Preparation Of High-toughness Polylactic Acid Blends By In-situ Reaction Blending With Polycaprolactone Polyol

Polylactic acid(PLA)is a biodegradable polymer polyester derived from renewable resources,which has high mechanical strength and good processability,However the shortcoming of toughness restricts its broad application.Polycaprolactone polyol is a low molecule material with high reactivity and low viscosity,which is usually used as a raw material for preparing elastomers.In this paper,high-toughness PLA/polycaprolactone-based elastomer blends were prepared by reactive blending,which provided a new approach and ideas for PLA toughening modification.The linear polycaprolactone diol and the branched polycaprolactone triol were used to react with IPDI in the blending process,respectively,and the PLA was toughened by the in-situ formed polycaprolactone-based elastomer.The in-situ reaction during the blending process was confirmed by FTIR,GPC and TG,etc.Polycaprolactone-based elastomer of a linear and crosslinked structure were formed by in-situ reaction of polycaprolactone diol and the triol,respectively.The effect of blending temperature on the degree of reaction and material properties was studied.When the blending temperature was 180?,the molecular weight of PLA was maintained and the performance of the material was better.The high-toughness blend was prepared by in-situ reaction of polycaprolactone diol with PLA.The elongation at break reached 177.2%and the impact strength reached7.19kJ/m~2,but the tensile and tensile modulus dropped significantly.The blend prepared by reactive blending of polycaprolactone triol and PLA has better performance,the elongation at break reaches 242.4%,and the impact strength reaches 14.5kJ/m~2,which is 27.5 And 5.8 times of pure PLA respectively,and the tensile strength and modulus were still 52.7MPa and 1946.46MPa.polycaprolactone-based elastomer acted as stress concentration point,which generates a large plastic deformation and absorbs a large amount of energy.At the same time,due to the reaction of the hydroxyl group of the PLA with the isocyanate group,the PLA had a good interfacial adhesion with the elastomer,and when the elastomer particles were debonded from the matrix,the PLA matrix triggered a large plastic deformation to absorb a large amount of energy.The crosslinked structural elastomer had a higher elastic modulus,and absorbs more energy during deformation to have a more significant toughening effect,the strength of the blend is maintained as while.Blends prepared by reactive blending of polycaprolactone ma K,Tabuani D,Camino G.Nanocomposites of PLA and PCL based on e memory property.The rigid PLA matrix in the blend acted to fix the temporary deformation and the crosslinked polycaprolactone-based elastomer functions to restore the shape.