Devices for preventing tissue adhesion

A device for preventing the binding of tissue to tissue or of tissue to bone, comprising a composite of a first layer and a second layer, wherein each of said first layer and said second layer comprises a biodegradable copolymer, said copolymer being a segmented thermoplastic copolymer comprising a plurality of recurring units of a first component and of a second component, wherein said first component comprises from about 30 wt. % to about 80 wt. %, based on the weight of said copolymer, of units having the formula:

• --OLO--CO--R--CO--, wherein L is selected from the group consisting of a divalent radical remaining after removal of terminal hydroxyl groups from a poly (oxyalkylene) glycol;
• and a polymer including a first moiety and a second moiety, said first moiety being a polyalkylene glycol and said second moiety being selected from the group consisting or glycine anhydride;
• alloxan;
• uracil;
• 5,6-dihydrouracil;
• glycolic acid;
• lactic acid;
• and lactones;
• and said second component comprises from about 20 wt. % to about 70 wt. %, based upon the weight of said copolymer, of units having the formula:
• --OEO--CO--R--CO--, wherein E is an organic radical selected from the group consisting of a substituted or unsubstituted alkylene radical having from 2 to 8 carbon atoms, and R is a divalent radical remaining after removal of carboxyl groups from a dicarboxylic acid, wherein said first layer is selected from the group consisting of a non-porous layer and a porous layer in which essentially all the pores have a pore size no greater than 3.mu., and said second layer includes pores having a pore size of at least about 30.mu..