基于水性聚氨酯端氨基测定的二次扩链研究

在准确测定水性聚氨酯分散体端氨基含量的基础上,采用二异氰酸酯对分散状态下的水性聚氨酯分散体进行二次扩链,研究了不同条件下二次扩链前后分散体端氨基含量、涂膜力学性能以及分散体粒径的变化。研究表明:二次扩链剂可以与水性聚氨酯分散体的端氨基反应;二次扩链可大幅度提高涂膜拉伸强度,而涂膜模量略有上升,说明反应形成扩链而非交联;扩链后分散体粒径略有增加,表明二次扩链不影响分散体稳定性。     

一种易乳化的阳离子型水性聚氨酯分散体的制备

为了解决阳离子型水性聚氨酯制备后期黏度较大、乳化困难的问题,通过改变亲水扩链剂的投料方式,得到一种工艺可控、易乳化的阳离子型水性聚氨酯分散体的制备方法.首先合成一种异氰酸酯封端的聚氨酯预聚体,将其逐步滴加到阳离子型亲水扩链剂的底料中,制备一种黏度适中、易于乳化的阳离子型聚氨酯预聚体,再将其乳化后得到阳离子型水性聚氨酯分...     

丙烯酸改性水性聚氨酯合成方法

介绍了聚氨酯预聚物分散制各水性聚氨酯的方法，讨论了丙烯酸酯改性对水性聚氨酯涂膜的性能影响。分析了亲水性物质、交联剂、扩链剂、引发剂、中和剂、有机溶剂等对水性聚氨酯涂膜外观及性能的影响。     

乙二胺扩链剂对水性聚氨酯性能的影响

以聚醚220、异佛尔酮二异氰酸酯(IPDI)为主要原料,二羟甲基丙酸(DMPA)为亲水性扩链剂,丁二醇(BD)和乙二胺(EA)为小分子扩链剂,按不同配比合成了系列水性聚氨酯分散体。主要考察了乙二胺扩链剂用量对水性聚氨酯乳液的稳定性、乳液粒径、粘度以及膜吸水性和力学性能的影响。结果表明,随乙二胺扩链剂用量的增加,乳液粒径增大、分散稳定性变差、粘度减小、胶膜的拉伸强度增加、断裂伸长率减小、耐溶剂性增加、吸水率变化不明显、硬段相Tg升高,软硬段相分离程度增加。胶膜的ATR红外表现为PPG类聚醚型聚氨酯典型的红外光谱。     

阳离子水性聚氨酯的合成与性能

采用不同聚合工艺对5种聚酯或聚醚二元醇、4种二异氰酸酯与N.甲基二乙醇胺亲水扩链剂合成阳离子水性聚氨酯进行了研究.结果表明,多元醇中加入亲水扩链剂后再加入多异氰酸酯进行加成聚合的工艺有较好的适用性,可制备稳定的阳离子水性聚氨酯.在35℃下进行水分散所得阳离子聚氨酯的乳液性能和膜力学性能好于70℃水分散的聚氨酯,其中拉伸强度最大可提高3倍以上.对不同亲水扩链剂含量和硬段含量的阳离子水性聚氨酯的研究表明,硬段含量达到30%(ω)以上时,亲水扩链剂用量增加,乳液的粒径变小,稳定性增加,聚氨酯膜的拉伸强度提高.由热性能分析可知,硬段含量达40%(ω)以上时,水性阳离子聚氨酯膜中的软、硬段有序结构被破坏,而其玻璃化转变温度在15℃以上.     

