生物羟基磷灰石的合成

综述了生物羟基磷灰石合成研究的最新进展，重点介绍和评述了羟基磷灰石的合成与制备方法，讨论了各种方法的特点和应用前景。最新的研究动态表明，羟基磷灰石研究从基本的化学反应合成向生物矿化与新生骨引导机理及硬组织再造技术方向发展。同时，羟基磷灰石在金属、陶瓷等植入体表面的涂层、以及天然材料制备羟基磷灰石依然是其合成研究的主要方向。     

亲水性聚氨酯复合材料的体外降解性和细胞相容性

采用摇床法和体外细胞培养法对亲水性羟基磷灰石/聚氨酯(HA/PU)纳米复合材料的体外降解性和体外细胞相容性进行了评估。结果表明:HA/PU纳米复合材料在磷酸缓冲溶液中浸泡不同时间后,材料发生了不同程度的降解。纳米HA含量对复合材料的降解性有一定影响,纳米HA含量较高的复合材料表现出较缓的降解速率。体外细胞相容性实验表明,MG63细胞在纯PU上成球型,抱团生长;而MG63细胞在HA/PU复合材料上生长良好,牢固地黏附在表面,并借助伪足在材料表面充分伸展,这说明HA/PU复合材料为细胞的黏附、增殖以及生存活力的维持提供了有利的环境。这些结果表明该HA/PU纳米复合材料有望用于骨组织工程修复。     

磷酰胆碱共聚物(MPC-co-EHMA)的合成及对聚氨酯膜的生物相容性影响

2-甲基丙烯酰氧乙基磷酰胆碱(MPC)与甲基丙烯酸异辛酯(EHMA)通过自由基聚合制备共聚物PMEH20,并将PMEH20添加到基材聚氨酯中制备了共混膜。牛血清蛋白(BSA)吸附性测试显示当PMEH20质量分数为15%时,BSA吸附量比空白聚氨酯下降了81.7%;血小板粘附性能测试显示,含有PMEH20的聚氨酯共混膜粘附了更少的血小板;动态水接触角测试发现共混膜中磷酰胆碱基团可以通过翻转重排于薄膜表面;薄膜力学性能测试显示,在PMEH20质量分数达到10%时,膜材料的综合力学性能最好。     

多代超支化聚氨酯的合成与表征

以六亚甲基二异氰酸酯(HDI)为A2型单体,二乙醇胺(DEOA)为CBx型单体,采用A2+CBx法,并结合逐步升温法和单体逐步加入法,用六氢吡啶法检测体系中的异氰酸根浓度,制备不同代数的超支化聚氨酯(HBPU)。利用红外光谱仪、核磁共振、旋转流变仪等对目标产物结构和性能进行表征。结果表明:通过该方法可以制得高支化度的多代超支化聚氨酯。     

聚氨酯人工血管的研究进展

聚氨酯由于其优良的机械性能和生物相容性而广泛应用于生物医用材料,如制作人工器官、药物释放载体及人工血管等.但是当它作为体内移植材料使用时会引起机体的炎症反应,并且与血液接触时还会引起持续的凝血和内膜增生.因此,要想将聚氨酯应用于人工血管,就要进一步提高它的生物相容性、血液相容性和细胞相容性等.目前主要是通过对聚氨酯进行本体改性、表面接枝聚合改性、等离子体处理聚氨酯表面、涂覆生物分子及结构设计等方法来提高其在体内使用时的性能.     

亲水性聚氨酯复合材料的制备与表征

选用湿态纳米羟基磷灰石（HA）与脂肪族聚氨酯（PU）为原料,采用溶液共混法和溶剂挥发法制备了亲水性羟基磷灰石/聚氨酯（HA/PU）纳米复合材料,并采用SEM、吸水实验和力学实验等方法对该复合材料的形貌和性能进行了研究。结果表明磷灰石晶体以纳米状态均匀地分布在PU基质中,过高含量的纳米HA易使纳米粒子团聚,不利于其在PU基体中的均匀分散;在制备PU的多元醇原料中引入亲水性较强的聚乙二醇,可提高PU表面和整体的亲水性;随着硬段含量的增加,复合材料的拉伸强度和弹性模量呈上升趋势,断裂伸长率下降;随着软段中聚乙二醇含量的升高,弹性模量大幅下降,拉伸强度和断裂伸长率先升高后下降;纳米HA的添加可同时提高复合材料的拉伸强度和断裂伸长率,当纳米HA的质量分数为30%时,复合材料的综合力学性能达到最佳。     

