Polyethylene radicals

Polyethylene Is well known to be cross-linked by ionizing radiation through the recombination of polyethylene radicals produced by the irradiation (1). The efficiency of the reaction is not so high and the G-value has been reported to be 1-5 (2, 3). 

The formation of a branched polyethylene radical with primary radical function... 

A previously described kinetic model for polyethylene radical chain oxidation is tentatively extended to include the conditions relevant to embrittlement behavior in the case of thermal oxidation at 90°C. The important roles of chemi-crystallization and morphology as a follow-up to initial chemical changes are discussed. The philosophy of how chemical reactions will ultimately lead to physical polymer changes apparent in Mw and lamellar properties, and how these processes could be discussed in terms of advanced modeling strategies is briefly reviewed. 

The polyethylene radical would be expected to react readily with oxygen and contribute to oxidative propagation as another peroxy radical ... 

HOPE high density polyethylene radical termination by... 

Polyethylene (PE) + peroxides (ROOR) polyethylene radical Intermediates [PE ] + peroxide radical Intermediates [R ]... 

At low concentrations of maleic anhydride, the initiator dissociation leads to a high concentration of polyethylene radicals that can react directly with maleic anhydride. This reaction is followed by a cross-linking or a disproportionating reaction. 

Also, polyethylene radicals will combine with each other, resulting in cross-linking. 

Maleic anhydride Maleic anhydride radieal Screw rotation rate (s ) Polyethylene Polyethylene radical... 

Polyethylene radicals are very reactive and will react with solvents or other trace... 

Polyethylene, polypropylene, peroxide radicals Polyethylene, radical conversion... 

Radical IX can combine with a polyethylene radical leading to a block copolymer. Chain transfer reaction with polyethylene leads to the radical —CH2—CH—CH2—CH2—. This radical, in turn, is able to react with Radicals VII, VIII, or IX. Graft, branched, and three-dimensional polymers are formed ... 

It was also found (for those compounds for which a direct onnparison could be made) that there is an excdlent correspondence between the E, Ep values calculated from gas phase ethyl rascal data at subatmos-pheric pressures and the data in Table 7, indicating that the ethyl radical is a good model for the polyethylene radical. Hydrogen atoms and methyl radicals are not good models for polyethylene radicals, and chain-transfer data obtained for the former two correlate only roughly with the latter (7,68, 71). 

Fig. 5. The three hindered rotations which dominate the value of the frequency factor for ethylene propagation with a polyethylene radical [23]. For clarity, only the last three carbons of the ethylenic macroradical are shown. The forming bond is shaded.

Ethene EDPE, low-density polyethylene Radical polymerization Containers, plastic bags, tubing... 

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