Free‐radical grafting of trans‐ethylene‐1,2‐dicarboxylic acid onto molten ethylene‐vinyl acetate copolymer

Abstract

Distinctive features of free-radical grafting of trans-ethylene-1,2-dicarboxylic acid (TEDA) onto macromolecules of molten ethylene-vinyl acetate copolymer (EVA) in the course of reactive extrusion have been investigated along with structure, mechanical characteristics, and high-elastic properties of molten functionalized products (EVA-g-TEDA). It is shown that EVA-g-TEDA yield depends on both the peroxide initiator concentration and content of vinyl acetate units in the copolymer molecular structure. At functionalization, acid grafting is accompanied by secondary reactions of macromolecular degradation and crosslinking. With a low-peroxide initiator concentration (0.1 wt %), degradation prevails; with a higher (0.3 wt %) concentration, crosslinking of macromolecules prevails. It is reported that monomers being grafted attach mostly over secondary carbon atoms in the polymer chain. EVA-g-TEDA appears to have a less perfect crystal structure with a lower-melting temperature and crystallinity as against the starting polymer. The functionalized products display enhanced rigidity and lower deformability in comparison with the initial copolymer. Variations in the swelling ratio and melt strength of EVA-g-TEDA depend on the course of competing secondary processes of macromolecular degradation and crosslinking.

A Review of Polymeric Refabrication Techniques to Modify Polymer Properties for Biomedical and Drug Delivery Applications

“…to work optimally (45,46) Radiation grafting Free radical/ionic Generation of radicals/ions by gamma radiation (11,47) Direct radical/ion generation eliminates the need of initiators and washout steps (48) Serious degradation and/or decomposition of the polymer can occur (49)(50)(51) the molecule capable of triggering a reaction (34). The reaction that eventuates is the transfer of this high energy radical to a substrate polymer that can subsequently react with monomer composites to effect a modification on the polymer surface presenting a grafted product (32).…”

Polyamide 6 and polyamide 66 blends with functionalized polyolefins: Effect of phenomenal increase in viscosity and melt strength of polyamide 66‐based materials

“…When selecting fPO for PA blend, consideration should be given to the reactivity of not only amine and amide groups, as well as to the end carboxyl groups of macromolecules. In this context, despite the preferential use of PA-anhydride reaction for compatibilization, technical characteristics can be improved by introduction (into fPO) of carboxyl, [17,18] neutralized carboxyl, [19,20] ester, [11] oxazoline, [21] epoxide, [11,22] isocyanate, [23] and other functional groups.…”

Reaction mechanism of suspension graft copolymerization of styrene and acrylonitrile in the presence of ethylene propylene diene terpolymer

“…Gra copolymers, commonly used as compatibilizers in polymer blends, are of particular scientic and industrial interest for ensuring the dispersion of one phase in another by reducing interfacial tension. 1,2 Many synthetic pathways have been used in order to obtain gra copolymers by traditional free radical polymerization, [3][4][5][6][7] due to its signicant advantages like simple operation, mild reaction conditions, and utility with a wide selection of different monomers. Currently, the ethylene propylene diene terpolymer-g-poly(styrene-co-acrylonitrile) (EPDM-g-SAN) is mainly produced in industry using the solution gra copolymerization method.…”