Acrylic resin reinforcement of reconstituted collagen films

The protein collagen is a major constituent of mammalian tissue. Treatment of calfskin with an enzyme under acid conditions simultaneously solubilizes much of the collagen and removes non‐helical telopeptides which are believed to contribute to immune response. Then, the solid collagen can be reconstituted by precipitating the solubilized material with weak alkali. Films from the enzyme‐treated, acid‐soluble collagen are strengthened by cross‐linking with glutaraldehyde. Composite films are made by coprecipitating collagen (from a solution) with an acrylic resin (from a latex). In one example, an acrylic resin to collagen ratio of 1:3 gives a wet‐tensile strength about 30 percent higher than that for collagen alone. The tensile strength range of these wetted films (20 to 30 megapascals) is typical of the upper range for such limp films as polyethylene. On the other hand, ‘bone‐dry’ collagen has a higher strength similar to that of glassy polymers such as polystyrene.