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生物降解型脂肪族不饱和聚脂碳酸酯2.生物降解 总被引:4,自引:0,他引:4
土埋法显示脂肪族不饱和聚酯碳酸酯(AUPEC)有良好的生物降解活性,单位面积失重(WPA)为其生物降解性能的较好指标,土埋三个月,AUPEC的WPA可达55mg.cm ̄-2,失重达0.15质量分数,此外,实验表明生物降解主要在AUPEC的表面进行,聚合物的特性粘数、链结构、玻璃化转变温度及热分解温度不随聚合物的降解失重而变化。 相似文献
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PHB与PCL,PECL可生物降解高分子共混体系的研究 总被引:4,自引:0,他引:4
本文讨论了聚β-羟基丁酸酯/聚ε-己内酯(PHB/PCL)、聚β-羟基丁酸酯/聚ε-己内酯-聚乙二醇嵌段共聚物(PHB/PECL)共混体系的相容性、结晶性、形态结构及断裂表面形貌。PHB/PCL体系是不相容的,PHB、PCL的结晶度随共混组成而改变。SEM结果表明,PHB/PCL共混膜断裂表面呈韧性断裂特征,PHB的脆性得到改善,PHB/PECL,共混体系的相容性有所改善。 相似文献
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对应用于矫形外科的可生物降解高分子材料研究进展进行了评述 ,介绍了这些高分子材料的发展历史、分类、合成方法及应用 ,对今后可能的研究方向进行了展望。 相似文献
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可生物降解的医用高分子矫形材料 总被引:1,自引:0,他引:1
对应用于矫形外科的可生物降解高分子材料研究进展进行了评述,介绍了这些高分子材料的发展历史、分类、合成方法及应用,对今后可能的研究方向进行了展望。 相似文献
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具有形状记忆功能的高分子材料 总被引:11,自引:0,他引:11
本文综述了具有形状记忆功能的高分子材料的发展概况 ,分析了形状记忆高分子材料的记忆效应原理 ,并对交联聚烯烃、聚氨酯、聚酯等具有形状记忆功能的高分子材料的特性及应用进行了评价和探讨 ,同时对形状记忆高分子材料的发展前景进行了展望 相似文献
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Copper nanoparticles were synthesized by a convenient and rapid chemical reduction method in ambient condition using \(\hbox {Cu}(\hbox {NO}_{3})_{2}{\cdot } 3\hbox {H}_{2}\hbox {O}\) as a precursor, hydrazine hydrate as reducing agent and deionized water as solvent. The product was characterized by X-ray diffraction (XRD) patterns, field emission scanning electron microscopy, Fourier transform infrared spectroscopy and UV–Vis spectroscopy. However, agglomerated copper nanoparticles were obtained by this chemical reduction method. Hence, the effects of three polymers of polyvinyl pyrrolidone, polyethylene glycol (PEG) and starch as stabilizers on the size and size distribution of Cu nanoparticles were investigated. According to the results, smallest copper nanoparticles (30–50 nm) with a narrow size distribution were obtained using PEG as the stabilizing polymer. Zero-valent copper nanoparticles with high purity were obtained by this method and there was no peak related to the oxidized impurities such as CuO and \(\hbox {Cu}_{2}\hbox {O}\) in the XRD and UV–Vis studies, both in the presence and in the absence of stabilizer. On the other hand, by this method, zero-valent copper nanoparticles were obtained in the absence of any anti-oxidant agent and any inert gas flow. The effects of synthesis parameters including initial concentration of precursor, polymer concentration and the reaction temperature on the size and size distribution of copper nanoparticles were investigated using the UV–Vis analysis to determine the optimum synthesis conditions. 相似文献
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含氟聚合物纳米多孔纳米纤维膜的制备 总被引:1,自引:0,他引:1
采用"电纺-相分离-沥滤"方法制备了聚(偏氟乙烯-co-六氟丙烯)(PVDF-HFP)以及聚偏氟乙烯(PVDF)纳米多孔纳米纤维膜.首先,将PVDF-HFP或PVDF和致孔剂聚乙烯吡咯烷酮(PVP)混合电纺,得到共混物纳米纤维膜.然后,将纳米纤维膜在水中沥洗出共混物中的PVP,获得纳米多孔纳米纤维膜.用场发射扫描电子显微镜(FESEM)观察水洗前后纤维表面精细结构.结果表明,纳米多孔纳米纤维表面呈多孔结构,孔径数10 nm.PVP的分子量对水洗后纤维表面结构有明显影响.致孔剂含量不同获得的PVDF-HFP纳米多孔纤维膜力学性能相近. 相似文献
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C H Bamford I P Middleton K G Al-Lamee J Paprotny Y Satake 《Bulletin of Materials Science》1989,12(1):3-15
This paper is concerned with the activation of platelets by polymers, a key-process in the behaviour of prosthetic devices
in contact with blood.
Platelets are activated by contact with many different types of polymer surfaces, which must therefore be regarded as thrombogenic.
Two procedures for reducing thrombogenicity are discussed: (i) the chemical attachment of inhibitors of platelet aggregation
and (ii) gross modification of the nature of the surface, e.g. by making it more hydrophilic. For purposes of (i) the potent
prostaglandin analogue BW 245C has been used, while for (ii) grafting of poly(ethylene glycol) (PEG) has been explored. Both
methods give greatly reduced platelet adhesion inin vitro tests.
