Why PPR water pipes exhibit low temperature brittleness

PP-R hot and cold water pipes are the most common and used plastic pipes on the market since galvanized water pipes were banned in 2000. Because of their light weight, corrosion resistance, heat preservation and energy saving, etc.

PPR is a random copolymer polypropylene, also called type III polypropylene. It can be obtained by random copolymerization of propylene monomer and a small amount of ethylene as monomer under pressure in heating system and under the action of catalyst.

Since the ethylene monomer is randomly distributed into the propylene during the polymerization, the ethylene monomer is controlled at 3-5%. Cold brittleness is determined by the ethylene content and the polymerization mode of ethylene and propylene.

PPR water pipe

When the temperature is relatively low, in the process of construction management in winter, the flexibility of the pipe can be reduced at low temperature, the rigidity is enhanced, and it is brittle.

Under the action of external force or excessive unexpected load, the pipeline may appear linear cracking and other phenomena. It will cause construction inconvenience. Therefore, in the case of low temperature construction in winter, attention should be paid to the low temperature brittleness of PPR pipes, and corresponding construction plans should be formulated.

PPR pipe

So at low temperatures, what are the main forms of cold brittleness of ppr tubes?

When the temperature is lower, the toughness can be reduced, showing brittleness, when the external force is impacted or heavy pressure, there will be a linear cracking problem, and it will extend from the inner tube to the outer tube.

After the pipeline is cracked by a little force, the crack will expand rapidly along the axial direction of the pipeline in an instant. This characteristic is called rapid crack growth.

Pipes are injured due to external forces during transportation and site installation at low temperatures in winter, and some brittleness and toughness (when transporting hot water) will continue to burst during our use and management.