PU/BA-HEMA互穿网络型聚合物的合成及性能

以异佛尔酮二异氰酸酯（IPDI）、二羟甲基丙酸（DMPA）为硬段,聚醚多元醇（N220）为软段,以丙烯酸丁酯（BA）和甲基丙烯酸羟乙酯（HEMA）改性,制备了水性聚氨酯（PU）分散液,测定了水分散液及其膜的物理性能和力学性能。结果表明,与未改性的PU水分散液相比,改性聚氨酯水分散液的粒径均有所增大,表面张力减小,力学性能和硬度提高。HEMA 的引入,形成了具有化学交联的核-壳互穿网络结构的聚合物,说明改性材料中分子链硬段与PA分子链具有较高的相容性。     

Low‐modulus siloxane‐based polyurethanes. I. Effect of the chain extender 1,3‐bis(4‐hydroxybutyl)1,1,3,3‐tetramethyldisiloxane (BHTD) on properties and morphology

A series of eight polyurethane elastomers was prepared using a two‐step bulk polymerization procedure to investigate the effect of the siloxane chain extender 1,3‐bis(4‐hydroxybutyl)1,1,3,3‐tetramethyldisiloxane (BHTD) on polyurethane properties and morphology. All polyurethanes were based on 40 wt % hard segment derived from 4,4′‐methylenediphenyl diisocyanate (MDI) and a mixture of 1,4‐butanediol (BDO) and BHTD in varying molar ratios. The soft segment was based on an 80 : 20 (w/w) mixture of the macrodiols α,ω‐bis(6‐hydroxyethoxypropyl)polydimethylsiloxane (PDMS, MW 965) and poly(hexamethylene oxide) (PHMO, MW 714). Polyurethanes were characterized by size‐exclusion chromatography, tensile testing, differential scanning calorimetry, dynamic mechanical thermal analysis, and FTIR spectroscopy. Clear and transparent polymers were produced in all cases with number‐average molecular weights in the range of 90,000 to 111,000. The ultimate tensile strength decreased only slightly (15%), but Young's modulus and flexural modulus decreased by 76 and 72%, respectively, compared with that of the pure BDO extended polyurethanes as the amount of BHTD was increased to 40 mol %. This change resulted in “softer” and more elastic polyurethanes. Polyurethanes with BHTD contents above 40 mol % were more elastic but had poor tensile and tear strengths. A 60 : 40 molar ratio of BDO : BHTD produced a “soft” polyurethane, which combined good tensile strength and flexibility. The DSC and DMTA results confirmed that the incorporation of BHTD as part of the hard segment yielded polyurethanes with improved compatibility between hard and soft segments. IR data indicated that the amount of hard segments soluble in the soft‐segment phase increased with increasing BHTD, contributing to the improved phase mixing. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 736–746, 2002     

PDA型PUR弹性体的制备与性能

以聚己二酸二乙二醇酯二醇(PDA)为软段,4,4′–二苯基甲烷二异氰酸酯(MDI)和1,4–丁二醇(BDO)为硬段,采用预聚体法制备一系列PDA型PUR弹性体。采用力学性能测试、广角X射线衍射(WAXD)、傅立叶变换红外光谱(FTIR)、差示扫描量热(DSC)、热重(TG)分析和维卡软化点温度测定等研究手段,研究硬段含量对其力学性能、微观形态和热性能的影响。结果表明,随着硬段含量的增加,PDA型PUR弹性体的硬度、拉伸强度、300%定伸应力、拉伸永久变形和撕裂强度都增大,当硬段含量为40.1%时,弹性体的综合力学性能最佳,硬度(邵A)为88,拉伸强度为33.9 MPa,300%定伸应力为12.5 MPa,拉伸永久变形为31%,撕裂强度为90.3 k N/m;WAXD分析表明,弹性体为无定型结构;FTIR分析表明,硬段含量的增加使弹性体总的氢键化程度增加,微相分离程度改善;DSC测试表明,硬段含量的增加使弹性体的微相分离程度提高;TG和维卡软化点温度测试表明,弹性体的热性能随着硬段含量的增加而提高,当硬段含量为40.1%时,弹性体的初始分解温度(失重5%的温度)和维卡软化点温度分别达到324.5℃和144.1℃,具有较好的热性能。     

