Polypropylene-graft-polyacrylic

Effect of Peroxides. In addition to benzoyl peroxide, lauryl-, acetyl-, 2,4-dichlorobenzoyl-, and methyl ethyl peroxide, and tert-hvXy hydroperoxide were studied and gave satisfactory results. The effectiveness of the peroxide is relatively independent of the half-life of the peroxide (Table X). By contrast, the catalyst AIBN is much less satisfactory, as found for methylvinylpyridine and acrylonitrile. The difference between these peroxides and AIBN suggests that the AFR polymer is not formed by a simple uncatalyzed free radical system which would give a graft polymer or a simple mixture of polypropylene and polyacrylate. It is well known that for the polymerization of acrylates AIBN is at least as good if not better than peroxide in initiating the free radical reaction (2). 

CORl s are the prime machines for polymer blending and reactive extrusion [Brown, 1992]. They have been used as reactors for the addition polymerization (polyacrylates, SAN, S-MMA, PA-6, POM, or TPU) and for the polycondensation (PA-66, polyarylates, PEST, PEI). Polymer grafting (polyolefin + silane, maleic anhydride, acetic anhydride, etc.) as well as mechanical and chemical degradation of polypropylene have also been carried out. 

As was found by microphotometration, the concentration gradient of the grafted PAA inside the membrane and its profile depend very much on the amount of the monomer absorbed. It was also evident that, because of the method used for preparation, polymerization of the acid was initiated mainly by PO radicals formed on polypropylene chains by thermal and redox decomposition of POOH hydroperoxides or POOP peroxides. The homopolymer of polyacrylic acid which was also formed inside the film was later removed by long time elution with methanol. 

Pore-filling MIP composite membranes had been first prepared by Dzgoev and Haupt [100]. They casted the reaction mixture into the pores of a symmetric microfiltration membrane from polypropylene (cutoff pore size 0.2 pm) and performed a cross -linking copolymerization of a functional polyacrylate for imprinting protected tyrosine. Hattori et al. [101] had used a commercial cellulosic dialysis membrane (Cuprophan) as matrix and applied a two-step grafting procedure by, (i) activation of the cellulose by reaction with 3-methacryloxypropyl trimethoxysilane from toluene in order to introduce polymerizable groups into the outer surface layer, (ii) UV-initiation of an in situ copolymerization of a typical reaction mixture (MAA/EDMA, AIBN) for imprinting theophylline. 

ESR spectroscopy has been applied to studies of unsaturation and other structural features in a wide range of homopolymers including polyethylene [101-110], polypropylene [111-121], polybutenes [115], polystyrene [122-124], PVC [125,126], polyvinylidene chloride [127], polymethylmethacrylate [128-137], polyethylene glycol polycarbonates [137-140], polyacrylic acid [136-139, 141, 142], polyphenylenes [143], polyphenylene oxides [143], polybutadiene [144], conjugated dienes [145,146], polyester resins [146], cellophane [143,147] and also to various copolymers including styrene grafted polypropylene [148], ethylene-acroline [149], butadiene-isobutylene [150], vinyl acetate copolymers [151] and vinyl chloride-propylene. 

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