聚氨酯脲的表面组成及结构

用ＡＴＲ－ＦＴ－ＩＲ和ＸＰＳ研究了聚氨酯脲以及聚二甲硅氧烷改性聚氨酯脲的表面组成和结构,发现与空气接触面和与模板接触面含有的ＰＤＭＳ和聚四亚甲基醚软段浓度远远大于其体体浓度,并且与空气接面比与模板接触面含有更多的ＰＤＭＳ和ＰＴＭＯ段。将聚酯脲水合至３个星期,其表面组成和氢键未发生任何变化。     

含聚二甲基硅氧烷聚氨酯(脲)的研究进展

综述了聚二甲基硅氧烷聚氨酯（脲）的合成及类型，讨论了材料本体相态结构特点和表面性质，总结了提高本体相容性的途径和表面表征方法，简要介绍了其性能与应用。     

微相分离结构聚氨酯膜的丁醇/水体系渗透汽化分离

制备了端羟基聚丁二烯-聚氨酯（HTPB-PU）和端羟基聚丁二烯-乙烯基三乙氧基硅烷-聚氨酯（HTPB-VTES-PU）两种聚氨酯膜。采用傅立叶变换红外光谱（FT-IR）、差示扫描量热仪（DSC）和透射电镜（TEM）分析表征了两种膜的结构,结果发现,HTPB-PU有两个玻璃化转变温度,其膜具有一定程度的微相分离结构;HT...     

以聚六亚甲基碳酸酯二醇和聚四亚甲基醚二醇为基的聚氨酯的合成与性能

以聚六亚甲基碳酸酯二醇（ＰＨＭＣＤ）和聚四亚甲基醚二醇（ＰＴＭＥＧ）、４．４′一对二苯基甲烷二导氰酸酯（ＭＤＩ）及１．４－丁二醇（ＢＤＯ）合成线型聚碳酸酯聚氨酯．研究了其软段相的Ｔｇ、力学性能和流变特性．结果表明随ＰＨＭＣＤ含量增大，聚合物的拉伸强度增加，而熔体的表观粘度则降低     

HPB－b－PMMA增容PVC／PE共混物相分离与相态结构研究

以激光散射（ＬＳ）跟踪升温过程光散射强度变化的方法，研究了氢化聚丁二烯－聚甲基丙烯酸甲酯嵌段共聚物（ＨＰＢ－ｂ－ＰＭＭＡ）增容聚氯乙烯（ＰＶＣ）／聚乙烯（ＰＥ）共混物溶液浇铸膜相分离行为的特点，还以广角Ｘ光衍射（ＷＡＸＤ）测定了该膜的结晶状况，扫描电镜（ＳＥＭ）和相差显微镜（ＰＣＭ）观察、记录了表面相态结构。提出增容剂在此既有增容作用又有“协调链段活动”作用的看法。     

HPB—b—PMMA增容PVC／PE共混物相分离与相态结构研究

以激光散射（ＬＳ）跟踪升温过程光散射强度变化的方法，研究了氢化聚丁二烯－聚甲基丙烯酸甲酯嵌段共聚物（ＨＰＢ－ｂ－ＰＭＭＡ）增容聚氯乙烯（ＰＶＣ）／聚乙烯（ＰＥ）共混物溶液浇铸膜相分离行为的点，还以广角Ｘ光衍射（ＷＡＸＤ）（测定了该膜的结晶状况，扫描电（ＳＥＭ）和相差显微镜（ＰＣＭ）观察、记录了表面相态结构。提出增容剂在此既有增容作用又有“协调链段活动”作用的看法。     

聚硫聚氨酯(脲)的热稳定性

对一系列聚硫聚氨酯(脲)的热降解进行了研究,由异佛尔酮二异氰酸酯(IPDI)、甲苯二异氰酸酯(TDI)、液体聚硫橡胶(LP)以及2,5-二氨基-3,6-二甲硫基甲苯(E300)合成聚硫聚氨酯脲,用TG、DTA、ATR-IR等研究其热降解性能。结果表明,聚硫聚氨酯(脲)的降解分两个阶段。在200℃条件下老化一段时间后,聚硫聚氨酯仍保持大部分力学性能。     

球磨法制备α′-Fe(N)超细粉末

通过球磨α－ Ｆｅ 和脲的混合粉末，制得α′－ Ｆｅ（Ｎ） 超细粉末．使用Ｘ 射线衍射仪（ＸＲＤ） 、透射电镜（ＴＥＭ） 和热失重（ＴＧＡ） 分析了在真空条件下经１３０ ｈ 和２００ ｈ 球磨后的粉末样品的结构和性能．结果表明，经１３０ ｈ 球磨后开始得到α′－ Ｆｅ（Ｎ） 相；热分析表明，α′－ Ｆｅ（Ｎ） 相在４３０℃以下是稳定的；经球磨２００ ｈ 后，得到α′－ Ｆｅ（Ｎ） 超细粉末（０ ．０３～０ ．０６ μｍ） ，它是ｒ（Ｎ） 为１３ ．４９％ 的过饱和固溶体．     

