The difference between PVC and commen plastic
The difference between PVC and ordinary plastics is that the plastics contain chlorine, so they can not directly contact drinking water or food.
Secondly, because the molecular chain polarity of PVC is too large and the plasticity is poor, more than 40% plasticizers (plasticizers) are often needed to be added, and they can not directly contact drinking water or food.
Ordinary plastic, perhaps refers to LDPE, which can be used directly by human beings. Many human bodies do not have too much harm.
PVC, abbreviated as PVC in English, is a polymer polymerized by vinyl chloride monomer under the action of peroxide, azo compound and other initiators, or under the action of light and heat according to the reaction mechanism of free radical polymerization. Vinyl chloride homopolymer and vinyl chloride copolymer are collectively referred to as vinyl chloride resin.
PVC is a white powder of amorphous structure, with small branching degree, relative density of about 1.4, glass transition temperature of 77-90 ℃, and decomposition at about 170 ℃. It has poor stability to light and heat. When exposed to sunlight for a long time or above 100 ℃, it will decompose to produce hydrogen chloride, and further Autocatalytic Decomposition will cause discoloration, and physical and mechanical properties will also decline rapidly. It is necessary in practical application Stabilizers must be added to improve the stability to heat and light.
The processing of PVC depends on some additives very much. PVC resin powder itself can not be processed into any products. It is necessary to add stabilizers, lubricants, processing aids, etc., as well as plasticizers in soft products.
PVC resin itself and other general-purpose plastics are heavy in the synthesis process and can not rely on petroleum by-products. Therefore, its relationship with petroleum industry chain is not as big as other general-purpose plastics.
PVC material is more important in building materials reuse, because it has an obvious advantage, that is, in the process of outdoor use, because of its different decomposition mechanism, its physical properties decline to a relatively small extent, and the price is relatively low.
