原位自发泡制备磷酸钙/聚氨酯复合骨修复支架

doi:10.15541/jim20150630

摘要/Abstract

摘要：

磷酸钙/聚氨酯(CaP/PU)复合骨修复支架制备过程中随着材料体系粘度逐渐增大, 后期加入的发泡剂难于均匀分散, 影响支架孔隙率及孔结构均匀性。本研究在CaP/PU材料合成过程中将发泡剂水以磷酸氢钙结晶水合物(DCPD)的形式均匀复合在材料中, 在一定条件下释放结晶水与聚氨酯(PU)中的异氰酸根反应生成CO₂, 实现自发泡成型。实验结果显示, 90 ℃条件下自发泡制备的CaP/PU支架孔隙率高、孔结构均匀、贯通性好。将90 ℃发泡成型的CaP/PU多孔支架在110 ℃再熟化处理, 可提高支架的力学性能高达1倍以上。该方法简便易行, 为聚氨酯基多孔支架的制备提供了新思路。

关键词: 磷酸氢钙, 聚氨酯, 骨修复, 支架, 自发泡

Abstract:

One of the main technical problems in preparation of calcium phosphate/polyurethane (CaP/PU) composite scaffold for bone repair is to obtain a porous structure with uniformly distributed pores. The reason for this is due to the heterogeneous dispersion of the added foaming agents within the composite resulting in the increasing viscosity of polymer precursor during the composite fabrication process. To solve this problem, we report a novel method through incorporation of calcium hydrogen phosphate (DCPD) with polymer phase to achieve a composite system in early period of the synthesis process of CaP/PU composite. The uniformly distributed crystal water from DCPD can be released when temperature reaches above 75 ℃ and serve as foaming agents to react with isocyanate group in the PU and generate CO₂ gas. The generation of gas leads to a self-foaming process and consequently induces CaP/PU composite to form a porous scaffold. Scanning electron microscopy (SEM) observations show that CaP/PU composite scaffolds with uniform porous structure, high porosity and interconnectivity were obtained at 90 ℃. The mechanical strength can be doubled by re-curing treatment for the scaffold at 110 ℃ for 24 h. The resulting CaP/PU composite scaffolds with uniformly porous structure, high porosity and interconnectivity have shown potential applications in bone tissue engineering. Moreover, this simple and efficient method may provide new approaches for the preparation of polyurethane- based porous scaffolds.

Key words: calcium hydrogen phosphate, polyurethane, bone repair, scaffold, self-foaming

中图分类号:

TB33

李根, 李炯炯, 李丽梅, 蒋佳兴, 李玉宝, 李吉东. 原位自发泡制备磷酸钙/聚氨酯复合骨修复支架[J]. 无机材料学报, 2016, 31(7): 719-725.

LI Gen, LI Jiong-Jiong, LI Li-Mei, JIANG Jia-Xing, LI Yu-Bao, LI Ji-Dong. Preparation of Calcium Phosphate/Polyurethane Composite Porous Scaffolds for Bone Repair by in situ Self-foaming Method[J]. Journal of Inorganic Materials, 2016, 31(7): 719-725.

图/表 10

表1 复合支架的编号及成分

Table 1 Abbreviation and composition of fabricated composite scaffolds

Samples	nHA percentage /wt%	DCPD percentage /wt%	PU percentage /wt%
DCPD/PU	0	30	70
nHA-DCPD/PU-1	15	15	70
nHA-DCPD/PU-2	20	10	70

图1 聚氨酯聚合反应示意图

Fig. 1 Synthetic scheme of polyurethane

图2 不同熟化发泡温度下制备的DCPD/PU复合多孔支架的SEM照片

Fig. 2 SEM micrographs of DCPD/PU composite porous scaffolds formed at different temperature(a) 80℃; (b) 90℃; (c) 100℃; (d) 110℃

图3 90℃熟化发泡制备的磷酸钙盐/聚氨酯(CaP/PU)多孔支架的SEM照片(a~c)及孔径分布图(d~f)

Fig. 3 SEM images (a-c) and pore size distribution (d-f) of CaP/PU porous scaffolds fabricated at 90 ℃ (a, d) DCPD/PU; (b, e) nHA-DCPD/PU-1; (c, f) nHA-DCPD/PU-2

表2 90 ℃发泡制备的DCPD/PU、nHA-DCPD/PU-1 和nHA-DCPD/PU-2支架的孔隙率和力学性能

Table 2 Porosity and mechanical properties of DCPD/PU, nHA-DCPD/PU-1 and nHA-DCPD/PU-2 composite scaffolds fabricated at 90 ℃

Composition	Porosity/%	Compressive strength/MPa	Compressive modulus/MPa
DCPD/PU	92.6±1.1	1.1±0.1	31.5±1.9
nHA-DCPD/PU-1	82.2±2.1	1.7±0.2	58.6±4.9
nHA-DCPD/PU-2	80.3±1.2	1.5±0.2	43.5±4.2

图4 90 ℃条件下制备的CaP/PU复合支架、nHA和DCPD粉末的XRD图谱

Fig. 4 XRD patterns of CaP/PU composite scaffolds fabricated at 90 ℃, nHA and DCPD powders

表3 90 ℃发泡制备的DCPD/PU、nHA-DCPD/PU-1 和nHA-DCPD/PU-2支架在110 ℃再熟化24 h后的力学性能

Table 3 Mechanical properties of DCPD/PU, nHA-DCPD/ PU-1 and nHA-DCPD/PU-2 composite scaffolds fabricated at 90 ℃ re-cured at 110 ℃ for 24 h

Composition	Compressive strength / MPa	Compressive modulus / MPa	Increase of compressive strength after re-curing / %
DCPD/PU	2±0.3	43.8±2.2	77
nHA-DCPD/PU-1	3.8±0.3	74.1±18.6	126
nHA-DCPD/PU-2	3.6±0.4	69.5±10.2	137

图5 90 ℃(a~c)发泡和发泡成型后在110 ℃(d~f)再熟化处理的CaP/PU复合支架的红外光谱图

Fig. 5 FT-IR spectra of CaP/PU composite scaffolds cured at 90 ℃ (a-c) and re-cured at 110 ℃ (d-f) (a, d) DCPD/PU; (b, e) nHA-DCPD/PU-1; (c, f) nHA-DCPD/PU-2

图6 90 ℃发泡和发泡成型后在110 ℃再熟化处理24 h的CaP/PU复合支架的TG曲线

Fig. 6 TG curve of CaP/PU composite scaffolds cured at 90 ℃ and re-cured at 110 ℃ for 24 h

表4 CaP/PU多孔复合支架的热分析结果

Table 4 Results of thermal analysis of CaP/PU composite scaffolds

	Onset decompositon temperature for samples cured at 90 ℃/℃	Onset decomposition temperature for samples recured at 110 ℃ for 24 h/℃
DCPD/PU	309.0	316
nHA-DCPD/ PU-1	310.0	321
nHA-DCPD/ PU-2	309.6	316

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