高分子专利：水性聚氨酯脲做性纳米CaCO3有机-无机杂化材料的制备方法EI北大核心

本发明涉及水性聚氨酯脲（PUU）催溶胶改性纳米CaCO3杂化水分散液的制备方法。其制备特点在于,以粒径10-100nm的硅溶胶改性纳米CaCO3水分散液代替部分水,采用原位法直接对聚氨酯脲预聚体进行分散,从而得到高固含量（25—30％）的有机一无机杂化材料。该杂化材料在室温时具有很好的稳定性,且高固含量使其具有节能等优点。     

液化MDI基形状记忆聚氨酯软段组成的选择

以液化MDI和BDO（1,4-丁二醇）为硬段,分别以聚乙二醇（PEG）,聚己二酸乙二醇酯（PEAG）,聚己二酸丁二醇酯（PBAG）,聚己二酸己二醇酯（PHAG）,聚己内酯（PCL）为软段合成了聚氨酯形状记忆材料。通过FT—IR,DSC等考察了它们的结构,比较了聚乙二醇聚氨酯（EGPU）,聚己二酸乙二醇酯聚氨酯（EAPU）,聚己二酸丁二醇酯聚氨酯（BAPU）,聚己二酸己二醇酯聚氨酯（HAPU）及聚己内酯聚氨酯（CLPU）的形状记忆性能和力学性能,研究表明,PHAG是液化MDI基形状记忆聚氨酯软段的最佳原料。     

Preparation and Application of Amino- and Dextran-Modified Superparamagnetic Iron Oxide Nanoparticles

Amino-dextran-functionalized superparamagnetic iron oxide nanoparticles (SPION) were synthesized by two-steps: Dextran-modified SPION was obtained by “one-step” co-precipitation method. Then, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPS) was added to the resultant dextran-SPION to prepare amino-dextran-functionalized SPION (AEAPS/Dex-SPION). The particles were characterized by vibrating sample magnetometer (VSM), transmission electron micrographs (TEM), atomic force micrographs (AFM), gas chromatography and atomic absorption spectrophotometry. The size of the modified particles varied in a range of 30 to 40 nm and did not change significantly after modification. The binding rate of AEAPS was 91.15%. A monoclonal antibody against S100 (anti-S-100), a gold standard for the diagnosis of melanocytic lesions, was conjugated to the AEAPS/Dex-SPION to prepare immuno-SPION. From the result in melanoma B16 cell, the immuno-SPION was proven to have a bio-targeting activity. Such AEAPS/Dex-SPION might be very useful for bio-magnetically targeted detection in early melanocytic lesions.     

New chiral liquid crystalline monomers, polymers, and elastomers derived from menthol derivatives: synthesis and mesomorphism

To investigate liquid crystalline properties and structure relationships of chiral compounds based on menthol, a series of new chiral monomers derived from menthol derivatives, a mesogenic crosslinking agent, the corresponding side chain homopolymers with siloxane backbone, and cholesteric elastomers were synthesized. The structures and purity of these chiral compounds obtained in this study were characterized using FTIR, ¹H NMR, and elemental analyses. The mesomorphism and thermal stabilities were investigated using differential scanning calorimetry, polarizing optical microscopy, thermogravimetric analysis, and X-ray diffraction. The selective reflection of light for the chiral monomers was studied with UV/visible/near IR. The effect of the crosslinking agent content on the phase transition temperatures of the elastomers was discussed. It was found that these chiral monomers seemed beneficial for the formation of the mesophases when a flexible spacer was inserted between the mesogenic core and the terminal menthyl groups. All obtained chiral monomers showed a cholesteric phase, chiral smectic C phase, and cubic blue phase. The crosslinking agent exhibited a smectic A (S_A) phase and nematic phase. However, their corresponding homopolymers with siloxane chains tended to form a lower order S_A phase. With an increase of the mesogenic rigidity, the melting temperatures, glass transition temperatures (T _g), and isotropic temperatures (T _i) of chiral monomers or homopolymers all increased. For the elastomers, general tendency was toward increased T _g and T _i with increasing the crosslinking agent content.     

