PU/OMMT纳米复合材料的制备与性能研究

采用单体插层聚合方法制备聚氨酯（PU）／有机蒙脱土（OMMT）纳米复合材料,并对其结构和性能进行分析。结果表明，经双羟乙基十二烷基三甲基氯化铵改性得到的OMMT（DK2）层间距较大；DK2质量分数为0．03时,PU／OMMT纳米复合材料中OMMT剥离程度较大，PU的插层效果较好,复合材料的物理性能和热稳定性能优良。     

PU/OMMT纳米复合材料的制备与性能研究

采用一步法和预聚体法制备聚氨酯（PU）／有机蒙脱土（OMMT）纳米复合材料，研究分散方式对OMMT层间距以及复合材料制备方法和OMMT用量对纳米复合材料拉伸性能的影响。结果表明，采用高速剪切分散法和超声波分散法均可使聚四氢呋喃醚二醇分子链进入OMMT片层间，增大其层间距；预聚体法PU／OMMT纳米复合材料拉伸性能优于一步法复合材料；与PU弹性体相比，当OMMT用量为0．5份时，一步法复合材料的强度和韧性均提高。牌号为DKIN的OMMT用量为7份时。复合材料的拉伸强度提高54％，拉断伸长率提高19．4％，增幅最大。     

丁腈橡胶/聚氯乙烯/有机蒙脱土纳米复合材料的结构与性能

采用胶乳共沉法和直接共混法制备了丁腈橡胶／聚氯乙稀／有机蒙脱土（NBR／PVC／OMMT）纳米复合材料。通过X射线衍射（XRD）法和透射电子显微镜（TEM）法对NBR／PVC／OMMT纳米复合材料的结构进行了袁征,并研究了复合材料的力学性能、耐油性能和耐老化性能。结果表明,2种方法所获得的复合材料是插层型纳米复合材料;胶乳共沉法制备的纳米复合材料中OMMT的分散更为均匀,其力学性能、耐油性能和耐老化性能优于直接共混法制备的复合材料。     

高气体阻隔性ECO/OMMT纳米复合材料的性能研究

采用熔体共混方法制备氯醚橡胶（ECO）／有机蒙脱土（OMMT）纳米复合材料，研究其微观结构、拉伸性能和气体阻隔性能。结果表明，即使在OMMT用量较大（100份）的情况下。ECO／OMMT纳米复合材料仍能够形成插层结构≠在OMMT用量较大的情况下，ECO／OMMT纳米复合材料中OMMT聚集形成刚性很强的填料网络，使复合材料的应力一应变行为趋向于塑料和短纤维补强橡胶复合材料。同时绝大多数橡胶大分子链被分隔在OMMT片层之间，显著提高了材料的气体阻隔性能。     

纳米有机蒙脱土改性SEBS/PP共混物的研究

通过熔融插层的方法将纳米有机蒙脱土（OMMT）与氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物（SEBS）／聚丙烯（PP）共混制备得到SEBS／PP／OMMT复合材料。X射线衍射实验证明,复合材料SEBS／PP／OMMT5％、SEBS／PP／OMMT10％片层间距分别为4．17nm,3．91nm,说明聚合物插层进入OMMT片层之间,制备得到SEBS／PP／OMMT插层复合材料。采用锥形量热仪测试材料的阻燃性能,燃烧测试结果表明,SEBS／PP／OMMT复合材料具有比较低的热释放速率和质量损失速率,并且随着OMMT添加量增加,复合材料的热释放速率、峰值热释放速率和总热释放先显著降低最后趋于一个稳定值。综合力学测试结果表明,当有机蒙脱土质量分数为5％～10％时,该复合材料的综合性能最好。     

PU/有机蒙脱土纳米复合材料的制备和性能研究

采用原位插层聚合法制备PU/有机蒙脱土(OMMT)纳米复合材料。通过X射线衍射和透射电镜分析发现,当OMMT质量分数为0 01和0 03时,OMMT完全剥离并较均匀地分散于PU基体中;当OMMT质量分数为0 05时,OMMT在PU基体中发生部分剥离。热重分析表明,加入OMMT可提高复合材料的耐热性。动态力学分析表明,OMMT对PU模量的影响不大。PU/OMMT复合材料的硬度、弹性模量、拉伸强度和拉断伸长率均比纯PU有所提高。     

端羟基聚丁二烯/聚氨酯/有机蒙脱土纳米复合材料的制备及性能

以双羟乙基甲基氢化牛脂基氯化铵为插层剂,采用单体插层法制备了端羟基聚丁二烯(HTPB)、聚氨酯(PU)和有机蒙脱土(OMMT)纳米复合材料.当OMMT为3质量份时,HTPB/PU/OMMT纳米复合材料的T型剥离强度是HTPB/PU复合材料的2.58倍.X射线衍射和透射电镜分析表明,OMMT在HTPB/PU/OMMT纳米复合材料中呈剥离状态.     