悬臂型阳离子水性聚氨酯分散体的合成

以2-乙基 -2-羟甲基氧杂环丁烷与二甲胺为原料，合成了一种亲水离子位于聚氨酯结构的侧链、且结构中不含有 β氢的阳离子亲水扩链剂 ——N，N-二甲基 -2-（二羟甲基）丁胺（DMDMOBA），将其作为扩链剂合成了阳离子水性聚氨酯。采用 ¹H NMR和液质联用对 N，N-二甲基 -2-（二羟甲基）丁胺进行结构表征，采用马尔文激光粒度仪对阳离子水性聚氨酯乳液的粒径进行测试，采用拉伸试验机对聚氨酯胶膜拉伸强度进行测试。结果表明：与常用阳离子亲水扩链剂 N-甲基二乙醇胺（MDEA）比较，新型扩链剂合成的阳离子水性聚氨酯的亲水离子位于聚氨酯侧链，其自乳化能力好于主链型阳离子水性聚氨酯，且具有更好的抗黄变性能，合成的水性聚氨酯胶膜力学性能也优于主链型阳离子水性聚氨酯。     

密集侧链有机硅改性水性聚氨酯分散体的合成与胶膜表面性能

首先采用单端双羟基聚硅氧烷与二异氰酸酯反应合成了硅氧烷密集侧链片段，而后与二异氰酸酯、聚醚（聚酯）二元醇、二羟甲基丙酸、小分子扩链剂合成有机硅侧链密集集中于聚氨酯链段中某些区域的改性水性聚氨酯分散体。采用GPC追溯了反应过程，采用接触角测定仪、XPS、SEM表征了胶膜表面特性；采用接触角测定仪研究了胶膜在水中浸泡72 h后表面疏水性变化。结果表明：密集侧链改性水性聚氨酯胶膜表面有机硅富集程度远高于对应的随机侧链改性水性聚氨酯，同时密集改性水性聚氨酯胶膜在水中浸泡72 h后，胶膜表面疏水性保持且略有提高。     

水性聚氨酯亲水性扩链剂的研究进展

水性聚氨酯在涂料、医学、胶黏剂等领域都有着广泛的应用,而扩链剂是合成聚氨酯的一种关键原料。在扩链剂上引入某些特征基团就会对聚氨酯的性能产生一定的影响,亲水性扩链剂可以使水性聚氨酯具有良好的分散性或自乳化性能。羧酸型和磺酸型亲水扩链剂是目前使用较为普遍的阴离子型亲水扩链剂材料。该文简述了扩链剂的定义、作用以及亲水性扩链剂的种类,综述了羧酸型和磺酸型亲水扩链剂的研究进展,详细分析了磺酸型水性聚氨酯的高耐水性、高柔软性,高固含量等性能以及相比于羧酸型水性聚氨酯在各方面性能上的优势。文中还简述了非离子型亲水扩链剂和两性亲水扩链剂的研究进展,并就成本、合成路线及环保方面对亲水性扩链剂的发展趋势作了展望。     

研究与述评

201102098扩链剂和选择性催化剂对水性聚氨酯分散体的热氧化稳定性的影响[刊，英]／Cakic，SuzanaM．等／／ProgressinOrganicCoatings．-2010，67（3）．-274～280     

扩链剂对含氟聚氨酯乳液性能的影响

采用预聚体分散法合成含氟聚氨酯乳液，分析了扩链剂种类及含量对乳液性能的影响。研究发现不同的扩链剂对含氟聚氨酯乳液的稳定性有不同的影响，而对于同一种扩链剂因其含量的不同对乳液性能影响也有差异。     

低温柔韧型水性聚氨酯丙烯酸酯复合分散体的合成与性能

以甲苯二异氰酸酯(TDI-80)、聚醚二元醇(N220)、1,4-丁二醇(BDO)、二羟甲基丙酸(DMPA)、环氧树脂(E-20)和甲基丙烯酸甲酯(MMA)等用原位合成技术制备具有核壳结构的水性聚氨酯-丙烯酸酯(WPUA)复合分散体。研究了环氧树脂(E-20)、MMA加入量等对分散体及涂膜性能的影响,从而确定了最佳合成配方,获得了具有优良的低温成膜性好、贮存稳定性好、高硬度、耐有机溶剂性佳和附着力强的水性聚氨酯涂料。     

Phosphated polyurethane-acrylic dispersions: synthesis, rheological properties and wetting behaviour

