纳米凹凸棒土改性聚氨酯纤维的热性能研究

用不同含量的纳米凹凸棒土(AT)改性聚氨酯(PU)纤维,研究了改性PU纤维热分解动力学,测定了分解活化能,讨论了AT对改性PU纤维热性能的影响。结果表明:AT的加入,提高了PU纤维的起始分解温度,改善了纤维的热稳定性;加入质量分数为1.5%的AT,改性PU纤维的起始分解温度相比纯PU纤维提高了近14℃,增强了PU硬段的热分解稳定性。     

纳米CaCO_3/EVA/PP共混制备多孔聚丙烯纤维

以纳米CaCO3为成孔剂,与聚丙烯(PP)、乙烯-乙酸乙烯酯嵌段共聚物(EVA)相混合制得共混纤维,将共混纤维进行酸处理和醇解处理后得到多孔聚丙烯纤维。研究了纳米CaCO3/EVA/PP共混物的力学性能,考察了纳米CaCO3/EVA/PP共混纤维的回潮率与表面形态。结果表明:随着EVA含量的增加,纳米CaCO3/EVA/PP共混纤维的力学性能下降,回潮率上升,纤维表面的微孔更加密集、均匀。     

软硬链段添加碳纳米管/炭黑对聚氨酯纳米纤维性能的影响

以聚丙二醇(PPG 2000)和二苯基甲烷二异氰酸酯(MDI-50)为原料,利用预聚法合成聚氨酯(PU)。在预聚过程中加入碳纳米管(CNT),合成碳纳米管/聚氨酯(CNT/PU);在扩链过程中加入炭黑(CB),合成炭黑/聚氨酯(CB/PU)。结合静电纺丝制备CNT/PU、CB/PU纳米纤维。采用SEM、TEM、FTIR、DSC、XRD对两种纳米纤维的结构进行了表征,对纳米纤维膜的电性能、力学性能及传感性能进行了测试。结果表明,由于CNT/CB在聚氨酯软硬链段的选择性嵌入,聚氨酯纳米纤维的微相分离程度分别增大/减小;相对纯PU纳米纤维膜,CNT/PU纳米纤维膜的断裂伸长率降低,CB/PU纳米纤维膜的断裂强度提高。导电填料(CNT、CB)的含量以聚氨酯的质量(PPG 2000、MDI-50和无水乙二胺的总质量)为基准,当CNT的含量为6.0%时,CNT/PU纤维膜的电阻率为1.22Ω·m,传感系数GF为45.64(拉伸应变在80%～120%);当CB含量为12.5%时,CB/PU纤维膜的电阻率为0.14Ω·m,传感系数GF为167.43(拉伸应变在80%～120%)。     

海藻酸钙/纳米TiO_2共混纤维的制备与表征

将含固体质量分数为5%的海藻酸钠纺丝原液与纳米二氧化钛(TiO2)水分散液均匀混合,制得海藻酸钠/纳米TiO2混合纺丝原液,采用湿法纺丝,通过氯化钙凝固浴,经拉伸、水洗,制备了海藻酸钙/纳米TiO2共混纤维,研究了纳米TiO2含量对共混纤维结构及性能的影响。结果表明:纳米TiO2的加入,提高了共混纤维的力学性能;加入质量分数为0.5%的纳米TiO2,海藻酸钙大分子链上的红外特征吸收峰峰形明显变宽,共混纤维的力学性能最佳,断裂强度为2.93 cN/dtex,断裂伸长率为7.34%,优于海藻酸钙纤维;添加纳米TiO2质量分数为3%时,纳米TiO2在共混纤维中仍能较好的分散,且纤维表面光滑。加入纳米TiO2后,共混纤维的热稳定性提高。     

原位聚合法合成PU弹性体/纳米Mg(OH)2复合材料的研究

将预分散的纳米氢氧化镁[Mg(OH)2]加入聚氨酯(PU)弹性体反应体系进行原位聚合。结果表明,所得PU弹性体/纳米Mg(OH)2复合材料有较好的力学性能,在聚醚脱水阶段加入纳米Mg(OH)2比扩链阶段加入得到的复合材料力学性能好,纳米Mg(OH)2在PU中基本达到纳米级分散。     

一种大分子改性剂对纳米SiO2的改性及其在PU中的应用

采用自制的大分子表面改性剂(MAA)m-(BA)n-NCO对纳米SiO2进行表面改性,对改性前后的纳米SiO2进行FTIR、TGA、粒径分析表征.结果表明,大分子改性剂和纳米SiO2的表面发生化学键合,有效地阻止了纳米SiO2的团聚.用改性后的纳米SiO2制备了纳米SiO2/聚氨酯(PU)复合材料,SEM观察到纳米SiO2颗粒在PU中分散良好,XRD检测表明纳米SiO2阻碍了PU分子硬链段有序排列.力学性能检测显示纳米复合材料的力学性能有明显提高,当SiO2的用量为3％时,复合材料的断裂伸长率和拉伸强度均达到最大值,分别为458％和80.4 MPa.     