聚氨酯/纳米羟基磷灰石/聚酰胺66股骨髁修复犬骨软骨缺损的实验研究

制备了PU/n-HA/PA66股骨髁,用扫描电镜观察材料表面情况并测定其孔隙率;将PU/n-HA/PA66股骨髁与自体髁植入犬股骨远端,以替代、修复骨软骨缺损,进行大体观察、组织学、免疫组化、CT、血常规和生化检测以及肝、肾、脾组织学检测。结果表明材料孔隙率为80.89%±5.01%,孔径主要分布在300～800μm之间。术后实验动物活动正常,切口愈合良好,两组髁假体均与自体骨结合紧密,PU/n-HA/PA66股骨髁网孔中的骨小梁逐渐增多成熟,材料孔穴中的新生骨Ⅰ型胶原阳性表达。术后动物碱性磷酸酶水平升高[(62.67±24.04)U/L],肝、脾、肾HE染色未见异常。PU/n-HA/PA66股骨髁具有良好的骨修复、软骨替代能力和生物相容性,具有应用前景。     

生物聚氨酯/羟基磷灰石微相分离与形状记忆性能

形状记忆功能化生物聚氨酯在医用植入体材料中备受关注,而聚氨酯的形状记忆性能与其微相分离结构密切相关。文中以可降解聚己内酯二醇(PCL-diol)、脂环形异佛尔酮二异氰酸酯(IPDI)、1,4-丁二醇(BDO)为单体通过两步法合成生物聚氨酯(PU),以溶液共混的方式加入PU基体中,制备了一系列聚氨酯/羟基磷灰石(PU/HA)复合材料。通过场发射扫描电子显微镜、傅里叶变换红外光谱、热失重分析和动态力学热分析等不同表征方法研究了HA的引入对PU基体微相分离的影响,及其与宏观形状记忆性能的关系,并考察了材料的生物安全性。结果表明,HA的引入明显促进了PU的微相分离,随着HA含量的增加,硬段与软段的玻璃化转变温度差值越大,表明微相分离程度越高。在HA质量分数低于15%时,HA的含量越高,形状回复越快,表明微相分离程度越高,形状记忆性能越好。L929细胞毒性测试结果显示,PU/HA具有良好的细胞安全性,在医用骨修复领域有潜在的应用价值。     

钛合金表面涂覆羟基磷灰石的研究进展

在钛合金表面制备羟基磷灰石涂层既有良好的生物相容性又兼有良好的力学性能,作为硬组织替换材料得到了广泛的研究.总结了钛合金表面涂覆羟基磷灰石的生物相容性,详细讨论了羟基磷灰石涂层的制备方法,总结和展望了该生物涂层材料在医学中的应用所存在的问题和应用前景.     

聚氨酯表面性能对其生物相容性的影响

特殊的微相分离结构,赋予聚氨酯弹性体良好的稳定性、优异的力学性能以及较好的生物相容性,已被广泛应用于生物医学领域.但其生物相容性仍不够理想.由于材料的生物相容性与材料表面的性质密切相关,对材料表面进行改性成为改善相容性的重要方法和途径,其研究受到广泛关注.对聚氨酯进行改性的诸多方法中,在材料表面进行化学接枝生物活性物质以提高生物相容性的方法是目前研究的热点.本文在对聚氨酯进行改性以提高其生物相容性的各种方法和途径进行评述的基础上,对聚氨酯表面结构性能与生物相容性的关系进行讨论,并重点对该研究领域的最新进展进行总结.     

