纳米材料的表面改性技术及在聚氨酯中的应用

针时国内外聚氨酯有机-无机纳米复合材料的研究进展进行了综述,重点介绍了聚氯酯改性研究中较常用的几种纳米材料以及纳米粒子的表面改性方法,并对聚氨酯纳米复合材料未来的发展趋势进行了展望.     

聚氨酯/蒙脱土纳米复合材料

综述了聚氨酯／蒙脱土纳米复合材料的制备、结构表征和热力学性能，对制备过程进行了热力学分析，并对其发展前景进行了讨论。聚氨酯／蒙脱土纳米复合材料是一种新型的有机／无机纳米复合材料。在无机材料含量远低于常规填充量的情况下复合材料就可以具有较好的力学性能、阻隔性，热稳定性能也显著提高。     

专利

<正>本发明涉及聚氨酯-纳米高岭土复合材料的制备方法。该复合材料主要由聚氨酯、纳米高岭土组成,先将纳米高岭土进行有机插层改性以获得层间距较大的有机改性纳米高岭土,然后采用本体-原位插层聚合法制备聚氨酯-纳     

聚氨酯无机纳米复合材料的研究进展

综述了近年来国内外聚氨酯无机纳米复合材料的种类及其制备方法,介绍了聚氨酯无机纳米复合材料的发展趋势和纳米技术在聚氨酯中应用的重要性。     

聚酰亚胺/无机纳米复合材料的制备、结构与性能

综述了国内外聚酰亚胺(PI)/无机纳米复合材料的最新研究进展,重点阐述PI/无机纳米复合材料的制备、结构、性能及应用,并展望了它的发展趋势。列举了几种常用无机纳米粉体的特性,介绍了PI/无机纳米复合材料的3种制备方法,即溶胶-凝胶法、插层复合法、直接分散法。     

富羟基蒙脱土/聚氨酯脲纳米复合材料的结构与性能研究

研究富羟基蒙脱土(HOMMT)/聚氨酯脲(PUU)纳米复合材料的结构与性能。结果表明:当HOMMT质量分数为0.02时,HOMMT在PUU基体中分散均匀,形成了以剥离型为主、插层型为辅的复合型结构,复合材料的剥离效果较好,物理性能和热稳定性最佳。     

聚氨酯/有机膨润土纳米复合材料的制备及性能表征

采用溶液插层和单体插层两种方法制备聚氨酯(PUR)/有机膨润土纳米复合材料。结果表明,溶液插层法和单体插层法制备的PUR/有机膨润土纳米复合材料的拉伸强度比纯PUR分别提高了6.4%和41.7%,断裂伸长率分别提高了4.9%和95.7%。单体插层法制备的纳米复合材料的结构和性能优于溶液插层法。     

有机蒙脱土纳米复合材料对聚氨酯弹性体耐热碱水性能的改善

采用有机插层蒙脱土(PU-C5)和分散剂分别对四氢呋喃均聚醚(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)和PTMG/4,4′-二苯甲烷二异氰酸酯(MDI)/1,4-丁二醇(BDO)两种体系的浇注聚氨酯弹性体进行纳米改性。改性后的弹性材料浸泡90℃含碱热水(pH=8.5)中老化试验一个月。实验结果表明,加入分散剂的PTMG/MDI/PU-C5/BDO体系纳米复合材料的耐热水性能最佳,拉伸强度和撕裂强度保持率分别为57.52%和82.38%。经动态力学试验(DMA)表明,PTMG/MDI/PU-C5/ME60纳米复合材料的储存模量(E′)和损耗模量(E″)明显增加。     

聚丙烯/蒙脱土纳米复合材料的制备和性能

采用熔融插层法在双螺杆挤出机中制备了聚丙烯(PP)/蒙脱土(MMT)纳米复合材料,纳米复合材料机械性能测试结果表明,当有机MMT质量分数为2%时,复合材料的弯曲强度明显优于PP。扫描电镜观测不到纳米复合材料中明显的有机-无机相畴,表明MMT片层分散均匀,分散尺度已基本达到纳米级。DSC(差示扫描量热仪)分析测试结果表明,MMT的加入提高了PP的结晶速率,并使结晶度增大。     

聚氨酯/无机纳米复合材料的应用研究进展

综述了无机纳米粒子改性聚氨酯复合材料在智能材料、导电材料、光学材料、生物医学材料等领域应用研究的进展,并对聚氨酯/无机纳米复合材料存在的问题和研究方向进行了展望。     

聚氨酯/蒙脱土纳米复合材料研究进展

综述聚氨酯/蒙脱土纳米复合材料的国内外研究进展,重点阐述蒙脱土的有机化改性,聚氨酯/蒙脱土纳米复合材料的结构分析表征、制备方法及性能研究,最后介绍聚氨酯/蒙脱土纳米复合材料的最新应用情况。     

