甲基丙烯酸酯和丙烯酸酯基团转移共聚的竞聚率

甲基丙烯酸酯和丙烯酸酯基团转移共聚的竞聚率邹友思郭金全戴李宗潘容华（厦门大学化工系，厦门，３６１００５）基团转移聚合是制备极性单体的嵌段或无规共聚物的有效方法。如用甲基丙烯酸甲酯（ＭＭＡ）和丙烯酸丁酯（ＢＡ）进行嵌段共聚，可制得热塑性弹性体［１...     

相同软硬段质量配比聚醚酯弹性体PEG/PBT的结构与表征

以熔融缩聚法合成了一系列聚乙二醇（PEG）／聚对苯二甲酸丁二醇酯（PBT）聚醚酯热塑性弹性体，用NMR，FTIR，DSC及力学性能测试等方法表征了材料的结构及性能。讨论了在相同软硬段质量配比下，不用软硬段长度对材料性能的影响。结果表明，随着软段PEG长度增加，硬段PBT长度相应增长，弹性模量基本保持不变，抗拉强度，屈服应力及特性粘度增加。     

可生物降解的聚乳酸弹性体的合成与表征

本文将丙交酯（ＤＬ－ＬＡ）与聚乙二醇（ＰＥＧ）的预聚体用甲苯－二异氰酸酯８０（ＴＤＩ）扩链，得到了一系列的聚乳酸（聚醚）型聚氨酯（ＰＥＧ－ＰＬＡ／ＰＵ）弹性体。对预聚体和弹性体分别进行了ＩＲ、ＨＮＭＲ和ＤＭＡ表征，并测定了弹性体的力学性能。结果表明，ＬＡ与ＰＥＧ生成的预聚体是一种三嵌段结构：ＨＯ－ＰＬＡ－ＰＥＧ－ＰＬＡ－ＯＨ。随着ＰＥＧ含量的增加，弹性体的玻璃化温度下降；ＰＥＧ分子量增大时，弹性体     

聚氨酯弹性体的形态结构和电性能研究不同起始反应温度的 …

以聚醚多元醇、丁二醇和甲二异氰酸酯为原料，在不同起始反应温度下（不用催化剂）合成了一系列硬段含量为３０％的聚氨酯弹性体（ＰＵ），它们的起始反应温度分别为２０℃（Ｓ－１）、４０℃（Ｓ－２）、６０℃（Ｓ－３）和８０℃（Ｓ－４）。用示差扫描量热分析、傅立叶变换红外光谱和透射电镜研究了它们的形态结构。研究结果发现：随着初始反应温度的升高，试样Ｓ－１的相分离程度较大，Ｓ－２次之，Ｓ－３的相分离程度较小，但Ｓ     

RIM聚氨酯脲的微相分离的DSC研究──硬段结构和含量对微相分离的影响

用ＤＳＣ法研究了二乙基甲苯二胺和４，４＇－氨基二苯基甲烷（ＭＤＡ）扩链的硬段含量为２７％～６０％的两个系列的反应注射成型（ＲＩＭ）聚氨酯脲（ＰＵＵ）弹性体的微相分离。聚合反应动力学对ＲＩＭＰＵＵ的微相分离有很大影响．随着硬段浓度的增加微相分离程度下降，ＭＤＡ扩链系列聚合总反应速度快，微相分离驱动力弱，在硬段生成反应比软段生成反应快的条件下，该系列的微相分离程度较低。聚合总反应快，且硬段间氢键化作用很强的性质造成ＲＩＭＰＵＵ非平衡的形态。聚合总反应速度的增加相当于微相分离驱动力的下降。     

沉淀分离法及高效凝胶色谱分析聚合物的共混物-聚苯乙烯、氯醇橡胶及苯乙烯与环氧丙烷嵌段共聚物

 ]脆性的聚苯乙烯塑料与韧性的氯醇橡胶共混，聚苯乙烯-聚环氧丙烷的多嵌段共聚物作为共混物的增容剂，这种共混高分子材料具有热塑性弹性体的基本特点。本文用沉淀分离法定量得到共混物的组分，并用高效凝胶色谱（GPC）分析各组分的含量；从GPC曲线计算嵌段共聚物的k和值；表征了聚苯乙烯-聚环氧丙烷的嵌段共聚物分子量、分子量分布及组成。     