Effects of surface-functionalized multi-walled carbon nanotubes on the properties of poly(dimethyl siloxane) nanocomposites

The effects of surface-functionalized multi-walled carbon nanotubes (MWNTs) on the properties of poly(dimethyl siloxane) (PDMS) nanocomposites are investigated in the present study. The surface functionalization of MWNTs is carried out by diphenyl-carbinol functionalization followed by reaction with multifunctional silane, 3-aminopropyltriethoxisilane. Fourier transform infrared spectroscopy (FT-IR) and energy dispersion spectroscopy (EDS) analysis are used to confirm the presence of diphenyl-carbinol and silane on the surface of the MWNTs. The effects of the MWNTs’ surface treatment on the thermal and electrical properties of poly(dimethyl siloxane)-based (PDMS) nanocomposites are also studied. The results show that the grafting of silane molecules onto diphenyl-carbinol-functionalized MWNTs (SD-MWNTs) improves the dispersion of MWNTs in PDMS; this subsequently enhances the thermal conductivity and dynamic mechanical properties as compared to those containing unmodified (U-MWNTs) and diphenyl-carbinol-functionalized MWNTs (D-MWNTs). The electrical conductivity of the nanocomposites is shown to decrease due to the wrapping of MWNTs with non-electrical-conducting organic materials.     

Synthesis and characterization of photoactive polyurethane elastomers with 2,3-dihydroxypyridine in the main chain

Photoactive polyurethane elastomers with pyridine derivatives in the polymer backbone were synthesized by chain-extending isocyanate end-capped prepolymers with 2,3-dihydroxypyridine. The isocyanate-terminated prepolymers were obtained from poly(tetramethylene oxide) glycol of molecular weight 1400 (Terathane 1400) and 1,6-hexamethylene diisocyanate. The properties of the linear heterocyclic polyurethane were compared with properties of the crosslinked heterocyclic polyurethane obtained by chain extension with various crosslinkers. Heterocyclic polyurethane elastomers were characterized using Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), dynamic mechanical analysis (DMA), contact angle measurements, and mechanical analysis. Static mechanical measurements showed greater elongation and tensile strength for polyurethanes with a lower content of heterocyclic groups in the hard segment. The static contact angles of the cast films of these polymers indicated that the nature of the hard segment influences the surface polarity. The dynamic mechanical spectra revealed that linear polymers have two transition temperatures as results from a clear phase separation caused by high-intermolecular hydrogen bonds in the regions of pyridine units and urethane groups. Polyurethane elastomer films with pyridine moieties in the main chain form a photosensitive material. If stored in laboratory conditions (light, ambient air atmosphere), the color of the films changes from white to black. These photo-induced structural changes are studied by H NMR measurements.     

The stability of polysiloxanes incorporating nano-scale physical property modifiers

Abstract

Reported here is the synthesis and subsequent characterization of the physical and chemical properties of novel polysiloxane elastomers modified with a series of polyhedraloligomericsilsequioxane (POSS) molecular silicas. The physical properties of the formulated nanocomposite systems have been characterized with a combination of dynamic mechanical analysis (DMA), broadband dielectric spectroscopy (BDS) and confocal Raman microscopy. The results of the physical property characterization demonstrate that the incorporation of low levels (1–4% by wt.) of POSS particles into the polysiloxane network leads to significant improvements in the mechanical properties of the elastomer and significantly alters the motional chain dynamics of the system as a whole. The results of studies performed to assess the long-term stability of these novel nanocomposite systems have demonstrated that POSS physical property modifiers can significantly alter the thermal stability of polysiloxane elastomers. Physically dispersed POSS has also been shown in some cases to be both mobile and disruptive within the polysiloxane networks, agglomerating into domains on a micron scale and migrating to the surface of the elastomers. This work demonstrates both the potential of POSS nanoparticles as physical property modifiers and describes the effects of POSS on the physical and chemical stability of polysiloxane systems.     

自修复聚氨酯弹性体的制备及性能研究

目的对自修复聚氨酯弹性体的制备工艺及性能进行综述,为制备高修复效率的聚合物提供指导,并指出其未来的发展趋势。方法从聚氨酯弹性体的修复机理出发,收集并分析自修复聚氨酯弹性体的最新研究进展,总结典型自修复聚氨酯弹性体的制备工艺和性能指标;根据修复机理进行分类,对近年来本征型(Diels-Alder反应、Disulfide键、氢键等)和外援型(微胶囊化)自修复聚氨酯弹性体的制备和性能进行综述,并讨论自修复聚氨酯弹性体的修复效率。结论虽然基于不同动态键的自修复聚氨酯弹性体取得了一定的发展,但开发高修复效率的材料仍然是一个巨大的挑战。总结了提高自修复聚氨酯弹性体力学性能的途径,为实现修复性能与力学性能的平衡提供了指导。     

