PVC modification method

PVC resin is a polar non-crystalline polymer with density of 1.38 g/cm3 and glass transition temperature of 87 ℃. Therefore, it has poor thermal stability and is not easy to process. It cannot be used directly. It can only be used after modification and mixing, adding relevant additives and fillers. However, due to the different types and fractions of relevant additives and fillers added, the properties and requirements of PVC materials prepared are different. We usually call it PVC formula. Strictly speaking, it is PVC modified formula, and PVC can only be used after modification. This category is often classified as polymer modified materials. The modification of polymer materials mainly focuses on the research of the high-performance of general plastics, the transformation of single-component materials to multi-component materials and composites (alloy, blending, composite), the functionalization of materials, and the optimization of performance and price. The modification methods mainly include chemical modification, filling modification, reinforcement modification, blending modification and nano-composite modification. The basic principle of modification is to endow materials with functions or improve some properties through additives. [2] Therefore, the level of PVC formula technology determines the level of technology and production capacity of a factory.
PVC generally needs to be modified and granulated first. After the particles are prepared by screw extruder, the plasticization is more sufficient and the processing is easier, especially for injection molding products. Screw extruder is one of the most important equipment for plastic molding and processing. It carries out solid conveying, compaction, melting, shearing, mixing and extrusion molding of plastic through external power transmission and heat transfer of external heating elements. Screw extruder plays an important role as both plasticizing and granulating machinery and molding and processing machinery. Strictly speaking, PVC products with special requirements and PVC modified formula are customized according to customer requirements. There is also copolymerization and derivation in the production process of PVC. Such modified varieties include vinyl chloride copolymer, PVC blend and chlorinated PVC
(The article is selected from Baidu Encyclopedia)