热塑性聚氨酯热熔胶的合成与性能研究

以己二酸系聚酯二醇为软段,二异氰酸酯与扩链剂生成的链段为硬段,制备了聚氨酯热熔胶;研究了软硬段组成、结构、相对分子质量、扩链剂、异氰酸酯指数等对聚氨酯热熔胶的力学性能、结晶性能、粘接性能及耐热性能的影响。     

异氰酸酯对聚乳酸/热塑性聚氨酯共混物性能的影响

以4,4^′-二苯基甲烷二异氰酸酯（MDI）为反应增容剂，采用熔融共混法制备了不同MDI含量的聚乳酸/热塑性聚氨酯（PLA/TPU）共混物，采用傅里叶变换红外光谱仪（FTIR）、万能试验机、冲击试验机、扫描电子显微镜（SEM）、差示扫描量热仪（DSC）和旋转流变仪对共混物力学性能、微观形态、热性能和流变性能进行了研究。结果表明：MDI可以有效改善共混物的力学性能，当MDI质量分数为1%时，共混物力学性能最佳，缺口冲击强度为40.0kJ/m²，断裂伸长率为214.1%，与未加MDI的共混物相比，分别增加了4.3倍和5.8倍，拉伸强度稍有下降（47.6MPa）；SEM表明，MDI的加入提高了共混物的相容性，加入MDI后，共混物的断面由海-岛结构变为核-壳包覆结构，相界面作用力增强；DSC测试表明，共混物的玻璃化转变温度、冷结晶温度和熔融温度随着MDI含量的增加而升高；流变测试表明，MDI质量分数的增加，共混物呈现更显著的剪切变稀行为，推测共混反应机理为：MDI质量分数的增加，体系内依次发生PLA的扩链、支化和TPU的交联。     

Foaming behavior of polyamide 1212 elastomers/polyurethane composites with improved melt strength and interfacial compatibility via chain extension

Long carbon chain thermoplastic polyamide elastomer (TPAE) with PA1212 as hard segment and polytetrahydrofuran as soft segment was synthesized successfully. Subsequently, thermoplastic polyurethane (TPU) incorporated to compensate for the high cost of TPAE and improved the foaming performance, in which a chain extender (ADR) was applied to enhance melt strength and interfacial compatibility simultaneously. The effect of ADR content on the mechanical, thermal, rheological, and foaming properties of TPAE/TPU composites were investigated in detail. It was found that the composite foams showed a more perfect cell structure, high cell density, and increased expansion ratio because of the enhanced melt strength and interfacial compatibility, when ADR was incorporated. With the increase of ADR content, the cell size and expansion ratio of the composite foams with TPU content of 30% showed a trend of first increasing and the following decreasing. The cell size reached a maximum value when the content of ADR was 2%, which was 25.81 μm. Consequently, the obtained TPAE/TPU composite foams showed an outstanding compressive modulus and resilient performance to broaden its application in footwear industry.     

IPDI／PEPA型热塑性聚氨酯的合成及表征

以异佛尔酮二异氰酸酯(IPDI)、聚己二酸乙二醇丙二醇酯二醇(PEPA)和1,4-丁二醇(BDO)为原料,用熔融预聚合两步法,后聚合温度60-90℃,合成硬段含量为50％的IPDI／PEPA型热塑性聚氨酯。采用凝胶渗透色谱仪测试其数均相对分子质量为78 650,重均相对分子质量为125 446,相对分子质量分布为1．59。红外光谱分析表明聚合较为完全,聚合物不存在支链结构,为热塑性材料。DSC分析表明聚合物软段和硬段的玻璃化转变温度分别为-34℃和48℃,透射电镜照片进一步说明该材料存在一定的相分离。     

