不同软链段对水性聚氨酯性能的影响

以低聚物多元醇、IPDI(异佛尔酮二异氰酸酯)、亲水扩链剂DMPA(2,2-二羟甲基丙酸)和成盐剂三乙胺为主要原料,合成一组软段成分不同的水性聚氨酯乳液。通过测定水性聚氨酯乳液的固含、黏度、结构,以及水性聚氨酯胶膜的耐水性、力学性能、T型剥离强度等,对比了不同类型软段对乳液及胶膜性能的影响。研究结果表明:由含6个碳的聚酯多元醇为软段合成的水性聚氨酯的黏度、耐水性、机械强度、T型剥离强度等数据较好。     

无溶剂水性聚氨酯人造革涂饰剂的制备与应用

采用甲苯二异氰酸酯(TDI)和聚酯多元醇作为预聚物反应单体,季戊四醇作为小分子扩链剂,合成一种支化型的大分子水性聚氨酯乳液。对比了软段分子量以及扩链剂对乳液性能的影响;并将水性聚氨酯用于人造革涂层,对涂层性能进行了测试。根据性能测定选择了最佳合成条件。     

聚酯聚醚混合二元醇对水性聚氨酯性能的影响

以异佛尔酮二异氰酸酯(IPDI)和异佛尔酮二胺(IPDA)为硬段,分别以聚四氢呋喃二醇(PTMEG2000)、聚己二酸新戊二醇酯二醇(PNA2000)及其混合物为软段,制备了系列水性聚氨酯(WPU)乳液。通过ATR-FTIR对聚氨酯结构进行了表征分析,采用拉伸测试、热失重分析、动态力学分析及耐水性测试等手段对WPU胶膜性能进行了研究,探讨了不同软段结构对WPU胶膜性能的影响。结果表明:聚酯聚醚混合型水性聚氨酯的力学性能优于单一软段水性聚氨酯,其中PTMEG与PNA质量比为2∶1时力学性能最好;PTMEG型WPU胶膜的初始分解温度高于PNA型WPU胶膜,失重50%时分解温度相反;PTMEG型WPU胶膜的耐水性好于PNA型WPU胶膜。     

己二酸系聚酯型水性聚氨酯胶黏剂的制备及性能研究

以己二酸系列聚酯二元醇为软段,合成了稳定的水性聚氨酯乳液,探讨了聚酯二元醇的分子量、链段长度及支链结构对于水性聚氨酯粒径、吸水率、力学性能、T-型剥离强度、热学性能的影响。结果表明,随着聚酯二元醇分子量的增加,乳液粒径先降低后增大,耐水性能、力学性能、T-型剥离强度、硬度及耐热性均逐渐提高,当PBA分子量为4 000时,拉伸强度及T-型剥离强度最优,分别可达28.6 MPa和26.8 N/cm;聚酯的链段结构越长,支链结构越少,耐水性能、力学性能及粘接性能越好,其中PHA为软段制备的水性聚氨酯综合性能最优,拉伸强度可达26.3 MPa,T-型剥离强度可达26.1 N/cm。     

己二酸系聚酯型水性聚氨酯胶黏剂的制备及性能研究

以己二酸系列聚酯二元醇为软段,合成了稳定的水性聚氨酯乳液,探讨了聚酯二元醇的分子量、链段长度及支链结构对于水性聚氨酯粒径、吸水率、力学性能、T-型剥离强度、热学性能的影响。结果表明,随着聚酯二元醇分子量的增加,乳液粒径先降低后增大,耐水性能、力学性能、T-型剥离强度、硬度及耐热性均逐渐提高,当PBA分子量为4 000时,拉伸强度及T-型剥离强度最优,分别可达28.6 MPa和26.8 N/cm;聚酯的链段结构越长,支链结构越少,耐水性能、力学性能及粘接性能越好,其中PHA为软段制备的水性聚氨酯综合性能最优,拉伸强度可达26.3 MPa,T-型剥离强度可达26.1 N/cm。     

