13C NMR Studies of Photoinitiated Cross-Linking of Low-Density Polyethylene

1997 ◽  
Vol 30 (5) ◽  
pp. 1408-1413 ◽  
Author(s):  
Qu ◽  
Xin Qu ◽  
Xu ◽  
Ulla Jacobsson ◽  
Bengt Rånby ◽  
...  
2014 ◽  
Vol 606 ◽  
pp. 265-268 ◽  
Author(s):  
Martin Bednarik ◽  
David Manas ◽  
Miroslav Manas ◽  
Martin Ovsik ◽  
Jan Navratil ◽  
...  

Radiation cross-linking gives inexpensive commodity plastics and technical plastics the mechanical, thermal, and chemical properties of high-performance plastic. This upgrading of the plastics enables them to be used in conditions which they would not be able to with stand otherwise. The irradiation cross-linking of thermoplastic materials via electron beam or cobalt 60 (gammy rays) is performed separately, after processing. Generally, ionizing radiation includes accelerated electrons, gamma rays and X-rays. Radiation processing with an electron beam offers several distinct advantages when compared with other radiation sources, particularly γ-rays and x-rays. The process is very fast, clean and can be controlled with much precision. There is no permanent radioactivity since the machine can be switched off. In contrast to γ-rays and x-rays, the electron beam can steered relatively easily, thus allowing irradiation of a variety of physical shapes. The energy-rich beta rays trigger chemical reactions in the plastics which results in networking of molecules (comparable to the vulcanization of rubbers which has been in industrial use for so long). The energy from the rays is absorbed by the material and cleavage of chemical bonds takes place. This releases free radicals which in next phase from desired molecular bonds. This article describes the effect of radiation cross-linking on the surface and adhesive properties of low-density polyethylene.


1999 ◽  
Vol 32 (5) ◽  
pp. 1620-1625 ◽  
Author(s):  
Griselda Barrera Galland ◽  
Roberto F. de Souza ◽  
Raquel Santos Mauler ◽  
Fernanda F. Nunes

2013 ◽  
Vol 658 ◽  
pp. 56-60
Author(s):  
Li Qiu Zou ◽  
Guang Feng Wu

In this paper, the linear low density polyethylene (LLDPE) was melted and cross-linked by dicumyl peroxide (DCP) used to prepare cross-linked polyethylene (XPE). The gel content was determined by extraction method. The effect of content of cross-linker, cross- linked time, cross-linked temperature and other factors on the gel content were studied. It was found that the extraction time should be 18h for XPE. The gel content increased with the increasing of cross-linked time. When the cross-linked time was 10-15min, DCP was almost complete decomposition. The gel content was basically stable when the cross-linked temperature was 170-175 oC. The maximum of gel fraction was about 90%.


1991 ◽  
Vol 42 (2) ◽  
pp. 399-408 ◽  
Author(s):  
M. De Pooter ◽  
P. B. Smith ◽  
K. K. Dohrer ◽  
K. F. Bennett ◽  
M. D. Meadows ◽  
...  

2018 ◽  
Vol 51 (3) ◽  
pp. 211-223
Author(s):  
M Aouinet ◽  
K Djakhdane ◽  
A Dehbi ◽  
D Castronuovo ◽  
P Picuno

The low-density polyethylene films used for greenhouse roof were naturally weathered for 9 months in harsh climatic conditions (Tiaret region, Algeria). The changes in the mechanical properties have been measured by tensile and creep-recovery tests. The measurements were carried out for both monolayer and tri-layer films. The anisotropic character of the films is preserved during ageing. The improvement in the creep resistance via cross-linking for both monolayer and tri-layer films affects different deformations. The results revealed that the degradation performance of these new tri-layer films is found to be quite better than that of the monolayer film, with regard to the mechanical properties.


2020 ◽  
Vol 2 (5) ◽  
pp. 1897-1908
Author(s):  
Syeda S. Abbas ◽  
Gregory J. Rees ◽  
Georgios Patias ◽  
Claire E. J. Dancer ◽  
John V. Hanna ◽  
...  

1987 ◽  
Vol 23 (10) ◽  
pp. 809-818 ◽  
Author(s):  
Daniele C. Bugada ◽  
Alfred Rudin

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