热塑性聚氨酯弹性体粘合剂的制备及力学性能的研究

以环氧乙烷—四氢呋喃无规共聚醚(PET)、异佛尔酮二异氰酸酯(IPDI)和1,4-丁二醇(BD)为原料,采用预聚法(二步法)合成热塑性聚氨酯弹性体(TPU)粘合剂。确定预聚温度为700C,反应温度为1000C,以及预聚反应时间为1.5～2.0小时。通过调整硬段、软段含量对TPU的性质进行优化,获得用于含能材料的粘合剂。通过凝胶渗透色谱(GPC)分析和力学性能测试对所合成的TPU进行表征。测试结果表明,随着硬段含量的增加,TPU的拉伸强度不断增大,断裂伸长率则降低。当硬段含量在45%～55%时TPU的综合性能达到最佳。     

Bio‐based thermoplastic polyurethane and polyamide 11 bioalloys with excellent shape memory behavior

Bio‐based blends of commercially available polyester based bio thermoplastic polyurethane (TPU) and castor oil based polyamide 11 (PA11) of different ratios are prepared by melt processing. The blends properties such as shape memory behavior through unconstrained and constrained recovery, interfacial interaction, morphology, dynamic mechanical, rheological, and mechanical behavior are studied. A strong interface between the two polymeric phases due to hydrogen bonding observed through morphology indicates that TPU and PA11 are well compatible. The complex viscosity of blends ranges between that of neat PA11 and TPU. Thermal analysis shows that higher the TPU content lower the melting point (T_m ) corresponding to PA11 and the crystallization temperature (T_c ) remains unaltered. Adding TPU to PA11 ductility and impact strength of the blends increases significantly with the small reduction in their tensile strength. Shape memory behavior investigation reveals that, blends recover almost 95% of the applied deformation when heated at zero load and they recovered a stress of 1.8–3.2 MPa in constrained recovery during three consecutive thermomechanical cycles. The reported results on bioalloys promotes the usage in multidisciplinary field of intelligent devices, such as ergonomic grips and sports shields. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44794.     

Shape Memory Thermoplastic Polyamide Elastomer Based on PA1212

Shape memory polyamide elastomers have attracted large attention owing to a variety of favorable properties (e.g., designable chemical structure, good thermal stability, flexibility, and elasticity, et al). However, the polyamide elastomer reported recently still lack good mechanical property. In the present work, a new type of shape memory thermoplastic polyamide elastomer (TPAE), composed of long carbon chain PA1212 and polytetramethylene ether glycol (PTMEG), is synthesized through two-step melt polycondensation, which is named as poly(ether-b-amide) (PEBA). The chemical structure of PEBA is confirmed by FTIR results and it also shows excellent mechanical properties. PEBA, possessing two melting temperatures, stay in microphase separation among PTMEG soft domains and PA1212 hard domains that are amorphous and α crystal, respectively. Furthermore, PEBA can fix a temporary shape after the heated strip is twisted and cooled down and then recover to the original shape after secondary heating, which is attributed to the fixing force provided by PTMEG domains and entropy elasticity of physically cross-linked PA1212 domains, respectively. Besides, PEBA elastomer can be reshaped between ≈190 and ≈380 °C and it also has shape memory behavior. This new kind of TPAE proposes a new smart material for sensors and soft robotics.     

Electrospinning of thermoplastic polyurethane microfibers and nanofibers from polymer solution and melt

Electrospinning technique was used to produce ultrafine fibers from thermoplastic polyurethane (TPU). A direct comparison between melt and solution electrospinning of TPU was provided for the evaluation of process–structure relationship. It was found that the deposition rate of melt electrospinning (0.6 g h^?1) is four times higher than that of solution electrospinning (0.125 g h^?1) for TPU under the same processing condition. However, the average fiber diameters of solution electrospun TPUs (220–280 nm) were much lower than those of melt electrospun TPUs (4–8 μm). The effect of processing variables including collection distance and electric field strength on the electrospun fiber diameter and morphology was also studied. The findings indicate that increasing the electric field strength yielded more electrical forces acting on polymer jet and resulted in a decrease in fiber diameter as a result of more fiber drawing in both solution and melt electrospun fibers. It was also demonstrated that increasing the collection distance led to an improvement in the solidification of melt electrospun fibers and thus less fused fibers were obtained. Finally, a close investigation of fiber structures revealed that melt electrospun TPU fibers had smooth surface, whereas solution electrospun TPU fibers showed high intensity of cracks on the fiber surface. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