硅氧烷化合物的合成与应用进展

基于硅氧键特点以及不同条件的化学反应是构建结构迥异、性能独特的新型有机/无机硅氧功能材料的重要方法,近年来,引起了学术界的普遍关注。新型硅氧功能材料兼具有机/无机化合物性质,以其良好的生物相容性、耐高低温性以及电绝缘性能被广泛应用于众多领域。本文综述了硅氧烷化合物设计、合成与应用的研究领域及发展现状,重点介绍线性结构(一维结构)、非线性结构(二维结构)、多面体低聚倍半硅氧烷化合物(三维结构)以及有机/无机杂化硅氧烷化合物的设计及合成方法,并通过研究可拉伸聚硅氧烷弹性体、硅氧烷化合物涂层、新型驱油用硅氧功能材料等多种方式以增进硅氧烷化合物在生物医学、航空航天、功能材料及三次采油方面的应用进展。     

Sustainable production of polyurethane from castor oil,functionalized with epoxy- and hydroxyl-terminated poly(dimethyl siloxane) for biomedical applications

A sustainable method has been employed for the production of a biomedical material in an economical way. Among biomedical polymers, two mostly used polymers are silicones (PDMS) and polyurethanes (PU). PDMS can outperform other polymers due to its biocompatibility and flexibility, but its high cost became a major roadblock for many applications. PU can be produced from a variety of sustainable resources in a cost effective manner. In this work, vegetable oil-based PU is blended with PDMS to produce a biomedical material which can contribute to the economy and environment. In this method, siliconized epoxy-terminated polyurethanes (EPDMS) were prepared from castor oil, 4,4’ methylene-bis-(cyclohexyl isocyanate), glycidol, and hydroxy-terminated poly-(dimethyl siloxane) (HTPDMS). The properties of the resulting products were compared with virgin PU with a NCO/OH ratio of 1.2:1 and epoxy-terminated PU (EPU) with a polyol/diisocyanate/glycidol ratio of 1:3:3. The structural elucidation of PU, EPU, and EPDMS were carried out by FTIR and ¹HNMR spectroscopic techniques. The effect of incorporation of siloxane and glycidol on the thermal properties of PU was analyzed by thermogravimetric analysis and differential scanning calorimetry analysis. The improved hydrophobicity of the EPDMS was observed from water contact angle measurements. The surface morphology was examined using atomic force microscopy analysis. In vitro cytotoxicity analysis revealed the cytocompatibility of the EPDMS which makes them suitable for biomedical applications.     

Liquid crystalline elastomers based on cyclic cyclosiloxane and mesogenic crosslinking units

Cholesteric liquid crystalline elastomers (LCEs) IP–VIP were graft copolymerized by a one-step hydrosilylation reaction with cyclo(pentamethylhydrogeno)siloxane, a cholesteric liquid crystalline (LC) monomer cholesteryl 3-(4-(undec-10-enoyloxy)phenyl)acrylate and crosslinking LC monomer biphenyl-4,4′-diyl bis(4-(allyloxy)benzoate). The effect of crosslinking mesogens on mesomorphic properties of the chiral LCEs was studied by swelling experiments. All the samples IP–VIP showed cholesteric mesophase when they were heated and cooled. The glass transition temperature (T _g) of elastomers increased slightly with increase of crosslinking mesogens in the polymer systems, but mesophase–isotropic phase transition temperature (T _i) decreased slightly, suggesting that the temperature range of mesophase became narrow with increase of crosslinking mesogens for all the elastomers. In XRD curves, all the samples IP–VIP exhibited diffuse reflections at 2θ ≈ 17° suggesting lack of the smectic-layered packing arrangement, and the intensity of these diffuse diffraction peaks decreases with increase of mesogenic crosslinking units, suggesting that the order between two neighbor LC molecules disturbed by the mesogenic crosslinking agents. The maximum reflection bands shift slightly to long wavelength and become broad at the same temperature, indicating that the helical structure is partially disrupted because of both the constraint of chemical crosslinking agents and the different mesogenic units.     

Adhesives with patterned sub-surface microstructures

Inspired by the complex hierarchical structures found in natural adhesives, we have embedded monolithic stack of several microchannels inside soft layers of silicon elastomers. These channels are rectangular in cross-section and their internal surfaces are textured with microscopic pillars arranged in regular arrays. Displacement controlled indentation experiment on these adhesives shows that adhesion and debonding occur not only on the surface of the adhesive but also at the interfaces of the embedded layers. These textures on the channel surface enhance adhesion via “crack arrest and initiation” mechanism. Furthermore, the adhesive is treated by hydrochloric acid so that the siloxane bonds present on the exposed surfaces are hydrolyzed generating silanol groups which on two contacting surfaces increase the effect of self adhesion hysteresis. Thus, the combined effect of surface texturing is integrated with the chemical treatment to increase adhesion.