WPU预聚体中羧基含量及其位置对树脂的粒径及其耐水性之影响的研究

本文先将马来酸酐与多元醇作用，然后再与其它单体反应，合成了含有羧基的聚氨酯预聚体，并用丁酮稀释后，在普通搅拌条件下使预聚体分散于三乙醇胺的水溶液中，合成出以水为分散介质的聚氨酯分散体系（WPU）。并通过改变羧基在预聚体中的含量和位置，发现随着羧基含量的增加，WPU的粒径减小，而耐水性下降。同时发现，在一定的羧基含量下，同侧羧基相比，端羧基更有利于预聚体的乳化，制得的WPU不仅颗粒较小，而且树脂耐水性明显优于侧基羧预聚体制备的WPU，从而提出羧基的运动自由度是影响羧基乳化活性和树脂耐水性的重要因素。     

水性丙烯酸酯聚氨酯涂料的研究

合成了含羟基的丙烯酸酯树脂,并与甲苯二异氰酸酯反应制备预聚体Ⅰ,Ⅰ与扩链剂二羟甲基丙酸反应得到含羧基的预聚体Ⅱ,最后用1,4-丁二醇交联,制得水性丙烯酸酯聚氨酯涂料,讨论了合成过程中影响乳液稳定性和涂膜性能的因素。测试结果表明：涂膜的强度、光泽、硬度等性能均优于传统的同类树脂。     

不饱和端基超支化聚合物/丙烯酸酯共聚乳液的研究

利用Si—H加成反应制得了以CC为端基的超支化含硅聚合物,并将其与丙烯酸酯类单体进行乳液共聚,对聚合反应机理及所得聚合物的性能进行了测试分析.结果表明,含有大量CC端基的超支化含硅聚合物能与丙烯酸酯类单体稳定聚合,制得了平均粒径小于100nm高度交联的乳胶粒子.共聚物的红外光谱证实,超支化聚合物的不饱和端基已全部反应,形成了以超支化聚合物为多臂交联点的交联型乳胶粒子.随聚合体系中超支化聚合物用量的增加,乳液聚合反应速率增大,乳胶粒粒径减小,共聚物热稳定性显著提高.     

丙烯酸酯/聚氨酯三层核壳复合乳液的合成与表征

以自制的聚酯多元醇(PPMBA)、甲苯二异氰酸酯(TDI)、1,6-六亚甲基二异氰酸酯(HDI)、二羟甲基丙酸(DMPA)合成聚氨酯预聚体,再用丙烯酸酯类单体代替有机溶剂对预聚体降黏,封端预聚体后中和分散乳化得包含丙烯酸酯类单体的聚氨酯乳液.向乳液中加入引发剂引发自由基聚合得到复合乳液,最后再加入乙烯基类单体及引发剂合成三层核壳结构的聚丙烯酸酯/聚氨酯复合乳液.研究表明,二异氰酸酯的-NCO与聚酯多元醇中的-OH的物质的量之比(R值)为1.6~4之间时,随R值增加,乳液稳定性增强;DMPA含量在4%~7%的范围内,随DMPA含量的降低,乳胶膜的耐水性提高.通过红外光谱对所合成聚酯多元醇及复合乳液结构进行表征.     

叔胺型水性聚氨酯的合成及其性能

将含有不同胺基的聚氨酯预聚体在酸性水溶液中乳化得到水性聚氨酯．结果表明，胺基摩尔量相同时，由二甲基乙醇胺制得的水性聚氨酯粒径最小（０．４～２μｍ），甲基二乙醇胺制得的预聚体乳化后乳胶粒较粗（２～１５μｍ），而由三乙醇胺制得的预聚体根本得不到聚氨酯乳液．提出胺基的运动自由度是影响乳化能力的关键．二甲基乙醇胺制得的水性聚氨酯具有贮藏稳定性好、耐水性好，并呈现假塑性流体的特点．随着二甲基乙醇胺用量的增加，水性聚氨酯涂膜的断裂强度由１．０ＭＰａ增加到４．８ＭＰａ，动态粘弹谱的内耗峰变宽．     

