Polyethylene-vinyl acetate graft

D. Mnnteanu and S. Turcn, Evaluation of kinetic parameters of the thermal decomposition of polyethylene-vinyl acetate graft copolymers, J. Thermal Anal, 20, 281 (1981). 

Polyethylene/ vinyl acetate/ graft acrylic acid Polybond 106 BP PO, PA, NBR... 

In one study, radicals and ions were created in a polyethylene surface by irradiation with 7-rays in the presence of vinyl acetate monomer. The resulting polyethylene-vinyl acetate graft showed excellent bonding with an epoxy adhesive. Other researchers have grafted acrylic acid onto polyethylene using electron irradiation. The greatly enhanced adhesion of the modified polymer to aluminum is shown in Fig. 13. 

Polyethylene, PE, blended with immiscible polymers (e.g., PVC, PIB, PS) was compatibilized by addition of graft copolymer (e.g., styrene or vinyl acetate grafted on PE)... 

Extension of the chlorosulfonation technology to base resins other than polyethylene, where value can be added, seems a logical next step. Polypropylene and ethylene copolymers containing additional functionaUty, ie, maleic anhydride graft, vinyl acetate, acrylic acid, etc, have been chlorinated and chlorosulfonated to broaden the appHcation base, particularly in coatings and adhesives (9,10). 

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. 

A number of other polymers have the characteristics of TPE and some are available commercially, such as (1) 1,2-polybutadiene, (2) tran -polyisoprene (PI), (3) modified polyethylene (PE) (e.g., ethylene vinyl acetate [EVA] and ethylene ethyl acrylate [EEA]), (4) nonhydrocarbon elastomer-based TPEs, (5) metallocene elastomers/TPEs (MEs/TPEs), and (6) graft copolymeric TPEs. 

II. B polyethylene glycol, ethylene oxide, polystyrene, diisocyanates (urethanes), polyvinylchloride, chloroprene, THF, diglycolide, dilac-tide, <5-valerolactone, substituted e-caprolactones, 4-vinyl anisole, styrene, methyl methacrylate, and vinyl acetate. In addition to these species, many copolymers have been prepared from oligomers of PCL. In particular, a variety of polyester-urethanes have been synthesized from hydroxy-terminated PCL, some of which have achieved commercial status (9). Graft copolymers with acrylic acid, acrylonitrile, and styrene have been prepared using PCL as the backbone polymer (60). 

Notes EVA, ethylene vinyl acetate LLDPE-MAH, maleic anhydride grafted linear low-density polyethylene COPA, co-polyamide. 

The selective oxidation of cellulose to dialdehyde by sodium periodate is well known. It has been postulated by Criegee (74) and by Waters (73) that this reaction proceeds by a free radical mechanism. Toda (76) and Morimoto, Okada, Okada, and Nakagawa (77) have concluded that sodium periodate oxidation should initiate graft polymerization. They succeeded in grafting methyl methacrylate and acrylonitrile onto cellulose substrates, such as rayon and paper. A similar procedure is recommended in a patent of Chemische Werke Huels (78) to graft vinyl monomers onto cotton, polyethylene oxide, copolymers of vinyl chloride-vinyl acetate, and others. 

Organic peroxides are used to initiate free-radical polymerization of ethylene, butadiene, styrene, vinyl chloride, vinyl acetate, and methyl methacrylate. They are also used to cure unsaturated polyesters, occasionally to cross-link thermoplastics such as polyethylene and polyacrylates, and increasingly for grafting and compatibiliza-tion of polymer blends. A variety of organic peroxides offer useful reactivity over a temperature range from 0 to 130°C or more, for different polymers and different processes. 

Impact modifiers are rubbery additives that improve the resistance of materials. Proper compatibility between the phases is essential. This is often achieved with graft and block copolymers. Most impact modifiers are elastomers such as ABS, BS, methacrylate-butadiene-styrene, acrylic, ethylene-vinyl acetate, and chlorinated polyethylene. 

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... 

Polyethylene glycol, vinyl acetate, vinyl caprolactam graft co-polymer... 

Other polymers which have been the subject of thermal degradation studies include ethylene-vinyl acetate [29, 66, 67], ethylene-vinyl alcohol [68], poly(aryl-ether ketone) [69], poly-2-vinyl-naphthalene-co-methyl maleate [34], polyphenylenes based on diethyl-benzophenone [70], polyglycollide [71-73], poly(a-methylstyrene tricarbonyl chromium [74], polytetrahydrofuran [75], polylactide [76-78], poly(vinyl) cyclohexane [79], styrene-vinyl cyclohexane [80], isopropenylacetate-maleic dianhydride [80], polyethylene glycol containing a 1,3-disubstituted phenolic group [81], poly-2-vinyl naphthalene-co-methacrylate [34], collagen biopolymers [82], chitin graft poly (2-methyl-oxazoline - polyvinyl chloride blends [83], cellulose [32, 83-88] and side-chain cholestric elastomers [89, 90]. 

Impact Modifiers Impact modifiers are either systems with spherical elastomer particles in a rigid polymer matrix or they are systems with a honeycomb, network type of dispersed elastomeric phase. For the spherical elastomeric particles, examples are acrylonitrile butadiene styrene (ABS), methacrylate-butadiene-styrene (MBS) and acrylics. These systems are either graft copolymers of methyl methacrylate-butyl acrylate-styrene or methyl methacrylate-ethylhexyl acrylate-styrene. For the honeycomb, network type of dispersed elastomeric phase ethylene vinyl acetate (EVA) and chlorinated polyethylene (CPE) or directly dispersed rubber are examples. Both of these two impact modifiers exist in the polymeric form, hence they can hardly migrate and evaporate because of their size. As a result, they pose almost no problems to health. For PVC window frame production, usually the first type (and acrylic impact modifiers) are used while MBS modifiers are found to be very effective in plasticised as well as in rigid PVC. CPE is mainly used in PVC for products like sheet, pipe, gutters and sidings. 

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