纳米蒙脱土-脂肪族聚氨酯弹性体的合成与制备

采用聚四氢呋喃醚（PTMG1000）为软段,4,4’-二环己基甲烷二异氰酸酯（HMD1）、异佛尔酮二异氰酸酯（1PD1）为硬段,层间距分别为1．95nm和2．40nm的2种有机蒙脱土,以插层聚合法制备出不同硬段含量和有机蒙脱土含量的纳米蒙脱土．脂肪族聚氨酯弹性体,并研究了硬段含量、有机蒙脱土含量、二异氰酸酯和有机蒙脱土种类对脂肪族聚氨酯弹性体力学性能的影响。结果表明,硬段含量对材料力学性能影响最大,其次是有机蒙脱土含量。当硬段质量分数达40％时,拉伸强度最高达14．06MPa;有机蒙脱土少量加入可有效提高材料的撕裂强度和断裂伸长率。以HMD1、PTMG1000和MMT2为原料,硬段质量分数为40％时,所合成的纳米蒙脱土-脂肪族聚氨酯弹性体具有较好的力学性能。     

The effect of chain extenders structure on properties of new polyurethane elastomers

Two series of polyurethane elastomers were synthesized to investigate what effect does the incorporation of various new chain extenders have on the mechanical and thermal properties of polyurethane elastomers. The polyurethane soft segments were based on poly(ε-caprolactone) polyol. The hard segment was based on 1,6-hexamethylene diisocyanate in combination with 2,5-dimethyl-3-hexine-2,5-diol (DHD), hexaethylene glycol, glycerin, or castor oil. The results showed that the degradation rate and mechanical properties of the final products can be controlled through the structure of diol chain extenders or/and hard segment cross-linking present in the polyurethane elastomers. The DHD-based polyurethane displayed a relatively low glass transition temperature of −57 °C and a tensile strength of 11–14 MPa and elongation at break of 600–700%. These kinds of materials have potential application in many domains.     

水性聚氨酯木器漆胶膜物性的研究

以甲苯二异氰酸酯（TDI）、聚己二酸己二醇酯二醇（PHA）、二羟甲基丙酸（DMPA）等为原料，采用内乳化法制备了水性聚氨酯，研究了NCO与OH摩尔比、PHA相对分子质量及交联剂三羟甲基丙烷用量对水性聚氨酯成膜物性能的影响。结果表明：通过提高硬段含量和交联度等方法可改善聚氨酯膜的力学性能和耐介质性，制得的水性聚氨酯成膜物拉伸强度20．58MPa、邵A硬度90、吸水率2．0％，在70％酒精中浸泡24h增重率12．4％，性能达到国外同类产品的技术指标。这种水性聚氨酯可用于木器漆。     

环氧大豆油和硅氧烷改性水性聚氨酯胶黏剂

以环氧大豆油(ESO)与3-氨基丙基三乙氧基硅烷(KH550)双重交联改性水性聚氨酯(WPU).通过FTIR、TG、DSC、DMA、AFM、粒径分析仪、拉力试验机等仪器对改性的水性聚氨酯进行了表征.研究了ESO和KH550的含量对水性聚氨酯乳液、胶膜以及胶黏剂性能的影响.分析了KH550对水性聚氨酯结晶性能和微相分离的影响.研究发现,随着ESO与KH550的加入,水性聚氨酯乳液的性能得到改善,胶膜的吸水率先减小后增大,拉伸强度逐渐增大,断裂伸张率逐渐减小.水性聚氨酯胶黏剂对PVC的T-剥离强度先增大后减小.随着KH550含量的增加,热稳定性逐步改善,结晶性降低,软段与硬段相混合程度提高.当ESO为4%、KH550为2%(均为质量分数)时,水性聚氨酯胶黏剂的综合性能最好.     

透明聚酯型水性聚氨酯的制备与性能研究

聚酯型WPU(水性聚氨酯)具有较高的力学强度和粘接强度,但是其较高的结晶性会导致胶膜透明性较差。以聚丙二醇(PPG)、聚己二酸丁二醇酯二醇(PBA)、异佛尔酮二异氰酸酯(IPDI)、2,2′-二羟甲基丙酸(DMPA)和1,4-丁二醇(BDO)等为原料,制备PPG改性聚酯型WPU。研究结果表明:PPG改性聚酯型WPU的黏度适中,储存稳定性良好;随着PPG含量的不断增加,WPU胶膜的透明性因结晶受阻程度增大而变好,相应胶粘剂的T型剥离强度和拉伸强度下降,而断裂伸长率升高;当w(PPG)=10%～20%时,相应WPU胶粘剂的透明性、T型剥离强度(≥1.97 N/mm)、拉伸强度(≥14.7 MPa)和断裂伸长率(≥421%)俱佳。     