可湿气固化的硅烷化聚醚的研究

以聚醚多元醇为原料 ,通过聚氨酯预聚体的方法制得了可湿气固化的硅烷化聚醚 ,研究了温度和时间对反应的影响 ,以及不同NCO/OH比值对固化物力学性能的影响。结果表明 ,固化后形成的弹性体的不同力学性能可通过调节不同NCO/OH的比值而获得     

聚硅氧烷聚丙烯酸酯改性聚氨酯三元复合乳液中偶联剂丙烯酸羟乙酯的作用

用异佛尔酮二异氰酸酯与仲羟基封端的聚硅氧烷( PMTS)反应在PMTS分子链端引入异氰酸酯基团,然后将其与聚丙二醇反应制得聚硅氧烷改性聚氨酯( PSU)预聚体,最后加入丙烯酸酯单体(AC)通过乳液聚合制备了非偶联型聚硅氧烷聚丙烯酸酯改性聚氨酯( PSU-AC)三元复合乳液.在PSU与AC聚合时加入丙烯酸羟乙酯(HEA)...     

偶联剂对丙烯酸酯改性聚氨酯聚合物接枝率和乳液性能的影响

合成了含双羟基的甲基丙烯酸甘油酯(GM)并将其作为偶联剂用于聚丙烯酸酯(PAC)对水基聚氨酯(PU)的改性.采用核磁共振、红外光谱和气相色谱等对GM进行了表征.分别以该双羟基GM和单羟基的丙烯酸羟乙酯(HEA)与异氰酸酯基(NCO)封端的PU预聚体进行反应以在PU分子链上引入双键,然后再与丙烯酸酯类单体通过自由基聚合制...     

羧基甜菜碱型两性离子聚氨酯水凝胶的制备及水下抗原油黏附性能

通过4-溴丁酸乙酯和N-甲基二乙醇胺之间的亲核取代反应制备得到季铵离子型二元醇. 以季铵离子型二元醇与六亚甲基二异氰酸酯(HDI)三聚体为基本原料, 通过聚加成反应制备得到聚氨酯预聚体. 进一步经碱性水解等过程后制备得到不同水解时间的羧基甜菜碱型两性离子聚氨酯水凝胶(CBPU). 结果表明, 水解 60 min后的羧基甜菜碱型两性离子聚氨酯水凝胶不仅具有较好的机械性能, 而且对十六烷、 煤油、 石油醚、 异辛烷甚至原油的水下油接触角(UOCA)均达160°以上, 水下油黏附力均为0. 该羧基甜菜碱型两性离子聚氨酯水凝胶在防油涂层、 油水分离膜以及防污减阻等方面均具有重大的应用前景.     

PMMA-PAN核壳结构复合乳胶的制备与表征

采用疏水引发剂引发的半连续无皂乳液聚合法,合成了Z均流体力学直径约70nm的聚甲基丙烯酸甲酯(PMMA)纳米乳胶。以PMMA纳米乳胶为种子,采用疏水引发剂引发的种子乳液聚合法,制备了PMMA-聚丙烯腈(PAN)核壳结构复合乳胶。采用动态光散射、傅里叶红外光谱、扫描电镜和透射电镜表征了各种乳胶粒的组成、尺寸、结构和微观形态。研究了反应温度、单体用量和表面活性剂用量对PMMA-PAN复合乳胶粒的结构和形态的影响。结果表明:PMMAPAN复合乳胶粒为核壳结构,其壳层厚度可通过改变单体用量进行调整。     

Rheological properties of polyurethane adhesives containing silica as filler: influence of the nature and surface chemistry of silica

Four silicas, two fumed silicas (one hydrophilic and one hydrophobic) and two precipitated silicas (one hydrophilic and one hydrophobic), were added as filler to solvent‐based polyurethane (PU) adhesive formulations. In general, the addition of silica increased the viscosity, the storage and loss moduli of the PU adhesives but only the hydrophilic fumed silica exhibited pseudoplasticity and thixotropy. The rheological properties imparted by adding filmed silicas to PU adhesive solutions were more noticeable than that of precipitated silicas. Interactions between the hydrophilic fumed silica, the polyurethane and/or the solvent seemed to be responsible for the improved rheological properties of filled PU adhesives.     

