loose carbonized layer,showing the different flame retardant mechanism between the hydroxide flame retardant and the Sb2O3 flame retardant.In this paper,the research of the forth chapter shows that the addition of blending resin in the system would reduce the viscosity to a certain extent,while the influence of plasticizer on the viscosity was exponential.When the addition amount of plasticizer was 280 phr,the viscosity of the system was about 20000 mPa·s.Different blending resins had little different effect on the gelation temperature of the system,while the amount of nano SiO2 added had an exponential effect on the thixotropic properties of the system.Therefore,the amount of nano SiO2 addition could be used to compensate for the thixotropic properties of the blending resin.In the fifth chapter of this paper,a one-dimensional heat conduction model was estab-lished,and the finite difference method was used to solve the heat conduction equation.Then the kinetic model of CPVC thermal decomposition reaction was established,and the model was solved by the data of thermogravimetry analysis.After we analyzing the kinetic param-eters of CP VC thermal decomposition reaction obtained,the thermal decomposition process of CPVC resin under air condition was divided into two first-order reaction stages naturally.The flame retardant Sb2O3 mainly played a role of flame retardant in the first reaction stage by promoting the removal of HCl from CPVC and formation of expanded carbon layer.Finally,the CPVC thermal decomposition model was implemented by establishing the concentration field equation and coupling the CPVC thermal decomposition reaction kinetic model as the internal heat source. |
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