The difference between chlorinated polyethylene and chlorinated polyvinyl chloride

Date:Sep 25,2019

No matter from which point of view, there are still differences between chlorinated polyethylene (CPE) and polyethylene, which reminds us when choosing, it is better not to use abbreviated names when choosing, and the probability of making mistakes with full names will be lower.

Chlorinated polyethylene (CPE) and polyethylene are similar, because their names are similar, many people mistakenly think that they are the same substance, but according to their names to determine their characteristics are different, let’s discuss according to the practice.

Chlorinated polyethylene (CPE) is prepared by chlorination of high density polyethylene (HDPE), and its structural unit is -CH2-CHCl-CH2-CH2-. Chlorinated polyethylene (CPE) is synthesized directly from vinyl chloride and its structural unit is – CH2 – CHCl-.

One of the two hydrogen groups attached to each carbon atom of polyethylene is replaced by chloride ion, and it becomes polyvinyl chloride. The tensile strength and aging resistance of polyvinyl chloride are much better than polyethylene.
There are still many advantages in using chlorinated polyvinyl chloride (PVC) or products made from its materials. For many people who do not understand it, they exist as a chemical substance. In fact, this statement is very one-sided. We can overthrow this idea through the detailed interpretation of the following.

Chlorinated polyvinyl chloride (CPVC) is a new type of Engineering plastics, which is prepared by chlorination modification of PVC resin. After chlorination of PVC resin, the irregular addition of molecular chains and polarity addition increase the solubility and chemical stability of the resin, thus improving the heat resistance of the data and the corrosion resistance of acid, alkali, salt and oxidant. The mechanical function of the thermal deformation temperature of the resin was improved, the chlorine content was increased from 56.7% to 63-69%, the Vicat softening temperature was increased from 72-82 to 90-125 C, the maximum operating temperature was 110 C, and the long-term operating temperature was 95 C, which was one of the few polymer materials that could be used in high temperature and high pressure for a long time. VC increased by about 50%, about twice as much as ABS resin and PP resin. Especially near 100 C, chlorinated polyvinyl chloride can still adhere to a strong rigidity, which can fully meet the requirements of equipment and pipelines at this temperature.

The chlorinated polyvinyl chloride has good chemical corrosion resistance. The chlorinated polyvinyl chloride not only has excellent chemical corrosion resistance at room temperature, but also has good acid, alkali and chemical resistance at higher temperature. It is far better than PVC and other resins. It can replace traditional materials to resist corrosive substances. Excellent flame retardancy, chlorinated polyvinyl chloride has excellent flame retardant and self-extinguishing properties. The limiting oxygen index (LOI) is 60, which has the characteristics of no flame dropping, confined flame diffusion and smoke formation. The thermal conductivity is low, and its thermal conductivity is only 0.105KW/(mk).

The heat-resistant pipeline processed with chlorinated polyvinyl chloride has less heat loss and can remove the heat insulation layer. Without the influence of residual chlorine in water, polyolefin data (such as PP, PE) may decompose when they encounter residual chlorine in water, while chlorinated polyvinyl chloride will not be affected by residual chlorine in water, and there will be no cracks and drip leakage. Bacteria are not easy to reproduce; chlorinated polyvinyl chloride pipeline is not affected by residual chlorine in water, its inner wall is smooth, bacteria are not easy to breed, not only resist the erosion of all forms of bacteria, but also have resistance to general sterile chemicals. Therefore, chlorinated polyvinyl chloride is a new engineering plastics with broad application prospects.

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