Polyfunctional monomers polyethylene grafting

Allyl methacrylate and allyl acrylate are difunctional monomers, triallyl phosphate is a trifunctional monomer, and polyethylene glycol dimethacrylate is a polyfunctional monomer. All these lead to cross-linked graft copolymers. 

In preliminary work (19), divinylbenzene (DVB) has been reported to be a useful additive for enhancing the above grafting reactions. These early data (19) indicate that there are possible common mechanistic pathways between the acid effect and the DVB process. More detailed DVB studies are discussed in this paper for enhancing the radiation grafting yields of styrene in methanol to films of polyethylene and polypropylene. The work has been extended to include the use of other polyfunctional monomers such as tri-methylol propane triacrylate (TMPTA) as additives. The possibility of being able to use these additives for copolymerisation of monomers to naturally occurring trunk polymers such as cellulose will also be considered. 

Comparison of Acid with Polyfunctional Monomers as Additives in Polyethylene Grafting. New additives, as well as acid, have been found to accelerate grafting in the presence of ionizing radiation. Much of this recent work has been performed with polyethylene. Only very preliminary studies of these new additives have been carried out with cellulose, however these early results suggest that these latest additives will also be very valuable for copolymerization reactions with cellulose. The more comprehensive polyethylene data will therefore be presented here to act as a guide for what might be predicted when cellulose is used as backbone polymer. 

The new additives are polyfunctional monomers, which are exemplified by divlnylbenzene (DVB) and trlmethylol propane triacrylate (TMPTA) and are used in concentrations of 1% (v/v). When these polyfunctional monomers are added to the monomer solution, the results show that the gamma ray grafting of styrene in methanol to polyethylene is enhanced to a comparable degree to that of inclusion of acid (Table VII). The polyfunctionality of DVB and TMPTA is obviously Important in these reactions, since the number of grafting sites in the system is potentially enhanced by the Increase in... 

Table VIII. Synergistic Effect of Acid and Polyfunctional Monomers as Additives for Enhancing UV and Ionizing Radiation Grafting of Styrene in Methanol to Polyethylene Film...

Although considerable work has been reported using preirradiation grafting, the present treatment will be confined to the mutual or simultaneous procedure since by this latter technique, much lower doses are needed to accomplish a particular percentage graft The simultaneous method is also amenable to the use of additives to accelerate copolymerization. The additives to be discussed in this paper include solvent, mineral acid and polyfunctional monomers for the grafting of styrene monomer to polyethylene and polypropylene films in the presence of gamma radiation ... 

Table 4. Synergistic effect of acid with polyfunctional monomers in the radiation grafting of styrene to polyethylene, (a)... 

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