Crosslinking, radiation

This industrial technology includes crosslinking of polymeric materials with the aid of ultraviolet light, ionizing radiation, or electron beams. All three processes are used industrially in many applications. 

Both electron beams and ultraviolet light initiate free-radical polymerizations with very low activation energy. This allows high polymerization rates at room temperature because the rates are not temperature dependent. Once initiated, free-radical polymerizations follow typical paths. It is, however, peculiar to radiation curing of coating materials that the gel states form at very early stages of the reactions. This is due to extensive use of polyfunctional monomers and prepolymers. In fact, it was demonstrated that the gel points occur at around 5% conversion of the prepolymers in typical commercial formulation, yet conversions to about 63% of the prepolymers to polymers are required to obtain dry films.  

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Both radiation and chemical crosslinking can produce amorphous, mechanically stable networks. Radiation crosslinking has a practical advantage in that polymer elec-... 

The very first studies with radiation crosslinked polyethylene oxide (PEO) have shown that SAH is able to substantially reduce the sensitivity of plants to water shortage [7], to promote their growth, particularly, under conditions of water deficiency [8], to improve seedling survival and the final crop [9], These results stimulated a more detailed analysis of the effects of SAH in the water balance of... 

Allcock, H. R., Gebura, M., Kwon, S., and Neenan, T. X., Amphiphilic polyphosphazenes as membrane materials Influence of side group on radiation crosslinking, semipermeability, and surface morphology. Biomaterials. 19. 500, 1988. 

METALLOCENE DERIVATIVES RADIATION CROSSLINKING TCNQ DERIVATIVES ENZYME IMMOBILIZATION... 

The SANS experiments of Clough et al. (21) on radiation crosslinked polystyrene are presented in Figure 9, and appear to fit the phantom network model well. However, these networks were prepared by random crosslinking, and the calculations given are for end-linked networks, which are not truly applicable. 

CPE has been used successfully in under-the-hood wire and cable-coating applications such as flex cord jackets, heater cords, jackets for industrial cables and radiation crosslink-able speciality cables. 

The heat behaviour can be increased through radiation crosslinking. 

The transport properties studies were made in the framework of the evaluation of the effect of radiation crosslinking and heat treatment on the PVA, and the possibility to Improve the RO performance of these membranes using these methods. The water... 

Therefore If the softening Is, Indeed, due to localized plastic deformation then the difference between unfilled specimens and ones with a low volume fraction of filler should be reduced by radiation crosslinking. This was found to be the case (Fig. 6). 

No.4, July 2001, p.333-52 INVESTIGATION OF THE RADIATION CROSSLINKED FOAMS PRODUCED FROM METALLOCENE POLYOLEFIN ELASTOMERS/ POLYETHYLENE BLEND Kim D W Kim K S... 

International Polymer Science and Technology 17,No.ll,1990,p.T/50-l HEAT STABILITY OF RADIATION CROSSLINKED PE FOAM... 

Properties of Crosslinked Films. Our purpose was to determine which commercially useful property improvements result from radiation crosslinking of ethylene-ethyl acrylate copolymers. Table III illustrates... 

Hot blown plastic films usually do not possess sufficient orientation to be heat shrinkable at temperatures below 100°C. For certain shrink packaging applications low temperature shrinkage is essential and can be obtained by biaxial orientation below the melting point. Radiation crosslinking was found to facilitate orientation of these copolymers greatly because of the much greater bubble stability which results from crosslinking. 

Figure I. Effect of radiation crosslinking on stiffness of 85/15 ethylene-ethyl acrylate copolymer over the temperature range 25°-300°C.

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