热塑性聚氨酯/石墨烯改性聚氨酯注浆材料的制备与性能研究

采用石墨烯、热塑性聚氨酯（TPU）复合改性聚氨酯注浆材料,并添加少量的粉煤灰、炉底渣及碱性激发剂制备一种低密度、高强度、快硬性的TPU/石墨烯改性聚氨酯注浆材料。借助聚氨酯弹性体材料密度测试仪、万能材料试验机、渗透系数测试仪、荧光显微镜对TPU/石墨烯改性聚氨酯注浆材料的密度、膨胀倍数、抗压强度、阻燃性能、渗透系数及微观形貌进行表征,深入分析了石墨烯和TPU的种类和含量对聚氨酯注浆材料基本物理性能、力学性能及微观结构的影响。结果表明,TPU/石墨烯改性聚氨酯注浆材料的密度为0.24~1.25 g/cm³,膨胀倍数最高可达38倍,抗压强度为15.0~43.8 MPa,相比普通聚氨酯注浆材料,改性聚氨酯注浆材料抗压强度提升1倍以上。酒精灯燃烧试验显示注浆材料无焰燃烧时间均小于20 s。石墨烯和TPU均可提高聚氨酯的强度和耐久性,改善TPU的微观形貌。TPU/石墨烯改性聚氨酯注浆材料表现出良好的强度、耐久性及弹性,是一种性能优异的注浆材料。     

Microstructure and tensile properties of injection molded thermoplastic polyurethane with different melt temperatures

The use of injection molding technology to prepare heterogeneous interlayer film of laminated glass holds strong applicable potential. This article aims to investigate the effects of melt temperature and melt flow on the microstructure evolution and tensile properties of thermoplastic polyurethane (TPU) specimens during the injection molding process. The tensile properties of the TPU specimens show dependency on the melt temperature and melt flow direction. The results of birefringence indicate that melt flow and lower melt temperature induce higher stretching deformation of the molecular chain network. Small-angle X-ray scattering analysis approves that besides the melt temperature and flow direction, the testing position on the cross section of the specimen has great influence on the microstructure of the TPU sheet. Further analysis and conclusions can be made using wide-angle X-ray scattering method. The above results demonstrate that both the tensile properties and microstructure of the injection molded TPU specimens tend to be isotropic with the increase of melt temperature. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48891.     

纤维级热塑性聚氨酯合成的研究

以聚己二酸乙二醇聚酯二醇（PFA）、4,4＇-二苯基甲烷二异氰酸酯（MDI）和1,4-丁二醇（BDO）为原料合成纤维级热塑性聚氨酯,研究了低聚物分子质量、硬段含量、反应温度以及物料含水量对热塑性聚氨酯（TPU）性能的影响,得出了三颈瓶法合成纤维级TPU的最佳配方和合适的反应条件。     

Fire safety of thermoplastic polyurethane based on pyromellitic dianhydride

In this paper, pyromellitic dianhydride (PMDA) was firstly used as fire safety agent for thermoplastic polyurethane (TPU). And, the fire safety improvement of PMDA in TPU was intensively investigated by limiting oxygen index (LOI), smoke density test (SDT), cone calorimeter test, and thermogravimetric/infrared spectroscopy, respectively. It has been found that PMDA could significantly improve the ignition level, and the LOI value increase to 28.5% when 8.0 wt% PMDA was incorporated into TPU; PMDA also could effectively suppress the smoke production and heat release during the combustion process. The peak heat release rate and total smoke release of the sample with 8.0 wt% PMDA were decreased by 68% and 22% compared with pure TPU in cone calorimeter test. The thermogravimetric/infrared spectroscopy results showed that PMDA could improve the thermal stability of TPU composites at high temperature and increased the release of CO₂, H₂O, and so on. All results confirmed that PMDA would have a good prospect in reducing the fire hazard of TPU.     