Properties of polyisobutylene polyurethane block copolymers: 2. Macroglycols produced by the ‘inifer’ technique

The structure-property relationships of a series of 4,4′-diphenylmethane diiscoyanate (MDI) based polyisobutylene (PIB) polyurethanes were investigated. The PIB glycol was synthesized via the ‘inifer’ technique and had a narrow functionality distribution with a number average functionality of 2.0. The use of a PIB glycol with improved functionality and solution polymerization of the polyurethane led to improved mechanical properties compared with previously studied PIB polyurethanes. However, the mechanical properties were still low compared with conventional polyurethanes; the absence of soft segment strain-induced crystallization and compositional heterogeneity due to reactant incompatibility are cited as possible causes of low mechanical properties. Sample compositions were designed for independent investigation of the effects of hard segment content and soft segment molecular weight on the properties of the materials. Increasing hard segment content resulted in improved dynamic and tensile modulus, lower elongation at break, and larger hard segment domains. Increasing soft segment molecular weight led to larger domains and reduced mechanical properties. The degree of phase separation as measured by the soft segment T_g and the amount of interfacial mixing measured by small angle X-ray scattering (SAXS) were unaffected by hard segment content and soft segment molecular weight and were indicative of a high degree of phase separation compared with conventional polyurethanes.     

Structure‐property relationships of degradable polyurethane elastomers containing an amino acid‐based chain extender

A series of degradable polyurethanes of variable soft segment chemistry and content were synthesized and characterized. An amino acid‐based diester chain extender was used to confer degradability and both polycaprolactone diol (PCL) and polyethylene oxide (PEO) were used as soft segments. In addition, the diisocyanate component was a potentially nontoxic diisocyanate (2,6‐diisocyanato methyl caproate, LDI). The physicochemical properties of these unique series of polyurethanes were investigated. It was found that the PEO containing polyurethanes were generally weak, tacky amorphous materials. In contrast, the PCL polyurethanes were relatively strong, elastomeric materials which ranged from completely amorphous to semicrystalline as noted by differential scanning calorimetry. The PCL containing polyurethanes exhibited increasing tensile strength, modulus, and ultimate strain with increasing PCL molecular weight because of increasing phase separation and increasing soft segment crystallinity. Fourier transform infrared analysis showed significant hard segment urea and urethane hydrogen bonding which increased with hard segment content, although interphase bonding is believed to be significant for the PCL polyurethanes. Surface characterization carried out by contact angle analysis and X‐ray photoelectron spectroscopy indicated soft segment surface enrichment for all of the polyurethanes. The PEO‐based polymers were very hydrophilic whereas the PCL‐based polymers displayed significantly higher contact angles, indicating greater surface hydrophobicity. The observed diversity in material properties suggests that these polyurethanes may be useful for a wide range of applications. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1522–1534, 2000     

Effects of emulsification on properties of quaternary ammonium ion-based polyurethane anionomer

Summary Quaternary ammonium ion-based Polyether polyurethane anionomer solution and emulsion are studied. In the un-ionized film, the soft segment crystallites are not present. Ionization creates soft segment crystallites and produces increased phase separation between the soft and hard domains, which leads to an increase in both tensile strength and elongation at break. Emulsification of the PU ionomer solution can lead to slightly increased phase mixing. During the emulsification, conductivity and viscosity variations show that water is first adsorbed on the surface of the hard-segment microionic lattices and then enters successively into the more disordered and less disordered hard domains. The morphology of the unionized film shows that the hard domains are dispersed in the soft domains and that the size of hard domain increases greatly after the ionization. After dispersion, the hard segments originally distributed in the dispersed phase can be inverted to become a hard domain network.     

Segmented block copolyetheramides based on nylon 6 and polyoxypropylene. II. Structure and properties

Structure–property relationships of segmented block copolyetheramides based on nylon 6 and polyoxypropylene (POP) were investigated as a function of the compositions and block lengths of the hard and soft segments by using differential scanning calorimetry, dynamic mechanical analysis, FT-IR spectroscopy, wide angle x-ray diffractometry (WAXD), and tensile testing. The nylon 6–D4 copolymers with the shortest soft segment exhibited the two-phase structure of a crystalline nylon 6 phase and an amorphous phase composed of the hard and soft segments. Also they showed the tensile properties characteristic of a plasticized thermoplastic. On the other hand, the nylon 6–D20 and nylon 6–D40 copolymers exhibited the three-phase structure of a crystalline nylon 6 phase, an amorphous nylon 6-rich phase, and an amorphous POP-rich phase. The nylon 6–D20 copolymers had better elastic properties with the increase of soft segment content; however, the nylon 6–D40 copolymers with the longest soft segment showed a substantial reduction of the elongation at break due to lack of the crosslinking density. © 1995 John Wiley & Sons, Inc.     