液晶型聚氨酯弹性体的固体高分辨核磁共振研究

采用固体高分辨＾１３Ｃ核磁共振谱以及溶液碳谱、氢谱的方法对以聚四氢呋喃（ＰＴＭＯ）为软段、４，４＇－二苯基甲烷二异氰酸酯（ＭＤＩ）为硬段、４，４＇－二羟已氧基联苯（ＨＢ６）为扩链剂的液晶型聚氨酯弹性体的相态结构、分子运动、氢键相互作用等问题进行了研究。探讨了样品的化学结构与上述问题间的关系。     

含呱嗪聚硅氧烷聚脲聚氨酸及其离聚物的研究

以氨丙基封端聚二甲基硅氧烷及脲键改性聚硅氧烷低聚体分别与4，4－二异氰酸酯二苯甲烷（MDI)反应，并用1，4二（2－羟乙基）－呱嗪（N）扩链，合成了一系列含氮杂环聚氨酯共聚物。产物为透明热塑性弹性体，具有良好的成膜性能和宽阔的使用温区，通过碘乙烷和γ－丙磺酸内酯对上述样品进行季铵化，合成了阳离子型及双离子型离聚物。用傅里叶红外光谱（FT－IR）、示差量热分析（DSC）、动态力学谱（DMTA）、力学性能等方面对样品进行了表征。结果表明，在聚硅氧烷中引入脲键，提高了软、硬段两相的相容性。体系中既有软段间的氢键作用又有两相间的氢键作用，从而使这类材料的杨氏模量、抗张强度和断裂伸长均明显高于相应的聚二甲基硅氧烷聚脲聚氨酯体系。     

硬段含量对聚氨酯弹性体的吸水动力学及力学性能的影响

合成了硬段含量分别为30 wt%、37 wt%和45 wt%的聚醚型聚氨酯弹性体(PTMG-PU).研究了硬段含量、水浸温度和试样厚度对PTMG-PU吸水动力学的影响.研究结果表明：PTMG-PU在25℃～60℃之间的吸水动力学过程可以用Fick模型进行拟合；扩散系数和平衡吸水率随着硬段含量的增加均呈逐渐降低的趋势，水分子扩散活化能和指前因子均随着硬段含量的增加而增加，说明硬段含量越高，水分子需要克服的传输能垒越高.进一步，吸水导致聚氨酯弹性体的拉伸断裂强度、100%定伸强度和拉伸模量等力学性能出现明显的下降，这不仅是由于水分子与聚氨酯弹性体的软段相发生了增塑作用，而且水分子也与部分硬段相微区发生了作用，导致部分硬段相微区瓦解.     

聚碳酸亚丙酯-聚醚聚氨酯的合成与性能

本文报道用CO2与环氧丙烷共聚产物聚碳酸亚丙酯和环氧丙烷均聚物来制备聚氨酯（PPCPOPU）弹性体。探讨了这类弹性体的最佳合成方法，考察了异氰酸酯基与羟基的比值；扩链交联剂用量等因素对弹性体的力学性能的影响。研究了弹性体的形态结构及其性能对配比的依赖关系。发现聚碳酸亚丙酯的耐热性因聚氨酯的形成而得到较大的改善，并发现该类弹性体具有优异的耐水性能。     

用DSC研究线形多嵌段聚氨酯与聚氯乙烯、氯化聚氯乙烯共混相容性

用示差扫描量热法（DSC）研究了线形多嵌段聚氨酯（PU）与聚氯乙烯（PVC）、氯化聚氯乙烯（CPVC）共混相容性，说明了PU／VC、PU／CPVC的相容是由于共混物中形成了新的氢键的缘故．聚酯型聚氨酯与PVC、CPVC的相容性要好子聚酸型聚氨酯，CPVC与PU的相容性又要好于PVC．聚氨酯中硬段的引入不利于PU／PVC、PU／CPVC的相容性．     

