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以聚醚多元醇和MDI-50为原料,采用预聚物法合成预聚体,再和扩链剂MOCA进行扩链合成聚氨酯弹性体。研究了预聚体中不同异氰酸酯基(—NCO)质量分数对MDI-50型聚氨酯弹性体性能的影响。采用差示扫描量热分析(DSC)、热重分析(TG)、红外光谱(FTIR)及力学性能等测试方法对聚氨酯弹性体的结构与性能进行了表征和分析。结果表明:预聚体反应体系中NCO/OH摩尔比增大,预聚体中—NCO质量分数增加,预聚体的黏度降低,相应的聚氨酯弹性体的硬度和玻璃化转变温度提高,断裂伸长率降低,而拉伸强度和撕裂强度先增加后下降;当NCO/OH摩尔比为2.22时,聚氨酯弹性体力学性能较好;—NCO质量分数对聚氨酯弹性体的热稳定性影响不大。 相似文献
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介绍了JZ-9聚氨酯弹性体的合成工艺,分析了-NCO质量分数对聚氯酯弹性体硬度、拉伸强度的影响及3,3-二氯4,4-氨基二苯甲烷用量对聚氨酯弹性体物理性能的影响。 相似文献
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Qingjun Ding Baolei Liu Qiang Zhang Qihui He Baixing Hu Jian Shen 《Polymer International》2006,55(5):500-504
In this paper, a new type of organophilic montmorillonite, co‐treated with cetyltrimethyl ammonium bromide (CTAB) and 4,4′‐diphenymethylate diisocyanate (MDI), was modified and applied to prepare polyurethane/montmorillonite nanocomposites via in situ polymerization. The nanoscale montmorillonite layers were exfoliated and dispersed relatively homogeneously in the polyurethane matrix, and characterized by X‐ray diffraction and transmission electron microscopy. The thermal degradation temperature of the nanocomposites increased, as compared with pristine polyurethane. Dynamic mechanical analysis confirmed the constraining effect of exfoliated montmorillonite layers on polyurethane chains, which benefited the increased storage modulus and increased glass transition temperature. Tensile tests showed that the exfoliated nanocomposites were reinforced and toughened by the addition of nanometer‐size montmorillonite layers. Copyright © 2006 Society of Chemical Industry 相似文献
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To explore a potential method for improving the toughness of a polylactide (PLA), we used a thermoplastic polyurethane (TPU) elastomer with a high strength and toughness and biocompatibility to prepare PLA/TPU blends suitable for a wide range of applications of PLA as general‐purpose plastics. The structure and properties of the PLA/TPU blends were studied in terms of the mechanical and morphological properties. The results indicate that an obvious yield and neck formation was observed for the PLA/TPU blends; this indicated the transition of PLA from brittle fracture to ductile fracture. The elongation at break and notched impact strength for the PLA/20 wt %TPU blend reached 350% and 25 KJ/m2, respectively, without an obvious drop in the tensile strength. The blends were partially miscible systems because of the hydrogen bonding between the molecules of PLA and TPU. Spherical particles of TPU dispersed homogeneously in the PLA matrix, and the fracture surface presented much roughness. With increasing TPU content, the blends exhibited increasing tough failure. The J‐integral value of the PLA/TPU blend was much higher than that of the neat PLA; this indicated that the toughened blends had increasing crack initiation resistance and crack propagation resistance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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Expanded graphite (EG) is prepared by microwave irradiation to expandable graphite. A stable aqueous suspension of EG is obtained through dispersing EG into deionized water in the presence of surfactant under ultrasonication. Nanocomposites are prepared by compounding EG aqueous suspension with alkyl acrylate elastomer latex. It is showed that, by the latex compounding method (LCM), EG platelets are finely dispersed in the elastomer matrix. The nanocomposites exhibit remarkable improvements in mechanical properties, wear resistance, and gas barrier property. The prepared compound also shows certain electrical conductivity, but soon loses it after milled on a miller. Meanwhile, a dramatic change in EG network is observed corresponding to the loss of electrical conductivity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
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叙述了聚氨酯弹性体耐热性能的研究进展,简述了聚氨酯弹性体结构与耐热性能的关系,探讨了提高耐热性能的一些有效途径。 相似文献
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A series of polyurethane (PU)/SiO2 composites were prepared via in situ polymerization through a prepolymer process. The effect of SiO2 content on mechanical and solvent‐resistant properties of PU/SiO2 composites was investigated. It was found that with increasing SiO2 content, the tensile strength and toughness, hardness, and modulus of PU composites increased. PU/SiO2 composites exhibited only one loss peak corresponding to the glass transition temperature of the soft‐segment of PU, which shifted insignificantly with increasing SiO2 content. The equilibrium swelling ratio and swelling rate constant in cyclohexanone and xylene were reduced by increasing SiO2 content, indicating the enhancement of the solvent resistance of the PU elastomer. Morphology observation of PU/SiO2 composites showed that the acicular SiO2 dispersed uniformly in PU matrix, and there was no obvious aggregation even at 9 wt % loading of SiO2. The reinforcing and toughening effects depended largely on the dispersion of SiO2 in PU matrix and the interfacial layer formed between the two phases. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
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以聚已二酸乙二醇丙二醇酯(PEPA)、4,4'-二苯基甲烷二异氰酸酯(MDI)为原料,用1,4-丁二醇(BDO)扩链剂或混合扩链剂制备了聚氨酯(PU)弹性体。讨论了预聚体NCO基质量分数、扩链剂和催化剂用量对聚氨酯弹性体力学性能的影响;同时,比较了MDI/BDO体系与2,4-甲基二异氰酸酯/3,3'-二氯-4,4'-二胺基二苯甲烷(TDI/MOCA)体系的性能。结果表明,聚氨酯弹性体的硬度、模量和强度随预聚体NCO基含量增加而增加;提高扩链剂的三元醇含量,弹性体力学性能呈下降趋势;MDI/BDO体系的扯断伸长率和撕裂强度比TDI/MOCA体系高。 相似文献
