取向模压成型技术增强聚乳酸力学性能的研究

Enhancement of the Mechanical Properties of Poly(lactic acid) by Oriented Compression Moulding

以取向模压成型制备了聚l -乳酸、聚dl -乳酸骨折内固定棒 (Φ =3 .2mm)。与通常的熔融成型相比 ,新的成型技术可以成倍地提高内固定材料的初始力学强度 ,其中聚l -乳酸棒的弯曲强度达 2 63±1 1MPa,聚 dl-乳酸棒的弯曲强度达 1 72± 4MPa。SEM观察显示取向后聚 l-乳酸棒的纵向纤化程度高 ,冲击断面有大量纤维尾端 ;取向后聚dl -乳酸棒弯曲断裂时呈韧性断裂。而熔融模压成型的聚l -乳酸及聚dl -乳酸棒弯曲断裂时呈脆性断裂特征。

The rods made of poly (l-lactic acid) (PLLA) and poly (dl-lactic acid) (PDLLA) were processed by oriented moulding. The mechanical strength of these rods were increased over two times by this method than that by melt moulding. The bending strength of PLLA rod is 263±11 MPa and the PDLLA rod is 172±4 MPa。SEM micrographs show that the longitudinal split surfaces of PLLA rod are of the fibrilar structure, and it impact fracture surfaces show numerous fibril ends. The bending fracture of oriented moulding PDLLA is showing ductile fracture behaviour, and those of melt moulding PLLA and PDLLA are showing brittle behaviour.