Grafting of vinyl monomer

Other common radical-initiated polymer processes include curing of resins, eg, unsaturated polyester—styrene blends curing of mbber grafting of vinyl monomers onto polymer backbones and telomerizations. 

Cardanol grafted cellulose. One of the advanced techniques to improve the properties of a polymer is to graft another polymer onto it. Grafting of vinyl monomers onto cellulose has been the subject of extensive studies during the last decade or two. Grafted cellulose copolymers have been found to have improved proper-... 

In the presence of radical initiators such as benzoyl peroxide (BPO), azobisisobutyronitrile (AIBN), persulfates (S208 ), etc., grafting of vinyl monomers onto polymeric backbones involves generation of free radical sites by hydrogen abstraction and chain transfer processes as described below ... 

Nayak et al. have also reported grafting of vinyl monomers onto wool [75] and silk [76] using metal chelates as initiators. 

Grafting of vinyl monomers onto preirradiated polymers either in vacuum or air by the preirradiation method. 

The double irradiation method involving the mutual method of grafting of vinyl monomers onto preirradiated polymer recently used by Kaur et al. [85]. 

On the basis of the above findings, grafting of vinyl monomers onto irradiated polypropylene has been attempted successfully by the mutual method. Upon irradiation hydroperoxide groups are introduced, which provide sites for grafting. During mutual irradiation in the presence of the monomer in aqueous medium, these hydroperoxide groups and water undergo decomposi-... 

Grafting reactions alter the physical and mechanical properties of the polymer used as a substrate. Grafting differs from normal chemical modification (e.g., functionalization of polymers) in the possibility of tailoring material properties to a specific end use. For example, cellulose derivatization improves various properties of the original cellulose, but these derivatives cannot compete with many of the petrochemically derived synthetic polymers. Thus, in order to provide a better market position for cellulose derivatives, there is little doubt that further chemical modification is required. Accordingly, grafting of vinyl monomers onto cellulose or cellulose derivatives may improve the intrinsic properties of these polymers. 

The use of ceric ions to initiate graft polymerization was first discussed by Mino and Kaizerman in 1958 [12]. Schwab and coworkers [13] were among the first to extend this method to the grafting of cellulose. Following their work, numerous papers have appeared in the literature on the grafting of vinyl monomers onto cellulose by this technique. 

Gaylord et al. [49] reported the dilution and matrix effects in grafting of the styrene/AN binary mixture onto cellulose with K2S2O8 as the initiator. Titledman and coworkers [50] reported the effect of hydroxypro-pylmethyl cellulose on the course of (NH4)2S20 decomposition and claimed a route for grafting of vinyl monomers onto the polymer backbone. The decomposition of the peroxo salt, under the catalytic influence of the... 

Peroxidic groups in oxidized polyolefins have frequently been employed as sources of free radicals to allow grafting of vinyl monomers to polyolefins (2f[). Some of the products from the gas reactions also have interesting potential as reactive sites. For example, chloroformate groups are well known to react with alcohols, and amines 2J[). Thus chloroformate groups could be useful for example in coupling highly oriented polyolefin fibres to resins such as epoxy based systems. 

Independently the Mn"5 pyrophosphate complexes were developed as efficient initiators at very low concentrations (1 to 3 mmole/1) for grafting of vinyl monomers to starch. High yields of polymer (over 90%) and very high grafting efficiencies (98-99%) were obtained by reactions for 1 to 3 h at room temperature ( 30°C) in moderately acidic aqueous media (pH = 1.5 to 2.0). Co rresponding grafting experiments have later been carried... 

Grafting of Vinyl Monomer by Trapped Radicals in Irradiated Polymer. The polymer is preirradidated in vacuo or in the presence of an inert gas and then immersed in monomer. The trapped free radicals in the irradiated polymer can then initiate graft polymerization. 

The cerium (IV) initiation has been used quite extensively to grafting of vinyl monomers to all kinds of cellulose substrates. 

Simultaneously Schwab, Stannett, Rakowitz, and Magrane (51) applied the ceric ion method to the grafting of vinyl monomers to paper. They studied the influence of a number of variables, such as the soaking of the paper with the monomer emulsion, the oxygen occlusion, the temperature during grafting, the monomer concentration, the time, and... 

Armstrong, and Rutherford have reported extensive studies on the vapor phase grafting of vinyl monomers to cellulosic fibers both mutual and pre-irradiation methods have been used (97, 120). Again, water or another swelling agent was found to be necessary for effective grafting to rayon and cotton for all the monomers studied. In the case of cellulose acetate water was helpful but not necessary except for styrene. Acetic acid and methanol vapors were also found to be effective promotors of vapor phase grafting to cotton and cellulose acetate fibers. 

Armstrong, A. A., and H. A. Rutherford A vapor phase technique for radiation-induced grafting of vinyl monomers to fibers. Text Res. J. 33, 264... 

Gkacintov, N., V. Stannett, and E. W. Abrahamson The photo-initiated grafting of vinyl monomers to cellulose and other polymers using anthra-quinone vat dyes. Makromol. Chem. 36, 52 (1959). 

Similarly the ozonization of several polyamides, mixed polyamides and polyethylene terephthalate followed by grafting of vinyl monomers has been successfully attempted (134, 135). 

Wilkie and co-workers [47, 158] have used TG and TG-FTIR to study grafting of vinyl monomers, such as methacrylic acid, onto styrene-butadiene block rubber (SBS) or ABS... 

RANBY and gadda Grafting of Vinyl Monomers onto Fibers... 

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