聚L-乳酸/聚丁二烯基聚氨酯的合成与表征

以乙二醇和L-乳酸熔融直接缩聚制备双端羟基聚L-乳酸预聚物(PLLA),并用1H、13C-NMR、DSC、XRD对PLLA结构和性能分析表征.以液化二苯基甲烷二异氰酸酯(MDI)为偶联剂,端羟基聚L-乳酸和端羟基聚丁二烯(HTPB)偶联反应制备橡胶改性聚乳酸基聚氨酯弹性体,并用FT-IR,1H、13C-NMR对聚合产物进行结构表征确认.DSC测试结果表明聚氨酯有聚丁二烯段和聚乳酸段两个玻璃化转变温度,熔融温度基本在130℃.随着聚丁二烯含量的增加,结晶衍射峰逐渐消失,聚氨酯的拉伸强度降低,断裂伸长率增加.断面扫描电镜结果显示聚氨酯呈微相分离结构和弹性断裂.     

多羟基醇类共溶剂对Mg/Al水滑石水热制备的影响

以Mg（NO3）2.6H2O为镁源、Al（NO3）3.9H2O为铝源,采用水热法制备Mg/Al水滑石。鉴于水滑石中广泛存在的氢键相互作用,以多羟基醇为共溶剂,对比分析了水、水/乙醇、水/乙二醇、水/丙三醇及水/季戊四醇等5种溶剂条件下水热合成得到的Mg/Al水滑石的结构和热性质。利用XRD、SEM、IR、DSC等的分析结果表明,随着共溶剂中醇羟基数目的增多,所得水滑石中结晶水的水合程度提高。共溶剂与水滑石之间水滑石,晶粒形貌类似于纯水得到的水滑石。而以水/丙三醇及水/季戊四醇为溶剂得到的水滑石,晶形变的不规则,且伴随着粒径尺寸变小和晶粒团聚现象。同时,随着共溶剂中醇羟基数目的增多,层间结合水的释放温度提高,而层间CO2脱除和基本层上的羟基脱水温度则相应降低。     

Synthesis,mechanical, thermal and chemical properties of polyurethanes based on cardanol

Cardanol, an excellent monomer for polymer production, has been isolated from CNSL and allowed to react with formaldehyde in a particular mole ratio in the presence of glutaric acid catalyst to give high-ortho novolac resin. Such characterized polyol has been condensed with diphenylmethane diisocyanate to produce rigid polyurethane. A commercially available polyol, polypropylene glycol-2000 (PPG-2000), has also been condensed with diphenylmethane diisocyanate and polyol to produce tough polyurethane. These polyurethanes were characterized with respect to their resistance to chemical reagents and mechanical properties such as tensile strength, percentage elongation, tear strength and hardness. Differential thermal analysis (DTA) and thermo-gravimetric analysis (TGA) were undertaken for thermal characterization.     

In vitro investigations of a novel wound dressing concept based on biodegradable polyurethane

Abstract

Non-healing and partially healing wounds are an important problem not only for the patient but also for the public health care system. Current treatment solutions are far from optimal regarding the chosen material properties as well as price and source. Biodegradable polyurethane (PUR) scaffolds have shown great promise for in vivo tissue engineering approaches, but accomplishment of the goal of scaffold degradation and new tissue formation developing in parallel has not been observed so far in skin wound repair. In this study, the mechanical properties and degradation behavior as well as the biocompatibility of a low-cost synthetic, pathogen-free, biocompatible and biodegradable extracellular matrix mimicking a PUR scaffold was evaluated in vitro. The novel PUR scaffolds were found to meet all the requirements for optimal scaffolds and wound dressings. These three-dimensional scaffolds are soft, highly porous, and form-stable and can be easily cut into any shape desired. All the material formulations investigated were found to be nontoxic. One formulation was able to be defined that supported both good fibroblast cell attachment and cell proliferation to colonize the scaffold. Tunable biodegradation velocity of the materials could be observed, and the results additionally indicated that calcium plays a crucial role in PUR degradation. Our results suggest that the PUR materials evaluated in this study are promising candidates for next-generation wound treatment systems and support the concept of using foam scaffolds for improved in vivo tissue engineering and regeneration.     

