PVC resin is a polar amorphous polymer with strong interaction between molecules and is a hard and brittle material with low impact strength. With the addition of impact modifier, the elastomer particles of impact modifier can reduce the total craze initiation stress, and use the deformation and shear band of the particles themselves to prevent the expansion and growth of the craze, absorb the impact energy into the material, so as to achieve the purpose of anti-impact. The particle size of modifier is very small, which can increase the amount of modifier per unit weight or volume, increase the effective volume fraction, and enhance the ability of dispersing stress. At present, organic impact modifier is widely used.
performance
PVC resin (polyvinylchloride) is one of the important organic synthetic materials. Polyvinyl Chloride, chemical structure formula: (CH2-CHCL) n, its products have good physical and chemical properties, widely used in industry, construction, agriculture, daily life, packaging, electricity, public utilities and other fields.
Physical property
PVC resin, the physical appearance of white *** end, non-toxic, odorless. Relative density 1.35-1.46, refractive index 1.544 (20 C), insoluble in water, gasoline, alcohol and vinyl chloride, soluble in ***, dichloroethane, xylene and other solvents, high chemical stability, good plasticity. Except for a few organic solvents, it can withstand any concentration of ***, sulfuric acid below 90%, nitric acid below 50-60% and caustic soda below 20% at room temperature. In addition, it is quite stable for salts. PVC can burn and emit hydrogen chloride (HCl) in the flame, but it is a kind of "self-extinguishing" and "non-flammable" material when it leaves the flame. PVC decomposes and slowly releases HCl at above 100 (?) The decomposition and release of HCl accelerated with the increase of temperature, resulting in the discoloration of PVC.
Form
PVC is synthesized by the *** radical polymerization of vinyl chloride. Suspension polymerization, emulsion polymerization and bulk polymerization are the main methods of suspension polymerization, accounting for about 80% of the total PVC output. In the industry, the production process of PVC is generally differentiated according to the method of obtaining vinyl chloride monomer, which can be divided into calcium carbide method, ethylene method and imported (EDC, VCM) monomer method (commonly referred to as ethylene method and imported monomer method). According to the different production methods, pure PVC powder can be divided into general PVC resin, high degree of polymerization PVC resin and cross-linked PVC resin. Universal PVC resin is formed by polymerization of vinyl chloride monomer with initiator; high degree of polymerization of vinyl chloride monomer is a kind of resin synthesized by adding chain growth agent into the system of vinyl chloride monomer polymerization; cross-linked PVC resin is a kind of resin synthesized by adding crosslinker containing diene and polyene into the system of vinyl chloride monomer polymerization.
Main uses
PVC resin can be processed into various plastic products. According to its use, it can be divided into soft and hard products. It is mainly used to produce transparent sheets, pipe fittings, gold cards, blood transfusion equipment, soft and hard tubes, plates, doors and windows, profiles, films, electrical insulation materials, cable sheaths, blood transfusion materials, etc.
