Stereo Structure Polycaprolactone Modified Polylactic Acid And Its Application In Scaffolds

Polylactic acid(PLA)has attracted a lot of research interest because of its biocompatibility,biodegradability and good mechanical properties.However,the brittleness of polylactic acid seriously limits its application.The toughness of polylactic acid can be increased and its application scope can be extended by the blending modification of polycaprolactone with three-dimensional structure.(1)Star-shaped polycaprolactone with different structures was synthesized by ring-opening polymerization.On this basis,reticulated polycaprolactone was synthesized.The synthesized products were characterized,and it was proved that the target products could be obtained by controlling the reaction conditions.The tape casting film was prepared by blending the synthesized polycaprolactone with polylactic acid.The thermodynamics and mechanical properties of the film were tested.The results show that the blending ratio of star-shaped polycaprolactone has the greatest influence on the toughening effect.Compared with star-shaped polycaprolactone with the same arm length,the six-arm products have better toughening effect than those with fewer arms.The arm length of polycaprolactone increases,and the toughening effect increases slightly.The toughening effect of reticular polycaprolactone is worse than that of star polycaprolactone because of its serious phase separation with polylactic acid.(2)Porous bio-tissue scaffolds were prepared by thermotropic phase separation using toughened polylactic acid.The porosity of the scaffolds was measured by ethanol substitution method,and the morphology of the scaffolds was observed by scanning electron microscopy.The results show that the performance of scaffolds is related to the concentration of polymer solution used: the scaffolds made from 2.5% polymer solution are relatively soft,with large pore size and disordered pore wall structure;the scaffolds made from 5% polymer solution have better mechanical properties,more uniform pore size and thicker pore wall,which make the scaffolds more suitable for tissue engineering application.The scaffolds are highly interconnected and can provide nutrient and metabolite transport channels for cell growth and proliferation.The hydrophilicity and cell affinity of modified polylactic acid materials were increased by adding P-123.