> Toxic PVC heat stabilizers Research Status and Development Trend
Toxic PVC heat stabilizers Research Status and Development Trend
2013-08-16 by seoer8
This article describes the mechanism of thermal decomposition of PVC heat stabilizer and mechanism of action. Comprehensive analysis of the types of PVC heat stabilizers and technical status quo! Pointed out that no heavy metals hydrotalcite! Rare earth compound heat stabilizer and will become the dominant species.
Polyethylene, polyvinyl chloride PVC is second only to the world's second-largest synthetic resin production over 90,000, however, PVC there are some difficult to overcome the shortcomings of poor thermal stability which was most prominent. PVC due to poor thermal stability, softening temperature and decomposition temperature difference is small, has caused great difficulties to the process, so the machining process must be a certain amount of heat stabilizer in order to improve its thermal stability. Currently, the largest amount of lead salt heat stabilizer. In building a harmonious society and to ensure sustainable development in mind, people's awareness of environmental protection and health gradually strengthened, therefore, low toxicity, no pollution, has become a complex and efficient PVC heat stabilizers direction of development.
Analysis of the thermal stability of PVC resin
PVC is one of the earliest synthetic thermoplastics, with difficult to burn, good mechanical properties, low prices, abundant source of raw materials, synthetic process maturity and other characteristics, widely used in construction, telecommunications, transportation, electronics, chemicals, packaging and other industries. pvc or subjected to high energy in the heat radiation, such as ultraviolet light "effect occurs under the autocatalytic reaction hcl off, the thermal decomposition mechanism generally believed that there are three kinds. oxygen environment of the free radical mechanism; (2) under a nitrogen atmosphere ionic mechanism; (3) of the single vacuum molecular mechanisms that affect the thermal decomposition pvc chain structure is the main factor, means branched, double, allyl chloride, head structure, and molecular weight conjugated double bonds "in influence; addition, oxygen, HCL additives and other external factors also have an impact.