Radiation processing of polyolefin blends. I. Crosslinking of EPDM-PP blends

Abstract

Radiation crosslinking of polymer blends containing the ethylene–propylene terpolymer (EPDM) and polypropylene (PP) was studied. Four binary systems with mixing ratios of 80/20, 60/40, 40/60, and 20/80 w/w and the individual components were γ‐processed. The development of the gel content formed in irradiated blends proved that the increase in PP concentration generated an increasing insoluble fraction. A linear dependence of the gel fraction on PP concentration was found. The optimal dose range for the efficient crosslinking of all EPDM/PP blends was 40–180 kGy. The use of PP customer waste was also examined. The thermal stability of the studied mixtures was assessed in order to state the contribution of the components to the radiation compatibilization of investigated polymers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 982–987, 2000

Accuracy in locating glass transitions: aging and gamma sterilization of vulcanized thermoplastic elastomers

“…Zaharescu and his colleagues have shown that at doses from 40 or 50 up to 200 kGy there can be significant cross-linking [2,10,11]. We recall that our samples were irradiated following an ASTM standard, between 18 and 30 kGy, hence below the Zaharescu threshold.…”

“…There has been a rapid rise in the use of polymer-based materials in medical applications ranging from drug-delivery systems to medical devices [1][2][3]. In particular, thermoplastic vulcanizate elastomers (TPVs) have found use in medical devices and implants due to their excellent combination of properties and processability.…”

“…γ irradiation has now begun to replace traditional methods of sterilization (such as ethylene oxide) for medical devices -in part because γ-irradiation is safer to implement and does not leave malignant traces on the products as ethylene oxide does [2,5]. Further, γ sterilization can be used after products are packaged, thus eliminating concern for recontamination introduced in packaging [3].…”

Aspects Regarding Radiation Crosslinking of Elastomers

“…In fact, the two effects, crosslinking and degradation, coexist and we need to point out the predominance of one of them. In addition, through appropriate surface treatments, some features of the feet such as appearance, adhesion to different materials or slip resistance can be significantly improved (Zaharescu, 2000).…”

“…Variables such as radiation dosage and the effect of polymer microstructure and chemical additives on the efficiency of electron beam cure have been studied. Some researchers (Zaharescu et al, 2000;Chowdhury & Banerji, 2005) studied radiation-induced crosslinking in thermoplastic elastomers based on ethylene-propylene rubber (EPDM) and polyethylene (PE) or polypropylene (PP) plastics.…”