聚氨酯/镀银纳米石墨导电胶的制备与性能研究

以聚氨酯(PU)预聚体为基体,以镀银纳米石墨为导电填料,采用共混法制备PU/镀银纳米石墨导电胶,并与PU/纳米石墨导电胶进行电学性能、力学性能和热稳定性能对比。结果表明:PU/镀银纳米石墨导电胶和PU/纳米石墨导电胶的导电渗流阈值分别为3%和9%,此时对应的电导率分别为0.044 S/cm和0.012 S/cm;前者的力学性能(最大剪切强度为5.76 MPa)高于后者(最大剪切强度为3.65 MPa),并且前者的起始分解温度比后者提高了近10℃,说明前者的应用前景比后者更广阔。     

静电纺淀粉/PVA纳米纤维的制备及其交联改性研究

为了提高淀粉纤维的力学性能和水稳定性,使淀粉纤维可以更好地应用于纺织、医药和生物工程等领域,采用静电纺丝法制备淀粉/聚乙烯醇(PVA)纳米纤维,并选择淀粉/PVA质量比为40/60的纳米纤维与戊二醛进行交联。通过扫描电镜、红外光谱(FTIR)仪、差示扫描量热(DSC)分析仪以及万能材料试验机等对纳米纤维的形貌、结构、热性能、力学性能和耐水性等进行了研究。结果表明:随着PVA含量的逐渐升高,淀粉/PVA纳米纤维的直径逐渐变小;FTIR和DSC测试显示淀粉和PVA仅仅是简单的物理共混;两种材料的共混可有效提高纳米纤维的力学性能,当淀粉/PVA质量比为40/60时,淀粉/PVA纳米纤维的力学性能最好;当淀粉/PVA纳米纤维与戊二醛进行交联3~24 h时,淀粉/PVA纳米纤维的接触角由28.31°提高到62.94°,其中交联时间9 h时,接触角为60.18°。     

针状硅酸盐增强氯丁橡胶复合材料的各向异性

以凹凸棒石(AT)为增强剂,将AT用γ-(甲基丙烯酰氧基)丙基三甲氧基硅烷处理后,通过常规熔体共混方法制备了改性AT(PAT)/氯丁橡胶(CR)复合材料,研究了复合材料的各向异性。结果表明,PAT具有良好的增强效果,由于纳米纤维的取向,复合材料在纤维取向方向和垂直取向方向具有明显的力学性能各向异性;借助混合过程的机械剪切力,PAT解离成直径约为30 nm、长度约为500~800 nm的纳米纤维分散在CR中;随着PAT用量的增加,PAT在CR中易形成聚集体。     

PU乳液对VAE乳液共混改性的研究

用系列聚氨酯（PU）乳液对VAE乳液进行共混改性，了共混乳液的稳定性，乳液膜性能，相容性等，结果表明，共混乳液的稳定性依赖于乳液的PH值，共混乳液胶膜的性能依赖于共混乳液的组成和PU链段中软段和硬段的比例，共混体系具有部分相容性，两者之间的相互作用主要发生在PU的硬段部分。     

透明聚氨酯胶粘剂的合成与性能研究

用异佛尔酮二异氰酸酯（IPDI）,聚氧四亚甲基二醇（PTMG－1000）,1,4－丁二醇（1,4－BD0合成了透明聚氨醋（PU）胶粘剂,并对该胶粘剂进行了红外光谱,热性能以及力学性能的测试,结果表明：CNO／OH摩尔比略大于1,适当的1,4－BD与PTMG比例能获得力学,光学性能优良的PU胶粘剂。不同的原料配比对聚氨酯分子链中的段与软段的比例,硬段区的有序性有较大的影响。     

Synthesis, Characterization and Surface Properties of Cross-linked Polyurethane Dispersions Modified by Organosiloxane