Properties of solvent based polyurethane adhesives containing fumed silicas

Five hydrophilic and two hydrophobic fumed silicas of different surface area and particle size were added to solvent based polyurethane adhesives. Silica addition produced a noticeable increase in the adhesive viscosity, imparted negative thixotropy, increased the storage modulus (G') and improved the green adhesion of chlorinated rubber/PU adhesive/chlorinated rubber joints. Those modifications were more pronounced in the adhesives which contain hydrophilic silicas.     

Semibatch emulsion polymerization of methyl methacrylate using different polyurethane particles

Aqueous acrylic‐polyurethane (AC–PU) hybrid emulsions were prepared by semibatch emulsion polymerization of methyl methacrylate (MMA) in the presence of four polyurethane (PU) dispersions. The PU dispersions were synthesized with isophorone diisocyanate (IPDI), 1000 and 2000 molecular weight (MW) poly(neopentyl) adipate, 1000 MW polytetramethyleneetherglycol, butanediol (BD), and dimethylol propionic acid (DMPA). MMA was added in the monomer emulsion feed. We studied the effect of the use of different PU seed particles on the rate of polymerization, the particle size and distribution, the number of particles, and the average number of radicals per particle. The PU rigidity was controlled by varying the polyol chemical structure, the polyol MW (M_n), and by adding BD. The monomer feed rate was varied to study its influence on the process. It was observed that the PU particles that had been prepared with a higher MW polyol swelled better with MMA before the monomer‐starved conditions occurred. There seemed to be no significant discrepancies between the series with different PU seeds in the monomer‐starved conditions. The overall conversion depended on the monomer addition rate, and the polymerization rate acquired a constant value that was comparable to the value of the monomer addition rate. The instantaneous conversion increased slightly. The average particle size increased, and the total particle number in the reactor was constant and similar to the number of PU particles in the initial charge. The average number of radicals per particle increased. The differences between the system with a constant particle number and average number of radicals per particle and the system with a fixed radical concentration are discussed. The semibatch emulsion polymerization of MMA in the presence of PU particles studied was better compared to the system with a fixed radical concentration. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 844–858, 2005     

Segmented polyurethane synthesized by frontal polymerization

Frontal polymerization (FP) is a mode of converting a monomer into a polymer via a localized reaction zone that propagates through the monomer. In this study, segmented polyurethane was successfully prepared by FP. The reactants, poly (propylene oxide) glycol, 2, 4-toluene diisocyanate and 1,4-butanediol and the catalyst stannous caprylate, were mixed together at an initial temperature in the presence of dimethylbenzene (as the solvent). The reactions were thermally ignited at one end of the tubular reactor, and the resultant hot fronts propagated throughout the reaction reactor. No further energy was required for polymerization to occur. The effect factors of front velocity, stannous caprylate concentration and temperature on the FP, along with comparison of FP with bulk polymerization, were thoroughly investigated. Fourier transform infrared and differential scanning calorimetry were employed to characterize polyurethane (PU). The polymer materials obtained by FP displayed features similar to those obtained by batch polymerization. The reaction time of FP for preparing PU was lower than that of BP.     

Graft copolymers of polyurethane with various vinyl monomers via radiation-induced miniemulsion polymerization: Influential factors to grafting efficiency and particle morphology

Graft copolymers of polyurethane (PU) with various vinyl monomers were synthesized through a one-pot but two-step miniemulsion polymerization process. Firstly, the polycondensation of isophorone diisocyanate (IPDI) with hydroxyl-terminated polybutadiene (HTPB) had been performed in aqueous miniemulsion at 40 °C in order to obtain PU dispersions. Consecutively, an in-situ graft copolymerization of the vinyl monomers with the synthesized PU was initiated by γ-ray radiation at room temperature. The grafting efficiency of PU with vinyl monomer (G_PU/monomer) was calculated from ¹H NMR spectra and the particle morphology of the final hybrid latex was observed by transmission electron microscopy (TEM). As there was no monomer transferring in miniemulsion system, homogenous hybrid particles would be synthesized provided that the monomer was miscible with PU, such as styrene. With the increase of the polarity of the monomer, the compatibility of PU with monomer decreased. G_PU/monomer varied as G_PU/styrene(37%)>G_{PU/butyl acrylate (BA)}(21%)>G_{PU/methyl methacrylate (MMA)}(12%). The proportion of homogeneous nucleation would increase as the hydrophilicity of the monomer increased. High temperature would destabilize the miniemulsion so as to result in a less grafting efficiency. Compared to the phase separation during the seeded emulsion polymerization, the miniemulsion polymerization method facilitated the preparation of homogeneous materials owing to its monomer droplet nucleation mechanism.     

