丁苯、丁腈基聚氨酯的形态与性能

用示差扫描量热法 (DSC)、红外分光光度计 (FTIR)和原子力显微镜 (AFM)研究了端羟基聚丁二烯 苯乙烯共聚物 (HTBS)、端羟基聚丁二烯 丙烯腈共聚物 (HTBN)和端羟基聚丁二烯 (HTPB)与甲苯二异氰酸酯、1 ,4 丁二醇构成的溶液法聚二烯烃基聚氨酯 (PU)的形态结构 .结果表明HTPB和HTBS基PU的相分离程度很大 ,而HTBN基PU的相分离程度小 .这可能归因于HTBS软段的极性低 ,不能与硬段形成氢键 ,而HTBN软段中的腈基具有很强的极性 ,且可以与硬段形成氢键作用 ,增加了软硬段间的相容性 ,相分离程度明显降低 .AFM表明HTBN PU随着硬段含量提高 ,表面粗糙度增大 ,由软段为连续相逐渐过渡到双连续结构 .在硬段含量 6 3%时 ,HTBN和HTPB基PU均呈双连续结构 ,而HTBS PU中硬段为连续相 .HTBN PU软段的相区尺寸在1 2nm左右 ,表面粗糙度较大 ,HPBS PU软段的相区尺寸在 1 1nm左右 ,表面粗糙度最小 ,HTPB PU存在 1 4nm和 5 0nm大小不等的软段相区尺寸 .力学性能表明 ,在软段中引入苯乙烯和丙烯腈结构 ,可使聚氨酯抗张强度分别提高 1 5和 2倍 ,模量和断裂伸长率也明显提高     

提高聚氨酯表面硅橡胶涂层粘接性研究

利用表面处理并借助硅烷偶联剂大幅提高了聚氨酯/硅橡胶(PU/SR)的界面粘接性.利用红外光谱、水接触角以及表面元素分析对PU表面处理效果及偶联剂的反应效果进行检测,利用扫描电镜对材料的表面形貌及界面情况进行观察.并对不同方法得到的PU/SR界面进行剪切和振动疲劳测试以考察其粘接效果并进行比较.结果表明,经过硫酸短时处理过的PU表面生成大量羟基,使得亲水性提高,并大大增强了端异氰酸酯基硅烷偶联剂与PU的接枝反应效果.当室温缩合固化的硅橡胶预聚体涂覆到其表面后,以化学键联接在PU表面的硅烷偶联剂又可以与硅橡胶一起缩合,从而有效的提高了PU/SR的界面粘接性.     

新型聚氨酯基液晶光定向层材料的合成与性能研究

设计并合成了一种新的二醇单体 5 羟基 1 ,3 间苯二甲酸二 (2 羟基 )乙酯 [Di(2 hydroxyethyl) 5 hydroxylisophthalate,DHHI],并用各种手段对其进行了表征 .DHHI与二苯基甲烷 4 ,4′ 二异氰酸酯 (MDI)溶液聚合得到一种侧链含有酚羟基的先驱聚合物PU OH ,通过肉桂酰氯的功能化反应制备出新型光敏聚氨酯 (PU CI) .用示差扫描量热分析 (DSC) ,红外光谱 (FT IR) ,紫外可见光谱 (UV Vis)等对PU CI进行了表征 .研究表明 ,PU CI在紫外光的照射下可发生环 (2 +2 )加成反应 .PU CI经线性偏振光聚合技术 (LPP)处理制成液晶光定向层 ,采用向列型液晶 5CB组装成液晶盒 ,在偏光显微镜下可以观察到均匀的液晶取向 ,表明该聚合物膜具有很好的液晶定向能力 ,是一类具有潜在应用价值的新型液晶光定向层材料     

