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.     

可生物降解聚氨酯在医学中的应用

可生物降解型聚氨酯材料具有良好的生物相容性,机械强度好,易加工等特点,在医学中具有十分广泛的应用.综述了可生物降解型聚氨酯材料在医学上的应用、研究进展,并对聚氨酯的组织相容性、血液相容性及降解性能进行了讨论.     

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.     

聚氨酯/沸石杂化材料的制备及性能

首次提出聚氨酯／沸石型有机-无机杂化的新模式，并选用表面富合活泼羟基且合有微孔直径大于0．7nm的沸石分子筛，制备出聚氨酯／沸石分子筛新型杂化材料。结果表明，其性能远优于纯聚氨酯的性能，与聚氨酯／有机蒙脱土纳米复合材料的力学性能和耐热性能相近，但耐溶剂性能和回弹性能优于前者。XRD分析表明分子筛在杂化材料中保持原状，FT—IR证实TDI能够与沸石分子筛表面的硅羟基进行接枝反应。     

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.     

分散法合成树枝状超支化聚酯及其表征

以三羟甲基丙烷、邻苯二甲酸酐和环氧丙醇为原料,探索了发散法合成末端含大量羧基和羟基的第一代、第二代树枝状超支化聚酯,并且通过测定分析研究了合成条件及性能.这种树枝状超支化聚酯具有可控的精确结构,大量分子末端基团易于改性,粘度低,热稳定性好,是一种性能优良的高分子材料,在光固化涂层和粘合剂等领域具有广阔的应用前景.     

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。     

羟基磷灰石/聚醚酯聚氨酯支架的体外降解行为和细胞相容性研究

采用XRD、DSC、体外降解实验和细胞相容性实验等方法对羟基磷灰石/聚醚酯聚氨酯(HA/PU)多孔支架的结构和性能进行了研究。结果表明,HA粒子添加到聚醚酯聚氨酯基体中,在一定程度上降低了聚氨酯软段的结晶,提高了聚氨酯基体的力学性能。体外降解实验表明HA/PU复合支架的降解不会引起浸泡液pH值较大的波动,且降解初期的力学性能衰减缓慢。MG63细胞与HA/PU复合支架共培养的实验表明,细胞生长良好,牢固地黏附在支架表面,并在支架表面充分伸展,复合支架具有良好的细胞相容性。这些结果表明HA/PU支架有望用于骨组织工程修复。     

纳米羟基磷灰石/壳聚糖-硫酸软骨素复合材料的制备及其性能研究

采用共沉淀方法制备了纳米羟基磷灰石/壳聚糖-硫酸软骨素复合材料, 用XRD、 SEM、 EDS、 TGA及万能材料实验机等对材料性能进行了分析表征, 并观察了材料在模拟体液中培养后表面结构、 形态以及体系pH值的变化。结果表明: 纳米羟基磷灰石／壳聚糖-硫酸软骨素复合材料具有良好的力学性能, 对机体微环境影响微小、 表面矿化效果好,有良好的生物活性和生物相容性。当羟基磷灰石含量为50%时, 抗压强度为42.3MPa, 该复合材料可满足骨组织修复与替代的要求, 有望成为治疗骨缺损的承力替代物。      

超支化聚氨酯与线型聚氨酯共混物相容性及力学性能分子模拟

利用分子模拟软件Materials Studio(MS)4.3对超支化聚氨酯与线型聚氨酯共混物的相容性及力学性能进行了分子模拟,包括用MS4.3的Visualizer程序建立模型、Blends程序计算相容性参数、Amorphous Cell程序计算共混物力学性能。模拟得到:决定低代数超支化聚氨酯与线型聚氨酯共混物的相容性和力学性能的主要因素是超支化聚氨酯外端的修饰基团种类,乙酯作为修饰基团好于丁羟聚氨酯。低代数超支化聚氨酯易与短链线型聚氨酯相容。决定高代数超支化聚氨酯与线型聚氨酯共混物的相容性和力学性能的主要因素是超支化聚氨酯的代数,各种修饰基团的高代数超支化聚氨酯与线型聚氨酯的相容性都能得到改善,且力学性能提高。高代数超支化聚氨酯易与长链线型聚氨酯相容。     

