What is the essential difference between chemical grade PVC pipe fittings and PVC pipe fittings

Update:16 Feb 2020
Polyvinyl chloride is made from acetylene gas and hydrogen chloride, and then polymerized. Has higher mechanical strength and better corrosion resistance. It can be used to make exhaust gas detoxification towers and gas-liquid conveying pipes in chemical and textile industries, and can also replace other corrosion-resistant materials to make storage tanks, centrifugal pumps, ventilators and joints.
When the plasticizer is added in an amount of 30% to 40%, soft polyvinyl chloride is produced, which has high elongation, soft products, and has good corrosion resistance and electrical insulation properties.
It is often made into films for use in Industrial packaging, agricultural seedlings, daily raincoats, tablecloths, etc. can also be used to make acid- and alkali-resistant hoses, cable sheaths, insulation layers, etc. The density of pure polyvinyl chloride is 1.4g / cm3. The density of polyvinyl chloride plastic parts with plasticizers and fillers is generally 1.15-2.00g / cm3. Rigid PVC has better tensile, bending, compression and impact resistance, and can be used alone as a structural material. Soft polyvinyl chloride has increased flexibility, elongation at break, and cold resistance, but decreases brittleness, hardness, and tensile strength. Polyvinyl chloride has good electrical insulation properties, and can be used as a low-frequency insulation material, and its chemical stability is also good.

Due to the poor thermal stability of polyvinyl chloride, heating for a long time will cause decomposition and release HCL gas, which will change the color of polyvinyl chloride, so its application range is relatively narrow, and the operating temperature is generally between -15 to 55 degrees.