Polyurethane or polyurethane-urea elastomeric compositions

A degradation resistant material which comprises a polyurethane or polyurethane-urea elastomeric composition which comprises a reaction product of:

• (A) a soft segment macrodiol which is either:
• (i) a homopolymer represented by formula I,
• HO--[(CH.sub.2).sub.n O].sub.m --H I
• wherein n represents an integer greater than 5 and less than 13, m is a number such that the number average molecular weight of the compound of formula I falls in the range from 218 to 5000 and at least one hydrogen atom represented in formula I is substituted by a halogen atom;
• (ii) a copolymer containing at least 25% by mass of repeating units --(CH.sub.2).sub.n O-- wherein n is as defined in formula I above;
• or
• (iii) a mixture of macrodiols comprising greater than 10% of a macrodiol as defined in formula I above;
• (B) an aliphatic or aromatic diisocyanate;
• and
• (C) optionally a chain extender.

An in vivo degradation resistant material which comprises a polyurethane or polyurethane-urea elastomeric composition which comprises a reaction product of:

• (A) a soft segment macrodiol which is either:
• (i) a homopolymer represented by formula I,
• HO--[(CH.sub.2).sub.n O].sub.m --H I
• wherein n represents an integer greater than 5 and less than 13, m is a number such that the number average molecular weight of the compound of formula I falls in the range from 218 to 5000 and optionally at least one hydrogen atom represented in formula 1 is substituted by a C.sub.1 to C.sub.3 alkyl group or a halogen atom;
• (ii) a copolymer containing at least 25% by mass of repeating units --(CH.sub.2).sub.n O-- wherein n is as defined in formula I above;
• or
• (iii) a mixture of macrodiols comprising greater than 10% of a macrodiol as defined in formula I above;
• (B) an aliphatic or aromatic diisocyanate;
• and
• (C) optionally a chain extender.