聚氨酯环氧树脂乳液互穿聚合物网络结构与性能研究

分别以聚四氢呋喃(PTMG)和聚己二酸丁二酯(PBA)为聚氨酯(PU)软段,制备了高环氧树脂(EP)含量的PU/EP乳液互穿聚合物网络(LIPN).通过红外光谱,动态力学分析,原子力显微镜等研究了不同类型软段对LIPN结构与性能的影响.结果表明,LIPN结构已经形成,PU与EP间无化学键结合.以PBA为PU软段制备的LIPN中PU与EP相容性更好,分相程度相对低,互穿程度高,导致EP对PBA软段运动的限制作用较强,EP含量的变化对LIPN的玻璃化转变温度影响更大.研究样品的力学性能和溶剂溶胀性能发现,PBA为软段制备的LIPN均优于以PTMG为软段制备的LIPN,水溶胀率等有大幅减小,表现出明显的互穿协同效应.     

PAA/PU合金制备多孔PI薄膜及结构与性能研究

以N,N-二甲基乙酰胺(DMAc)为溶剂, 在聚氨酯(PU)溶液中使均苯四酸二酐(PMDA)与4,4′-二氨基二苯醚(4,4′-ODA)缩聚成聚酰亚胺(PI)预聚体聚酰胺酸(PAA), 从而制成PAA/PU的混合溶液, 然后刮涂成膜, 经过热处理使得PAA亚胺化和PU降解, 制备多孔PI薄膜. 通过对薄膜进行红外光谱,热失重分析及透射电镜(TEM)观察, 结果表明, 最佳的PU热降解温度为360 ℃, PU降解后在PI基体中留下长条状纳米孔, 且孔径大小随聚氨酯含量的增加而增大. 通过对薄膜进行力学性能、 介电性能和吸水率研究, 结果表明, 随着体系中PU用量的增加, 热处理后的多孔PI薄膜的介电常数逐渐下降, 但拉伸强度降低, 吸水率上升.     

具有超支化结构的聚醚型脂肪族聚氨酯弹性体的合成与表征及力学性能研究

用聚四氢呋喃醚二醇、端羟基超支化聚酯(HB-20)、异佛尔酮二异氰酸酯和1,4-丁二醇,合成了含有超支化结构的聚醚型脂肪族聚氨酯(PU)弹性体.通过Flory-Rehner公式计算了体系的交联密度;用FT-IR、WAXD和DSC表征了超支化PU的氢键化程度和形态.实验结果表明,在PU弹性体中引入少量的HB-20,能提高氨基甲酸酯羰基的氢键化程度和软硬段间的微相分离程度,从而显著提高材料的拉伸强度.由于氢键化程度和交联密度双重效应的影响,含6 wt%HB-20的聚醚型PU与不含HB-20的PU相比拉伸强度提高了2倍多,达到37.9 MPa,断裂伸长率仍高达414%.     

阳离子型自乳化端羟基硅油/聚氨酯微乳液的形态及流变性能

在催化剂和少量助溶剂的作用下,以端羟基硅油(HPMS)/聚(四亚甲基醚)二醇(PTMG)为软段,异佛尔酮二异氰酸酯(IPDI)为硬段单体,以三羟甲基丙烷TMP为交联剂、N-甲基二乙醇胺(MDEA)为扩链剂合成了一系列自乳化双软段HPMS/PU微乳液.分析了HPMS用量对HPMS/PU微乳液粒径及微观形态的影响;研究了HPMS/PU中HPMS含量、MDEA用量、TMP用量、预聚体分子量对其流变性能的影响.研究结果表明,HPMS的加入使乳液粒径增加,HPMS/PU乳液为非牛顿流体,且具有一定的假塑性和触变性,表观粘度随切变速率的变化规律呈现一定的切力变稀特征,流动指数范围为0.885~0.531之间;其零剪切粘度值为13.59~25.08mPa.s,随HPMS用量、MDEA用量、预聚体相对分子质量、TMP用量而异.     