1,5-萘二异氰酸酯型聚氨酯弹性体的制备及性能

通过预聚法合成了以己二酸乙二醇丙二醇二酯、聚四氢呋喃二醚、1,5-萘二异氰酸酯(NDI)、甲苯二异氰酸酯(TDI)、1,4-丁二醇及4,4'-二氨基-3,3'-二氯二苯甲烷为主要原料的聚氨酯弹性体。通过水解后弹性体的拉伸、撕裂等力学性能保持率的比较,发现NDI型聚氨酯弹性体比TDI型具有更好的水解稳定性;通过不同温度下和热空气老化后弹性体力学性能保持率的对比,证明NDI型聚氨酯弹性体的耐热稳定性要优于TDI型。     

热塑性聚氨酯共混物的增容方法

综述了作为聚氨酯弹性体的一种,热塑性聚氨酯（TPU）与其他聚合物共混改性时,可提高增容性的6种方法（如调整分子链结构、改变共混聚合物的极性、化学改生引入反应性官能团、改变分子极性、加入相容剂、形成互穿网络等）,并提到了对相容性影响很大的共混方法和工艺条件.     

Advanced compounding: Extrusion of polypropylene nanocomposites using the melt pump

A melt pump was assembled into the compounding line to ensure both sufficient time for diffusion process of polymer chains into the silicate gallery and sufficient mechanical shear energy for exfoliation of clay layers. The melt pump in front of the open co‐rotating twin‐screw extruder controls the throughput rate and the residence time, whereas the screw speed and screw geometry in the extruder determine the mechanical shear energy applied on the compound. Due to melt pump employment, the melt in metering zone can be accumulated, which results in higher mixing efficiency. It was found that using the melt pump leads to up to two times higher residence time and, consequently, higher level of material reinforcement as investigated by extensional rheology. Different melt pump adjustments, screw geometries, and screw speeds were tested and their effect on processing characteristics and material reinforcement was investigated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

热塑性聚氨酯弹性体共混改性聚偏氟乙烯研究进展

聚偏氟乙烯(PVDF)是一种半结晶性线型高分子,具有耐热、抗酸碱、易成膜等特点,一直被作为成膜物质的优选材料。然而PVDF表面能低、有极强的疏水性,纯PVDF膜通量低,用于水相分离时易吸附蛋白质、胶体粒子等而导致膜孔堵塞,造成膜污染。因此,在实际应用中需要对PVDF膜进行改性,以改善膜的抗污染能力。常用的改性方法有表面涂覆、物理共混、物理填充、表面化学接枝等,其中,共混是经济有效而又简便易行的方法,已成为改善膜性能、降低制膜成本的重要手段。热塑性聚氨酯弹性体(TPU)因其具有优异耐低温、高弹性和耐磨特性、丰富的结构-性能可设计性,在PVDF改性中具有独到的优势,应用十分广泛。本文综述了TPU改性PVDF的研究进展。     

基于导电涂层微结构TPU柔性传感器的制备和性能

将具有表面微结构和平整的热塑性聚氨酯（TPU）传感基片封装成压阻型柔性压力传感器,其中前者（尺寸为10 mm×10 mm）的表面喷涂不同质量（0.02、0.05、0.1 g）的多壁碳纳米管（MWCNTs）,并对微结构柔性传感基片表面形貌及传感器性能进行了表征和分析。结果表明,微结构传感基片表面上微柱顶面形成一定厚度的MWCNTs层,层内MWCNTs形成网络;喷涂较高MWCNTs质量时,传感器具有较高的灵敏度和较低的检测限,这归因于压力所致MWCNTs的网络搭接程度和传感基片间接触面积的增加量较大;喷涂0.1 g MWCNTs时,传感器的灵敏度为0.143 kPa^-1（0~3 kPa）,检测限低至100 Pa,在较宽压力范围内（3~200 kPa）仍有一定的压阻响应,能在4 000次的循环压缩/释放测试（峰值压力约200 kPa）中保持稳定的压阻响应,且可准确检测典型人体运动所产生的压阻响应,具有应用于智能穿戴领域的潜能。     

