​Are PE pipes and HDPE pipes the same kind of pipes?#Pipe extrusion#PE pipe#JWELL

Since I came into contact with pipelines, this seemingly simple question has been asked every now and then. Many friends mistakenly believe that the two types of pipelines are actually two names for the same pipeline. Strictly speaking, this is wrong.

 HDPE pipe is actually a type of PE pipe. The full name of HDPE pipe is high-density polyethylene pipe, and PE pipe is polyethylene pipe. It is divided into high-density polyethylene pipe, low-density polyethylene pipe and linear low-density polyethylene pipe. Among them High-density polyethylene pipe is HDPE pipe.

一、High density polyethylene (abbreviation: HDPE)

High-density polyethylene (HDPE) is produced using a low-pressure polymerization process. It is linear, has a density of 0.94-0.965q/cm³, and a crystallinity of 80%-95%. It is a white powder or granule.

Compared with low-density polyethylene, its molecular chain has no branches and has an almost linear structure. The molecules are regularly arranged and tightly packed. Therefore, it has high crystallinity and high density, with a relative molecular mass of hundreds of thousands to hundreds of thousands. , the melt flow rate range is narrow.

High-density polyethylene has high rigidity and toughness, excellent mechanical strength and heat resistance, as well as good solvent resistance and steam permeability resistance. High-density polyethylene has the smallest permeability, the strongest corrosion resistance, and good stiffness among all types of polyethylene. It is mainly used in the production of various pressure pipes, injection molded products, etc.

二、Low density polyethylene (abbreviation: LDPE)

Low-density polyethylene is generally produced by high-pressure polymerization, with a density of 0.910-0.925g/cm³. The molecular structure of low-density polyethylene is a linear macromolecule with many branches. The branches of different lengths on its main chain affect the regularity of the arrangement of macromolecules, and the stacking is not tight, which hinders the crystallization of polyethylene. Therefore the crystallinity is 55% -65%.

Low-density polyethylene has a low melting point, soft texture, and long branched chains, giving it low viscosity at high shear rates during processing and high melt strength during drawing. Therefore, it is very suitable for the blown film process and is mainly used for agricultural films. , production of heavy packaging film, etc.

三、Linear low density polyethylene (abbreviation: LLDPE)

Linear low-density polyethylene (LLDPE) is a molecular structure in which ethylene is copolymerized with a small amount of α-olefin to form a linear ethylene main chain with very short comonomer branches.

Linear low-density polyethylene is non-toxic, tasteless and odorless milky white particles with a density of 0.918-0.935g/cm³. Compared with LDPE, it has a higher softening temperature and melting temperature, and has the advantages of high strength, good toughness, rigidity, heat resistance, and cold resistance. It also has good resistance to environmental stress cracking, impact strength, and resistance to cold. It has excellent tear strength and other properties, and is resistant to acids, alkali, organic solvents, etc. and is widely used in fields such as industry, agriculture, medicine, health and daily necessities.