Thermal and surface characterization of polyurethane–urea clay nanocomposite coatings

This paper reports synthesis and characterization of polyurethane–urea (PU‐urea) and the nanocomposites derived from the PU‐urea with silicate clays. Organophilic montmorillonite cotreated by cetyl trimethyl ammonium bromide (CTAB) was synthesized and used to prepare PU‐urea/montmorillonite nanocomposites coatings. PU‐ureas were prepared from polyethylene glycol (PEG), polypropylene glycol (PPG), trimethylol propane (TMP), and 4,4′‐diphenylmethane diisocyanate (MDI) by reacting excess diisocyanate with polyether glycols. The excess isocyanate of the prepolymers was cured with atmospheric moisture. The synthesized moisture cured PU‐urea and nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetric (DSC), and angle resolved X‐ray photoelectron spectroscopy (AR‐XPS). The thermal stability of the PU‐urea nanocomposites was higher relative to the mother PU‐urea films. DSC results showed a slight enhancement in the soft segment glass transition temperature after 3 wt % clay loading. The surface properties showed an enrichment of the soft segment toward the surface. An enhancement in the hard segment composition in the nanocomposite coatings has resulted in enhancing the phase mixing process. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2393–2401, 2006     

纳米二氧化硅水溶胶改性UWPU的研究

通过丙酮法合成光固化水性聚氨酯丙烯酸酯预聚体,用三乙胺中和后在乳化过程中原位引入纳米二氧化硅水溶胶(Wv33、R900、R301)制备二氧化硅/光固化水性聚氨酯(SiO2/UWPU)纳米复合乳液,并进一步通过紫外光固化制备了SiO2/UWPU复合膜。通过电子扫描显微镜(SEM)和电子拉力机研究了不同纳米二氧化硅水溶胶对UWPU/SiO2复合膜的微观结构和力学性能的影响。SEM分析表明表面有机改性的pH值接近中性的硅溶胶(Wv33)较pH为酸性或碱性的硅溶胶在聚氨酯基体中有较好的分散性;应力-应变曲线分析表明Wv33能有效实现对复合膜的增强,即提高了复合膜的储存模量、拉伸强度和邵A硬度。     

Synthesis and properties of self‐crosslinkable polyurethane–urea with silsesquioxane formation

Based on the typical two‐step polyurethane–urea synthesis, a new series of self‐crosslinkable polyurethane (PU)–urea formulations, consisting of poly(tetramethylene oxide) and 4,4′‐diphenyl methane diisocyanate, and extended by ethylenediamine (EDA)/aminoethylaminopropyltrimethyoxysilane (AEAPS), were prepared. FTIR, ESCA, WAXD, DSC, and mechanical properties of samples were recorded. The results show that the self‐crosslinkable polyurethane–urea could be crosslinked by hydrolysis of the trimethyloxysiloxane group to form the silsesquioxane structure. These structures represent a kind of nanosize, cagelike, chemical crosslink site as well as filler, which affect the properties of PU. The morphology, varied with different ratios of EDA/AEAPS, was also discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 190–195, 2004     

Thermal transitions of montmorillonite/polyurethane nanocomposites

The hard-segment phase thermal transitions and heat-resistance of benzidine-modified-montmorillonite (BZD-Mont)/polyurethane nanocomposites of different hard segment contents were found to be affected by a small amount of BZD-Mont. In particular, the presence of less than 5 wt% layered silicates from BZD-Mont can result in hard segments not only having a more thermally stable long-range order and a higher melting temperature, but also showing a loss of crystallinity of the hard segment in polyurethane. Additionally, the degradation temperature of BZD-Mont/polyurethane nanocomposite was slightly higher than that of pure polyurethane.     

Hyperbranched polyurethane/triethanolamine functionalized multi‐walled carbon nanotube nanocomposites as remote induced smart materials

Triethanolamine functionalized multi‐walled carbon nanotubes (TEA‐f‐MWCNTs)/hyperbranched polyurethane nanocomposites were prepared by the in situ polymerization technique. The functionalization of the MWCNTs was confirmed by Fourier transform infrared spectroscopy and Raman spectroscopy studies. The homogeneous distribution and the strong interfacial interaction of TEA‐f‐MWCNTs with the polyurethane chains were confirmed by transmission electron microscopy and Fourier transform infrared spectroscopy studies, respectively. Significant enhancements of tensile strength (6.5 ? 28.5 MPa) and scratch resistance (3–7 kg) with content of TEA‐f‐MWCNTs (0–2 wt%) were observed. Thermogravimetric analysis showed an increase in thermal stability from 240 to 287 °C by the formation of nanocomposites. X‐ray diffraction and differential scanning calorimetry studies confirmed an increment in the degree of crystallinity of the nanocomposites with increase in TEA‐f‐MWCNT content. The extent of shape recovery as well as recovery speed were enhanced with increase in the output power of the microwave. Thus the studied nanocomposites could be utilized as non‐contact microwave energy tunable shape memory materials. © 2013 Society of Chemical Industry     