Features of the in situ formation of a linear poly(methyl methacrylate)-crosslinked polyurethane blend in the presence of an oligomeric initiator

The process of the in situ formation of a linear poly(methyl methacrylate)-crosslinked polyurethane blend in the presence of different amounts of an oligomeric azo initiator containing fragments of a polyurethane chain and groups capable of initiating the radical polymerization of methyl methacrylate has been studied. It has been shown that the use of an azo initiator providing for the formation of block copolymers retards the phase separation in the system and favors the formation of a finer blend structure that is characteristic by a domain size several times smaller than that of the pristine blend, without the azo initiator. The optimum azo initiator concentration that results in a better dispersion of polyurethane in poly(methyl methacrylate) has been determined.     

The study of domain structure in polyurethanes by nuclear magnetic resonance

Polyurethanes are block copolymers composed of hard and soft segments which often undergo microphase separation with the resultant formation of hard and soft domains. The nuclear-magnetic-free induction decay of such systems is shown to consist of a fast Gaussian component corresponding to glassy domains and a slow exponential component corresponding to rubbery domains. Thus, by being sensitive to the microscopic mobility of a material, nuclear magnetic resonance (NMR) has the potential to determine when a polyurethane has separated into domains and the relative amounts of material in each domain. After annealing the free-induction decay of a linear polyurethane showed a distribution of relaxation times indicating that mixing of the domains had taken place and a continuum of compositions exist in the material. The free-induction decay of a cross-linked polyurethane was unaffected by annealing, confirming the results of an earlier study.     

A pH‐responsive self‐fluorescent polymeric micelle as a potential optical imaging probe

A series of methoxypolyethylene glycol‐terminated self‐fluorescent polyurethane multi‐block copolymers with excellent pH‐responsivity, self‐fluorescence, and biocompatibility are designed and synthesized. In our design, 1, 4‐bis (hydroxyethyl) piperazine is chosen as a pH‐responsive segment which can donate or accept protons in response to the change of environmental pH, and fluorescein isothiocyanate is used as a fluorescent dye conjugated into the micelles to offer self‐fluorescence. The chemical structure of the polyurethane multi‐block copolymers is characterized by nuclear magnetic resonance and Fourier transform infrared spectroscopy. The results of the acid‐based titration, the fluorescence spectrometry, and the ultraviolet visible spectroscopy indicate that the polyurethane multi‐block copolymers own an excellent pH‐buffering capacity responded to the change of pH values and the favorable self‐fluorescence property in an aqueous solution. And the ultraviolet absorption peaks of samples are strengthened with increasing of pH values, indicating that methoxypolyethylene glycol‐terminated self‐fluorescent polyurethane multi‐block copolymer can be a pH‐dependent fluorescent probe in a broad pH range. In addition, the in vitro cytotoxicity test showed that the polyurethane multi‐block copolymer has low cytotoxicity and good biocompatibility, which make it a promising nanoplatform for molecular imaging, diagnosis, and treatment of disease.     

Model fluorous polyurethane surface modifiers having co-polyoxetane soft blocks with trifluoroethoxymethyl and bromomethyl side chains

Polyurethanes containing poly(2-trifluoroethoxymethyl-2-methyl)-co-(2-bromomethyl-2-methyl)-1,3-propylene oxide (co-polyoxetane) soft blocks, P[3FOx:BrOx-m:n], were prepared and used (0.5-2 wt %) to modify the surface properties of a conventional polyurethane. The substrate polyurethane was composed of an isophorone diisocyanate/butanediol hard block and a polytetramethylene oxide soft block [IPDI/BD(50%)-PTMO(2000)]. A combination of tapping mode atomic force microscopy (TM-AFM), X-ray photoelectron spectroscopy (XPS), and dynamic contact angle (DCA) studies showed that the fluorous polyurethane surface modifiers confer surface properties similar to those of the parent at 0.5-1.0 wt %. The retention of initial wetting behavior in water was enhanced with higher ratios of 3FOx:BrOx that corresponds to increasing fluorous character. A semifluorinated chaperone is necessary to surface concentrate -CH2Br groups. Negligible Br was detected by XPS when the P[BrOx]-soft block polyurethane was used as a surface modifier (0.5%) and the wetting behavior was similar to that of the bulk polyurethane. Despite being hydrophobic (theta adv = 102 degrees) the P[BrOx]-soft block polyurethane is not a polymer surface modifier under the conditions described herein. The calculated solubility parameters for PTMO and P[BrOx], which are similar, support the notion of BrOx miscibility with the base polyurethane. The combination of miscibility of BrOx repeat units and lack of an end-group-like architecture minimizes BrOx surface concentration in the chosen bulk polyurethane.     

