纳米凹凸棒土改性聚氨酯纤维的结构与性能

以物理共混的方法制备了纳米凹凸棒土(AT)/聚氨酯(PU)共混纤维。通过红外测试表明:AT与PU的硬段发生相互作用,增强了PU链段之间的氢键作用。动态力学性能分析的结果表明:AT可视作为物理交联点,限制了PU分子链的运动。相对于纯PU纤维,纳米AT/PU共混纤维的拉伸力学性能有了明显的提高,热稳定性能也有一定改善。     

磁性纳米凹凸棒土改性聚乙烯醇复合材料的性能

在通过化学沉降法制备不同复合率的磁性凹凸棒土(MAT)的基础上,以溶液共混的方法制备了聚乙烯醇(PVA)-MAT纳米复合材料,并用扫描电镜、红外光谱、X射线衍射、热重分析等方法对复合材料的形貌、结构、热性能进行了分析,同时测试了复合材料的力学性能,对磁性凹凸棒土的改性和增强机制进行了探讨。     

聚氨酯/凹凸棒土纳米复合材料的热稳定性研究

采用四氢呋喃均聚醚(PTMG)、2,4-甲苯二异氰酸酯(TDI)、3,3’-二氯-4,4’-二氨基二苯基甲烷(MOCA)为原料,将不同用量的凹凸棒土通过原位聚合法制备了聚氨酯(PU)/凹凸棒土(AT)纳米复合材料。采用FT-IR、TG、拉伸试验对聚氨酯/凹凸棒土纳米复合材料进行表征和测试。结果表明,复合材料的热稳定性、力学性能得到提高。将纯PU和AT质量分数为2%的复合材料分别置于100℃烘箱中,老化72 h进行拉伸测试后发现,复合材料的耐热空气老化性能得到提高。     

聚丙烯/木粉/纳米凹凸棒土复合材料性能研究

采用双螺杆挤出机制备了一系列聚丙烯(PP)/木粉/纳米凹凸棒土(AT)木塑复合材料(WPC.研究了AT用量对复合材料力学性能、热性能、加工性能的影响.结果表明,随着AT用量的增加,复合材料拉伸强度逐渐增加、冲击强度逐渐减小,硬度先增加后减小,AT用量为5份时复合材料硬度最大;复合材料维卡软化点不断提高;熔体流动速率(M...     

纳米蒙脱土改性水性聚氨酯的研究进展

纳米蒙脱土因其特殊结构而在制备纳米复合材料领域起着举足轻重的作用。本文综述了纳米蒙脱土改性水性聚氨酯的制备方法、结构表征及国内外最新研究进展。     

凹凸棒土改性及应用状况的研究

介绍了凹凸棒土资源概况,综述了凹凸棒土改性研究的进展及其开发利用状况。     

纳米凹凸棒土母粒的制备及对聚丙烯性能的影响

将纳米凹凸棒土制备成母粒并与PP复合，制备n-ATP／PP纳米复合材料。对纳米复合材料的性能进行测试。结果表明，当纳米凹凸棒土质量分数为1％时，复合材料的拉伸强度达最大值；而冲击强度在纳米凹凸棒土质量分数为5％时，出现峰值。纳米凹凸棒土的加入一定程度上改善了复合材料的加工性能。     

凹凸棒土填充聚氨酯弹性体力学性能的研究

采用聚己二酸乙二醇酯多元醇(PEA)、TDI-100(T-100)及3,5-二甲硫基甲苯二胺(E-300),通过预聚物法及半预聚物法,研究了低聚物多元醇种类、凹凸棒土用量、偶联剂改性凹凸棒土对聚氨酯弹性体力学性能的影响。结果表明,填充凹凸棒土后聚氨酯弹性体的弯曲强度明显提高;随着凹凸棒土用量的增加,聚氨酯弹性体的弯曲强度逐渐增大;与未改性的凹凸棒土相比,经偶联剂改性的凹凸棒土填充聚氨酯弹性体可显著提高其力学性能;采用半预聚物法,将凹凸棒土首先与补加的多元醇混合合成聚氨酯弹性体的力学性能显著提高。     

凹凸棒土改性方法及水处理应用研究进展

介绍了凹凸棒土的矿物特性、资源概况,对近年来凹凸棒土的改性方法与效果及其在水处理中的应用研究进行了综述,为凹凸棒土在水处理领域中的应用提供理论依据和技术参考。     

热活化凹凸棒土对磷吸附性能的研究

将凹凸棒土高温煅烧活化,通过静态实验研究其对磷的吸附行为。结果表明,温度773 K时热活化效果显著。在研究的浓度范围内,吸附平衡数据显著符合Langmuir、Freundlich和Dubinin-Radushkevich模型(P<0.01),优惠吸附过程,磷吸附量随试验温度的升高而增加,328 K时理论饱和吸附量为2 408 mg P/kg。吸附动力学数据显著符合Lagergren伪二级动力学、Elovich和Kannan颗粒内扩散模型(P<0.05),非均相扩散、物理吸附过程,主要控速步骤为液膜扩散和颗粒内扩散联合控制。吸附热力学参数ΔG<0、ΔH>0、ΔS>0,热活化凹凸棒土对磷的吸附为自发吸热反应。研究结论为凹凸棒土在提高磷肥与复混肥料养分利用率中的应用提供了科学依据。     

