Polyethylene of high density
Polyethylene of the high density (HDPE) - PE with a linear macromolecule and rather high density (0,960 g/cm ³).
It is the polyethylene called also by polyethylene of the low pressure (PEND), it is received polymerization with special catalytic systems.
Linear polyethylene forms areas of crystallinity which strongly influence physical properties of samples. This type of polyethylene is usually called polyethylene of high density; it represents very solid, strong and rigid thermolayer which is widely applied to molding and blown formation of the capacities used in a household and the industry.
Polyethylene of high density is stronger than polyethylene of low density.
Essential properties of all types of polyethylene:
- small density;
- very good chemical firmness;
- very insignificant water absorption;
- impermeability for water vapor;
- high viscosity, flexibility, tensile properties and elasticity in the range of temperatures from-70 to +100 °C;
- good transparency;
- easy pererabatyvayemost by all methods, suitable for thermolayers;
- very good svarivayemost.
Scopes of polyethylene of high density, as a rule, coincide with the areas consuming material of small density, but the changed properties of the first, undoubtedly, improve quality of the developed products. So, the film from polyethylene of high density will be stronger and is more transparent, the formed details can have smaller section, and pipes and fibers will have bigger durability. Temperature increase of melting of new polyethylene allows to carry out sterilization by water vapor. These factors in combination with an opportunity will regulate properties of products to promote growth of use of the polyethylene produced on superficial catalysts. It should be noted that in some cases use of polyethylene of high density can be limited by cracking at the long appendix of loading.
Successful and rare combination in polyethylene of chemical firmness, mechanical durability, frost resistance, good dielectric properties, resistance to radioactive radiations, extremely low gas permeability and moisture absorption, ease and harmlessness do polyethylene irreplaceable in a number of scopes.
PEND is processed practically by all basic ways used during the work with thermolayers - extrusion, having blown, molding under pressure, a rotoformovaniye.
PVD, film, PEND