硬段含量对水性聚氨酯软段结晶性能的影响

以异佛尔酮二异氰酸酯、六亚甲基二异氰酸酯、聚己二酸丁二醇酯为主要原料合成了水性聚氨酯(WPU),通过FT-IR、DSC、XRD、SEM表征手段,研究了硬段含量对软段结晶性及WPU粘结性能的影响。研究表明,随着硬段含量的增加,WPU分子链上氨基甲酸酯键之间的氢键化程度提高,软硬两相相混严重,WPU软段结晶熔融焓变小,熔融温度变低;结晶衍射峰变弱,软段结晶性变差;粘结性能测试表明,在硬段含量较低时,聚氨酯体现出良好的结晶性能,初粘性较好。     

氨基硅油微乳液改性水性聚氨酯的合成和性能

合成了水性聚氨酯乳液和氨基硅油(AEAPS)微乳液改性水性聚氨酯乳液,研究了两种水性聚氨酯的性能及在织物上的涂层效果。结果表明,当氨基硅油相对于聚丙二醇的质量百分比为8.18%时,有机硅改性水性聚氨酯乳液的离心稳定性好,乳液胶膜表面硅原子的质量分数为0.92%;该有机硅改性水性聚氨酯软段相与硬段相的微观相分离增大,乳液胶膜的耐水性能和热稳定性提高;该有机硅改性水性聚氨酯乳液作为织物涂层剂时,可以赋予织物柔软、滑爽的风格。     

水性聚氨酯涂膜耐水性影响因素研究

以聚酯多元醇、甲苯二异氰酸酯为主要原料合成了水性聚氨酯乳液。研究了NCO/OH值、亲水扩链剂DMPA及交联剂TMP的用量、硬段软段质量比对乳液涂膜耐水性的影响,获得了较优的实验配比;研究了环氧树脂、蓖麻油、有机硅对水性聚氨酯的改性,实验表明,改性后的水性聚氨酯涂膜的耐水性能得到较大的提高。     

聚酯型热致形状记忆水性聚氨酯的制备与性能研究

采用聚己二酸丁二醇酯(PBA)、异佛尔酮二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)、三乙胺(TEA)、乙二胺(EDA)等单体,通过自乳化法合成了聚酯型热致形状记忆水性聚氨酯(TSMWPU)。利用偏光显微镜(POM)、差示扫描量热仪(DSC)、动态黏弹谱仪(DMA)和形状记忆性能分析等手段,探讨了不同分子量的PBA,以及不同异氰酸酯基与羟基的摩尔比(NCO/OH)对TSMWPU的结晶性能和形状记忆性能的影响。结果表明;增加PBA分子量,有利于软段结晶,从而提高TSMWPU的形状记忆性能;而增加NCO/OH值,则抑制了软段结晶,进而导致TSMWPU的形状记忆性能下降。     

形状记忆聚氨酯的结构与性能研究

以2,4 甲苯二异氰酸酯(2,4 TDI),不同分子量的聚己二酸丁二醇酯(PBAG)和1,4 丁二醇(BDO)为原料合成了具有形状记忆功能的聚氨酯材料。通过DSC、弯曲实验和力学实验研究了形状记忆聚氨酯的性能,发现软段高度结晶和硬段聚集形成硬段微区是其具有较好形状记忆性能的必要条件。     

聚碳酸酯型水性聚氨酯分散体的合成与性能研究

采用聚碳酸酯二元醇Desmophen C与TDI合成了水性聚氨酯分散体。拉伸试验结果表明,乳胶膜具有优异的拉伸强度(高达60 MPa)和断裂伸长率(高达600%)。研究了软段分子量、软段用量对聚碳酸酯聚氨酯力学性能和微观相分离结构的影响。结果表明,随着软段用量的增加,乳胶膜的断裂强度迅速下降,断裂伸长也有所下降。不同分子量的聚碳酸酯也具有相同的规律。但相同软段用量,随着分子量的增加,断裂强度并没有下降,反而有所上升,且断裂伸长略有下降。同时聚碳酸酯型水性聚氨酯乳胶膜具有优异的水解稳定性。     

