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。     

RIM聚氨酯脲的微相分离的DSC研究—硬段结构和含量对微相…

用ＤＳＣ法研究了二乙基甲苯二胺和４，４＇－二氨基二苯基甲烷扩链的硬段含量为２７％－６０％的两个系列的反应注射成型聚氨酯脲弹性体的微相分离，聚合反应动力学对ＲＩＭ ＰＵＵ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ＲＩＭ ＰＵ     

N－丙烯酰基－N＇－苯基脲及其衍生物的合成与聚合反应

 以三种合成路线分别合成了含有脲键的一类单体，Ｎ－丙烯酰基－Ｎ’－苯基脲（ＡＰＵ）、Ｎ－甲基丙烯酰基－Ｎ’－苯基脲（ＭＰＵ）、Ｎ－甲基丙．烯酰基－Ｎ’－对甲苯基脲（ＭＴＵ），通过单体的自由基聚合与共聚合，制备了均聚物和共聚物，经ＩＲ、１Ｈ—ＮＭＲ表征和ＴＧＡ、ＤＳＣ测定．     

N－丙烯酰基－N＇－苯基脲及其衍生物的合成与聚合反应

以三种合成路线分别合成了含有脲键的一类单体，Ｎ－丙烯酰基－Ｎ’－苯基脲（ＡＰＵ）、Ｎ－甲基丙烯酰基－Ｎ’－苯基脲（ＭＰＵ）、Ｎ－甲基丙．烯酰基－Ｎ’－对甲苯基脲（ＭＴＵ），通过单体的自由基聚合与共聚合，制备了均聚物和共聚物，经ＩＲ、１Ｈ—ＮＭＲ表征和ＴＧＡ、ＤＳＣ测定．     

二胺扩链剂对RIM聚氨酯－脲弹性体的结构与性能的影响

采用实验室小型ＲＩＭ机制备了一组不同芳香二胺扩链的嵌段聚氨酯－脲（ＰＵＵ）弹性体，借助于ＩＲ、ＤＳＣ、ＤＭＴＡ、ＳＥＭ以及拉伸试验等测试手段对其结构与性能进行了研究．通过比较由ＭＤＡ、ＤＥＴＤＡ以及ＣＡＭＤＡ三种不同活性和结构的芳香二胺扩链剂与二异氰酸酯反应形成的硬链段对ＲＩＭＰＵＵ弹性体的结构与性能的影响，表明：ＭＤＡ基ＲＩＭＰＵＵ中软、硬链段微区界面作用指数很小，微相分离程度却很大，其性能最差；ＤＥＴＤＡ基ＲＩＭＰＵＵ弹性体有理想的界面作用指数，以及适当的微相分离程度，其性能位于三者之中最佳．ＤＭＴＡ研究证实在一定的温度范围内ＤＥＴＤＡ基ＲＩＭＰＵＵ的模量稳定性最好．     

聚氨酯型互穿网络聚合物的研究

以甲苯二异氰酸酯和蓖麻油反应，合成了一系列室温固化的蓖麻油型聚氨酯。分别研究了蓖麻油聚氨酯（ＣＯＰＵ）／聚苯乙烯（ＰＳｔ）ＩＰＮｓ、ＣＯＰＵ／聚丙烯腈（ＰＡＮ）ＩＰＮｓ的结构和性能。结果表明：ＣＯＰＵ／ＰＡＮ的力学性能较ＣＯＰＵ／ＰＳｔ的力学性能为好。为进一步改善聚合物之间的相容性，在聚苯乙烯网络中引入极性较大的丙烯腈制备了ＣＯＰＵ／Ｐ（Ｓｔ－ＣＯ－ＡＮ）ＩＰＮｓ，并对它的力学性能、热分析、动态力学性能、热稳定性等作了系统的研究。结果表明：当聚氨酯浓度为６０％时，改变Ｓｔ、ＡＮ的比例，随ＡＮ含量的增加，体系的微相分离程度降低。改变ＣＯＰＵ／Ｐ（Ｓｔ－ＣＯ－ＡＮ）的比例，ｔａｎδ－Ｔ曲线上均呈现一个较宽的玻璃化转变温度；热重分析表明，其初始分解温度可达２４４℃。     

