PPR is the abbreviation of PolypropyleneRandom, and its chemical name is random copolymerized polypropylene, which is commonly referred to as type 3 polypropylene. Propylene monomer and a small amount of ethylene monomer (3%-5%) are randomly copolymerized under the action of heating, pressure and catalyst.
As a high polymer, polypropylene's toughness is greatly affected by temperature and loading speed. When the temperature is higher than the glass transition temperature, the impact fracture is ductile fracture, and when the temperature is lower than the glass transition temperature, it is brittle fracture. When the temperature is lower than the glass transition temperature, the impact force required for brittle fracture of polymer materials will be greatly reduced. It is worth mentioning that the glass transition temperature of different materials is different, and the temperature of PPR material is relatively high, so its low temperature resistance is relatively poor, which is also the reason why PPR water pipes are not impact resistant at low temperature.
The composition of ppr is mainly composed of propylene monomer, and the introduction of a small amount of ethylene monomer (polyethylene polypropylene glass transition temperature is lower than that of polypropylene polypropylene polypropylene polypropylene) has improved the impact resistance, but the introduction of ethylene will affect the ppr High-temperature performance, for domestic water pipes, must also have high-temperature performance, so this is a contradiction, and the technology itself is a difficult problem to solve.
Cold and brittle is actually an inherent material characteristic of PPR, which is unavoidable, which is why heat insulation sleeves must be installed when PPR pipes are installed outdoors. After everyone understands its principle, they should pay attention to avoiding damage to PPR pipes due to brittleness and violent construction.