A series of cross-linked polyether-polyester polyurethane dispersions modified with organosiloxane were prepared based on hydroxyl-terminated polydimethylsiloxane (HTPS) as hydrophobic component and 3-aminopropyl-triethoxysilane (APTS) as cross-linker as well as a bridge between polyurethane (PU) and polysiloxane (PSIL). It was discovered that polydimethylsiloxane segments were incorporated into PU chains chemically and organosiloxane was preferentially oriented toward the surface layer of the film by making a comparison of attenuated total reflection (ATR) spectra between the copolymer and the blend of PU and PSIL, which was further confirmed by investigation of electron spectroscopy for chemical analysis (ESCA). The relationships between surface properties of the film formed from polyurethane dispersion and organosiloxane content were also studied. The results showed that water contact angle of the film increased with the increase of organosiloxane content. Interestingly, it was also found that water contact angle of PUS film increased firstly and then decreased when film-forming temperature varied from 25℃ to 55℃.     

抗氧剂Irganox1010对聚氨酯弹性体老化性能的影响

通过傅里叶红外变换光谱、热分析与力学性能测试,研究了抗氧剂四(3,5-二叔丁基-4-羟基苯丙酸)季戊四醇酯(Irganox1010)对聚氨酯弹性体老化性能的影响。力学测试结果表明,150℃下老化48h后,未加抗氧剂的聚氨酯弹性体的拉伸强度与老化前相比较下降11.6%,而添加抗氧剂的聚氨酯弹性体的拉伸强度与老化前相比较没有下降。热重分析、差示扫描量热分析和红外光谱分析结果表明,抗氧剂Irganox1010能阻碍聚氨酯分子链的断裂,减缓材料的老化,因此能促进聚氨酯弹性体的抗老化性能。     

Preparation and properties of reactive polyurethane polyacrylate blends based on carbonyl‐hydrazide reaction

A new reactive polyurethane/polyacrylate (PU/PA) blend was developed by mixing a core–shell polyacrylate latex containing keto groups in shell layer and a polyurethane dispersion incorporating multiple hydrazide groups which was synthesized by introducing the poly‐hydrazide groups into the end of the vinyl‐terminated polyurethane chains. Fourier transform infrared (FTIR) spectroscopy and gel permeation chromatography (GPC) results indicated that poly‐hydrazide groups had been incorporated in the polyurethane chains. Transmission electron microscopy (TEM) micrograph revealed that polyacrylate particles had a clear core–shell structure. The results of FTIR, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) indicated that the crosslinking reaction between two polymer systems had happened and crosslinking structure could effectively improve the compatibility between PA and PU. Thermogravimetric analysis (TGA) and mechanical tests results suggested that crosslinking structure could enhance the thermal stability and mechanical properties of blends. The influence of the PA content and the n(? CO? )/n(? NHNH₂) ratio on the hardness, water resistance, solvent resistance, and gel fraction of the blend films were comprehensively studied. The optimal PA content and n(? CO? )/n(? NHNH₂) ratio was 30% and 1.5:1 in this experiment, respectively. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44443.     

The effect of component addition order on the properties of epoxy resin/polyurethane resin interpenetrating polymer network structure

Epoxy resin (ER) is one of the most important synthetic resins, but it has the disadvantage of lacking impact resistance. However, it can be improved by mixing with polyurethane resin (PU). In this study, Epon 828, triethylenetetramine (TETA), polytetramethylene ether glycol (PTMG), isophorone diisocyanate (IPDI), and dibutyltin dilaurate (DBTDL) were used as raw materials to prepare ER/PU interpenetrating polymer network structures (IPNs) by three different blending processes. The results showed the reactivity between TETA and IPDI were greater than that between TETA and ER. When ER/TETA/PTMG/IPDI/DBTDL were mixed at the same time, or ER and PU resins were prepared separately and then mixed, the ER/PU composites produced had a phase separation inside the structure. The most appropriate blending method was to mix ER with PTMG, IPDI, DBTDL first, and then add TETA after 10 min. The composite formed had a uniform appearance, and had better physical, mechanical, and thermal properties than the others did.     

A Study on Structure and Mechanical Properties of Polyurethane/Organic-Montmorillonite Nanocomposites

The intercalated nanocomposites of polyurethane (PU) with organic-montmorillonite (OMMT) treated by cetryltrimethyl ammonium bromide was prepared. The interlayer spacing of PU/OMMT nanocomposites was 3–4 nm. The interface interaction of PU/OMMT nanocomposites was improved compared to that of PU/montmorillonite (MMT) composites. The orderly arrangement of the PU chains was hindered because of strong interface interaction between the silicate layers dispersed in the nanometer and PU chains. By adding 2 wt% OMMT to PU, tensile strength and tear strength of the PU/OMMT composites were increased from 10.5 MPa and 36.4 KN/m to 13.8 MPa and 42.2 KN/m, respectively. The tensile strength and tear strength increased with OMMT content firstly, reaching its maximum when the OMMT content was 8 wt%. After that, the tensile strength and tear strength decreased with the further increase of the OMMT content. Compared to that of PU, the elongation at break of the PU/OMMT nanocomposites increased, indicating that the stretch of PU/OMMT nanocomposites increased.     