Hydrophobic polyurethane polyHIPEs templated from mannitol within nonaqueous high internal phase emulsions for oil spill recovery

Although amphiphilicity is an integral component for the applications of polyHIPEs (PHs), it is challenging to produce hydrophobic PHs from hydrophilic monomers. Herein, hydrophobic polyurethane (PU) PHs have been fabricated from a water‐soluble mannitol within block copolymer surfactant‐stabilized, nonaqueous high internal phase emulsions (HIPEs). These highly porous, interconnected, macroporous PU PHs were hydrophobic with water contact angles between 102° and 140°, demonstrating that water‐soluble monomers could be used for fabrication of hydrophobic PHs. The block copolymer surfactant acted not only as the HIPE stabilizer, but also as a monomer, enhancing hydrophobicity and overcoming some drawbacks imposed by conventional inert stabilizers. The solvents used for PU PH synthesis and purification were easily recovered and reused, showing that nonaqueous HIPE templating for PU PH preparation is an efficient and facile route. The PU PHs were investigated for oil spill reclamation and they were demonstrated to be an ideal candidate for such an application. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1315–1321     

Preparations and properties of polyurethane aqueous dispersion from uncatalyzed systems of H12MDI,PTAd/bisphenol A polyol,and DMPA

Aqueous dispersions of polyrethane (PU) containing ionic and nonionic hydrophilic segments were prepared in a prepolymer mixing process using substantial amount of solvent. The acid groups were neutralized with tertiary amine, and chain extension in aqueous media was carried out with triethylene tetramine. Average particle size and particle size distribution of the dispersion, and mechanical and viscoelastic properties of the emulsion cast films were determined.     

Investigation of covalently colored polyurethane latexes based on novel anthraquinone polyurethane chain extenders

Novel red and yellow polyurethane (PU) chain extenders with one anthraquinone chromophore and two hydroxyls were synthesized, and then used to fabricate covalently colored PU latexes with pendent chromophores on the PU backbone. The chemical structures of the chain extenders were characterized by ¹H-NMR and FTIR, and the properties of PU latexes and their films were investigated by UV-Vis absorption spectra, particle size analysis, FTIR, Soxhlet's extraction and xenon arc aging testing. Results showed that the covalently colored PUs had the same UV-Vis absorption behavior as the corresponding chain extenders, and amount of the chain extenders had no obvious influence on the latex preparation process and the resulted latex colloidal properties. Compared with the corresponding non-covalently colored PU latex films, both the light fastness and the solvent fastness of the covalently colored PU latex films were significantly enhanced by the covalent incorporation of chromophores with PU matrix.     

Modification of the rheological properties of polyurethanes by adding fumed silica: influence of the preparation procedure

The way of addition of fumed silica determined the rheological properties of polyurethane (PU) adhesives. The higher the shear rate during preparation of fumed silica containingPU adhesives, the higher viscosity and improved plasticity and thixotropy in the solutions. The improved properties of these adhesive solutions were ascribed to the creation of interactions between the silanol groups on the fumed silica, the polar groups in the soft segments of the polyurethane and/or the solvent. However, the way of incorporate the fumed silica in the polyurethane did not affect the rheological properties of fumed silica-PU composites (obtained by solvent removal from the solutions), indicating the key role of the solvent in the rheology of PU adhesive solutions.     

苯乙烯在阴离子型聚氨酯纳米水分散液中聚合过程的研究

采用自乳化法制备出阴离子聚氨酯纳米水分散液,以其作为乳化剂使苯乙烯单体在其中进行聚合,制备出不同聚苯乙烯与聚氨酯质量比的阴离子型PS/PU纳米复合物水分散液;对苯乙烯单体的聚合过程进行了研究;采用光子相关谱仪和透射电镜对其微观结构、粒径及其分布进行了测试,结果表明,该方法能够制备出稳定的具有核壳结构的PS/PU纳米复合物水分散液,但当苯乙烯单体浓度增大到一定程度(PS/PU质量比为50∶100)时,粒子不稳定而发生聚集.