醇化改性蓖麻油基聚氨酯/n-HA复合支架材料的结构及力学性能

有机/无机材料的两相界面作用和均匀复合是影响复合支架材料性能的主要因素。本研究通过工艺改进, 对聚氨酯软段成分进行改性得到醇化蓖麻油, 经原位聚合发泡制备出多孔复合支架, 较好地实现了纳米羟基磷灰石(n-HA)颗粒的均匀分散。结果表明, 改性聚氨酯基体有效增加了羟基值, 其与极性n-HA两相界面复合良好, 无明显界面分相和颗粒团聚发生。支架孔径分布均匀, 但支架材料的孔隙率、孔径大小和结晶度略有减小。红外光谱和X射线衍射分析表明, n-HA和醇化蓖麻油基聚氨酯基体的分子间存在丰富的氢键和化学键, 促进了无机-有机相的相容性和稳定性。醇化改性和纳米无机粒子添加对材料性能的协同作用有效改善了支架的力学性能, 复合支架的压缩强度和模量均大幅增长。该种n-HA/聚氨酯复合支架有望用于进一步的骨再生和骨组织工程研究。

Structural and Mechanical Properties of Composite Scaffolds Based on Nano-hydroxyapatite and Polyurethane of Alcoholized Castor Oil

The interfacial interaction between two phases and homogeneous dispersion of inorganic phase in the organic matrix are critical factors for composite scaffolds with good structure and properties. Based on the modified soft-segment (alcoholized castor oil, ACO) of polyurethane (PU) and nano-hydroxyapatite (n-HA), porous n-HA/PU composite scaffolds were fabricated with in situ foaming method by controlling the process technology in this study. The results demonstrate that there exists good interfacial interaction between PU polymer matrix and polar n-HA due to increased hydroxyl number of modified polyurethane. Moreover, the n-HA filler can homogeneously disperse among the matrix and the miscibility is also dramatically improved. The micropore size of scaffolds is uniform, while the porosity, pore sizes and crystallinity are slightly decreased. FTIR and XRD analyses reveal that there are a large amount of hydrogen bond and chemical linkages between n-HA and ACO-PU matrix, which enhance the miscibility and stability of organic and inorganic phases. Correspondingly, the compressive strength and compressive modulus of scaffolds are significantly improved by alcoholized polyurethane and the uniformly dispersed n-HA particles. The nanocomposite scaffold can be used for further researches on regenerative medicine and bone tissue engineering.