Joel L. Williams

Highly swollen hydrogels: vinyl pyrrolidone copolymers☆

Abstract The objective was to prepare hydrogels which, though highly swollen, would have sufficient strength to allow crosslinked poly(vinyl pyrrolidone). Inclusion of tetraethyleneglycol dimethacrylate resulted in only a low physical (hydrophobic) crosslinks. The most successful results were achieved by gamma-irradiation of aqueous solutions of vinyl pyrrolidone plus methyl acrylate. Glass transitions of xerogels were characterized by differential scanning calorimetry. It was deduced that the hydrophobic comonomer (methyl acrylate or methyl methacrylate) is concentrated in microphase domains embedded in a matrix of almost pure crosslinked poly(vinyl pyrrolidone). Inclusion of tetraethylene glycol dimethacrylate resulted in only a low crosslinking efficiency but, nevertheless, had a marked influence in preventing phase separation, which gives hydrogels of improved clarity and mechanical strength.

Blood compatible polyurethane elastomers

Medical applications of blood compatible polyurethane elastomers contribute significantly to the quality and effectiveness of the nations health system. These projects range from artificial hearts to diagnostic/therapeutic cardiac catheters which are saving the lives of many critically ill patients.