Polyurethane electrospun mats strengthened and toughened by physically blended polyhedral oligomeric silsesquioxane

In this work, polyfunctional polyhedral oligomeric silsesquioxane (POSS) with glycidyl ether groups was physically blended with end‐capped polyurethane (PU) to improve the mechanical strength of PU electrospun mats. It was found that not only the tensile strength was elevated, but also the elongation‐at‐break was greatly improved. Fourier transform infrared spectroscopy results suggested that no chemical reaction happened, and there was no hydrogen bonding between POSS and PU, but the mobility of the PU chains was restricted. Wide‐angle X‐ray diffraction patterns showed that POSS aggregated inside the PU electrospun fibers. Scanning electron microscopy observation showed apparent die‐swelling, indicating that the elasticity of PU chains was enhanced. This was always the result of strengthened chain–chain interactions. From the experimental observations, it was speculated that a physical polymer–particle network was established through attachment of PU chains onto the POSS nanoparticles and embedment of PU chains inside the POSS aggregates, which results in the simultaneous improvements in strength and extensibility. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40902.     

Synthesis and characterization of new polyurethane based on polycaprolactone

Different polyurethane (PU) were synthesized from ε‐polycaprolactone diol, 4,4′‐diphenyl methane diisocyanate (MDI) and bis(2‐hydroxyethyl)terephthalate (BHET), using a two‐step method and a one‐step method providing regular and random distributions of starting monomers in the PU chains. Even with an identical molar monomer composition, the properties of obtained PU are different depending on the method of synthesis. The structure of PU was characterized by ¹H and ¹³C‐NMR and Fourier transform infrared spectroscopy (FTIR). The thermomechanical properties of synthesized PU were also studied demonstrating the influence of aromatic ring in the macromolecular chain. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Biocidal polyurethane and its antibacterial properties

The antimicrobial finishes on the cotton fabrics has been known and reported recently. Particularly, the reactive-antimicrobial finishes are the most attractive. In this study, we synthesized three types of polyurethane (PU) polymers; type A (molecular weight of polytetramethylene glycol (PTMG) is 2000), type B (molecular weight of PTMG is 1000), and type C (molecular weight of PTMG is 650). Firstly, the PU prepolymers were prepared by reacting PTMG with 4,4′-diphenylmethane diisocyanate (MDI), then were extended with diethylenetriamine (DETA) (or DETA/hydrazine mixture) to form the PU polymer. The polymer was then grafted with epichlorohydrin and further reacted with different amounts of biocide (QAS) to form biocidal active PU quaternary ammonium salts. The biocidal properties of the PU films were evaluated by the agar plate and the shake flask method. From the experimental results, it demonstrates that these films and finished fabrics exhibit a high biocidal activity against Staphylococcus aureus. The biocidal activity is found to increase with the amount of QAS. After rinsing with water, the biocidal characteristics of these films and finished fabrics remain. From IR spectra, PU films with covalent bond of QAS show an absorption peak at 2300 cm⁻¹, which corresponds to the presence of silicon in QAS. For the mechanical properties, the PU films with QAS sustain the mechanical properties in spite of the increasing amount of grafted QAS.     

Tunable stress transfer efficiency of polyurethane to spiropyran by multi-functionalization and its effects on mechano-chromic response

Spiropyran (SP) derivatives with different hydroxyl groups have been synthesized and incorporated with polyurethane (PU) to prepare mechano-chromic composites. With the content of hydroxyl groups in SP increasing, the stress transfer along PU molecular chain to SP have been effectively enhanced, resulting in the refined mechano-chromic response. The correlation coefficient between mechano-chromic efficiency and effective stress has been defined, which increased by using bishydroxyspiropyran (SP₂) instead of SP. With an optimized SP₂ content of 1.5 wt%, the composites demonstrated the improved mechano-chromic effect and mechanical properties. The double hydroxyl groups in SP₂ grasped the PU chain in form of chemical bonding, leading to construction of micro-phase structures in PU matrix.