镁/聚己内酯的熔融挤出增材制造工艺研究

Fused Extrusion Material Additive Manufacturing for Mg/PCL Composites

为了解决聚己内酯(PCL)在骨修复领域应用中力学性能差、降解时间长、表面疏水、不具有骨诱导性等缺点,采用在PCL基底内引入镁(Mg)粉末颗粒的方法,制备了Mg/PCL复合材料,并通过熔融挤出增材制造技术制造了骨修复植入物。制备了可用于熔融挤出打印的Mg/PCL复合丝材,并研究了不同温度对挤出丝材质量和均匀度的影响,改变不同的打印参数,打印了拉伸、弯曲样件,研究了打印温度、打印层厚和镁含量对PCL机械性能的影响。利用熔融挤出增材制造工艺,制造了孔径为300～500μm、杆径为600μm的骨组织工程支架和狗的下颌骨假体,并在电镜下观察了支架表面形貌,加入镁颗粒,使纯PCL的拉伸模量增加了45.6%,抗弯模量增加了89.4%,同时弯曲强度增加了27.3%。PCL基底内Mg含量越高,电镜微观形貌越粗糙。结果表明:加入Mg颗粒,可以改善PCL的力学性能,弹性模量达到了人体松质骨的范围;电镜下镶嵌在PCL表面的镁颗粒改善了PCL表面粗糙度和亲水性,有利于细胞附着和增殖。

The poor mechanical properties,long degradation time,hydrophobic surface and worse osteoinductive behavior of polycaprolactone(PCL)limit its application to bone tissue repairing.We incorporate Mg micro-particles into the PCL matrix to produce Mg/PCL composite material and fabricate bone repairing substitute by fused extrusion additive manufacture technology.The influences of temperature on quality and evenness of extruded Mg/PCL composite filament are analyzed.The tensile and bending samples are made to verify the influences of printing perimeters on the mechanical properties of Mg/PCL.We fabricate the bone tissue engineering scaffolds with the pore size of 300-500μm and strut size of 600μm and observe the scaffold surface morphology by scanning electron microscope(SEM),then customize dog mandible prosthesis.Compared with pure PCL,the tensile and flexible modulus are heightened by 45.6%and 89.6%respectively,while the bending strength is heightened by 27.3%.The more the Mg particle content in PCL matrix,the rougher the surface morphology in SEM.The results show that incorporating Mg particles improves the mechanical properties of PCL,which approach those of human cancellous bone.Mg micro-particles inserted on the PCL matrix promote the surface roughness and hydrophilicity to facilitate cell attachment and growth.