Degradable composite material with fibres having various degradation rates

1. A degradable composite comprising a degradable matrix, a first fibre type and a second fibre type, wherein the first and second fibre types are phosphate glass fibres, in which phosphate is the primary component, and wherein at least one of the first or second fibre type is thermally treated after being drawn to alter their rates of degradation such that the first fibre type has a different rate of degradation to that of the second fibre type.

2. The composite according to claim 1 wherein the first and second fibre types have the same chemical composition.

3. The composite according to claim 1 wherein the first and second fibre types are derived from fibres of the same chemical composition.

4. The composite according to claim 1 wherein at least one of the first or second fibre type is thermally treated to alter their degradation rates by an annealing treatment.

5. The composite according to claim 1 wherein the matrix is made of a material selected from the group consisting of acrylics, polyesters, polyolefins, polyurethanes, silicon polymers, vinyl polymers, halogenated hydrocarbons, nylons, and proteinaceous materials, including copolymers or combinations thereof.

6. The composite according to claim 1 wherein the matrix is a thermoplastic polymer.

7. The composite of claim 1 , wherein at least one of the first fibre type, the second fibre type, or the matrix is biodegradable.

8. The composite according to claim 1 , wherein at least one of the first or second fibre types has a degradation rate which is faster than that of the matrix.

9. The composite according to claim 1 , wherein the matrix has a faster rate of degradation than either the first or second fibre type or both.

10. The composite according to claim 1 , further comprising additional fibres of one or more different type.

11. The composite according to claim 10 , wherein the additional fibres are reinforcing fibres.