Synthesis of Degradable Materials Based on Caprolactone and Vinyl Acetate Units Using Radical Chemistry

Present studies are carried out with an aim to make degradable materials based on caprolactone and vinyl acetate units using radical chemistry. Radical ring-opening copolymerization of 2-methylene-1,3-dioxepane (MDO) with vinyl acetate in presence of AIBN initiator at 70 degrees C was carried out to achieve the aim. The copolymerization introduced degradable PCL repeat units onto the C-C backbone of poly(vinyl acetate). Microstructure analysis of the copolymers is done using different 1D and 2D NMR techniques. Complete ring-opening polymerization of MDO to give ester units was observed during copolymerizations. Reactivity ratios were found out by Kelen Tados method and were r(VAc) = 1.53 and r(MDO) = 0.47 leading to statistical introduction of ester linkages onto the polymer backbone. The materials showed varied glass transition temperatures (from 37 to -44 degrees C) depending upon the amount of ester linkages and very high elongations. The hydrolysis products were also tested for cytotoxicity studies in L929 cells and compared with that of known and accepted standard materials like poly(ethyleneimine). The hydrolysed products were non toxic and showed a cell viability > 95%. Keeping in view the combined properties like degradability, non-toxicity and low glass transition temperatures, the resulting materials could therefore be proposed for different applications like degradable gums, coatings etc.