Graft acetate copolymers

Gross-Linking. A variety of PE resins, after their synthesis, can be modified by cross-linking with peroxides, hydrolysis of silane-grafted polymers, ionic bonding of chain carboxyl groups (ionomers), chlorination, graft copolymerization, hydrolysis of vinyl acetate copolymers, and other reactions. 

Polymers ndResins. / fZ-Butyl peroxyneopentanoate and other peroxyesters of neopentanoic acid can be used as free-radical initiators for the polymeri2ation of vinyl chloride [75-01-4] (38) or of ethylene [74-85-1]. These peresters have also been used in the preparation of ethylene—vinyl acetate copolymers [24937-78-8] (39), modified polyester granules (40), graft polymers of arninoalkyl acrylates with vinyl chloride resins (41), and copolymers of A/-vinyl-pyrrohdinone [88-12-0] and vinyl acetate [108-05-4] (42). They can also be used as curing agents for unsaturated polyesters (43). 

Several authors have discussed the ion exchange potentials and membrane properties of grafted cellulose [135,136]. Radiation grafting of anionic and cationic monomers to impart ion exchange properties to polymer films and other structures is rather promising. Thus, grafting of acrylamide and acrylic acid onto polyethylene, polyethylene/ethylene vinyl acetate copolymer as a blend [98], and waste rubber powder [137,138], allows... 

It has been found that, for a fixed mineral filler content, the viscosity of PMF-based composites increases when the coat is made of polyethylene [164, 209, 293], poly(vinyl chloride) [316] and polypropylene [326, 327], The picture was different, however, for composites based on the ethylene/vinyl acetate copolymer to which kaolin with grafted poly (vinyl acetate) was added [336]. Addition of PMF with a minimum quantity of grafted polymer results in a sharp drop of flowability (rise of viscosity), in comparison to addition of unmodified filler but with a further increase of the quantity of grafted polymer the flow gradually increases and, depending on the kaolin content and quantity of grafted polymer, may even become higher than in specimens with unmodified filler, for equal concentrations. 

Similar grafting experiments by the emulsion technique were described (34) in the system vinyl chloride/copolymer butyl methacrylate-methacrylic acid and in the reverse system, and also in the system styrene/polyvinyl chloride. In this last case again as in homogenous medium, the inverse process failed (vinyl chloride on polystyrene). Grafted acrylonitrile copolymers were also prepared in order to improve their dyeability, by polymerizing acrylonitrile in emulsion in the presence of many different polymers as polyvinyl alcohol, polymethacrylamide and polyvinylpyrrolidone (119, 120, 121), polyvinyl acetate and polyacrylic acid (115), wool (224,225), proteins (136), etc. 

The possibility of fracture on impact can be reduced by dispersing an elastomeric phase uniformly through the rigid material, as it is done in polyblends or better in grafting vinyl monomer upon rubber. H. Bartl and D. Hardt describe the manufacture of a tough rigid PVC by grafting vinyl chloride upon an elastomeric ethylene—vinyl acetate copolymer. 

Graft Polymerization of Vinyl Compounds on Ethylene-Vinyl Acetate Copolymers... 

Because of their content of hydrogen atoms, which can be separated by a radical reaction, ethylene-vinyl acetate copolymers have a good basis for grafting. In earlier papers on the radical crosslinking of EVA copolymers with peroxides, we showed that polyunsaturated compounds, such as triallyl cyanurate, can be incorporated completely in the copolymers by graft reactions (2). 

Table V. Grafting of Vinyl Chloride on Ethylene—Vinyl Acetate Copolymers with Non-uniform Molecular Weight (50% VAC in the Backbone)...

Table VIII. Graft Copolymer Containing 8% Ethylene—Vinyl Acetate Copolymer (45% VAc) and 92% PVC°...

H5V was used as grafting monomer for atactic polypropylene, ethylene/propylene copolymer, ethylene/vinyl acetate copolymer, poly(methyl acrylate) and poly(methyl methacrylate) (32). In all cases, grafting was achieved in chlorobenzene with ditertiarybutyl peroxide as the initiator. Up to now, we have not succeeded in grafting 2H5P under the same conditions onto these polymers. 

In 1968 we reported on the effect of the monomer radical activities on the grafting of various vinyl monomers onto ethylene-vinyl acetate copolymers (EVA) (I). We found that the grafting activity of vinyl monomers corresponds to the monomer radical activity published by Mayo and Walling (2) and others (3, 4). This feature of vinyl monomers is depicted in Figure 1. 

Ethylene-vinylacetate blends with PVC have been widely used in Europe as permanent polymeric plasticizers for PVC. Low cost and good weatherability of these blends permitted their use in window profiles, cable jacketing and other outdoor applications. Ethylene vinylacetate copolymer with 65-75% vinyl acetate content is quite miscible with PVC exhibiting a single T for the blend [Hammer, 1971 Ranby, 1975 Rellick and Runt, 1985]. Two phases are apparent when the vinylacetate is < 45%. Vinylchloride grafted ethylene-vinyl acetate copolymers have also been used for blending with PVC. 

There have been many studies of graft copolymer formation initiated by ionizing radiation, and methods have been discussed.88 Among the systems studied are styrene onto polyethylene,88 styrene onto polypropylene,100 styrene onto Nylon-6,101 styrene onto ethylene-vinyl acetate copolymers,102 styrene and MMA onto natural rubber,103 pentafluorostyrene onto Nylon and polyethylene,104 acrylamide onto Nylon-6,105 acrylamide onto starch,100 vinyl monomers... 

Figure 6. Coefficients of friction (p) as a function of UV preirradiation time for ethylene-vinyl acetate copolymer films surface-grafted with poly(N,N- dimethy lacry lamide).

Ryton R-404] Ryton R-406] Ryton R-702] Ryton V-1. See Polyphenylene sulfide resin Ryuron Graft H-110] Ryuron Graft H-120] Ryuron Graft H-130. See EVA/PVC graft polymer Ryuron Paste. See Polyvinyl chloride Ryuron TC-705. See Vinyl chloride/vinyl acetate copolymer... 

To achieve good toughness, required for many applications, impact modifiers are added to PVC. Chlorinated polyethylenes, ethylene-vinyl acetate copolymers, styrene-methyl methacrylate grafted elastomers, vinyl rubbers, and polyacrylates are the most frequently used (316). These polymers are blended together with other additives. Blending conditions are extraordinary important for morphology control and consequently for final properties of the blends. 

Particular studies of the IR spectra of polymers include isotactic poly(l-pentane), poly(4-methyl-l-pentene), and atactic poly(4-methyl-pentene) [18], chlorinated PE [19], aromatic polymers including styrene, terephthalic acid, isophthalic acid [20], PS [21, 22], styrene-glycidyl-p-isopropenylphenyl ether copolymers [23], styrene-isobutylene copolymers [24], vinyl chloride-vinyl acetate-vinyl fluoride terpolymers [25], vinyl chloride-vinyl acetate copolymers [26], styrene copolymers [27], ethylene-vinyl acetate copolymers, graft copolymers, and butadiene-styrene [28] and acrylonitrile-styrene copolymers [29]. 

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