In vitro investigations of a novel wound dressing concept based on biodegradable polyurethane

Non-healing and partially healing wounds are an important problem not only for the patient but also for the public health care system. Current treatment solutions are far from optimal regarding the chosen material properties as well as price and source. Biodegradable polyurethane (PUR) scaffolds have shown great promise for in vivo tissue engineering approaches, but accomplishment of the goal of scaffold degradation and new tissue formation developing in parallel has not been observed so far in skin wound repair. In this study, the mechanical properties and degradation behavior as well as the biocompatibility of a low-cost synthetic, pathogen-free, biocompatible and biodegradable extracellular matrix mimicking a PUR scaffold was evaluated in vitro. The novel PUR scaffolds were found to meet all the requirements for optimal scaffolds and wound dressings. These three-dimensional scaffolds are soft, highly porous, and form-stable and can be easily cut into any shape desired. All the material formulations investigated were found to be nontoxic. One formulation was able to be defined that supported both good fibroblast cell attachment and cell proliferation to colonize the scaffold. Tunable biodegradation velocity of the materials could be observed, and the results additionally indicated that calcium plays a crucial role in PUR degradation. Our results suggest that the PUR materials evaluated in this study are promising candidates for next-generation wound treatment systems and support the concept of using foam scaffolds for improved in vivo tissue engineering and regeneration.     

Synthesis methods, chemical structures and phase structures of linear polyurethanes. Properties and applications of linear polyurethanes in polyurethane elastomers, copolymers and ionomers

Chemical and supermolecular structures occurring in linear polyurethanes were presented and they were referred to the analysis of the reactions connected with the step-growth polyaddition process of diisocyanates and polyols. Based on the general kinetic model of the step-growth polyaddition process, which is available in papers, inclusive of our own reports published on that subject, and based on experimental verification of that model by GPC chromatography and MALDI-ToF spectrometry, the influence was discussed of reactivity specifications of the diisocyanate and polyol monomers, and of intermediate products (urethane oligomers), on the size of molecules and on molecular weight distribution in linear polyurethane products. The applicability of such research methods as SAXS, SEM, AFM and DSC for the analysis of phase structures and micro-phase separation in the linear polyurethanes was presented. Also, the influence of phase separation on thermal and mechanical properties of the polyurethane products was addressed. Special attention was paid to the influence of polarity of polyurethane chemical structures, dispersion interactions, hydrogen bonding and ionic interactions on the value of free surface energy of polyurethane anionomers and cationomers. The effects on chemical and biological stability of those products were considered, too. Derived from the above analysis, the latest trends were provided for the applications of linear polyurethanes: as liquid crystalline materials, urethane-acrylic and polyurethane-siloxane copolymers in electronics, medicine and civil engineering, and as environmentally friendly elastomers in protective coatings produced from waterborne polyurethane dispersions.     

聚氨酯IPN阻尼材料研究进展

介绍了互穿聚合物网络(IPN)材料的阻尼机理及其表征方法,并重点综述了聚氨酯(PU)IPN材料的研究进展。     

Physical characterization of polyurethanes reinforced with the in situ-generated silica-polyphosphate nano-phase

A series (SPUN) of segmented polyurethanes reinforced with the in situ-generated sodium silica-polyphosphate nano-phase (SSP) was characterized by thermogravimetry, differential calorimetry, wide-angle and small-angle X-ray diffraction and stress–strain relationships.

Cross-over from the rubber-like to the solid-like mechanical behavior of the SPUN above the apparent percolation threshold w ≈ 40% was considered as evidence for the onset of the “infinite clusters” of SSP nano-domains spanning the entire volumes of initial (i.e., undeformed) samples. The infinite clusters of SSP nano-domains crossed over from the mass fractal-like to the surface fractal-like behavior at the composition-dependent, characteristic X-ray scattering vectors q*. A continuous nano-phase of the polyurethane coexisting with a continuous nano-phase (infinite cluster) of the SSP is likely to be expanded due to the “negative pressure” effect.