水性聚氨酯链段序列分布对乳液固含及性能的影响

通过改变预聚加料顺序,采用"拼接软段"的方法,合成了一系列总体成分相同而链段分布不同的水性聚氨酯乳液。着重研究了乳化过程相反转完成时乳液的固含变化,进而对乳液的黏度、粒径、分子量以及乳液表干速度进行测试,藉此分析链段分布对乳液粒子结构和性质的影响。结果表明,适度地改变软硬段在聚氨酯主链上的相对分布,能有效提升水性聚氨酯乳液的固体含量,其机理是增加软硬段平均长度,使它们更容易各自聚集,因此乳化时乳液粒径增大,而且羧基更多迁移到粒子的壳层,使得粒子内部水分较少,表干速度大大加快。     

聚氨酯结晶性的研究进展

概述了聚氨酯(PU)结晶性的研究方法,讨论了软硬段种类和结构、硬段含量、软段相对分子质量、带电离子及其它基团和热处理等对PU结晶性的影响,并介绍了结晶性PU在形体记忆材料中的应用状况。     

水性聚氨酯-有机硅共聚物的制备与性能

以聚醚二元醇(GE2000)为软段,环氧树脂(E-20)为部分硬段,制备出有机硅交联改性的聚氨酯乳液,探讨了有机硅含量对乳液性能的影响。结果表明,随着有机硅含量增大,乳液黏度、分子量增大,胶膜耐水(溶剂)性、机械性能、疏水性增强。FTIR分析证实有机硅键合到聚氨酯结构中。SEM分析表明,有机硅改性聚氨酯胶膜结构致密。DSC与DMA分析表明,有机硅改性聚氨酯软硬段之间存在一定程度的微相分离,有机硅含量的增加提高了其耐热性能。     

水性环氧改性聚氨酯乳液的制备与讨论

在制备水性聚氨酯基础上引入了环氧树脂,制得了水性环氧改性聚氨酯乳液。环氧树脂的引入增加了水性聚氨酯的交联结构,与改性前的水性聚氨酯相比,其涂膜耐水性、耐溶剂性以及机械性能都得到了提高。并研究了环氧树脂的引入方法及环氧树脂加入量对分散体及其涂膜性能的影响。傅里叶红外光谱分析显示出了环氧树脂与水性聚氨酯之间存在化学键的连接...     

Influence of ionic groups on the crystallization and melting behavior of segmented polyurethane ionomers

The isothermal crystallization kinetics and melting behavior of the soft segment in polyurethane (PU) ionomer/nonionomer based on PCL‐4000 (poly(ε‐caprolactone)) were investigated using polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). In general, the presence of ionic groups in PU ionomers can promote the formation of a more stable crystalline structure and lower the equilibrium melting temperature of the crystallizable phase. Comparison between the crystallization characteristics of PU nonionomers and ionomers suggests that the Coulombic Forces between ionic groups within hard segment can increase the crystallization rate and decrease the crystal size of soft segment when the total molecular weight (M_w) of PU ionomer is higher than ～71,000. On the other hand, the opposite effect of ionic groups on the crystallization rate is observed in PU ionomers with M_w below ～20,000. The DSC thermograms illustrate that the ionic groups can significantly enhance the microphase separation in PU ionomers with higher M_w values. By the control and manipulation of crystallization and microstructure formation in PU ionomer, it is possible to achieve shape memory PUs with superior physical property. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4603–4613, 2006     

小分子氨基硅油改性水性聚氨酯的合成及性能探究

以异佛尔酮二异氰酸酯(IPDI)、聚醚(N-220)等为主要原料,通过在后扩链中加入不同比例的小分子氨基硅油而合成一系列稳定的氨基硅油改性水性聚氨酯乳液。经测试研究表明,氨基硅油的加入可以显著提高水性聚氨酯的耐水性能,对于力学性能没有太大影响。     

Synthesis of anionic water‐borne polyurethane with the covalent bond of a reactive dye