OMMT/NBR纳米复合材料结构与性能的研究

采用熔体插层法制备有机蒙脱土（OMMT）／NBR纳米复合材料，并对其微观结构及性能进行研究。结果表明，采用熔体法制备的OMMT／NBR复合材料，NBR大分子链插入OMMT片层中，OMMT在NBR基体中呈纳米级分散;与未加OMMT的NBR硫化胶相比，OMMT／NBR纳米复合材料的物理性能明显改善，相同剪切变形下的OMMT／NBR纳米复合材料的储能剪切模量较大；随着OMMT用量的增大，OMMT／NBR纳米复合材料的物理性能提高。     

ALSR/OMMT纳米复合材料的制备与性能研究

采用原位聚合法制备加成型液体硅橡胶（ALSR）／有机蒙脱士（OMMT）纳米复合材料，并对其结构和性能进行研究。结果表明，经改性的OMMT的层间距是钠基蒙脱士（Na-MMT）的1．4～3．6倍；OMMT质量分数为0．01时，ALSR／OMMT纳米复合材料的物理性能和热稳定性较好，OMMT的剥离程度较大，基本以纳米尺度的剥离片层分散在ALSR基体中。     

OMMT/IIR纳米复合材料结构与性能的研究

采用熔体插层法制备有机蒙脱土(OMMT)／IIR纳米复合材料。试验结果表明，OMMT／IIR纳米复合材料是插层型纳米复合材料；与无机粘土／IIR微米复合材料及IIR相比，OMMT／HR纳米复合材料具有良好的物理性能，且其物理性能均随OMMT用量的增大而明显提高；与IIR相比，OMMT／HR纳米复合材料具有优异的气密性。     

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.     

Synthesis and characterization of poly(urethane‐benzoxazine)/clay hybrid nanocomposites

Poly(urethane‐benzoxazine)/clay hybrid nanocomposites (PU/Pa–OMMTs) were prepared from an in situ copolymerization of a polyurethane (PU) prepolymer and a monofunctional benzoxazine monomer, 3‐phenyl‐3,4‐dihydro‐2H‐1,3‐benzoxazine (Pa), in the presence of an organophilic montmorillonite (OMMT), by solvent method using DMAc. OMMT was made from cation‐exchange of Na‐montmorillonite (MMT) with dodecyl ammonium chloride. The formation of the exfoliated nanocomposite structures of PU/Pa‐OMMT was confirmed by XRD from the disappearance of the peak due to the basal diffraction of the layer‐structured clay found in both MMT and OMMT. DSC showed that, in the presence of OMMT, the curing temperature of PU/Pa lowered by ca. 60°C for the onset and ca. 20°C for the maximum. After curing at 190°C for 1 h, the exothermic peak on DSC disappeared. All the obtained films of PU/Pa–OMMT were deep yellow and transparent. As the content of OMMT increased, both the tensile modulus and strength of PU/Pa–OMMT films increased, while the elongation decreased. The characteristics of the PU/Pa–OMMT films changed from plastics to elastomers depending on OMMT content and PU/Pa ratio. PU/Pa–OMMT films also exhibited excellent resistance to the solvents such as tetrahydrofuran, N,N‐dimethylformamide and N‐methyl‐2‐pyrrolidinone. The thermal stability of PU/Pa were enhanced remarkably even with small amount of OMMT. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4075–4083, 2003     

Study on Polyurethane/MDI-Modified-Organic Montmorillonite Nanocomposites

Polyurethane (PU)/MDI-modified-organic montmorillonite (MOMMT) nanocomposites were prepared by in situ polymerization and intercalation technology. Compared with that of organic montmorillonite (OMMT), the interlayer spacing of MOMMT was increased from 1.50 nm to 2.05 nm because MDI was grafted on the surface of the silicate layers through reaction between MDI and -OH. The dispersion of silicate layers in PU/MOMMT nanocomposites was better than that of silicate layers in PU/OMMT nanocomposites. Compared with those of PU/OMMT nanocomposites, the tensile strength and tear strength of PU/MOMMT nanocomposites were increased, and the MOMMT showed a higher stiffened effect. Because of the improvement of the dispersion and interfacial interaction, the temperature of initial weight loss of PU/MOMMT nanocomposites was higher than that of PU/OMMT nanocomposites, so PU/MOMMT nanocomposites had better thermal stability.     