烯丙基硫脲与支持电解质阴离子在银电极上共吸附的拉曼光谱

用表面增强拉曼散射光谱（ＳＥＲＳ）和时间分辨ＳＥＲＳ光谱（ＴＲＳＥＲＳ）等技术首次研究了烯丙基硫脲（ＡＴＵ）在ＨＣｌＯ４、Ｈ２ＳＯ４和ＨＮＯ３介质中与无机阴离子在银电极上的电化学共吸附行为．提出ＡＴＵ很可能以Ｓ端与银电极表面形成化学吸附键，仲氨基相对伯氨基距离表面较近，整个分子偏向烯丙基一侧倾斜吸附在表面上．ＣｌＯ－４、ＳＯ２－４和ＮＯ－３等弱吸附无机阴离子均能被ＡＴＵ诱导共吸附在其质子化了的仲氨基上，这３种无机阴离子被ＡＴＵ诱导共吸附的强弱顺序是ＣｌＯ－４＞ＳＯ２－４＞ＮＯ－３．被诱导共吸附的无机阴离子对ＡＴＵ在电极表面的化学吸附起到稳定剂的作用，有利于ＡＴＵ在电极表面形成致密的吸附层     

聚环氧氯丙烷聚氨酯／聚（甲基丙烯酸甲酯－苯乙烯）IPN的研究

改变聚（甲基丙烯酸甲酯－苯乙烯）（Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）中甲基丙烯酸甲酯的含量（Ｗ_（ＭＭＡ）），通过一步法合成出聚环氧氯丙烷聚氨酯（ＰＵ（ＰＥＣＨ）／Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）ＩＰＮ．ＤＳＣ、ＴＥＭ和动态粘弹谱研究结果表明：当Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）中Ｗ_（ＭＭＡ）大于０．６时，ＩＰＮ仅有一个Ｔｇ；当Ｗ_（ＭＭＡ）小于０．４时，ＩＰＮ有２个Ｔ_ｇ，ＴＥＭ上出现相区，Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）溶度参数（δ）及δ的氢键作用分量（δｈ）与相态、力学性能有密切关系。     

聚环氧丙烷聚氨酯／聚（甲基丙烯酸甲酯—苯惭烯）IPN的研究

改变聚（甲基丙烯酸甲酯－苯乙烯（Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）中 甲基丙烯酸甲酯的含量（ＷＭＭＡ），通过一步法合成出聚环氧氯丙烷聚氨酯（ＰＵ（ＰＥＣＨ）／Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）ＩＰＮ．ＤＳＣ、ＴＥＭ和动态粘弹谱研究结果表明：当Ｐ（ＭＭＡ＿ｃｏ－Ｓｔ）中ＷＭＭＡ大于０．６时，ＩＢＮ仅有一个Ｔｇ；当ＷＭＭＡ小于０．４时，ＩＰＮ有２个Ｔｇ，ＴＥＭ上出现相区，Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）深度参数（δ）及δ的氢键作     

高分子金属微球的磁性能研究

在苯乙烯和丙烯酸共聚物「Ｐ（Ｓｔ－ｃｏ－ＡＡ）」，苯乙烯和４－乙烯吡啶共聚物「Ｐ（Ｓｔ－ｃｏ－４ＶＰ）Ｎｉ、Ｐ（Ｓｔ－ｃｏ－４ＶＰ）Ｃｏ金属微球，研究了它们的交流磁化率，磁滞回线，居里温度等磁性能。结果表明制得的了的微球为软磁材料，热重（ＴＧ）分析了则得Ｐ（Ｓｔ－ｃｏ－ＡＡ）Ｎｉ和Ｐ（Ｓｔ－ｃｏ－４ＶＰ）Ｎｉ的居时温度（Ｔｃ）分别为１７５℃和１８０℃，远远低于块状金属的居里温度值。     

FTIR快速跟踪聚氨酯脲的反应注射成型研究

ＦＴＩＲ快速跟踪聚氨酯脲的反应注射成型研究罗宁，潘肇琦，王得宁，应圣康（华东理工大学材料科学研究所，上海，２００２３７）关键词聚氨酯脲，红外光谱，反应注射成型，动力学，相分离反应注射成型（ＲＩＭ）是生产聚氨酯制品的重要技术。以二醇扩链的聚氨酯的ＲＩＭ...     

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.     

Blends of a siloxane/urea/urethane-segmented copolymer with an IPDI-based polyetherurethane

A series of copolymer blends have been prepared using a poly(ether urethane) and a poly(siloxane–urea–urethane). The copolymers were prepared by a hardsegment first, two-step polymerization method. The hard segments of the copolymers were derived from isophorone diisocyanate (IP) and 1,4-benzenedimethanol (B), and the soft segments were based on polytetrahydrofuran (PTMO, M_w = 2000), and polydimethylsiloxane (PDMS, M_w =27,000), respectively. The siloxanecontaining copolymer, PDMS27K-IP-B2 (2 moles diol chain extender/mole PDMS27K), was used as the minor component (1.6, 2.5 and 6.0 wt%) in a series of blends. These blends were found to preserve the mechanical properties of the poly(ether–urethane) as well as the surface properties of the poly(siloxane–urea–urethane).     

