Study On The Preparation And Properties Of CPPF/PLA Composites

Polylactic acid is a high molecular polymer which can be degraded and absorbed in the human body.It has good biocompatibility and has high application value in the field of biomedical materials.However,the mechanical strength of Polylactic acid is low and shortcoming of the decline rate of mechanical properties after degradation,it can not meet the requirements of cortical bone internal fixation material and limit its application.Therefore,the mechanical properties can be improved and the attenuation rate of polylactic acid can be declined by means of fiber reinforced PLA,and the application of polylactic acid in the internal fixation can be brought into full play.In this study,CPPF was prepared by melt drawing process,and the effect of boron oxide on mechanical strength and degradation properties of CPPF was studied.At the same time,the molding process of PLA was studied by orthogonal experiment.The CPPF/PLA composites with degradable were prepared,and the effects of CPPF content on the mechanical properties and degradation properties for composites were studied.The effects of modified concentration and time on the mechanical properties and degradation properties of composites were studied by KH-550 modified CPPF.The results of the experiment are as follows:(1)The mechanical properties and chemical stability of CPPF was obviously improved the addition of boron oxide,andand its best mixing amount was 9%.(2)The best molding condition of PLLA is 30 min at 200 ℃.(3)The mechanical properties of PLLA can be greatly improved by adding CPPF.When the fiber mass fraction is 50%,the optimum flexural strength and flexural modulus are 285.78 MPa and 11.76 GPa,respectively,which are 73.77% and 203.35% higher than pure PLLA,and the flexural strength and modulus of the composites with mass fraction of 50% are 75.93 MPa and 2.97 GPa after 56 days of degradation.(4)The surface of CPPF was modified with KH-550.It was found that the maximum flexural strength and modulus were obtained when the modified concentration was 3% and the modified time was 30 min,The flexural strength and modulus was 29.77% and 25.8%higher than that of the unmodified composite.After 56 days of degradation,the flexural strength and modulus of the composites increased by 30.12% and 23.23% respectively than those of the unmodified composites.The results show that the interface between KH-550 modified composites increases the mechanical properties of composites,and reduces the mechanical decay rate of composites.