Structure and Property of PU/MMT Nanocomposites by In-Situ Polymerization

A montmorillonite modified by octadecylammonium salt (OMMT) was prepared. A polyurethane (PU)/montmorillonite nanocomposite was synthesized by in-situ polymerization using the OMMT, poly(propylene glycol), 4,4-diphenylmethylate diisocyanate, and 1,4-butanediol. The MMT platelets were dispersed in PU matrix on a 10 ～ 50 nm scale. Compared to that of pure PU, the tensile strength and tear strength of the PU/OMMT nanocomposites increased, respectively, and the MMT platelets dispersed on a nanometer scale enhanced the PU. The temperature of initial weight loss of the PU/OMMT nanocomposites was lower than that of pure PU because of the acid catalytic action of protonated MMT platelets in the first thermodegradation step. But its temperature of initial weight loss was higher than that of pure PU because of the barrier effect of the MMT platelets in the second thermodegradation step.     

Crystallization behavior of poly(p‐dioxanone)‐PU/montmorillonite nanocomposites prepared by chain‐extending reaction

Organo‐modified montmorillonites and poly(p‐dioxanone) (PPDO) diol prepolymers were used to prepare Poly(p‐dioxanone)‐PU/organic montmorillonite (PPDO‐PU/OMMT) nanocomposites by chain‐extending reaction. The crystallization behavior and spherulitic morphology of PPDO‐PU/OMMT nanocomposites were investigated by WXRD, differential scanning calorimetry, and polarized optical microscopy. The results show that the regularity of the chain structure plays a dominant role during the crystallization process rather than that of OMMT content and its dispersion status in PPDO matrix. With similar molecular weight and same OMMT content, PPDO‐PU/OMMT nanocomposite, which derived from lower molecular weight PPDO prepolymer, exhibits lower crystallization rate, melting point, and crystallinity. The influence of the clay content on the crystallization behavior highly depends on its dispersing state. The nucleating effect of OMMT can be only observed at high loading percentage. For the nanocomposites with low clay loading percentage, the retarding effect of exfoliated platelets on the chain‐ordering into crystal lamellae became the key factor. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

OMMT／WPU复合乳液的制备及其性能研究

采用超声辅助法制备了有机蒙脱土/水基聚氨酯(OMMT/WPU)复合乳液,采用透射电镜(TEM)、红外(FT-IR)、X-射线衍射(XRD)、激光粒度仪等对复合乳液及材料进行了分析及性能测试.结果表明,OMMT在WPU乳液中得到较好的分散,并与聚氨酯(PU)大分子间有强烈的相互作用;WPU中加入OMMT有助于提高PU硬段微区的结晶性和微相分离的程度;随着OMMT含量的增加,OMMT/WPU复合材料的耐水性、拉伸强度先增加后下降,伸长率降低,OMMT的质量分数为1.0%时,OMMT的剥离程度最好,复合材料的综合性能最佳.     

Characterization of structure and corrosion resistivity of polyurethane/organoclay nanocomposite coatings prepared through an ultrasonication assisted process

In this study, a series of castor oil based polyurethane/organically modified montmorillonite (OMMT) clay nanocomposite coatings have been successfully prepared by effective dispersing of OMMT nano-layers in polyurethane matrix through an ultrasonication assisted process. Effectiveness of ultrasonication process in de-agglomeration of clay stacks in castor oil dispersions was evaluated by optical microscopy and sedimentation test. Structure of nanocomposite coatings was investigated by wide angle X-ray diffraction (WAXD) and Fourier-transform infrared spectroscopy (FT-IR). The anticorrosive properties of nanocomposite coatings were characterized by electrochemical impedance spectroscopy (EIS), Tafel polarization study, water absorption and pull-off adhesion tests. The experimental results showed that PU/OMMT nanocomposite coatings were superior to the neat PU in corrosion protection effects. Also, it was observed that the corrosion protection of polyurethane organoclay nanocomposite coatings is improved as the clay loading is increased up to 3 wt.%.     

Effect of OMMT on the phase morphology controlling of PU/EP IPN

Organic montmorillonite (OMMT) modified polyurethane (PU) /epoxy resin (EP) (OMMT-PU/EP) graft interpenetrating polymer network nanocomposites with different content of OMMT were prepared. The effect of the OMMT content on the phase behavior of the PU/EP IPN system has been studied by Dynamic mechanical analysis (DMA). With the content of OMMT increased, the tan δ turned from single peak to two peaks and the damping temperature range became wider when the isocyanate index is low. Transmission electron microscope (TEM) and atomic force microscope (AFM) results showed that high content of OMMT favored phase separation to form a larger-size domain in nanocomposites, resulting in the broadening of damping temperature range. This work demonstrates that we can control phase behaviour of OMMT-PU/EP IPNs by changing the OMMT content. This result provides potential opportunity for this type of materials to be used as sound and vibration damping polymers over wide temperature ranges.