Hydrogen bonding and crystallization in biodegradable multiblock poly(ester urethane) copolymer

The hydrogen bonding and crystallization of a biodegradable poly(ester urethane) copolymer based on poly(L ‐lactide) (PLLA) as the soft segment were investigated by FTIR. On slow cooling from melt, the onset and the progress of the crystallization of the urethane hard segments were correlated to the position, width, and relative intensity of the hydrogen‐bonded N? H stretching band. The interconversion between the “free” and hydrogen‐bonded N? H and C?O groups in the urethane units in the process was also revealed by 2D correlation analysis of the FTIR data. The crystallization of the PLLA soft segments was monitored by the ester C?O stretching and the skeletal vibrations. It was revealed that the PLLA crystallization was restricted by the phase separation and the urethane crystallization, and at cooling rates of 10 °C/min or higher, the crystallization of the PLLA soft segments was prohibited. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 685–695, 2009     

Structure and properties of segmented poly(urethaneurea)s with relatively short hard‐segment chains

We report the structure and properties of segmented poly(urethaneurea) (SPUU) with relatively short hard‐segment chains. The SPUU samples comprised poly(tetramethylene glycol) prepolymer as a soft segment and 4,4′‐diphenylmethane diisocyanate (MDI) units as a hard segment that were extended with ethylenediamine. To discuss quantitatively the conformation of the soft‐segment chain in the microphase‐separated domain space, we used SPUU samples for which the molecular weights of the hard‐ and soft‐segment chains are well characterized. The effects of the cohesive force in the hard‐segment chains on the structure and properties of SPUU were also studied with samples of different chain lengths of the hard segment, although the window of x_H, the average number of MDI units in a hard‐segment chain, was narrow (2.38 ≤ x_H ≤ 2.77). There were urethane groups in the soft segments and urea groups in the hard segments. Because of a strong cohesive force between the urea groups, we could control the overall cohesive force in the hard‐segment chains by controlling the chain lengths of the hard segment. First of all, microphase separation was found to be better developed in the samples with longer hard‐segment chains because of an increase of the cohesive force. It was also found that the interfacial thickness became thinner. The long spacing for the one‐dimensionally repeating hard‐ and soft‐segment domains could be well correlated with the molecular characteristics when the assumption of Gaussian conformation was employed for the soft‐segment chains. This is unusual for strongly segregated block copolymers and might be characteristic of multiblock copolymers containing rod–coil chains. The tensile moduli and thermal stability temperature, T_H, increased with an increase of the cohesive force, whereas the glass‐transition temperature, the melting temperature, and the degree of crystallinity of the soft‐segment chains decreased. The increase in T_H especially was appreciable, although the variation in the chain length of the hard segment was not profound. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1716–1728, 2000     

Influence of the soft segment length on the properties of water‐cured poly(carbonate‐urethane‐urea)s

Poly(carbonate‐urethane‐urea)s (PCUU) based on oligocarbonate diols (M_n ≈ 2000) with different length of the hydrocarbon chain as soft segments were synthesized and investigated. Carbonate oligomerols were obtained in a two‐step method from dimethyl carbonate (DMC) and linear α,ω‐diols (1,4‐butanediol, 1,5‐pentanediol, 1,6‐hexanediol, 1,9‐nonanediol, 1,10‐dekanediol and 1,12‐dodecanediol). Oligo(trimethylene carbonate) diol was synthesized using ring‐opening polymerization of trimethylence carbonate. PCUUs were obtained by prepolymer method using isophorone diisocyanate (IPDI) and water as a chain extender. Changes in polymers properties with increase of methylene group number between carbonate linkages were investigated by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), tensile strength and hardness measurements. The thermal stability was also analyzed by means of thermogravimetric analysis (TGA). Based on FTIR analysis influence of methylene groups number between carbonate linkages on phase separation and concentration of allophanate and biuret groups in the samples were investigated. The obtained poly(carbonate‐urethane‐urea)s exhibited very good mechanical properties. Tensile strength and elongation at break were 40 MPa and 400–600%, respectively, depending on the oligocarbonate used. Copyright © 2014 John Wiley & Sons, Ltd.     