碳纤维对聚氨酯弹性体的增强作用

将长１－３ｍｍ的碳纤维添加到聚ε－己酯多元醇溶液中,用该溶液合成的聚氨酯弹性体,其物理机械性能,耐磨性和热性均比未添加碳纤维的高。结果表明：碳纤维对聚氨酯弹性体有增强作用,碳纤维用量以７％为佳。     

丁腈基聚氨酯/芳纶浆粕纤维复合材料的结构与性能

以端羟基聚丁二烯-丙烯腈、甲苯二异氰酸酯、扩链剂2,4/2,6-二氨基-3,5-二甲硫基甲苯为原料,芳纶浆粕纤维为填料制备丁腈基聚氨酯(PBA-PU)/芳纶浆粕纤维复合材料,并对其结构和性能进行了研究。结果表明,扫描电子显微镜显示芳纶浆粕纤维与PBA-PU基体结合得很好。随着芳纶浆粕纤维用量的增加,拉伸强度和撕裂强度先增大后降低,当其质量为0.5份左右(以预聚体为100份计)时,复合材料力学性能最佳;芳纶浆粕纤维的加入使PBA-PU复合材料的耐热性明显提高,而玻璃化转变温度下降,损耗因子降低。     

聚氨酯改性不饱和聚酯的徽观结构与性能

利用与天然纤维具有良好亲和性的聚酯聚氨酯(PU)改性不饱和聚酯(UP),通过扫描电镜（SEM）、傅里叶红外光谱（FT-IR）、接触角和力学性能等,研究了改性不饱和聚酯的微观结构、反应程度和主要性能.研究结果表明,引入PU提高了不饱和聚酯树脂的韧性,增加了与天然纤维的界面浸润性,降低了不饱和聚酯树脂的固化收缩率.所得改性不饱和聚酯的冲击断裂截面表现为韧性断裂;与天然纤维的接触角随着聚氨酯添加量的增加而降低,表明改性不饱和聚酯与天然纤维的浸润性增强.力学性能测试表明,当PU含量为5%时,其冲击强度可提高80%,弯曲模量降低小于20%,固化收缩率低于4%.     

Thermal properties of hydrophobically modified methacrylic acid–ethyl acrylate copolymer solutions

The thermal behavior of a water‐soluble associating polymer system, hydrophobically modified alkali‐soluble emulsion (HASE) polymer, was investigated. This polymer contains a methacrylic acid–ethyl acrylate copolymer backbone with 1 mol % of pendant hydrophobic groups grafted to it. The thermal behavior of the HASE polymer exhibits different trends compared to the hydrophobic ethoxylated urethane (HEUR) system. The lifetime of the hydrophobic junction of the HASE polymer increases with temperature due to the increase in the entropy of the system. However, the structural relaxation time decreases with temperature, caused by the enhanced Brownian dynamics of polymer chains. The relaxation behavior of HASE polymers is either governed by the lifetime of the hydrophobic junction, the structural relaxation time, or a combination of both, depending on the degree of network formation and temperature. Temperature studies indicated that the transient network theory proposed by Tanaka and Edwards is inadequate for describing the activation process of hydrophobic junctions in the HASE associative polymer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 604–612, 2004     

纳米SiO_2改性聚氨酯胶粘剂的制备及性能研究

采用预聚体一步法制备了单组分湿固化nano-SiO2(纳米SiO2)改性PU(聚氨酯)胶粘剂,并利用红外光谱(FT-IR)法、热失重分析(TGA)法、差示扫描量热(DSC)法和扫描电镜(SEM)等对nano-SiO2改性PU胶粘剂的性能进行了分析和探讨。结果表明:纳米粒子的存在使PU的氢键结构发生了变化;随着nano-SiO2含量的不断增加,改性PU胶粘剂的初始粘接强度和最终粘接强度均呈先升后降态势,并且在w(nano-SiO2)=1.2%(相对于PU预聚体质量而言)时相对最大,而且分别比纯PU胶粘剂增加了117%和108%;同时,与纯PU胶粘剂相比,用1.2%nano-SiO2制备的PU胶粘剂,其熔融温度和分解温度分别提高了2.67℃和2.92℃;当w(nano-SiO2)≤1.2%时,nano-SiO2在PU胶粘剂基体中的分散性相对较好。     