The second part of the paper deals with the properties of adducts of inhibitors of platelet aggregation (BW 245C, dipyridamole)
with water-soluble macromolecules [poly(N-vinyl pyrrolidone), PEG, dextran]. Adducts have been synthesized with terminal and
side-chain coupling. On adduction the two inhibitors mentioned show opposite types of behaviour: the molar activity of BW
245C is dramatically reduced, but that of dipyridamole is significantly increased. Remarkable synergistic effects have been
recorded for BW 245C adducts. These observations are interpreted in terms of differences in stereochemistry in the drug-receptor
interactions.
Appropriate chemical techniques for coupling are outlined, attention being drawn to the special uses of haloalkyl- and haloacyl-isocyanates
and 2-isocyanatoethyl methacrylate as reagents. 相似文献
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以杂萘联苯聚芳醚酰胺(PPEA)为膜材料,N,N-二甲基乙酰胺(DMAc)为溶剂通过相转化法制备超滤膜.研究了PPEA浓度、添加剂种类和用量对膜结构和性能的影响.结果表明,PPEA浓度提高,膜孔结构由宽的指状孔向海绵孔转变,膜表层致密化,膜的水通量降低而截留率提高;添加剂乙二醇甲醚(EG-ME)含量增加,膜孔结构趋于疏松,通量上升,截留率先有增加后下降;添加剂乙醚则使膜表面更致密.EGME含量10%时,膜的通量达到480L/(m2·h)左右,对聚乙二醇(PEG)10000截留率约93%;乙醚含量10%时,对PEG6000的截留率达到100%,而通量降低至56L/(mg·h)左右. 相似文献
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以丁二酸、丁二醇、1,6-己二胺为原料,二丁基二月桂酸锡为催化剂,甲苯二异氰酸酯(TDI)为扩链剂,通过熔融共聚,合成了Mw为40~65 k的聚丁二酸-丁二醇-1,6-己二胺共聚物,并采用压延成膜法制得聚酯酰胺薄膜。研究了1,6-己二胺含量对聚酯酰胺的热性能、结晶性能、降解性能和流变性能的影响。结果表明,合成了聚酯酰胺,其熔点达到100.97℃,热分解温度为317.85℃;随着1,6-己二胺添加量增加,聚酯酰胺的拉伸强度不断变大,断裂伸长率略有下降;1,6-己二胺的加入并未改变聚酯酰胺的晶型,但降低了其结晶度;1,6-己二胺的加入提高了聚酯酰胺降解性能,而且改善了其流变性能,这有利于聚酯酰胺的成型加工和应用。 相似文献
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D Ratna M Patri B C Chakraborty C Madhavan P C Deb 《Bulletin of Materials Science》1995,18(8):1013-1019
Synthesis of carboxyl terminated poly (ethylene glycol adipate) (CTPA) and amine terminated poly(amide sulfone) (PS) based
on the CTPA and an aromatic diamine has been described. The products were characterized by13C NMR and IR spectroscopic analysis, nonaqueous titration, viscosity measurement and solubility characteristic studies. Effect
of incorporation of the developed PS on epoxy matrix was studied. Epoxy-PS blends were evaluated with respect to their thermal
and dynamic mechanical properties.
Paper presented at the poster session of MRSI AGM VI, Kharagpur, 1995 相似文献
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聚乳酸(PLA)是一种新型的生物基可再生生物降解材料,因具有高机械强度、易加工性、高熔点、可生物降解性和生物相容性等优点而得到广泛的关注。然而,其固有的脆性,即低断裂伸长率和断裂强度严重限制了它在实际中的应用,但也因此吸引了更广泛的深入研究。本文综述了以生物可降解高分子增韧聚乳酸的研究进展,重点阐述了生物基聚酯,生物基弹性体,植物基生物高分子,天然橡胶和植物油以及生物大分子增韧聚乳酸的最新研究发展概况,同时提出了在经过改善韧性之后,聚乳酸存在的冲击韧性弱以及低结晶速率和低热转变温度等问题,并分析了未来的发展方向和需要关注的主题。 相似文献
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通过浓硫酸(95%~98%)和聚醚醚酮(PEEK)制备了磺化度为84%的磺化聚醚醚酮(SPEEK)。以去离子水、N,N-二甲基甲酰胺(DMF)和N-甲基吡咯烷酮(NMP)为溶剂,分别制备了SPEEK-H2O、SPEEK-DMF以及SPEEK-NMP三种薄膜。采用万能材料试验机和扫描电镜(SEM)对比分析了成膜溶剂对SPEEK薄膜力学性能以及拉伸断面微观结构的影响。结果表明,成膜溶剂对薄膜力学性能和拉伸断面微观结构有明显影响。相同条件下,SPEEK-NMP薄膜具有最高的拉伸强度和弹性模量,拉伸断面凸凹程度最大。 相似文献
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以杂萘联苯聚芳醚酰胺(PPEA)为膜材料,N,N-二甲基乙酰胺(DMAc)为溶剂通过相转化法制备超滤膜.研究了添加剂种类,制膜过程中停留蒸发时间及凝胶浴温度对膜性能的影响.将PPEA超滤膜应用于硫化染料含盐粗产物水溶液的脱盐实验,膜的通量随操作压力或温度提高明显增加,而对染料的截留率保持在100%.在0.3MPa,80℃下经过3个循环约210min的恒容脱盐实验,染料溶液中的盐即可除净.在6h 5个循环的染料脱盐实验中,膜对染料的截留率基本不变,第五循环的初始通量约为260L/(m2·h),仅比第一循环时降低约10L/(m2·h). 相似文献