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Polyethylene
From;    Author:Stand originally

Polyethylene is most the high polymer with simple structure, also be the high polymer data with the most extensive application.
Be joined by reduplicative –CH2– unit and it is become. Polyethylene is to pass ethylene (CH2=CH2) addition is aggregate and those who become.

The function of polyethylene depends on its aggregate means. In medium pressure (15-30 atmosphere) , what Ziegler-Natta group has below condition of organic compound catalysis and become is high density polyethylene (HDPE) . The aggregate polyethylene element below this kind of condition is linear, and molecular chain is very long, molecular quantity is as high as hundred thousands of. If be in high-pressured force (100-300MPa) , high temperature (190–210°C) , cross oxide catalysis condition to leave freedom radical group, what production goes out is low density polyethylene (LDPE) , it is to raise those who change a structure.
Polymerization controls force bulk: High pressure, middling pressure, low-pressure;
Polymerization implements a method: Slurry law, solution law, gas phase law;
Product density size: High density, medium density, low density, linear low density;
Product element measures: Element of small element quantity, common member quantity, freeboard is measured.   
Polyethylene character
Polyethylene is not had smelly, avirulent, feel is like candle, have be able to bear or endure admirably microtherm function (lowermost use temperature can be amounted to - 70 ~ - 100 ℃ ) , chemical stability is good, ability great majority is acid-base erode (do not be able to bear or endure the acerbity) that has oxidation quality, below normal temperature not dissolve at general dissolvent, water imbibition is small, dielectric protecties is admirable; Dan Juyi Xi to environmental stress (chemistry and mechanical action) it is very sensitive, heat-resisting ageing sex is poor.
The property of polyethylene because of breed different, basically depend on molecular structure and density.
The sort of polyethylene
(1) LDPE: Low density polyethylene, high pressure polyethylene
(2) LLDPE: Polyethylene of line form low density
(3) MDPE: In colophony of density polyethylene, double peak
(4) HDPE: High density spends polyethylene, low-pressure polyethylene
(5) UHMWPE: Freeboard element measures polyethylene
(6) modified polyethylene: Polyethylene of CPE, cross-linking (PEX)
(7) ethylene copolymer: Ethylene - propylene copolymer (plastic) , EVA, ethylene - butene copolymer, ethylene - other olefin (be like olefin of Xin Xi POE, annulus) copolymer, ethylene - copolymer of not saturated ester (EAA, EMAA, EEA, EMA, EMMA, EMAH)
Molecular quantity is achieved 3, 000, 000-6, 000, the linear polyethylene of 000 calls freeboard element to measure polyethylene (UHMWPE) . The intensity of polyethylene of freeboard element quantity is very high, can use make ballproof clothing.
Main method:
Fluid look doctrine (divide again for solution law and slurry law) polite bearing doctrine (stock the photograph form type in reactor) . Our country basically uses Qi Ge to force the slurry law of activator.
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