Spinal fusion devices can be fabricated from composites based on combining hydroxyapatite and poly(ether ether ketone) phases. These implants serve as load-bearing scaffolds for the formation of new bone tissue between adjacent vertebrae. In this work, we report a novel approach to covalently bond hydroxyapatite and poly(ether ether ketone) to produce a novel composite formulation with enhanced interfacial adhesion between phases. Compared to non-linked composites (HA_PEEK), covalently linked composites (HA_L_PEEK), loaded with 1.25 vol% hydroxyapatite, possessed a greater mean flexural strength (170 ± 5.4 vs 171.7 ± 14.8 MPa (mean ± SD)) and modulus (4.8 ± 0.2 vs 5.0 ± 0.3 GPa (mean ± SD)). Although the mechanical properties were not found to be significantly different (p > 0.05), PEEK_L_HA contained substantially larger hydroxyapatite inclusions (100-1000 µm) compared to HA_PEEK (50-200 µm), due to the inherently agglomerative nature of the covalently bonded hydroxyapatite and poly(ether ether ketone) additive. Larger inclusions would expectedly weaken the HA_L_PEEK composite; however, there is no significant difference between the flexural modulus of poly(ether ether ketone) with respect to HA_L_PEEK (p = 0.13). In addition, the flexural modulus of HA_PEEK is significantly lower compared to poly(ether ether ketone) (p = 0.03). Ultimately, covalent linking reduces hydroxyapatite particulate de-bonding from the polymeric matrix and inhibits micro-crack development, culminating in enhanced transfer of stiffness between hydroxyapatite and poly(ether ether ketone) under loading.

中文翻译：

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共价键合羟基磷灰石和聚（醚醚酮）复合材料的配制。

脊柱融合装置可以由基于羟基磷灰石和聚醚醚酮相组合的复合材料制成。这些植入物充当承载支架，用于在相邻椎骨之间形成新骨组织。在这项工作中，我们报告了一种共价键合羟基磷灰石和聚醚醚酮的新方法，以生产具有增强的相间界面粘附力的新型复合配方。与非连接复合材料 (HA_PEEK) 相比，负载 1.25 vol% 羟基磷灰石的共价连接复合材料 (HA_L_PEEK) 具有更高的平均弯曲强度（170 ± 5.4 vs 171.7 ± 14.8 MPa（平均值 ± SD））和模量（4.8 ± 0.2 与 5.0 ± 0.3 GPa（平均值 ± 标准差））。尽管机械性能未发现显着差异 (p > 0.05)，但由于共价键合羟基磷灰石固有的团聚性质，与 HA_PEEK (50-200 µm) 相比，PEEK_L_HA 含有更大的羟基磷灰石夹杂物 (100-1000 µm)和聚醚醚酮添加剂。较大的夹杂物预计会削弱 HA_L_PEEK 复合材料的强度；然而，聚醚醚酮的弯曲模量与 HA_L_PEEK 之间没有显着差异 (p = 0.13)。此外，HA_PEEK 的弯曲模量明显低于聚醚醚酮 (p = 0.03)。最终，共价连接减少了羟基磷灰石颗粒从聚合物基体上的脱离，并抑制了微裂纹的发展，最终增强了负载下羟基磷灰石和聚醚醚酮之间的刚度传递。