超支化聚酯的非等温热分解动力学

利用热重(TG)分析技术研究了端羟基超支化聚酯(HBP)以及十八酸改性的超支化聚酯(MHBP)的热失重行为,运用Flynn-Wal-l Ozawa法和Coats-Redfern法对非等温热分解动力学数据进行了分析。结果表明,HBP的分解过程分为三个阶段,三个阶段的表观活化能分别为120.238 kJ/mol、149.775 kJ/mol、173.540 kJ/mol,指前因子分别为1.386×109min-1、1.341×109min-1、4.569×1012min-1;MHBP的分解过程仅有一个阶段,表观活化能和指前因子分别为204.275kJ/mol和2.417×1014min-1。超支化聚酯的热稳定性与其端基有关,十八酸改性的超支化聚酯由于长链烷烃具有结晶性,因而热稳定性优于端羟基超支化聚酯。     

含金刚烷聚合物的研究进展

含金刚烷聚合物在气体分离、液晶显示材料、通讯技术、微电子、生物医学等高新技术领域已显示出潜在用途。文中对以金刚烷衍生物为单体的聚合物的合成、结构与性能等方面的研究进展做了分析和评述,对这一领域的发展趋势进行了展望。     

Modifizierung organischer Konstruktionswerkstoffe für technische Anwendungen

Modification of Organic Engineering Materials for Technological Applications It is reported about experiments for synthesis of novel reactive, thermotropic, liquid‐crystalline polymers (LCPs) as well as about investigations concerning the use of these LCPs as a blend component for the production of modified polyamide and polyester fibres and their properties. These reactive LCPs are synthetically easy accessible p oly e ster i mid a nhydrides ( PEIA ) bearing lateral as well as terminal anhydride groups. The average number of anhydride groups is variable between 4 and 18. Molecular weights of 30 kg/mol up to 80 kg/mol could be obtained. During mixing of the reactive LC‐PEIAs with polyamide 6 [PA 6] or poly(ethylene terephthalate) [PET] in an extruder under melting conditions both components evidently react within some few minutes to form graft‐block‐copolymers containing on their backbone chains lateral and terminal polyamide respectively polyester blocks. These quickly occurring modification reactions are the base for the industrial application in form of a continuously arrangeable “reactive blending‐spinning‐drawing”‐process. Graft‐block‐copolymers synthesised by this way in the sense of “reactive blending” can be processed together with the corresponding adequate matrix material polyamide 6 or polyester into drawable filaments. After spinning and drawing under suitable conditions lc‐PEIA‐fibrils modified by molecules of the basic polymer with diameters of less than 500 nm are detectable in the resulting filaments. The desired “microphase distribution” of the PA‐modified respectively PET‐modified lc‐PEIA‐macromolecules as the reinforcing system components could be achieved. Moreover these graft‐block‐copolymers built by “reactive blending” in‐situ have a high thermodynamic compatibility because of their chemical similarity to the primary structure of the respective matrix materials resulting in a relatively high reinforcing effect. These both aspects as well as the proceeding orientation of the lc‐PEIA‐microphases by the filament drawing cause, though optimising processes are still remaining, a remarkable increase of the tensile strengths as well as clearly improved initial moduli at a simultaneously raised stretchability of the lc‐PEIA‐modified polyamide and polyester filaments. These effects could be achieved with PEIA‐amounts of lower than 5 percentages by weight .     

