Polyisobutylene-based polyurethanes for medical implant devices

A method of preparing a polyurethane or polyurea polymer, the method comprising:

• synthesizing or obtaining hydroxyl-terminated polyisobutylene that includes a thermal-activated crosslinker;
• reacting the hydroxyl-terminated polyisobutylene with a diisocyanate to form a prepolymer;
• reacting the prepolymer with a chain extender to form a polyurethane or polyurea polymer that includes hard segments and soft segments, wherein the hard segments include at least one of a urethane, urea, or urethane urea derived from the diisocyanate, wherein the soft segments include polyisobutylene derived from the hydroxyl-terminated polyisobutylene, and wherein the a polyurethane or polyurea polymer includes first crosslinks that link to the hard segments, wherein the first crosslinks include parts of the chain extender linked to the hard segments;
• and
• applying heat to the polyurethane or polyurea polymer derived from the reaction of prepolymer and the chain extender to form second crosslinks that link to the soft segments of the polyurethane or polyurea polymer, wherein the second crosslinks include parts of the thermally-activated crosslinker linked to the soft segments.

An artificial meniscus comprising:

• an inner core encapsulated by an outer shell,
• wherein the inner core is formed from a first polyurethane or polyurea polymer including hard segments and soft segments, wherein the hard segments include at least one of a urethane, urea, or urethane urea derived from a diisocyanate, wherein the soft segments include polyisobutylene derived from hydroxyl-terminated polyisobutylene;
• wherein the outer shell is formed from a second polyurethane or polyurea polymer including hard segments and soft segments, wherein the hard segments include at least one of a urethane, urea, or urethane urea derived from a diisocyanate, wherein the soft segments include polyisobutylene derived from hydroxyl-terminated polyisobutylene;
• wherein the first polyurethane or polyurea polymer of the inner core is softer than the second polyurethane or polyurea polymer of the outer shell;
• and
• wherein at least one of the first polyurethane or polyurea polymer of the inner core and the second polyurethane or polyurea polymer of the outer shell includes crosslinks between polymer chains, wherein the crosslinks between polymer chains include first crosslinks that link to the hard segments of the polymer chains and second crosslinks that link to the soft segments of the polymer chains, wherein the first crosslinks include parts of a chain extender linked to the hard segments, and wherein the second crosslinks include parts of a thermally-activated crosslinker linked to the soft segments.