蓖麻油作交联剂的聚氨酯弹性体的合成及性能

以不同摩尔比的四氢呋喃均聚醚（PTMG）和1,6-亚己基二异氰酸酯（HDI）合成聚氨酯（PU）预聚体,再分别用丁二醇（BD）、蓖麻油（CO）以及BD和CO混合物进行扩链交联,合成了一系列不同CO含量的PU.通过FTIR、AFM、拉伸实验和TGA,对不同硬段含量和CO含量PU的氢键化程度、相形态结构、力学性能和热性能进行了比较。结果表明,二异氰酸酯和扩链剂的种类及用量对PU的性能均有很大的影响。随着PU中二异氰酸酯用量的增加,其力学性能和热稳定性能提高。随着扩链剂中CO用量的增加,PU氨酯键的氢键化程度降低,其软、硬段的微相分离程度降低,导致其力学性能降低。但CO用量的增加会提高PU分子链的交联和支化,因而其热稳定性能得到提高。     

浇注型耐热聚氨酯树脂材料的热性能和力学性能

聚氨酯（PU）作为一类合成高分子材料具有许多优异性能和优良的加工性能,被广泛地应用于国防、医疗、食品等行业,然而普通聚氨酯耐热性能较差．一般认为,PU弹性体在80℃以下能长期使用,短期使用温度不超过120℃,因而使其应用受到了限制．关于提高聚氨酯弹性体耐热性能的研究已有许多报道．国外不断有耐热PU材料实用专利推出,而国内在这方面的报道还是不多见．     

Mechanical and thermal properties of phenolic/glass fiber foam modified with phosphorus‐containing polyurethane prepolymer

Phenolic foam exhibits outstanding flame, smoke and toxicity properties, good insulation properties and low production costs. However, the brittleness and pulverization of phenolic foam have severely limited its application in many fields. In this study, a novel phosphorus‐containing polyurethane prepolymer (DOPU) modifier was firstly synthesized, and then the foaming formula and processing of toughening phenolic foam modified with DOPU and glass fiber were explored. The structure and reactive behavior of prepolymer and phenolic resin were investigated using Fourier transform infrared spectroscopy. The effects of DOPU and glass fiber on the apparent density, compressive strength, bending strength and water absorption were investigated. The results suggested that the apparent density, compressive strength and bending strength of modified phenolic foam tended to increase irregularly with increasing content of DOPU. The addition of DOPU led to lower water absorption of glass fiber‐filled foam. Thermal stability and flame retardancy were examined using thermogravimetric analysis and limiting oxygen index (LOI) tests. It was found that foam with 3% DOPU and 0.5% glass fiber added exhibited good thermal stability and high char yields. The LOI value of modified phenolic foams decreased with increasing DOPU content, but it still remained at 41.0% even if the amount of modifier loaded was 10 wt%. © 2012 Society of Chemical Industry     

聚氨酯/水滑石复合材料的制备及性能研究

以水滑石(LDH)和聚氨酯(PU)为原料,采用溶液流延法成膜,制备了一系列不同LDH含量的复合材料;借助广角X射线衍射和扫描电镜对PU/LDH复合材料的结构和形貌进行了表征,并对其热稳定性能和力学性能进行了测试。结果表明:LDH在PU基体中以插层结构为主,PU大分子链部分插入LDH层间;适量的LDH粒子能够均匀分散在PU基体中;LDH对PU材料的热分解无阻隔作用;适量的LDH粒子能有效提高PU材料的拉伸强度和断裂伸长率,当PU/LDH复合材料中LDH的质量分数为5%时,复合材料的拉伸强度和断裂伸长率达到最大,分别为15.9 MPa和443.8%。     

Preparation,mechanical properties of waterborne polyurethane and crosslinked polyurethane‐acrylate composite

The waterborne polyurethane (PU) prepolymer was first prepared based on isophorone diisocyanate, polyether polyol (NJ‐210), dimethylol propionic acid (DMPA), and hydroxyethyl methyl acrylate via in situ method. The crosslinked waterborne polyurethane‐acrylate (PUA) dispersions were prepared with the different functional crosslinkers. The chemical structures, optical transparency, and thermal properties of PU and PUA were confirmed by Fourier transform infrared spectrometry, ultraviolet–visible spectrophotometry, and differential scanning calorimetry. Some physical properties of the aqueous dispersions such as viscosity, particle size, and surface tension were measured. Some mechanical performances and solvent resistance of PUA films were systemically investigated. The experimental results showed that the particle sizes of the crosslinked PUA aqueous dispersions were larger than the PU and increased from 57.3 to 254.4 nm. When the ratios of BA/St, BA/TPGDA, and BA/TMPTA were 70/30, PUA films exhibited excellent comprehensive mechanical properties. The tensile strength and elongation at break of the film were 2.17 MPa and 197.19%. When the ratio of BA/St was 30/70, the film had excellent water resistance and was only 6.47%. The obtained PUA composites have great potential application such as coatings, leather finishing, adhesives, sealants, plastic coatings, and wood finishes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012