组分对含羟基磷灰石/脂肪族聚氨酯复合骨组织工程支架的理化性能及生物学性能的影响

以异佛尔酮二异氰酸酯为聚氨酯硬段,通过原位聚合使聚合过程中释放的气体发泡,制备了用作骨组织工程材料的羟基磷灰石/脂肪族聚氨酯多孔支架.系统考察了不同组成配方,即羟基磷灰石(HA)含量、发泡剂含量以及聚氨酯(PU)软硬段的比例对三维支架材料的机械性能和微观孔隙结构等的影响,并通过体外细胞培养和体内肌肉植入初步评价了该复合...     

端羟基聚丙烯酸酯改性水性聚氨酯

将丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)通过溶液自由基聚合,用巯基乙醇作为链转移剂调控合成了一定分子量的端羟基聚丙烯酸酯(PA),再与聚氨酯(PU)预聚体反应,在水中分散得到PA-PU-PA三嵌段共聚复合乳液。 采用FTIR和¹HNMR测试技术对共聚物结构进行了表征。 结果表明,随着PU与PA质量比的降低,共聚物中丙烯酸酯含量随之增加;PU软硬链段之间的氢键化作用减弱。 TEM显示,复合乳胶粒子形态均匀规整,并呈现明显的核壳结构。改性后的乳胶膜耐水、耐热性能均随着PU/PA质量比的减小而提高,吸水率由25%降低至5%,最大热失重温度由369 ℃提高至432 ℃。     

纳米层状双金属氢氧化物改性PU/PMMA的制备及其弛豫行为

采用原位聚合法,制备了聚氨酯(PU)/聚甲基丙烯酸甲酯(PMMA)/层状双金属氢氧化物(LDH)纳米复合体系(PU/PMMA/LDH).通过广角X射线衍射(WXRD)、透射电子显微镜(TEM)对其结构和形貌进行了表征,并通过热失重(TGA)、动态力学分析(DMA)和宽频介电谱(BDRS)研究了LDH含量(φ)对PU/PMMA体系热稳定性和弛豫行为的影响.结果表明,当φ<1 wt%时,LDH在聚合物基体中以剥离结构为主,PU/PMMA/LDH体系的玻璃化温度(Tg)降低,最大损耗因子(tanδmax)增大;而当φ>1 wt%时,LDH在聚合物基体中以插层结构为主,插层结构对聚合物分子链的限制使复合体系的Tg升高、tanδmax降低.LDH表面与PU硬段间的氢键作用,使复合体系的α介电弛豫转变随φ增加而向高温方向移动,弛豫过程激活参数增大.     

Determination of Crosslinking and Grafting in Polyurethane-acrylic Hybrid Material and Their Theoretical Calculations

A theoretical method to calculate the mode of polyurethane(PU) prepolymers grafted to polyacrylic(PAC) was presented. Using hydroxyethyl acrylate(HEA) as coupling agent, polyurethane-acrylics(PU-AC) hybrid latexes were prepared with varying HEA level and the reaction of HEA with PU prepolymers at different temperatures, and PU grafted to PAC was experimentally determined. The results show that PU grafted to PAC regularly increased, and the non-grafted and linear free PU regularly decreased with increase in ...     

丙烯酸羟乙酯对丙烯酸酯改性水性聚氨酯性能的影响

以异佛尔酮二异氰酸酯、二羟甲基丙酸和聚丙醚二醇等为聚氨酯原料, 丙烯酸丁酯、甲基丙烯酸甲酯、三羟甲基丙烷三丙烯酸酯为丙烯酸酯类单体, 丙烯酸羟乙酯(HEA)为聚氨酯和聚丙烯酸酯间的偶联剂合成了丙烯酸酯改性水性聚氨酯(PU-AC)乳液. 首先建立并验证了一种测定PU接枝率, 即PU与丙烯酸酯发生接枝的部分占PU总数的百分比的方法, 然后探讨了加入HEA后的反应温度和HEA用量对PU接枝率、PU-AC乳胶粒径、胶膜吸水率和交联度等性能的影响. 随着HEA与PU预聚体反应温度和HEA用量的提高, 体系中的最终残余NCO逐渐降低. 当HEA用量低于其加入前体系中残余NCO量时, 增加其用量使PU接枝率和PU-AC乳胶粒径逐渐增加; 当HEA用量大于体系残余的NCO量后继续增加其用量对PU接枝率和PU-AC乳胶粒径的影响不大. 胶膜吸水率随着HEA用量的增加而降低.     

