Feasibility study on the melt processing of radiation-grafted ethylene–vinyl acetate copolymer resins

✍ Scribed by B. J. Ringrose; E. Kronfli

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 196 KB
• Volume: 18
• Category: Article
• ISSN: 0730-6679
• DOI: 10.1002/(sici)1098-2329(199924)18:4<343::aid-adv5>3.0.co;2-v

✦ Synopsis

The feasibility of melt processing radiation-grafted polymer powder was investigated by preirradiation grafting of acrylic acid onto ethylene -vinyl acetate (EVA) copolymer resins containing 9, 18, and 28% by weight vinyl acetate. The relationship between graft weight and melt processability was determined from melt flow index (MFI) measurements. Films were obtained by both compression molding and extrusion and were characterized in terms of their hydrophilicity. The limiting value for graft level for processability was found to be in the region of 30 -35% at the two extremes of the range of MFI values of the base polymer. The preferred polymer has an MFI of 35 dg/min, giving a limiting maximum graft weight for processability of 45%. It was demonstrated that high graft weight EVA copolymer resins are melt processable and that this would be a viable method for the production of hydrophilic membranes for applications such as drug delivery membranes, medical devices, including catheters and stents and, semipermeable battery separator membranes.