Maximizing the utility of bio-based diisocyanate and chain extenders in crystalline segmented thermoplastic polyester urethanes: Effect of polymerization protocol

High molecular weight semi crystalline thermoplastic poly(ester urethanes), TPEUs, were prepared from a vegetable oil-based diisocyanate, aliphatic diol chain extenders and poly(ethylene adipate) macro diol using one-shot, pre-polymer and multi-stage polyaddition methods. The optimized polymerization reaction achieved ultra-high molecular weight TPEUs (>2 million as determined by GPC) in a short time, indicating a very high HPMDI – diol reactivity. TPEUs with very well controlled hard segment (HS) and soft segment (SS) blocks were prepared and characterized with DSC, TGA, tensile analysis, and WAXD in order to reveal structure–property relationships. A confinement effect that imparts elastomeric properties to otherwise thermoplastic TPEUs was revealed. The confinement extent was found to vary predictably with structure indicating that one can custom engineer tougher polyurethane elastomers by “tuning” soft segment crystallinity with suitable HS block structure. Generally, the HPMDI-based TPEUs exhibited thermal stability and mechanical properties comparable to entirely petroleum-based TPEUs.     

Enhanced properties of polyvinyl chloride modified by graphene reinforced thermoplastic polyurethane

Graphene sheets with a range of unusual properties and thermoplastic polyurethane (TPU ) were combined to modify polyvinyl chloride (PVC ), and the enhanced properties such as flexibility, thermal stability and mechanical properties of the PVC were investigated. In order to avoid the C ? Cl bonds in PVC being weakened, graphene was incorporated into TPU in the melting state first and then this TPU was employed as a modifier to enhance and plasticize PVC in another melt blending step. In comparison with the ternary blending method, this step‐by‐step melt blending method was more efficient and convenient. The distribution of graphene sheets in the polymer matrix is uniform and no C ? Cl bond weakened effect can be observed. Due to the similar polarity, TPU showed good compatibility with PVC and its plasticizing effect allowed a broader range of low temperature flexibility of the modified PVC matrix. Moreover, other properties of the resultant PVC matrix (PTG ‐x ) including mechanical properties, thermal stability and plasticizer migration resistance were all found to be improved. With innovative applications in mind, the development of new graphene‐based materials will certainly lead to many future advances in science and technology. © 2017 Society of Chemical Industry     

High-efficiency shape memory copolymers of polycaprolactone/thermoplastic polyurethane fabricated via in situ ring-opening polymerization

Shape memory blends of polycaprolactone/thermoplastic polyurethane (PCL/TPU) were prepared by in situ ring-opening polymerization (ROP) of ε-caprolactone (CL) and thermoplastic polyurethane (TPU). Fourier infrared spectrometer and ¹H-NMR were used to characterize the chemical structure of PCL/TPU copolymers. The results show that TPU has been involved in the ROP of CL, leading to the formation of copolymers with homogeneous morphologies. Besides, pure PCL and all the blends exhibit an excellent shape fixation ratio of 100%, due to their high crystallinity. When a small amount of TPU is introduced, the crystallinity of PCL decreases, and as a result, the shape recovery ratio of the copolymer is enhanced compared with pure PCL. However, with the increased loading of TPU, the content of PCL as the reversible phase decreases and the storage modulus of the PCL/TPU blend declines, so the driving force for the blends to return from the temporary shape to the initial shape becomes smaller, leading to a decrease in the shape recovery ratio. Notably, when the amount of TPU is only 5%, the shape recovery ratio of the blend could reach 83.3%, which is 26% higher than that of pure PCL, and meanwhile, the tensile strength of the blend decreases slightly. This study provides a new strategy for the design of shape-memory materials with high shape-memory properties.