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)...     

Structure and properties of polyurethane/polyacrylate latex interpenetrating networks hybrid emulsions

Some new kinds of novel polyurethane (PU)/polyacrylate (PA) latex interpenetrating networks (LIPNs) were synthesized. Firstly PU dispersions were synthesized by self-emulsification polymerization. Then PU/PA LIPNs using PU dispersion as the seed were prepared by soap free emulsion polymerization. The effects of different PU/PA ratios, the blending method and the NCO/OH molar ratio of PU components on PU/PA LIPNs performance were also investigated. The structure and properties of PU/PA LIPNs such as mechanical properties, particle size, morphology of the surface were characterized by dynamic mechanical analysis, scanning electron microscopy, and dynamic light scattering. It was found that PU/PA LIPNs can markedly improve the water resistance and the mechanical properties of PU latex much more than those of PU/PA physical blends due to a great deal of interpenetrating and entangling between PU and PA latex. Moreover, the particle size of PU/PA LIPNs is related to the PA content and NCO/OH molar ratio of PU components: the higher the NCO/OH molar ratio in PU dispersions, the larger is the particle size of PU/PA LIPNs, and the average particle size of PU/PA LIPNs becomes larger with an increase in PA content.     

Chemical graft polymerization of sulfobetaine monomer on polyurethane surface for reduction in platelet adhesion

Surface modification is an effective way to improve the hemocompatibility and remain bulk properties of biomaterials. Recently, polymer tailored with zwitterions was found having good blood compatibility. In this study, the zwitterionic monomer of sulfobetaine was graft polymerized onto polyurethane (PU) surface in a three-step heterogenous system through the vinyl bonds of acrylic acid (AA) or hydroxyethyl methacrylate (HEMA), which was immobilized with hexamethylene diisocyanate (HDI) beforehand. First, PU was activated with isocyanate groups using HDI as coupling agent. Second, AA or HEMA was introduced through reaction of AA or HEMA with NCO groups bonded on PU surface. Last, zwitterionic monomer of sulfobetain was graft polymerized with vinyl group of AA or HEMA using AIBN as polymerization initiator. The reaction process was monitored with ATR-IR spectra and XPS spectra. Variation of graft yield with temperature and monomer feed concentration was investigated and feasible conditions were optimized. The wettability of films was investigated by water contact angle measurement and water absorbance. Platelet adhesion experiment was conducted as a preliminary test to confirm the improved blood compatibility of PU. The number of platelets adhering to PU decreased greatly comparing with the originals after 1 and 3 h of contact with human plate-rich plasma (PRP).     

Effects of altered reaction conditions on the synthesis of polyurethane-poly(2,2,2-trifluoroethyl methacrylate) triblock copolymer aqueous dispersion

Polyurethane-poly(2,2,2-trifluoroethyl methacrylate) (PU-PTFEMA) triblock copolymer aqueous dispersions were synthesized by three-step polymerization. In the first step, polyurethane prepolymers (PU) based on 2,4-toluene diisocyanate (TDI), polyether binary alcohol (N₂₂₀), α,α-dimethylol propionic acid (DMPA), hydroxypropyl acrylic acid (HPA), and butanediol (BDO) were prepared with butanediol as the chain extender and methylethylketon as solvent. The next step involved neutralization and dispersion in water, where prepolymers were neutralised by the addition of triethylamine (TEA). The last step was the seeded emulsion polymerization, where PU emulsion was used as seed, kalium persulfate (KPS) as initiator and 2,2,2-trifluoroethyl methacrylate (TFEMA) as comonomer. Factors influencing the synthesis of PU-PTFEMA copolymer aqueous dispersion were studied. Experimental data indicate that factors influencing the synthesis of PU-PTFEMA copolymer aqueous dispersion mainly involve reaction temperature, reaction time, the concentration of initiator, DMPA content, TFEMA content. Rotational viscometer and dynamic light scattering (DLS) were used to characterize the properties of copolymer aqueous dispersion.     

