三元无规芳—脂族聚酯酰胺的热致液晶行为

采用低湿溶液缩聚的方法合成了对苯二甲酰氯，二甲基联苯胺和己二醇为单体的芳酯族液晶聚酯酰胺。用ＤＳＣ，Ｘ光衍射分析和偏光显微镜等手段研究了该系列聚酯酰胺的热致液晶行为，确认了二甲基联苯胺单体用量在２０％（ｍｏｌ）的情况下，所得聚酯酰胺仍为向列型液晶聚合物。由于聚酯酰胺分子间聚酰胺链段之间的氢键作用，随着二甲基联苯胺用量增加至６０ｍｏｌ％时，所得的聚酯酰胺己无液晶转变温度，其液晶区间即从熔融温度直至分     

由脂肪族二酰胺二醇合成聚酯酰胺及表征

利用脂肪族二元酸酯与乙醇胺反应容易获得的对称二酰胺二醇,经缩聚合成聚酯酰胺预聚体,并针对端羧基和端羟基同时扩链来提高分子量,获得可生物降解的聚酯酰胺.首先将N,N′-二(2-羟乙基)草酰胺(HEOA)或N,N′-二(2-羟乙基)己二酰胺(HEHA)与己二酸和丁二醇缩聚,制备同时带有端羧基及端羟基的脂肪族聚酯酰胺预聚体,通过1,4-双(2-噁唑啉)苯及己二酰双己内酰胺混合扩链剂扩链,获得高分子量脂肪族聚酯酰胺,并通过红外、1H-NMR、DSC及TGA对其结构和热性能进行了表征.结果表明,预聚体在制备过程发生了一定的酯-酰胺交换反应;扩链后聚合物的熔点、熔融焓和热稳定性有所下降;但热稳定性仍接近或略高于聚己二酸丁二酯.     

一种合成聚酰胺,羟基聚酰胺和聚酯的新方法

本文研究了四氢噻唑-2-硫酮(TTT)双活泼酰胺与胺的N-酰基化反应,与醇的O-酰基化反应及与羟胺的选择性N-酰基化反应。以四氢噻唑-2-硫酮的双活泼酰胺作为双功能团单体,合成了一系列聚酰胺、羟基聚酰胺和聚酯化合物。对所合成化合物的结构用IR、NMR和元素分析方法进行了验证,测定了聚合物的比浓粘度。     

聚酯酰胺的合成

聚（酯酰胺）（PEA）的主链中同时具有酯键和酰胺键,兼具了聚酯（polyester）的生物降解性和相容性以及聚酰胺（polyamide）优异的机械性能,在药物控释、组织工程以及热塑性弹性体等领域应用广泛。缩合聚合是合成聚酯酰胺最初的方法,近年来开环聚合（ROP）成为制备聚酯酰胺的主要策略,本文从环状单体均聚、环状单体共聚、环状单体和线形单体共聚等方面总结了聚酯酰胺合成的研究进展。同时,介绍了基于多组分聚合反应（MCP）的新合成方法,并对聚酯酰胺材料的发展进行了探讨和展望。     

新型脂肪族酯和磷酸酯共聚物的合成与表征

为了优化脂肪族聚酯和聚磷酸酯在药物控释及基因治疗领域的性能, 以己二酰氯、二氯磷酸乙酯和二缩三乙二醇为原料, 用共缩聚的方法合成了一类新型脂肪族酯和磷酸酯的共聚物. 运用1H NMR, IR对共聚物的结构进行了表征; 利用MALDI-TOF MS测定了共聚物的分子量; 研究了反应时间、投料顺序、溶剂、反应温度和缚酸剂对聚合反应的影响; 通过动态接触角的测定, 探讨了此类聚合物的亲疏水性能; 以中性红为模型药物, 研究了该类聚合物的药物缓释性能.     

生物降解高分子——一类重要的生物材料 1．脂肪族聚酯的本体改性

生物降解高分子作为一类重要的生物医用材料而被广受关注;脂肪族聚酯则因所具的许多优良性能而更已成为研究和应用最多的一类生物降解高分子。本文通过78篇参考文献,回顾和小结了化学研究所为改进脂肪族均聚酯亲水性、降解速率、生物相容性等方面所存在的缺陷而开展的本体改性工作。文中报道了采用共聚和共混改性而形成的新脂肪族聚酯高分子,...     

由对苯二甲酰胺二醇合成聚酯酰胺及其扩链反应的研究

以N,N′-二(2-羟乙基)对苯二甲酰胺与己二酸及丁二醇缩聚,合成了同时带有端羧基与端羟基的聚酯酰胺预聚体,研究了不同扩链剂的扩链反应,获得了特性黏度达1.05 dL/g的聚酯酰胺.对预聚体及扩链后聚合物进行了红外与核磁表征,研究了聚合物的结构,并对聚合物进行了DSC与TG分析.     