Surface modification of TiO2 particles with 12-hydroxy stearic acid and the effect of particle size on the mechanical and thermal properties of thermoplastic polyurethane urea elastomers

The efficient surface modification of titanium dioxide (TiO₂) particles with different sizes was first carried out with “water only method” (Appl. Surf. Sci. 2018, 447, 664–672) developed in our group using 12-hydroxy stearic acid (12-HSA) as the modifier. The 12-HSA-modified TiO₂ particles with different sizes were then used to explore their effect on the mechanical and thermal properties of a thermoplastic polyurethane urea (TPUU) elastomer with superior mechanical and thermal properties produced newly in our lab using nonsymmetric alicyclic diisocyanate and diamine. Orthogonal experimental results showed that the order of impact of each factor on the modification efficiency of TiO₂ particles was: Temperature > time > modifier content. It was found that, in the nanometer (≤100 nm) range, smaller particles were more helpful to enhance the tensile strength of the TPUU elastomer, while larger ones to increase more significantly the elongation at break. Besides, the TiO₂/polyurethane urea nanocomposites exhibited much better thermomechanical performance than the pristine TPUU elastomer, and the thermomechanical performance of the nanocomposites increased with decreasing particle size.     

Vegetable Oil-Based Hyperbranched Thermosetting Polyurethane/Clay Nanocomposites

The highly branched polyurethanes and vegetable oil-based polymer nanocomposites have been showing fruitful advantages across a spectrum of potential field of applications. Mesua ferrea L. seed oil-based hyperbranched polyurethane (HBPU)/clay nanocomposites were prepared at different dose levels by in situ polymerization technique. The performances of epoxy-cured thermosetting nanocomposites are reported for the first time. The partially exfoliated structure of clay layers was confirmed by XRD and TEM. FTIR spectra indicate the presence of H bonding between nanoclay and the polymer matrix. The present investigation outlines the significant improvement of tensile strength, scratch hardness, thermostability, water vapor permeability, and adhesive strength without much influencing impact resistance, bending, and elongation at break of the nanocomposites compared to pristine HBPU thermoset. An increment of two times the tensile strength, 6 °C of melting point, and 111 °C of thermo-stability were achieved by the formation of nanocomposites. An excellent shape recovery of about 96–99% was observed for the nanocomposites. Thus, the formation of partially exfoliated clay/vegetable oil-based hyperbranched polyurethane nanocomposites significantly improved the performance.     

SiO2/聚氨酯纳米复合物的在位合成及其在环氧树脂中分散行为的研究

以水性阳离子聚氨酯纳米粒子为纳米微囊,利用原位水解法使正硅酸乙酯(TEOS)在囊内水解、聚合生成二氧化硅(SiO2)纳米粒子,从而合成出SiO2/聚氨酯纳米复合物的稳定水基乳液,实现纳米复合物中SiO2纳米粒子的均匀分散和良好的界面结合。并以此作为已表面改性的纳米粒子实现SiO2纳米粒子在环氧树脂的均匀分散。通过能谱扫描、透射电镜和乳液粒子粒径与分布等测试方式对含有环氧树脂的水性SiO2/聚氨酯纳米复合物进行测试。结果表明,SiO2/聚氨酯纳米复合物可以在环氧树脂中均匀分散且不团聚,同时也可促进环氧树脂在水中的分散。     

Polyurethane/clay nanocomposites foams: processing, structure and properties

Polyurethane (PU)/montmorillonite (MMT) nanocomposites were synthesized with organically modified layered silicates (organoclays) by in situ polymerization and foams were prepared by a batch process. Clay dispersion of polyurethane nanocomposites was investigated by X-ray diffraction and transmission electron microscopy. The morphology and properties of PU nanocomposites and foams greatly depend on the functional groups of the organic modifiers, synthesis procedure, and molecular weight of polyols because of the chemical reactions and physical interactions involved. Silicate layers of organoclay can be exfoliated in the PU matrix by adding hydroxyl and organotin functional groups on the clay surface. The presence of clay results in an increase in cell density and a reduction of cell size compared to pure PU foam. In the polyurethane with high molecular weight polyol, a 6 °C increase in T_g, 650% increase in reduced compressive strength, and 780% increase in reduced modulus were observed with the addition of 5% organically treated clays. Opposite effects were observed in PU nanocomposite foams with highly crosslinked structure. The interference of the H-bond in the presence of clay is probably the reason.