Synthesis and characterization of hyperbranched polyurethane-urea coatings

A series of hyperbranched polyurethane (HBPU)-urea coatings were synthesized by a systematic two-step reaction process. Initially, isocyanate terminated PU prepolymers were prepared from a hyperbranched polyester polyols with isophorone diisocyanate at NCO/OH ratio of 1.6:1 for 5 h at 70-80 °C. The excess NCO content after the synthesis of NCO terminated HBPU prepolymer was completely reacted with atmospheric moisture. The obtained HBPU-urea networks were characterized with Fourier transform-infrared (FT-IR) spectroscopy for the quantitative evolution of the extent of urethane and urea bonds as well as to study the structure-property relationship. In order to find out the changes and types of intermolecular H-bonding interaction in the HBPU-urea films with the variation in polyester structure, the deconvolution of FT-IR spectra were carried out using Origin 6.0 software through Gaussian curve-fitting method. The viscoelastic properties and thermal stability of the synthesized coatings were determined by dynamic mechanical and thermal analyzer and thermogravimetric analyzer, respectively. For HBPU-urea samples glass transition temperature and thermal stability increased with the generation number from the first to the third. Polyester samples showed single step decomposition profile and HBPU-urea samples showed two-steps decomposition with good thermal stability.     

聚醚聚氨酯/环氧树脂互穿网络聚合物的研究(Ⅱ)

合成了不同类型聚醚聚氨酯/环氧树脂(PU/EP)互穿网络聚合物(IPN),通过改变PU中聚乙二醇分子量、3OH/2OH及NCO/OH比值等,研究IPN组份间分子混合程度,采用电镜、动态力学分析及应力应变等测试方法表征。结果表明:聚乙二醇分子量降低及3OH/2OH、NCO/OH比的提高,可使相容性提高,材料力学性能增强。     

聚氨酯/环氧树脂互穿网络硬质泡沫塑料反应过程和微观结构

聚氨酯／环氧树脂互穿网络(PU／EPIPN)硬泡中异氰酸根的消耗速度较纯PU硬泡高，是由于环氧树脂的固化荆同时也是异氰酸根反应的催化荆。而PU／EP IPN硬泡中环氧基的反应速度和反应程度均较纯EP网络低，归因于互穿网络对基团扩散的阻碍。在互穿网络硬泡形成过程中，存在环氧开环中所新产生的羟基与异氰酸根的反应、大分子多元醇中羟基与环氧基的反应以及异氰酸根与环氧基形成嗯唑烷酮的反应三种形成网络间的化学键的途径。同时由于PU／EPIPN硬泡高度的交联，使得IPN硬泡中两个网络具有良好的相容性。动态力学性能表明所有IPN样品都只有一个玻璃化温度。透射电镜表明IPN样品无明显的相界面。     

端羟基聚丁二烯型聚氨酯/聚苯乙烯(或聚甲基丙烯酸甲酯)互穿网络的形态和玻璃化转变

互穿聚合物网络(IPN'S)已经成为高聚物共混改性,高聚物间相容性的一个重要研究领域,IPN材料的宏观性能与其微观形态有着密切的关系,如能通过改变结构、组成、交联密度及合成条件等因素来控制IPN的形态,则就可以入为地制备各种性能优良的材料。本文用透射电镜和差示扫描量热仪对同步法合成的端羟基聚丁二烯型聚氨