PREPARATION OF POLY(EPSILON-CAPROLACTONE)-CO-POLY(ACRYLIC ACID) BY RADIATION-INDUCED GRAFTING

Acrylic acid was grafted onto poly(epsilon-caprolactone) (PCL) films b y using electron beam (EB) preirradiation technique. The effect of rea ction time, monomer concentration, radiation dose, time between irradi ation and grafting, radiation atmosphere, and polymer crystallinity on the extent of grafting were studied. Silver and tin ions were attache d to the grafted chains in order to study the grafting process. The ir radiation in air was initially more rapid, but the final extent of gra fting was the same when irradiated in nitrogen atmosphere. Maximum gra fting extents exceeding 400% could be obtained. The optimal grafting w as obtained at an acrylic acid to water ratio of 30 : 70. The grafting process could be initiated at a dose as low as 12 kGy. The grafting p rocess proved to start at the surface and was extended into the bulk w ith time. The ability to form crystals was reduced as the grafting ext ent increased. The water uptake of the poly(epsilon-caprolactone)-graf t-poly(acrylic acid) was increasing with increasing grafting extent, b ut reached a maximum of ca 100% for all grafting extents above 85%. (C ) 1998 John Wiley & Sons, Inc.