Synthesis and properties of MDI-50 type polyurethane elastomer

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。     

透明性聚氨酯弹性体的合成

采用预聚体法以不同的聚合物多元醇、异氰酸酯与1,4-丁二醇合成了透明聚氨酯弹性体,分析了异氰酸酯种类、n(-NCO)/n(-OH)(R值)、聚合物多元醇种类及分子质量、熟化时间和温度等对聚氨酯弹性体透明性、力学性能的影响。结果表明,采用脂肪族的IPD I,R值取1.02,硬段质量分数36.9%,相对分子质量1 000~2000的聚四亚甲基二醇,熟化条件为130℃/3 h时合成的PU弹性体具有较好的透明性和力学性能。     

半预聚物法RIM聚氨酯弹性体的合成

采用半预聚物法合成了以L—MDI、DMTDA、PPO为原料的双组分RIM聚氨酯弹性体。研究了合成方法、扩链剂种类、硬段含量、异氰酸酯指数、催化剂用量、热处理时间、料温等因素对RIM聚氨酯弹性体性能的影响。结果表明，采用L—MDI／PPO／DMTDA半预聚物法制备的RIM聚氨酯弹性体具有良好的物理性能。     

JZ-9型聚氨酯弹性体的合成

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。     

半预聚体法合成聚醚型聚氨酯弹性体

采用半预聚法合成了聚醚型聚氨酯弹性体;分别对预聚反应的时间、温度进行了考查。确定了合适的反应条件;并对影响弹性体性能的几种因素：水分的含量、软硬段比例、NCO／OH、聚醚的分子质量以及后熟化时间等进行了研究。     

Synthesis and characterization of polyurethane/montmorillonite nanocomposites by in situ polymerization

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     

Morphologies and mechanical properties of polylactide/thermoplastic polyurethane elastomer blends

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     

聚氨酯/聚丙烯酸酯复合弹性体的力学性能研究

采用预聚体法合成了一系列聚氨酯／聚丙烯酸酯复合弹性体，研究了组成比例对PU／PA复合弹性体的力学性能的影响。结果表明：聚丙烯酸甲酯的比例在一定范围内时，可以较大程度地提高材料的力学强度和断裂伸长率，而将丙烯酸甲酯和甲基丙烯酸甲酯混合加入聚氨酯中，形成的复合弹性体的力学性能无明显改善。     

Functional and mechanical properties of acrylate elastomer/expanded graphite nanocomposites

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     

聚氨酯弹性体耐热性能的研究进展

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。     

Structure and property of polyurethane/SiO2 composite elastomer prepared via in situ polymerization

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     

PBA/MDI体系聚氨酯弹性体力学性能的研究

采用二步法以聚己二酸丁二醇酯(PBA)、4,4-′二苯基甲烷二异氰酸酯(MDI)和二元醇1,4-丁二醇(BDO)或混合扩链剂(二元醇和三元醇)合成了聚氨酯(PU)弹性体。研究了软段相对分子质量、预聚体-NCO质量分数和扩链剂对聚氨酯弹性体力学性能的影响。实验结果表明:PBA相对分子质量大,PU断裂伸长率和冲击弹性好;PU硬度、撕裂强度和模量随预聚体-NCO相对质量分数增加而增加;弹性体的交联密度过高,硬度和撕裂强度下降。     

PEPA/MDI体系聚氨酯弹性体力学性能的研究

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。     

Structure and properties of in situ compatibilized polystyrene/polyolefin elastomer blends

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     

聚氨酯弹性体磁带粘合剂的合成研究

介绍了聚氨酯弹性体磁带粘合剂的合成工艺，讨论了原料含水量、反应温度、ｎ（ＮＣＯ）：ｎ（ＯＨ）及聚酯分于量对聚氨酯合成的影响。     

Preparation and properties of the main-chain-fluorinated thermoplastic polyurethane elastomer

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.     

热塑性聚氨酯弹性体与ABS共混物的力学性能

通过融熔共混法制备了TPU／ABS共混物。对共混比例为0／100，5／95，7／93，10／90，20／80，30／70和40／60的共混物的力学性能进行研究，发现材料的抗冲性能得到改善，在比例为20／80时冲击强度达到最大，同时其它的力学性能下降。     

Synthesis and characterization of polyurethane/titanium dioxide nanocomposites obtained by in situ polymerization

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.     

The structure and dynamic properties of thermoplastic polyurethane elastomer/hindered phenol hybrids

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