微相分离促进剂对MDI型聚氨酯弹性体的耐热性能影响研究

在聚氨酯弹性体固化过程中添加微相分离促进剂,通过差示扫描量热分析（DSC）和动态力学性能测试（DMA）表明,微相分离促进剂的加入提高了4,4′-二苯基甲烷二异氰酸酯（MDI）弹性体的微相分离程度;通过不同温度下的热失重分析（TGA）和力学性能高温保持率对比分析表明,添加了微相分离促进剂的聚氨酯弹性体耐热性能得到了提高。     

聚氨酯弹性体耐热性的影响因素

耐热性是聚氨酯弹性体的一项重要性能指标。微相分离结构对聚氨酯弹性体的耐热性能有很大的影响。主要介绍了聚氨酯弹性体微相分离结构及其他因素对其耐热性的影响。介绍了聚氨酯弹性体耐热性的改性方法。提高微相分离程度是改善其耐热性的重要方法之一。     

聚氨酯弹性体微相分离促进剂研究

聚氨酯弹性体中少量高级脂肪醇可显著提高硬度、强度和伸长率等物性，可解释为在聚氨酯弹性体形成过程，这些添加剂降低了软硬链段的运动阻力，促进了微相分离，提高了结晶度，同时降低了橡胶相的玻璃化温度，从而提高了综合性能。     

NDI型聚氨酯弹性体的合成与其耐热性能研究

以1,5-萘二异氰酸酯(NDI)和甲苯二异氰酸酯(TDI)分别与聚己二酸乙二醇丙二醇酯二醇(PEPA)合成了聚氨酯弹性体,通过热失重分析和差示扫描量热分析发现,NDI型聚氨酯弹性体的热分解温度比TDI型聚氨酯弹性体高,说明NDI型聚氨酯弹性体具有更好的耐热性能;通过不同温度下弹性体的力学性能高温保持率对比分析,也说明了NDI型聚氨酯弹性体的耐热性能优于TDI型聚氨酯弹性体。     

聚氨酯弹性体微相分离促进剂

聚氨酯弹性体微相分离促进剂方治齐（合肥工业大学化工学院，２３０００９）１实验原料聚己二酸乙二醇酯二元醇，Ｍｗ为２０００，烟台合成革厂产品；ＴＤＩ（８０／２０），美国进口；１，４－丁二醇（ＢＤ），上海吴淞化工厂产品；ＭＯＣＡ，苏州前进化工厂产品；辛酸亚...     

新型热塑性聚氨酯弹性体微相分离的定量研究

基于端羟环氧乙烷 -四氢呋喃无规共聚醚、异佛尔酮二异氰酸酯以及 1,4-丁二醇 ,采用熔融二步法合成了一系列新型的用于固体推进剂的热塑性聚氨酯弹性体。以 DSC及 FTIR为主要测试手段 ,建立了影响热塑性弹性体性能的微相分离程度的定量方程 ,并以此对所合成的 TPU进行了评估     

十八醇对TDI型聚氨酯弹性体耐热性能的影响

聚氨酯弹性体固化时添加微相分离促进剂十八醇,在不同温度下对聚氨酯弹性体热失重(TGA)、力学性能以及力学性能高温保持率进行分析。结果表明,加入十八醇增加了PU弹性体微相分离程度,提高了材料的耐热性能;加入十八醇的TDI型PU弹性体的初始热分解温度比未加十八醇的提高了12.6℃,20℃下加入十八醇的PU弹性体的力学性能比未加十八醇的PU弹性略差;80℃和100℃下,加入十八醇的TDI型弹性体力学性能要好于未加十八醇的,且PU弹性体的耐热性能提高。     

提高聚氨酯弹性体耐热性能的研究

在２，４，６－三（二甲氨基甲基）苯酚催化剂作用下，使－ＮＣＯ三聚生成异氰脲酸酯。采用异氰酸酯三聚法和预聚物三聚法，对聚氨酯弹性体，进行ＩＳ耐热改性，考察了改性方式及改性程度对ＰＵＥ性能的影响。     

