Polyethylene pipe

La description

【 properties 】
High density polyethylene for white particles, non-toxic, tasteless, odourless, melting point is **0 ℃, the relative density of 0.**1 ~ 0.**0. It has good heat resistance and cold resistance, good chemical stability, also has high rigidity and toughness, good mechanical strength. Dielectric properties, environmental stress cracking resistance is also good.
The melting temperature of **0 ~ **0 c. For larger molecular materials, it is recommended that the melting temperature range between **0 ~ **0 c.
【 characteristics 】
A variety of unique characteristics of grade HDPE is the appropriate combination of four basic variables: density, molecular weight, molecular weight distribution and additive. Different catalyst is used in the production of customized special performance polymers. These variables combine to produce different USES of the HDPE grade; In performance to achieve the best balance.
"Density"
This is the main variable decided to HDPE features, although mentioned four variables does influence each other. Ethylene is a major raw material of polyethylene, few other monomer, such as a 1 butene, l alone or a 1 octene, often used for improving the performance of polymer, the HDPE, more than a handful of monomer content is generally not more than 1% - 2%. The addition of monomer slightly reduced the crystallinity of polymer. This kind of change is usually measured by density, density and crystallization rate of a linear relationship. The United States generally classified according to the provisions of the ASTM D***8 HDPE density in 0.**0 g/CC above; Medium density polyethylene (MDPE) density range of 0.**6 ~ 0.**0 g/CC. Other classification the MDPE sometimes classified as HDPE or LLDPE. Homopolymer has the highest density, maximum stiffness, good permeability and high melting point, but generally has a poor resistance to environmental stress cracking (ESCR). ESCR is PE caused by mechanical or chemical stress cracking resistance ability. Higher density generally improved mechanical strength properties, such as tensile strength, rigidity and hardness. Thermal properties such as softening point temperature and thermal deformation temperature; The permeability, such as permeability and water vapour permeability. Improve its impact strength and low density E - SCR. Density of the polymer is mainly affected by monomer to join, but is less affected by the molecular weight. High molecular weight percentage density slightly reduced. For example, in a relatively wide range of homopolymer with different molecular weight density.