Phosphated polyurethane-acrylic dispersions were prepared by a new method that is free from organic solvents and requires a very low dispersion force. After the carboxylic acid groups of the phosphated polyurethane were neutralised by suitable bases, water was added to form the phosphated polyurethane seed dispersion. Polyurethane-acrylic dispersions were obtained from the phosphated polyurethane seed by emulsion copolymerisation. The polyurethane seed polymer was found to be stable over the initiator concentration used and the rheological properties of the polyurethane acrylics were found to follow Newtonian behaviour under the prescribed experimental conditions. This is a good indication that the dispersions may be used as pigment wetting media. The dynamic contact angle study showed the poor wettability of the phosphated polyurethane-acrylic dispersion films, indicating good hydrophobicity.     

Study of ionic/nonionic polyurethane dispersions with high solid content and low viscosity using a complex hydrophilic chain-extending agent

An ionic/nonionic polyurethane dispersion with high solid content and low viscosity with a complex hydrophilic chain-extending agent was prepared using isophorone diisocyanate as a hard segment and propylene oxide glycol as a soft segment. The complex hydrophilic chain-extending agent consisted of DPSA and BDSA. The effects of the molar ratio of DPSA/BDSA on the properties of the resultant polyurethane dispersions were studied. The morphologies and properties of the ionic/nonionic PU dispersions were examined using particle-size, TEM, and viscosity analyses. It was found that the ionic/nonionic dispersions possessed wide particle-size distributions due to the addition of the complex hydrophilic chain-extending agent. The ionic/nonionic PU dispersions possessed higher solid content than conventional WPU dispersions because the number and volume percentage of the large particles and small particles of the ionic/nonionic dispersions met the requirements for high solid content. It was observed that the solid content of the ionic/nonionic dispersion increased and then decreased with an increasing molar ratio of DPSA/BDSA. When the ratio ranged from 4:10 to 5:10, the solid content of the ionic/nonionic PU dispersion reached up to 55%. It was also noticed that the apparent viscosity of the ionic/nonionic polyurethane dispersion decreased with an increasing molar ratio of DPSA/BDSA. The complex hydrophilic chain-extending agent consisting of DPSA and BDSA enhanced the solid content and decreased the viscosity of the ionic/nonionic dispersions, which are very important for improving the properties and expanding the applications of PU dispersions. In addition, the ionic/nonionic polyurethane dispersion had good electrolyte-resistance properties, stability at both high and low temperatures, and storage stability.     

超支化聚氨酯水分散体的合成及其涂膜性能

将聚氨酯预聚体接枝到以双季戊四醇为核、二羟甲基丙酸为单体的超支化聚酯上,得到了超支化聚氨酯水分散体。采用IR、SEM和化学滴定等方法对产物进行了表征和分析。结果表明,超支化聚氨酯水分散体的粒径约100nm,并在水中有良好的分散性和稳定性;其树脂具有良好的成膜性、耐水性和物理机械性能。     

双组分水性聚氨酯涂料的合成与表征

随着环境法规对涂料的挥发性有机化合物（VOC）含量的限制，高性能与低VOC含量相结合的双组分水性聚氨酯涂料成为涂料工业发展的趋势。采用三羟甲基丙烷（TMP）为扩链剂合成具有交联结构的水性聚氨酯分散体多元醇，与多异氰酸酯固化剂组成双组分水性聚氨酯涂料。研究发现双组分涂膜的机械性能和外观是由合成的水性聚氨酯多元醇的扩链剂（TMP）含量，中和度，中和工艺和双组分涂料的配比等决定的。当扩链剂含量为2％－4％，中和度为100％，NCO:OH=1．0－1．2时所得双组分水性聚氨酯涂膜外观好，快干，硬度高和施工方便。     

Structure and property characterization of nanograde core‐shell polyurethane/polyacrylate composite emulsion