氨基酸衍生可生物降解聚酯酰胺的合成与表征

以L-酪氨酸、乙二醇与4种不同的二酸酰氯为起始材料合成了4种具有酚羟基侧链的聚酯酰胺.用FT-IR、NMR表征了聚酯酰胺的化学结构;DSC、TG分析了聚合物的热性质;乌氏黏度计法测算了合成聚合物的特性黏度值,研究了聚酯酰胺的亲水性与主链结构的关系.结果表明:合成了预期结构的聚合物,该聚合物的玻璃化温度较低,而热分解温度较高,具有较好的热处理性能.同时,随着主链中柔性链段增加,玻璃化温度与热分解温度随之降低,热稳定性变差,在相同时间的吸水率明显提高.     

开环可控聚合制备脂肪族聚酯的最新研究进展

近年来,作为生物降解高分子材料,脂肪族聚酯由于良好的生物降解性及生物相容性受到人们的广泛关注。脂肪族聚酯在环境友好材料和生物医用材料领域都具有极大的应用价值,目前,部分聚酯材料已经商品化。与此同时,脂肪族聚酯的合成方法尤其是活性开环聚合也成为学术界及工业领域的研究热点。采用开环聚合法得到的聚合产物化学组成精确、分子量分...     

生物降解高分子——一类重要的生物材料 2.生物相容性及脂肪族聚酯的表面改性

脂肪族聚酯是一类越来越受到关注的生物可降解生物材料。由于所有的医疗和药物制品在临床应用时都将不同程度地同机体组织或血液接触,而其表面又将是首先与机体组织或血液接触的部分,因此脂肪族聚酯医用制品的表面生物相容性更是同制品生物安全性和有效性有直接关系的性质。本文在分析脂肪族聚酯自身特性及对其制品表面生物相容性影响因素的基础上,介绍了采用物理、化学和等离子体处理方法对脂肪族聚酯制品表面生物相容性的改进。在分析和讨论各表面改性方法优点的同时,也指出了该法所存在的缺点、不足和应用的局限性。从而可为提高具体的脂肪族聚酯医用制品的表面生物相容性提供可供选择的表面改性方法。     

A New Zirconocene Complex and Its Catalytic Properties for Olefin Polymerization

As metallocene olefin polymerization catalysts,unbridged metallocenecomplexeshave re-ceived much attention because they are relatively easy to be synthesized and can produce notonly polyethylene butalso oligo-or polypropylenes with differentstereoregularities and prop-erties depending on their structures[1 ,2 ] .It has been known that a rather small structuralchange for a metallocene compound may cause a remarkable effect on its catalytic properties,such as catalytic activity,polymer molecule w…     

Two-dimensional NMR spectra of poly(N-vinylcarbazole)

Two-dimensional NMR spectra of commercially available poly(N-vinylcarabazole) are presented and analyzed. Complete assignments for the aromatic region of the carbon spectrum are made using the edited spectrum and literature references for model compounds. The proton spectrum is assigned from its correlations with the carbon spectrum and with a J-correlated two-dimensional spectrum. One of the protons (number 1) is shifted to rather unusual high fields by the stacked structure of the carbazole rings, independent on the polymer tacticity. From the aliphatic carbon spectrum a meso probability of 0.45 is estimated for the commercial polymer, and another J-correlated two-dimensional spectrum helps assigning the triad and tetrad splittings in the aliphatic proton spectrum.     

Physico-chemical analysis of semi-crystalline PEEK in aliphatic and aromatic solvents

Polyether ether ketone (PEEK) is a semi-crystalline thermoplastic polymer having excellent mechanical and thermal properties. Exposure of this polymer to aliphatic and aromatic solvents can lead to degradation or swelling of the polymeric material. The present work described the plasticization and stability analysis of semi-crystalline PEEK under different aromatic and aliphatic solvent environment. A variety of solvents (acetone, benzene, benzyl alcohol, chloroform, methanol, and toluene), based on their Hildebrand’s Solubility Parameter, were chosen for investigation. The physico-chemical characteristics of virgin and treated polymeric samples were investigated using Gas Chromatography–Mass Spectrometry (GC–MS), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Fourier Transform Infrared Spectroscopy (FTIR) techniques. The results indicated that the solvent exposure did not significantly affect the thermal behavior and chemical structure of the polymer. However, it seems that certain components of the polymer were leached into the solvent phase as revealed by the GC–MS analysis. The present study identified PEEK as a potentially suitable polymer for the applications where high resistance to aliphatic and aromatic solvents is needed.     

