What is the difference between PE pipe and HDPE pipe?
Both PE pipes and HDPE pipes have PE, so are they the same pipe material? Is there a difference between PE pipes and HDPE pipes? In fact, HDPE pipes are a type of PE pipes, but there are still differences between them. Below, we will share with you in detail what the differences are.
The difference between HDPE pipe and ordinary PE pipe is:
1. Pressure Handling
HDPE pipes must withstand a certain amount of pressure. PE resins with large molecular weight and good mechanical properties, such as HDPE resin, are usually used. Their strength is nine times that of ordinary polyethylene pipes (PE pipes).
2. Wear Resistance
Among all engineering plastics, HDPE has the highest wear resistance among plastics. The higher the molecular weight, the more wear-resistant the material is; in fact, HDPE is even more wear-resistant than many metal materials like carbon steel, stainless steel, and bronze. Ordinary PE lacks this characteristic.
3. Replacement for Traditional Pipes
HDPE pipes are an ideal replacement for traditional steel pipes and polyvinyl chloride drinking water pipes, which ordinary PE pipes cannot fulfill.
4. Usage and Applications
HDPE pipes are mainly used in municipal water supply systems, indoor and outdoor water supply systems, buried water systems in residential and factory areas, pipeline repair, water treatment systems, garden irrigation, and other industrial water pipes. On the other hand, medium-density polyethylene pipes are suitable for transporting gaseous artificial coal gas, natural gas, and liquefied petroleum gas. Low-density polyethylene pipe is a flexible pipe.
High-density Polyethylene Pipe (HDPE)
High-density polyethylene pipe is made from "HDPE" which stands for "High Density Polyethylene." HDPE is a highly crystalline, non-polar thermoplastic resin. The original HDPE is typically milky white, and it appears translucent in thin sections.
Polyethylene (PE) Pipe
PE pipe is essentially a polyethylene plastic pipe. PE is a basic plastic that has excellent resistance to many domestic and industrial chemicals. PE pipes can be categorized into low-density polyethylene pipes, medium-density polyethylene pipes, and high-density polyethylene pipes.
Properties of HDPE
HDPE exhibits exceptional thermal and chemical stability, making it a valuable material for various applications. It consists of non-toxic, tasteless, and odorless white particles with a melting point of approximately 130°C and a relative density of 0.941 to 0.960. It features good heat and cold resistance, high rigidity, and toughness, which make it resilient under a variety of conditions. The dielectric properties and environmental stress cracking resistance are also strong. Melting temperature ranges between 120 to 160°C, with larger molecular weight materials recommended for melting between 200 and 250°C.
HDPE's density ranges between 0.940 to 0.976 g/cm³, with a crystallinity of 80% to 90%, and a softening point of 125 to 135°C. Its maximum service temperature can reach up to 100°C. Compared to low-density polyethylene, HDPE has better hardness, tensile strength, and creep properties. While its wear resistance, electrical insulation, toughness, and cold resistance are excellent, its insulation is slightly inferior to low-density alternatives.
Environmental considerations are also crucial since HDPE is resistant to room-temperature solvents, acids, alkalis, and various salts. Its films feature lower permeability to water vapor and air and lower water absorption. However, HDPE is prone to aging and environmental cracking more so than low-density polyethylene, especially under thermal oxidation. Therefore, antioxidants and ultraviolet absorbers are added to enhance its durability. Notably, HDPE films have lower heat distortion temperatures under stress.
For those interested in more detailed technical specifications and applications, you can Learn more.