Radiation crosslinking of polyethylene–polyfunctional monomer mixtures

Abstract

Polyfunctional monomers such as allyl methacrylate, allyl acrylate, and diallyl maleate have been found to greatly enhance the radiation crosslinking of polyethylene. The radiation dose for incipient gelation is decreased by a factor of approximately 25 by the presence of small amounts of these monomers. The ultimate scission/crosslinking ratio is unchanged by the presence of these monomers and the swelling behavior of the gels follows the Flory‐Rehner equation. The monomer‐crosslinking process is compared to the monomer‐free process as regards the physical properties (tensile strength, elongation, modulus) of the crosslinked materials. A mechanism is presented for the enhancement of polyethylene crosslinking by polyfunctional monomers.

Aspects Regarding Radiation Crosslinking of Elastomers

“…The most important stage in the EPDM rubber processing technology is vulcanization / crosslinking by sulphur and accelerator or by peroxides. Radiation vulcanization is applicable, but the dose required for EPDM vulcanization is very high (Odian, 1964). To reduce the dose for vulcanization of EPDM, s o m e r e s e a r c h e s h a v e w o r k e d o n t h e introduction of coagents/polyfunctional monomers such as ethylene glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate, trimethylolpropane trimethacrylate etc (Manaila, Stelescu, Ighigeanu et al, 2011) The following materials were used in the study: EPDM rubber (Nordel 4760); trimethylopropane-trimethacrylate Luvomaxx TMPT DL 75; dibenzoyl peroxide Perkadox 14-40B for he control blends (Manaila, Stelescu, Ighigeanu et al, 2011).…”

The Mechanical Properties of Ethylene-Vinyl-Acetate Copolymer/Triallylcyanurate Mixture Cross-linked by Electron Beam and Microwave Processing

“…Polyfunctional monomers are effective on modification of elastomeric material by cross-linking. It is suggested that the reaction be depicted as a two step process: step 1, rapid initial polymerization of the polyfunctional monomer, and step 2, reaction of the polymerized polyfunctional monomer with elastomeric material chains to which it eventually binds, forming a cross-linked elastomeric material-polyfunctional monomer network [26].…”

“…Monomerii polifuncþionali sunt eficienþi pentru modificarea materialului elastomeric prin reticulare. Reacþia poate fi descrisã ca producându-se în douã etape: etapa 1, în care loc iniþial o polimerizare rapidã a MP ºi etapa 2, în care se produce reacþia dintre MP polimerizat ºi lanþurile elastomerului cu care se leagã în cele din urmã, rezultând o reþea de tip elastomer reticulatmonomer polifuncþional [26].…”

The Influence of Electron Beam Irradiation Dose and Polyfunctional Monomers Concentrations on the Physico-mechanical Characteristics of the EPDM/HPDE Blends

“…Studiile anterioare [5,6] au arãtat cã cei mai eficienþi MPF pentru EPDM au fost trimetilol-propantrimetacrilat (TMPT) ºi zinc-diacrilat (ZDA). Reacþia poate fi descrisã ca un proces în douã etape: (1) polimerizarea iniþialã rapidã a monomerului polifuncþional ºi (2) reacþia monomerului polifuncþional polimerizat cu lanþurile de EPDM cu formarea unei reþele reticulate de EPDM-monomer polifuncþional [7].…”

“…Previous studies [5][6] show that the most efficient PFMs in the case of EPDM were trimethylolpropane-trimethacrylate (TMPT) and zinc-diacrylate (ZDA). The reaction can be depicted as a two-step process: (1) rapid initial polymerization of the polyfunctional monomer and (2) reaction of the polymerized polyfunctional monomer with EPDM chains which ''ties'' the latter with the former to form a crosslinked EPDM-polyfunctional monomer network [7]. Blends were prepared by melt blending technique, on a laboratory electrically heated roller mill equipped with a cooling system.…”