We successfully synthesized an anionic water‐borne polyurethane (PU) capable of reacting with a reactive dye to form a covalent bond with the dye molecule. The anionic water‐borne PU was synthesized and grafted with the reactive dye to form a dyed PU. First, the PU prepolymer was synthesized from 4,4′‐methylene bis(isocyanatocyclohexane), poly(tetramethylene glycol), 2,2′‐bis(hydroxymethyl) propionic acid (as an anionic center), and triethyleneamide (as a neutralizer). Then, pure water was added to emulsify and disperse the prepolymer to form an anionic water‐borne PU prepolymer. Finally, the extender N‐(2‐hydroxyethyl) ethylene diamine was used to extend the anionic water‐borne prepolymer to form a PU polymer with hydroxyl groups that could further react with the reactive dye molecule. With respect to the heating properties, the dyed PU polymers exhibited higher glass‐transition temperatures of the hard segment than those without dye molecules. However, neither the glass‐transition temperature of the soft segment nor the melting temperature of the soft segment varied in the presence of dye molecules, but they were changed with various chain lengths of the soft segment. As for the mechanical properties, the modulus and strength of the dyed PU polymers decreased because of the bulkiness of their dye molecules, but the breaking elongation increased. Moreover, the inherent viscosity decreased in the presence of the dye molecules. As for the dyeing properties, the percentage of dye grafting was greater than 90%. The dye‐grafted PU exhibited a lower percentage of migration than PU extended with ethylene diamine (without hydroxy groups) and also showed a higher grade of colorfastness to light. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 797–805, 2002; DOI 10.1002/app.10336     

Morphology and water vapor permeability of temperature‐sensitive polyurethanes

A series of segmented polyurethanes (PUs) were prepared, in which five different polyols and hexamethylene diisocyanate were used as soft segments, and 4,4′‐diphenylmethane diisocyanate, hydrophilic segment poly (ethylene glycol) 200 (PEG 200), and chain extender 1,4‐butanediol were used as hard segment. Morphology of the PUs was investigated using differential scanning calorimetry, wide angle X‐ray diffraction, polarizing microscopy, and transmission electron microscopy. Water vapor permeability of the membranes as a function of temperature was tested accordingly. Results show that the presence of PEG200 interferes the crystallization of hard segment in these PUs, and at the same time, increases phase compatibility between soft and hard segment in the PET‐PU. It leads to a lower crystal melting temperature and degree of crystallinity of soft segment in the segmented PU than those of pure polyols, and no crystallization existing in hard segment. A morphological model is proposed, that is, aggregated soft‐segment‐rich domains can be observed clearly in the PUs with high crystallinity in soft segment, while identifiable hard domains are well‐distributed in the soft segment domains in the PU with low crystallinity. Within the temperature range of crystal melting, water vapor permeability of the PU membranes increases significantly with increase of temperature. Such temperature‐sensitive property is triggered by crystal melting of soft segment. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Evaluation of nanoparticulate fillers for development of shape memory polyurethane nanocomposites

The effects of nano-size fillers on shape memory (SM) properties of polyurethane (PU) nanocomposites were evaluated. Organoclay, carbon nanofiber (CNF), silicon carbide (SiC), and carbon black (CB) were selected as the fillers in an attempt to reinforce the PU and to obtain significantly increased shape recovery stress. The shape memory PU was synthesized from diphenylmethane diisocyanate, 1,4-butanediol, and poly(caprolactone)diol, the latter with a molecular weight of 4000 g/mol. The composites were prepared by melt mixing of extended chain PU with the fillers. The shape memory behavior was triggered by heating the specimen above the melting point of the crystalline soft segment. Our results indicate that exfoliated organoclay significantly augments SM performance, while CNF and SiC diminish it by interfering with crystallization of the soft segment. CB destroys the shape memory properties beyond a certain loading. Better SM performance with organoclay can be attributed to mechanical reinforcement without much interference with the soft segment crystallinity. The reduction of soft segment crystallinity in the presence of CNF and SiC was analyzed. It was found that the extent of crystallinity, as well as the crystallization temperature, was significantly reduced in the presence of these fillers.