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Zhenghong Guo Lifang Tong Zhongbin Xu Zhengping Fang 《Polymer Engineering and Science》2007,47(6):951-959
To increase the compatibility of polystyrene (PS) and polyolefin elastomer (POE) blends, a Lewis acid catalyst, aluminum chloride (AlCl3), was adopted to initiate the Friedel–Crafts alkylation reaction for the formation of PS‐graft‐POE copolymer. Dynamic mechanical analysis indicated that PS/POE and PS/POE/AlCl3 blends are partially miscible, and the formation of PS‐graft‐POE copolymer increased the compatibility between PS and POE. Scanning electron microscope and transmission electron microscope results showed that the domain size of the blends decreased dramatically and the size distribution became more uniform with the addition of AlCl3. Such in situ compatibilization also induced hindrance to the macromolecular chain movement, as reflected by the results of the dynamic rheological analysis. The dynamic rheological behaviors of PS/POE and PS/POE/AlCl3 blends under different temperature showed that in situ compatibilization weakened the effects of thermooxidation on PS/POE blends. Moreover, in situ compatibilization decreased the activation energy of viscous flow and reduced the influence of temperature on PS/POE blends. POLYM. ENG. SCI., 47:951–959, 2007. © 2007 Society of Plastics Engineers 相似文献
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A series of main-chain-fluorinated thermoplastic polyurethane elastomers (FTPU) based on fluoropoly(oxyalky1ene)diol (FPOA)
were prepared by a one-step bulk polymerization. Polybutylene adipate (PBA) was combined with FPOA as a soft-segment in order
to improve the solvent solubility of FTPU. The effects of the mass ratio of FPOA/PBA and the mass fraction of hard-segment
on the mechanical properties of FTPU were investigated. The structure and morphology of FTPU were characterized by FTIR, GPC,
DMA, surface property, and AFM analysis. The results indicated that the tensile strength and elongation at break for the sample
of FTPU with FPOA/PBA ratio 30/70 can reach as high as 36.6 MPa and 1228.1%, respectively. It exhibited relatively high molecular
weight, high damping property, enhanced thermal stability, and extremely low surface tension. The introduction of fluorinated
blocks made the extent of incompatibility of the two phases of FTPU greater and the trend of micro-phase separation more serious. 相似文献
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Vinícius Demétrio da Silva Leonardo M. dos Santos Suelen M. Subda Rosane Ligabue Marcus Seferin Carlos L. P. Carone Sandra Einloft 《Polymer Bulletin》2013,70(6):1819-1833
The development of new polymeric and polymeric based materials is fundamental to meet the market demands. This work aims the synthesis and characterization of polyurethane/titanium dioxide nanocomposite, using low cost commercial raw materials. Nanocomposites were synthesized by in situ polymerization reactions in which titanium dioxide were added in the following proportions, by weight, in relation to the mass obtained from the pure polymer: 0.5, 1.0, 2.0, 3.0, 5.0, 7.0, and 10.0 %. These reactions were based in poli (ε-caprolactone) and 1,6-diisocyanatohexane. The materials were characterized by infrared spectroscopy Fourier transform, scanning electron microscopy, differential scanning calorimetry analysis, thermogravimetric analysis, dynamic mechanical thermal analysis, and UV–Vis spectroscopy. Based on the obtained results it was concluded that the nanocomposites synthesized by in situ polymerization presented, in general, thermal properties (degradation temperature) and mechanical properties higher than the pure polymer. 相似文献
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The structure and dynamic properties of thermoplastic polyurethane elastomer/hindered phenol hybrids
Daling Xiao Xiuying Zhao Yiping Feng Ping Xiang Liqun Zhang Weimin Wang 《应用聚合物科学杂志》2010,116(4):2143-2150
The organic hybrids of thermoplastic polyurethane (TPU)/hindered phenol (AO‐80) were prepared through melt blending, which was followed by hot and cold pressing procedure. The microstructure and dynamic mechanical properties of the hybrids were systematically investigated through SEM, DSC, XRD, FTIR, DMA and a tensile tester. The experimental results indicated that AO‐80 was completely dissolved in the matrix. The glass transition of the soft segments of TPU was found to shift to higher temperature with the amount of AO‐80 increasing, whereas the glass transition of the hard segments exhibited nearly no evident change, indicating that AO‐80 was selectively located in the soft region of TPU and the formation of the strong intermolecular interactions (hydrogen bonding) between AO‐80 and the soft region of TPU. With the increase of AO‐80 in the hybrids, the tanδ peak gradually shifted to higher temperatures and the maximal tanδ value increased from 0.4 to 1.6. Meanwhile, the glass transition temperature ranges broadened and the TA value increased greatly with the more content of AO‐80. Because of the decrease of the hard segments amount in the hybrids, the tensile stress of these hybrids decreased, but still maintained at a high level. The hybrids were expected to have potential applications as high performance damping materials combined with good mechanical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献