The effects of morphological transitions on hydrogen bonding in polyurethanes: Preliminary results of simultaneous DSC–FTIR experiments

The influence of morphological transitions on the hydrogen-bonding behavior of polyurethanes is investigated by simultaneous measurements of Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The materials examined are a noncrystalline polyurethane hard segment, a crystallizable polyurethane hard segment, and a segmented polyurethane block copolymer containing crystallizable hard segments. Integrated absorbance data show that the hydrogen-bonding behavior is insensitive to crystalline transitions within the hard segment microdomains, but that it does reflect morphological transitions in the block copolymer that are associated with intersegmental mixing. In addition, the spectral data show conclusive evidence for reversal of the urethane reaction at high temperatures.     

主链型液晶聚硅氧烷聚氨酯的合成及性质

合成了主链型联苯类及氧化偶氯苯类液晶聚硅氧烷聚氨酯弹性体，采用红外光谱，示差扫描量热，动态粘弹谱及带热台偏光显微镜等方法对聚合物进行了表征，讨论了它们的结构与性能．研究结果表明，这一系列多嵌段聚氨酯多数是向列型的液晶高分子聚合物，液晶相的形成同嵌段聚氨酯样品的软硬段相互作用有着密切的联系     

Macromolecular N-nitroso-acylamines as initiators for polyreactions. I. Synthesis of block copolymers from polycondensates and olefinic monomers,

The synthesis of block copolymers in three-step reactions from linear polycondensates (e.g., nylon 6. nylon 6,6, nylon 6,10 and polyurethane) and olefinic monomers (e.g., styrene, acrylic acid and acrylonitrile, methyl methacrylate, vinyl acetate, vinyl chloride, and isoprene) is reported. Macromolecular radicals are formed by the thermal decomposition of partly nitrosated peptide group containing polycondensates at elevated temperatures (60–200°C). These polyradicals initiate the copolymerization of the olefinic monomers. The conversion and reaction rates were generally high (up to 100% within a few hours). Most of the block copolymers prepared were soluble in organic solvents. Some, however, were insoluble or rubberlike. The reaction mechanism involved are analyzed. Applications are discussed.     

Hydrogen bonds in heterogeneous blends based on semicrystalline polyurethane and styrene-acrylic acid block copolymer

New film-forming polymer composites based on the semicrystalline polyurethane and the styreneacrylic acid block copolymer have been synthesized. The effect of hydrogen bonds on the phase structure and properties of the composites has been studied by dynamic MTA, DSC, thermogravimetry, and IR spectroscopy. Formation of the network of intermolecular hydrogen bonds between urethane groups of polyurethane and carboxyl groups of block copolymer components leads to a decrease in the microphase separation of the composites under study and improves their thermooxidative stability.     

Effect of spatial constraints on phase separation during polymerization in sequential semi-interpenetrating polymer networks

The viscoelastic properties of sequential semi-interpenetrating polymer networks prepared via the swelling of network polyurethane in different monomers (butyl methacrylate, styrene) followed by their polymerization in the polyurethane matrix have been studied by means of dynamic mechanical analysis. It is found that the relaxation behavior of the test systems and the degree of segregation of the components depends on M _c of the polyurethane matrix because of a change in the molecular mass of the polymer block. The compatibility of the components in sequential semi-interpenetrating polymer networks substantially increases when the network inner space in the polyurethane matrix decreases.