Phase separation in segmented poly(urethane urea) copolymers during reaction injection molding (RIM) polymerization

In situ experiments were performed with a portable RIM (reaction injection molding) minimachine interfaced to an FTIR spectrophotometer to follow the reaction chemistry and monitor phase separation of copoly(urethane urea)s during RIM polymerization. The PUU copolymers were based on ethylene oxide-capped poly(propylene oxide) polyether diol, 3,5-diethyltoluenediamine (DETDA), and uretonimine liquefied 4,4′-diphenylmethane diisocyanate. The effect of catalyst concentration on the degree of phase separation in the as-molded RIM PUU copolymers was investigated by using differential scanning calorimetery and scanning electron microscopy as supplementary methods. The results suggested that an increase of degree of phase separation and a decrease of the size of hard-segment-rich domains take place with a rise of catalyst concentration. The morphological feature was a consequence in combination with the increase in relative rate of urethane formation and the ordering of hydrogen bonding through urea groups. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35 : 865–873, 1997.     

Structure formation of hydrophobically end-capped poly(ethylene oxide) in the solid state

The conformational transition of hydrophobically end-capped poly(ethylene oxide), HP-PEO-HP [hydrophobic-poly(ethylene oxide)-hydrophobic], was studied using X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR) methods. Conformational transitions of HP-PEO-HP from a planar zigzag to a 7/2 helical conformation were observed as the molecular weight of the PEO main chain increased. HP-PEO-HP 1(18), with a PEO molecular weight of 1000 and 18 hydrocarbons on each end, has mainly an alpha-helical structure in poor solvents, whereas alpha and beta conformations coexist in good solvents. This means that the alpha-helical structure caused by the hydrogen bonds between the urethane linkages was broken by the high chain mobility caused by the melted adjacent chains of PEO, and instead, the beta-sheet was formed by the interaction of multiple hydrogen bonds. Another indication of hydrogen bonds breaking at increasing temperature is the transition of the N-H stretching peak in the FTIR data. HP-PEO-HP 2(18) and 4(18), which have 18 hydrocarbons on each end and PEO molecular weights of 2000 and 4000, respectively, and consist mostly of PEO, showed spherulites. This result also suggests that the PEO molecule has a 7/2 zigzag helical conformation. In contrast, HP-PEO-HP 1(18), which is composed of less PEO than HP-PEO-HP 2(18) and 4(18), did not show a spherulite structure.     

Preparation and characterization of waterborne poly(urethane urea) with well‐defined hard segments

A series of polyester‐based poly(urethane urea) (PUU) aqueous dispersions with well‐defined hard segments were prepared from polyester polyol, 4,4′‐diphenylmethane diisocyanate, dimethylolpropionic acid, 1,4‐butanediol, isophorone diisocyanate, and ethylenediamine. These anionic‐type aqueous dispersions had good dispersity in water and were stable at the ambient temperature for more than 1 year. For these aqueous dispersions, the particle size decreased as the hard‐segment content increased, and the polydispersity index was very narrow (<1.10). Films prepared with the PUU aqueous dispersions exhibited excellent waterproof performance: the amount of water absorption was as low as 5.0 wt %, and the contact angle of water on the surface of this kind of film was as high as 103° (this led to a hydrophobic surface). The water‐resistant property of these waterborne PUU films could be well correlated with some crystallites and ordered structures of the well‐defined hard segments formed by hydrogen bonding between the urethane/urethane groups and urethane/ester groups, as well as the degree of microphase separation between the hard and soft segments in the PUU systems. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2606–2614, 2005     

Enhanced self-healing driving force in polymer materials by regulating molecular structure

For self-healing polymers, obtaining excellent healing ability and mechanical properties usually need complex chemical structure, external healing conditions, and high manufacturing difficulty. Therefore, self-healing efficiency and rate, mechanical strength, and simple structure design as well as no additional healing conditions of the material are contradictory properties and are difficult to optimize simultaneously. Herein, self-healable thermoplastic poly (urethane urea) elastomers driven by surface energy were fabricated by the introduction of asymmetric alicyclic structures and the healing properties in polymers were optimized by regulating surface energy. The results showed that with the increasing of isophorone diamine contents, the surface energy driving force increased from 36 kPa to 149 kPa, the healing time decreased from 30d to 5d, and healing efficiency, and tensile strength reached 100.9% and 4.04 MPa at room temperature. At the same time, polymers also obtained a high healing efficiency under high-temperature healing conditions. The healing mechanism is that asymmetric alicyclic structures with steric hindrance and ring flip promote the dissociation of hydrogen bonds, provide sufficient chain mobility, decrease the junction density, and improve the surface energy as well as the dissociation and reconstruction of hydrogen bonds. Energetic polymer composites using thermoplastic poly (urethane urea) elastomers as matrix obtained excellent healing properties. This study will offer a novel healing approach for developing advanced self-healing polymer materials.