Bioabsorbable composites. I: Fundamental design considerations using free radically crosslinkable matrices

Abstract

AbstractBioabsorbable composites have been fabricated, consisting of poly (glycolic acid) surgical mesh embedded in free radically crosslinked poly (D, Iactide‐co‐8‐caprolactone) fumarate‐ or poly(D, Iactide‐co‐‐glycolic acid) fumarate‐based matrices. Styrene and methyl methacrlate were investigated as hydrophobic comonomers and were found to significantly improve the degree of crosslinking, tensile strength and retention of physical properties during the initial stages of degradation particularly styrene. Hydrolytic degradation studies showed that the neat poly(D, L‐lactide‐co‐8caprolactone) fumarate matrix dwas excessively hydrophilic, failing after 10 days of immersion; a matrix modified with 25 wt% styrene underwent a steady, nearly linear loss in mass over a period of 35 days without fragmentation. A composite based on neat poly (D, L‐lactide‐co‐8‐caprolactone) fumarate displayed a tensile strength of 37 Mpa and modulus of 107 Mpa; addition of 25 wt% styrene yielded tensile strength and modulus of 64 Mpa and 689 Mpa, respectively. A silane coupling agent was shown to dramatically improve the fiber‐matrix interfacial adhesion; tensile strength of a poly(D, L‐lactide‐co‐glycolic acid) fumarate compsite was increase from 84 to 92 MPa upon fiber pretreatment. Improved adhesion was also demonstrated using SEM. Bioabsorbable composites are rigid at biological temperatures, but some can be custom formed at elevated temperatures, which might be useful in certain surgical applications.