Anionic aqueous polyurethane dispersion was synthesized through self‐emulsifing method from cycloaliphatic isophorone diisocyanate (IPDI) and dimethylolpropionic acid (DMPA). The carboxyl acid group in DMPA was used to make the polyurethane dispersible. The polyurethane/polyacrylate (PU/PA) composite particles were also prepared by seeded surfactant‐free emulsion polymerization; the cycloaliphatic polyurethane aqueous dispersion was used as seed particles. The structures and properties of the composite emulsion as well as the physical mixture of polyurethane dispersion and polyacrylate emulsion were characterized by FTIR, DSC, dynamic light scattering, TEM, X‐ray photoelectron spectroscopy (ESCA), and electronic tensile machine. The results showed that the synthesized PU/PA composite emulsion was found to form inverted core‐shell structure with polyacrylate as the core and with polyurethane as the shell, and its diameter of particles is in the range of nanograde, the crosslinking reaction was existed in composite emulsion. The intimate molecular mixing of crosslinking polymers are also claims to result in a superior balance of properties compared to physical blends of polyurethane dispersion and acrylate emulsion. The crosslinking mechanism of PU/PA composite emulsion was also discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

聚氨酯/碳纳米管功能复合材料的电学性能研究

采用溶液共混法制备了聚氨酯(PUR)/碳纳米管(CNTs)功能复合材料,并分别利用磁力分散和超声分散方法对CNTs进行分散,探讨了CNTs含量对PUR/CNTs复合材料电学性能的影响。结果表明,利用超声分散方法比磁力分散方法获得的CNTs在基体中的分散效果更好,并且随着超声分散时间的延长,分散效果越好;当分散时间为2 h、CNTs的质量分数为5%时,PUR/CNTs复合材料的体积电阻率趋于稳定,可以降到50 MΩ.cm,比纯PUR的体积电阻率下降了6个数量级。     

水性聚氨酯/蒙脱土复合乳液的合成及性能表征

本文通过蒙脱土插层聚合法制备了水性聚氨酯/蒙脱土复合乳液。通过单体插层于蒙脱土中,与聚氨酯聚合反应,均匀分散于水性聚氨酯中。用FTIR和TEM测试表征,观察到蒙脱土均已聚合入聚氨酯包裹。研究结果表明:当蒙脱土含量在5%左右时,该乳液涂膜具有较好的耐热性、10%分解温度比普通聚氨酯提高了大约20℃,拉伸强度和断裂强度达到最高值,分别为2.31Mpa和17.94N/mm。随着蒙脱土含量的增大,乳液粒子粒径增大,耐水性增强。蒙脱土含量达到5%时,乳液粒径为108nm,吸水率降至31.9%。     

复色多相聚合物/ 油/ 水分散体系的悬浮稳定性及分散稳定性

采用Ｓｔｏｋｅｓ落球模型研究了两相密度差对油／水分散体系悬浮稳定性的影响规律,考察了水相粘度及水相界面张力对油／水分散体系分散稳定性的影响。结果表明：复色多相分散体系的悬浮稳定性主要由两相密度差决定,当两相密度差降至０．５ｋｇ／ｍ３时,可以制得悬浮稳定性很好的复色多相分散体系。水相粘度增大,悬浮稳定性提高。水相界面张力对丙烯酸酯－聚氨酯油相形成的分散体系影响较大,当其界面张力大于６９．５×１０－３Ｎ／ｍ时,分散稳定性好。只要粒子间不易相互融结,形成的复色多相分散体系便不发生渗色现象。     

不同结构水性聚氨酯分散体的合成与性能研究

用不同结构不同分子质量的聚酯多元醇合成一系列水性聚氨酯分散体,探讨了其力学性能、黏度、粘附力和贮存稳定性,还分析了结晶性、扩链剂和硬段含量对水性聚氨酯性能的影响.结果表明,用PBA和PHA合成的水性聚氨酯具有较好的性能,适度的结晶性有利于提高粘附力,扩链交联剂在一定的比例范围才能保持分散液的稳定性,40%～46%硬段含量可以保证水性聚氨酯既有较好的力学性能和黏度,又有满足使用要求的干燥速度.