Polyethylene, polyvinyl chloride PVC is second only to the world's second-largest synthetic resin production over 90,000 , however , PVC , there are some shortcomings difficult to overcome , including poor thermal stability 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 process Aluminum hydroxide must be added a certain amount of heat stabilizers to improve its thermal stability. Currently , lead salt is the largest amount of heat stabilizer. In building a harmonious society and ensure the sustainable development of the premise that people 's awareness of environmental protection and health gradually strengthened, therefore , low toxicity , no pollution, has become complex and efficient development direction of PVC heat stabilizers .
Thermal stability of PVC resin
PVC is one of the oldest plastic additive synthetic thermoplastics , has difficulty burning, good mechanical properties, low prices, abundant sources of raw materials , synthetic mature technology , which is widely used in construction, telecommunications , transportation, electronics, chemicals , packaging and other industries. PVC heat stabilizers in the heat or subjected to high energy radiation, such as ultraviolet light , "the impact of de- hcl autocatalytic reaction occurs , the thermal decomposition mechanism is generally believed that there are zinc stearate three kinds of radical mechanism oxygenated environment ; . ( 2 ) ion mechanism under a nitrogen atmosphere ; main factors ( 3 ) single molecular mechanism under vacuum conditions affect the thermal decomposition is pvc chain structure , refers to a branched , double, allyl chloride, head structure and molecular weight of conjugated double bonds etc. "effect ; addition, oxygen , HCL additives and other external factors also have an impact .
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