端基对超支化聚合物改性环氧树脂性能的影响

研究了分别具有羟端基和环氧端基的脂肪族超支化聚酯对双酚A环氧树脂/酸酐固化体系力学性能及热性能的影响,分析对比了两种不同端基超支化聚酯改性环氧树脂浇注体性能时机理上的差别。结果表明,在相同含量和代数时,具有环氧端基的超支化聚酯能更好地提高环氧树脂浇注体的力学性能,同时还使玻璃化转变温度有所提高。分析发现,这是由于环氧端基的存在使得超支化聚酯与树脂基体有很好的相容性,从而有利于形成合适的第二粒子分散相,表现出比羟端基超支化聚酯更好的改性效果。     

Study on Novel Polyester/Epoxy Powder Coatings for Energy Conservation

Thermosetting polyester/epoxy powder coatings have the advantages of solvent-free and pollution-free,however traditional thermosetting polyester/epoxy powder coatings cured at temperature between 180℃ to 200℃.It not only increased energy consumption but also negatively affected substrate sensitive to heat.Therefore,in this paper,a novel polyester/epoxy powder coatings were prepared by unsaturated polyester (UP) with groups cured at low temperatures synthesized by ourselves,and the effects of the synthesis of UP,the coating formulations and the curing system on the properties of the novel powder coatings were discussed.Meanwhile we tried to reduce the curing temperature and improve the storage stability of the coatings based on the excellent performances of the film to achieve energy conservation.     

聚砜—热致液晶嵌段共聚物的合成

针对聚砜—热致液晶聚合物 (PSF TLCP)共混体系相容性差的问题 ,在合成不同分子量羟基封端聚砜 (PSF -OH)低聚体的基础上 ,通过溶液缩聚反应 ,合成了以下 3类嵌段共聚物增容剂 :聚砜—对羟基苯甲酸 (PSF—PHB) ,聚砜—对苯二甲酸乙二醇酯 (PSF -PET)和聚砜—对苯二甲酸对苯二酚酯 (PSF—PHQT)。红外光谱和流变性分析表明 ,合成了具有预期结构的嵌段共聚物 ,并且所合成的嵌段共聚物包含了较长的聚酯链段。     

Asymmetrically functionalized gold nanoparticles organized in one-dimensional chains

Organized assembly remains a major challenge for optimizing and extending the application of nanoparticles. Here we report a simple method to assemble spherical gold nanoparticles (AuNPs) in one-dimensional (1D) chains. The chain-forming process takes advantage of asymmetrically functionalized AuNPs that serve as building blocks. The 1D AuNP chains were prepared by covalent attachment of spatially localized functional groups on the AuNPs to polymer backbone pendent groups. We demonstrate control of interparticle spacing and the preparation of 1D chains containing AuNPs of different sizes.     

合成方法对超支化聚酯/PP共混物流变性能和力学性能的影响

以三羟甲基丙烷为核、二羟甲基丙酸为单体,分别采用"一步法"和"准一步法"合成了1～5代脂肪族超支化聚酯(HBPE).以硬脂酸对聚酯进行了端基改性,并对两类改性后的HBPE与线型聚丙烯(PP)共混物的流变性和力学性能进行了比较.结果表明,3%HBPE的加入即可大幅度降低PP熔体的黏度,而准一步法比一步法合成的聚酯具有更好的改性效果.与纯PP相比,当共混物中准一步4代(pg4)政性聚酯的添加量为3%,拉伸强度几乎相同,但降低熔体黏度50%以上,伸长率提高14%.     

Dielectric and impedance spectroscopy studies on sisal fibre-reinforced polyester composite

Frequency and temperature dependence of dielectric constant (ε_r), dielectric loss (tanδ), ac conductivity (σ_ac) and complex impedance spectroscopy studies on cured polyester matrix and sisal fibre-reinforced polyester composites (SFRPC) have been investigated in the frequency range from 180 Hz to 1 MHz and temperature range from room temperature to 200 °C. The experimental results showed that with the incorporation of sisal fibre, the values of ε_r, tanδ and σ_ac are increased. It is also found that the values of ε_r and tanδ for both cured polyester matrix and SFRPC are decreased with increasing frequency, which indicates that the major contribution to the polarization may come from orientation polarization and interfacial polarization. The increasing value of ε_r with increasing temperature at a particular frequency is due to free motion of the dipole molecular chains within the cured polyester matrix and SFRPC at higher temperature.