Organogel formation by coaggregation of adaptable amidocarbamates and their tetraamide analogues

Mixtures of derivatives of Hanabusa's bolaamphiphilic amidocarbamates containing two Z-valinyl subunits and aliphatic spacers that range from ethylenic to octamethylenic are able to form organogels. A coassembly of them is observed in their acetonitrile and toluene gels; namely, the concentration of a given compound at which a gel is formed is lowered by the presence of equimolar quantities of any other compound in the series. The aggregates were studied by wide-angle X-ray diffraction (WAXD) and the results can be rationalized if the gel fibers are formed by supramolecular copolymers. NMR studies reveal that in solution these molecules adopt folded conformations containing intramolecular H-bonds, but IR studies indicate that these are not present in their aggregates. Additionally, analogues of the amidocarbamates obtained by replacement of the carbamate functionality by amide have been shown to behave in a similar way. For these molecules it can be shown that the central aliphatic subunit is not completely extended in the conformations present in the aggregates according to IR and WAXD studies. The tetraamide-type compounds described are robust organogelators that form gels in a variety of organic solvents with good thermostability and present improved feasibility for the synthesis of envisaged functional organogelators.     

脂肪族聚碳酸酯及其在医学中的应用

脂肪族聚碳酸酯具有优良的生物降解性、生物相容性和可功能化性等特点,近十几年来在生物医学领域得到了迅速发展。结合本实验室对生物可降解脂肪族聚碳酸酯的研究工作以及国内外研究现状,根据高分子链的几何形状对脂肪族聚碳酸酯进行了分类介绍,综述了它们的合成方法及其在生物医学领域中的应用,同时展望了脂肪族聚碳酸酯的未来发展趋势。     

Aliphatic polyester polymer stars: synthesis, properties and applications in biomedicine and nanotechnology

A critical review: the ring-opening polymerization of cyclic esters provides access to an array of biodegradable, bioassimilable and renewable polymeric materials. Building these aliphatic polyester polymers into larger macromolecular frameworks provides further control over polymer characteristics and opens up unique applications. Polymer stars, where multiple arms radiate from a single core molecule, have found particular utility in the areas of drug delivery and nanotechnology. A challenge in this field is in understanding the impact of altering synthetic variables on polymer properties. We review the synthesis and characterization of aliphatic polyester polymer stars, focusing on polymers originating from lactide, ε-caprolactone, glycolide, β-butyrolactone and trimethylene carbonate monomers and their copolymers including coverage of polyester miktoarm star copolymers. These macromolecular materials are further categorized by core molecules, catalysts employed, self-assembly and degradation properties and the resulting fields of application (262 references).     

The effect of flexibility on the photodegradation of aromatic diisocyanate-based polyurethanes

The photolytic degradation of 2,4-TDI/aliphatic diol polyurethanes is directly dependent on the flexibility of the polymer backbone. The extent of photodegradation is accelerated above the glass transition temperature, indicating the role of chain flexibility and/or oxygen diffusion in the decomposition process. Photolysis of the model compound ethyl N-phenylcarbamate (EPC) in neutral host polymer matrices indicates that the para photo-Fries to ortho photo-Fries product ratio experiences an accelerated increase with temperature above the glass transition of the polymer matrix.     

单分散大粒径聚合物微球的合成及应用

单分散，大粒径聚合物微球是近２０年来开发的一类球形高分子粒子，在标准计量、情报信息、化学化工、医学免疫及生物化学等许多领域里有着广阔的应用前景，其合成和应用在高分子科学领域里已成为人们致力于研究和开发的热门课题。     

Thermoreversible gelation of poly(vinylidene fluoride) in phthalates: the influence of aliphatic chain length of solvents

Thermoreversible gelation of poly(vinylidene fluoride) (PVDF) has been studied in a new series of solvents (phthalates), for example, dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), and dihexyl phthalate (DHP) as a function of temperature and polymer concentration, both by test tube tilting and dynamic light scattering (DLS) method. The effect of aliphatic chain length (n) of diesters on the gelation kinetics, structure/microstructure and morphology of PVDF gels has been examined. Gelation rate was found to increase with increasing aliphatic chain length of diester. DLS results indicate that the sol-gel transformation proceeds via two-steps: first, microgel domains were formed, and then the infinite three-dimensional (3D) network is established by connecting microgels through polymer chains. The crystallites are responsible for 3D network for gelation in phthalates, and alpha-polymorph is formed during gelation producing higher amount of crystallinity with increasing aliphatic chain length of diester. Morphology of the networks of dried gels in different phthalates showed that fibril thickness and lateral dimensions decrease with higher homologues of phthalates. The scattering intensity is fitted with Debye-Bueche model in small-angle neutron scattering and suggested that both the correlation length and interlamellar spacing increases with n. A model has been proposed, based on electronic structure calculations, to explain the conformation of PVDF chain in presence of various phthalates and their complexes, which offer the cause of higher gelation rate for longer aliphatic chain length.     

Structural aspects in polymers: interconnections between conformational parameters of the polymers with their physical properties

This article focuses on the influence of the geometric structure of the polymer chain on the physical properties of polymers. It is shown that for polyheteroarylenes the Kuhn segment calculated based on the geometric structure of the polymer chain has a good correlation with the physical properties of those polymers. For aliphatic polymers, a volume factor is suggested that equals the ratio of the Van der Waals volume of pendant substitute to the volume of the whole polymer chain. It is shown that the properties of aliphatic polymers that depend on free volume are well described by this value.