Study On The Structure And Properties Of PVC Suspension Polymerization And Its Derivatives CPVC

Polyvinyl chloride(PVC) and chlorinated polyvinyl chloride(CPVC) resin, due to their excellent flame retardant properties, chemical resistant, acid and alkali corrosion performance and cheap price, have been widely used in various fields of production and life, but the two resins also have their own shortcomings. In daily using, the thermal stability of PVC resin is weak and easy to aging. he thermal stability of CPVC is better than PVC, but the melt viscosity of CPVC has poor mobility and difficult to processing. The macro and micro structure of PVC resin particles have a great influence on PVC performance; particle size, oil absorption rate, density, primary particles melting degree and PVC particles coating coated case concept will have certain effect on PVC performance; and PVC resin particles structure is directly related to the performance of CPVC resin. The current international crude oil prices continued to decline, to Xinjiang by calcium carbide acetylene method of PVC resin produced a lot of pressure, Xinjiang enterprise urgent need of special high-performance PVC derived resin to get rid of the threat of oil prices downward.Firstly through increasing the content of the initiator of PVC suspension polymerization, through a series of oil absorption rate, apparent density, laser particle size analyzer and other characterization methods, to study the effect of the macro and micro structures of PVC resin particles, constructs the initiator in PVC resin grain graph model. Then the macro structure and properties of three kinds of CPVC resins at home and abroad were studied. The reasons for the performance of the three kinds of CPVC resins were analyzed by means of XPS, SEM, GPC and other characterization methods. Finally, through the study of the macro particle morphology of PVC resin under different conversion rate, the process of PVC granulation in the early stage of polymerization was obtained. The following results are obtained:1.Increasing the contents of initiator,average particle size of PVC resin and oil absorption rate becomes smaller, the apparent density increases, the molecular weight is reduced, the balance time of processing is also shortened.2.According to XPS analysis, it was found that CPVC resin particle coating is thinner with the Cl/C ratio of CPVC surface is higher,the Cl/C ratio of CPVC of SEKISUI is the highest, the film is the thinnest。Skin area is smaller, oil absorption rate is higher, processing is helpful for the absorption of additives, improving processing performance, The oil absorption rate of CPVC resin of SEKISUI production 23.43%, machining stability time reaches 372 seconds is the best of the three.3.The worse the mobility of the processing and more difficult to processing with the higher number average molecular weight of CPVC, molecular weight of the CPVC of SEKISUI reached 85918, the 25 Nm viscosity is also the largest torque 25 Nm.4. Through comparing the graph of scanning electron micrograph in different reaction time of PVC resin particles, understand the PVC resin pre granulation process.