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通过电镜分析及理论推导对羟基磷灰石(Hydroxyapatite,HA)/高密度聚乙烯(High density polyethylene,HDPE)复合材料界面粘结状态、HA颗粒对裂纹扩展的钝化、钉扎作用、复合纤维对体系分子热激活能的影响及复合纤维的能量吸收机制与增强增韧等进行了深入研究。结果表明:HA/HDPE复合材料通过纳米HA颗粒与HA/HDPE复合纤维在不同尺度上协同作用达到增强增韧的效果。即在纳米尺度,纳米HA颗粒的均匀分散和高的HA/HDPE界面结合强度显著提高了HDPE的结晶度,细化了HDPE晶粒尺寸,并在HA颗粒表面形成取向结晶层,从而使材料在断裂过程中通过HDPE取向结晶层的基体形变和HA脱粘过程对微裂纹起钝化和钉扎作用,并扩大能量耗散的区域,以阻滞微孔隙和银纹的长大和破断,抑制大裂纹的早期形成。在微米尺度,由于HA/HDPE复合纤维的定向排列,使体系的活化体积显著降低,大大增加了材料的断裂热激活能,从而显著提高材料的强度。另一方面,复合纤维在应力作用过程中通过纤维断裂、纤维拔出、裂纹偏转机制使材料在形变与破坏过程中耗散更多的能量,从而显著提高材料的强度和韧性。
Electron microscopy and theoretical analysis were used to deduce the bonding state of hydroxyapatite (HA) / high density polyethylene (HDPE) composites, passivation of HA particles to crack propagation, pinning, On the heat-activated energy of the system molecules and the energy absorption mechanism of composite fibers and enhanced toughening conducted in-depth study. The results show that HA / HDPE composites can enhance the toughening effect through the synergistic effect of nano-HA particles and HA / HDPE composite fibers on different scales. That is, at the nanoscale, the uniform dispersion of nano-HA particles and the high HA / HDPE interfacial bonding strength significantly increase the crystallinity of HDPE, refine the HDPE grain size and form oriented crystalline layers on the surface of HA particles, In the process of fracture, the substrate deformation and HA debonding process of the HDPE oriented crystal layer act as passivation and pinning of microcracks and expand the energy dissipating region to retard the growth and breakage of micropores and silks, inhibiting large Early formation of cracks. At the micrometer scale, the activation volume of the HA / HDPE composite fibers decreases significantly due to the directional arrangement of the HA / HDPE composite fibers, which greatly increases the thermal activation energy of the fracture and significantly increases the strength of the material. On the other hand, the composite fibers can dissipate more energy during deformation and failure by fiber breakage, fiber pull-out and crack deflecting mechanism during the stress process, thereby significantly improving the strength and toughness of the material.