聚氨酯弹性体结构与耐热性能的研究

简述了聚氨酯弹性体的结构特点及近年来对聚氨酯弹性体耐热性方面的改性研究进展,包括通过改变聚合物多元醇结构,选择适当的异氰酸酯及扩链剂,在聚氨酯分子内引入杂环,加入填料,以及改变工艺条件等。     

Rheological investigation of microphase separation transition of polyurethane elastomer

A technique of linear viscoelasticity measurements coupling with temperature scanning was found effective in the detection of microphase separation transition (MST) and in the determination of MST temperature. The validity and accuracy of the technique were confirmed and reinforced by atomic force microscopy and differential scanning calorimetry (DSC). The technique was applied to a study of the MST of a series of 13 polyurethane (PU) elastomers based on mixed toluene diisocyanate (TDI), 1,4 butadiol, and poly(tetramethylene oxide) (PTMO) of two different molecular weights; the MST temperatures of the PU elastomer samples were measured. Although each of the 13 polymer samples had distinct hard segment content and used PTMO of different chain lengths, or mixed PTMO, the MST temperatures of the 13 samples formed a linear master curve when the MST temperature was plotted against the fraction of hard segment. The master curve indicated that the MST temperature is independent of the length and type of PTMO. It was also found that 2,4 TDI prevailing over its isomer 2,6 TDI played a dominant role in the MST of this series of PU elastomers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2107–2112, 2007     

硬段对聚酯型聚氨酯弹性体微相分离的影响

以聚己二酸-1,4-丁二醇酯二醇(PBA)、4,4′-二苯基甲烷二异氰酸酯(MDI)、乙二醇(EG)、1,4-丁二醇(BDO)和1,6-己二醇(HD)等为主要原料,采用预聚体法制备了一系列热塑性聚氨酯弹性体(TPU)。通过对TPU流变性能、结晶性能、硬度与力学性能的研究,考察了不同扩链剂及不同硬段含量对TPU体系内部微相分离的影响。结果表明,HD-TPU与BDO-TPU微相分离情况相当,均大于EGTPU,且HD-TPU具有较好的结晶性能、拉伸强度及断裂伸长率;随TPU体系硬段含量增加,硬度和拉伸强度增加,断裂伸长率减小,相分离发生越早越快,结晶熔融温度越高,但相分离程度并不高。     

单组分聚氨酯密封胶耐热性能的研究

对单组分聚氨酯密封胶耐热性能进行了研究,实验了不同分子质量的聚醚多元醇、扩链剂、抗氧剂、异氰酸酯三聚体对其耐热性能的影响。提高聚醚多元醇分子质量、提高交联度、加入抗氧剂和异氰酸酯三聚体对耐热性能有明显改善,可以使密封胶固化后在较高的温度下保持优异的机械性能。     

Effect of hydroxyl‐terminated poly(fluoroalkyl methacrylate) main‐chain length on the microphase separation of waterborne fluorinated polyurethane

Waterborne fluorinated polyurethanes (WFPUs) based on hydroxyl‐terminated poly(fluoroalkyl methacrylate)s (HTPFMAs) with different main‐chain lengths were synthesized. The structure of HTPFMA was characterized using ¹H NMR spectroscopy, measurements of hydroxyl values and gel permeation chromatography. The microstructures of WFPUs were investigated using Fourier transform infrared spectroscopy, which indicated that hydrogen bonding interactions in hard segments of WFPUs were enhanced by the introduction of HTPFMA and increased with increasing main‐chain length of HTPFMA. The results of X‐ray diffraction demonstrated that increasing the main‐chain length of HTPFMA resulted in an increase of crystallinity in hard segments. Differential scanning calorimetry revealed that the melting temperature of micro‐crystallites in hard segments and the microphase separation increased with an increase of HTPFMA main‐chain length. Dynamic mechanical analysis and scanning electron microscopy also confirmed that HTPFMA with longer main‐chain length can promote the extent of microphase separation of WFPUs between soft and hard domains. The mechanical properties of WFPUs were improved due to the increase of microphase separation with increasing HTPFMA main‐chain length. © 2018 Society of Chemical Industry     

