Effect of the Introduction of Fish Collagen on the Thermal and Mechanical Properties of Poly(lactic acid)

Collagen/poly(lactic acid) composite was developed by covalent combination of collagen and poly(lactic acid) and the thermal and mechanical properties of the composites were also investigated. Owing to the triple helix structure, collagen exhibited important advances in the improvement of thermal and mechanical properties of poly(lactic acid) compared with other polymers. In our work, collagen molecules were covalently grafted on the poly(lactic acid) chains through the condensation of amino- and carboxyl- groups with the catalyzation of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. Moreover, the enthalpy of collagen/poly(lactic acid) materials was 30.09 J/g at the highest, compared to the enthalpy of 1.52 J/g for pure PLA. In addition, 88.60% improvement in tensile strength and 176.88% improvement in elongation at break were observed. The strategy for improving the properties of poly(lactic acid) by protein can be useful to develop high impact resistance of PLA-based composites and expand the application fields of PLA materials.