短碳纤维增强羟基磷灰石生物材料的制备与性能

Preparation and Properties of Short Carbon Fiber Reinforced Hydroxtapatite Biocomposites

以短碳纤维(C_f)为增强体,采用湿法搅拌均化和自组装合成工艺使短碳纤维均匀分散于反应生成的羟基磷灰石(HA)粉体中,30 MPa下将复合粉体压制成型,并于1250℃氮气保护气氛常压烧结制备了短碳纤维增强羟基磷灰石生物复合材料(C_f/HA)。为提高复合材料的界面结合,低温氧化法对碳纤维进行表面处理。采用IR,SEM技术研究短碳纤维处理前后的表面状态;SEM观察复合粉体的分散效果及复合陶瓷的断口形貌:三点弯曲法测其抗弯强度;单边切口梁法测其断裂韧性。实验结果表明:碳纤维的表面处理对力学性能有很大影响,可大大提高复合材料界面结合强度,C_f添加量为0.5%(质量分数)时,增强效果最为理想,最大抗弯强度为67.70 MPa,断裂韧性达1.18 MPa.m^(1/2),比C_f未氧化处理的复合材料分别提高近20%和18%。研究表明湿法搅拌均化和自组装合成工艺是一种行之有效的均化技术,具有最小的纤维损伤度、高的碳纤维体积分数以及操作便利等优点,常压下烧结制备的短Cf/HA复合材料是一种很有发展前途的骨替代植入材料。

The uniformly dispersal Cf and HA mixed powders were obtained using a wet stirring homogenization and self- assembly synthesis technique （WSHSAST）, and short carbon fiber reinforced hydroxyapatite biocomposite （Cf/HA） was successfully prepared by normal pressure sintering of the compacts of Cf and HA mixed powders at 1250 ℃ for 2 h under nitrogen atmosphere, Cf surface was modified by low temperature oxidation treatment for improvement of interfacial bonding of composite. The surface states of Cf treated before and after were investigated by FTIR and SEM analysis, and dispersal effect of mixed powders and fracture morphologies of composite ceramics were evaluated by SEM method. The flexural strength and fracture toughness of composites were measured by three-point bending and single-edge-notched beam technique, respectively. The results show that surface oxidation treatment of Cf can improve effectively mechanical properties of composite ceramics, and the peak values of flexural strength （67.70 MPa） and fracture toughness （1.18 MPa.m1/2） at 0.Swt% Cf content increase by about 20% and 18%, respectively in comparison to those without oxidation treatment of Cf. It is concluded that WSHSAST is an effective homogenization process with the least Cf damage, a higher fiber volume fiction and easy operation, and the Cf/HA composite obtained is a kind of very promising bone graft substitute.