含异氰脲酸酯基团浇注型聚氨酯弹性体的合成及其耐热性能的研究

在催化剂作用下,合成了TDI-100型异氰脲酸酯,并与己二酸乙二醇丙二醇酯（PEPA）合成了浇注型聚氨酯弹性体,通过不同温度下的热失重分析（TGA）和弹性体的力学性能高温保持率对比分析表明,在TDI型聚氨酯弹性体中引入异氰脲酸酯基团,可明显提高弹性体的耐热性能。     

The effect of mixed soft segment on the microstructure of thermoplastic polyurethane

In this work, we fixed the hard segment content (Ch%) and synthesized thermoplastic polyurethane (TPU) elastomers with one-soft segment (HTPB-PU, PTMG-PU, and PCL-PU) and bi-soft segment (PTMG-HPU and PCL-HPU), using 4,4′-diphenylmethane diisocyanate, 1,4-butanediol, and different oligomer diols as raw materials. This work was used to explore the impact of two polar diols (polytetrahydrofuran diol [PTMG]; polycaprolactone diol [PCL]) of the hydroxy-terminated polybutadiene (HTPB)-based TPU on the microstructure and macroscopic properties. Using Fourier transform infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry to characterize TPU, the results showed that the introduction of PCL was better than PTMG in promoting microphase mixing and crystallization, and reducing microphase separation. This result was closely related because the carbonyl group in PCL was stronger than the ether bond in PTMG in forming hydrogen bonds with ─NH bond. Through mechanical test and isopropyl alcohol (IPA) resistance test, the results showed that HTPB-based TPU with PCL (PCL-HPU) significantly improved tensile strength and elongation at break, and only a small reduction of Young's modulus was observed. PCL-HPU had the best retention of the IPA resistance of HTPB-based TPU.     

Effect of chain extender on microphase structure and performance of self-healing polyurethane and poly(urethane-urea)

In this work, four aliphatic chain extenders, hexanediol (HDO), hexane diamine (HDA), cystamine (CY), and cystine dimethyl ester (CDE), were chosen to synthesize four kinds of polyurethane and poly(urethane-urea)s (PUs), respectively. HDO extended polyurethanes, HDA extended poly(urethane-urea), CY extended poly(urethane-urea), and CDE extended poly(urethane-urea) were denoted as OPU, APU, CPU, and SPU, respectively. The effect of chain extender type on microphase structure and performance of four PUs was investigated. Our research showed that mechanical strength increased in the following order: OPU < SPU < CPU < APU, and self-healing performance increased in the opposite direction. This result is attributed to the increasing degree of microphase separation: OPU < SPU < CPU < APU. The optimal sample SPU has not only excellent mechanical properties (tensile strength of 27.1 MPa and elongation at break of 397.7%), but also exhibits superior self-healing performance (self-healing efficiencies of 95.3% and 93.5% based on tensile strength and elongation at break). The moderate degree of microphase separation between the soft segments and the hard segments, the introduction of disulfide bonds and low degree of hydrogen bonding are responsible for preparing a polyurethane or poly(urethane-urea) system with high mechanical strength and excellent self-healing performance simultaneously. This work provides useful information for us to develop self-healing polyurethane or poly(urethane-urea) materials in the future.     

Enhanced adhesion force based on microphase separation induced by complexation of ferric ions and polyurethane matrix

Waterborne polyurethane elastomer (WPU) has been widely used as a glue, but it still has some drawbacks, including a long cure time and weak adhesive force. In order to overcome these drawbacks, a new composite [PU/ferric ion complexation (Fe/PU)] with high adhesive strength was successfully prepared using ferric ion (Fe³⁺) as a complexing agent. Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, and tensile testing were used to characterize the chemical structure and mechanical properties of the as‐obtained composites. Introduction of the ferric ion induces a certain degree of microphase separation, resulting in better mechanical strength and interfacial adhesion. The mechanical properties of the PU composite with ferric ions are higher than that of pure PU. The adhesive strength of the 25%‐Fe/PU composite is 32.46 ± 3.1 MPa, exhibiting superior adhesive strength. The tensile strength was enhanced 34%, and the elongation was enhanced 23.6% compared to pure PU. Furthermore, the Fe/PU composite, coordinated with ferric ions, exhibits an enhanced storage modulus and reduced loss coefficient compared to PU. We can foresee that Fe/PU composites will play an important role in the building and engineering areas. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46069.