Effects of reaction and cure temperatures on morphology and properties of poly(ester‐urethane)

Poly(ester‐urethane) was synthesized from poly(ethylene glycol adipate) (PEG) and 2,4‐toluene diisocyanate (TDI) to study the effects of reaction temperature and cure temperature on the crystallization behavior, morphology, and mechanical properties of the semicrystalline polyurethane (PU). PEG as soft segment was first reacted with TDI as hard segment at 90, 100, and 110°C, respectively, to obtain three kinds of PU prepolymers, coded as PEPU‐90, PEPU‐100, and PEPU‐110. Then the PU prepolymers were crosslinked by 1,1,1‐tris (hydroxylmethyl) propane (TMP) and were cured at 18, 25, 40, 60, and 80°C. Their structure and properties were characterized by attenuated total reflection Fourier transform infrared, wide‐angle X‐ray diffraction, scanning electron microscopy, dynamic mechanical analysis, and tensile testing. With an increase of the reaction temperature from 90 to 100°C, the crystallinity degree of soft segment decreased, but interaction between soft and hard segments enhanced, leading to the increase of the glass transition temperature (T_g) of soft domain and tensile strength. When the cure temperature was above 60°C, miscibility between soft and hard segments of the PEPU films was improved, resulting in relatively low crystallinity and elongation at break, but high soft segment T_g and tensile strength. On the whole, all of the PEPU‐90, PEPU‐100, and PEPU‐110 films cured above 60°C possessed higher tensile strength and elongation at break than that of the films cured at other temperatures. The results revealed that the reaction temperature and cure temperature play an important role in the improvement of the crosslinking structure and mechanical properties of the semicrystalline PU. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 708–714, 2006     

Effect of polymer architecture and hard/soft segment ratio on the surface morphology and mechanical properties of polyurethane films for potential orthodontic treatment

In this study, polyurethane (PU) films are prepared by using 1,4-butanediol and trimethylolpropane as chain extender and crosslinking agent, respectively. A series of prepolymers are synthesized by varying the feeding molar ratios of methylene diisocyanate to polytetramethylene ether glycol, which are hard and soft segments, respectively. The influence of polymer architecture, chemical composition, and artificial saliva treatment on the surface morphology and mechanical strength of PU films are studied. The crosslinking polymer architecture and higher content of hard segment correlates with enhanced tensile strength and less decrease of tensile strength in the condition of artificial saliva, but reduced elongation at break. The in vitro cytotoxicity study demonstrates that PU films have excellent cytocompatibility.     

聚氨酯弹性体的力学性能影响因素研究

研究了合成方法,软段及硬段组成结构,熟化条件等因素对聚氨酯弹性和学性能的影响,结果表明,聚氨酯弹性体的结构与组成,以及由此引起微相分离程度的变化,是影响弹性体性能的重要因素,不同的低聚物二醇,二异氰酸酯及扩链剂合成的弹性体性能不同,采用预聚法,以及适当熟化有助于提高弹性体的性能。     

Polyurethane elastomers based on molecular weight advanced poly(ethylene ether carbonate) polyols. IV. Effects of poly(propylene glycol) modified diols

A series of polyurethane elastomers with a (A{BC}_m)n type of structure have been prepared and characterized based on poly(propylene glycol) modified poly(ethylene ether carbonate) polyols, where the poly(propylene glycol) content and block length were varied systematically. Strength and modulus properties showed a marked dependence on modifier level and exhibited synergistic property improvements at 25–50 wt % modifier, relative to both unmodified poly(ethylene ether carbonate) diol and poly(propylene glycol) controls. DMA results indicated an increased modulus for the modified plaques throughout the rubbery plateau region, with higher thermal dissociation temperatures. Excellent organic solvent resistance was maintained with 25–50 wt % poly(propylene glycol) modification in the soft segment. Chemical structure of the polyurethane elastomers was established by proton and ¹³C-NMR spectroscopy. The morphology of these modified polyurethanes appears to be quite complex. Since the modified soft segments are block copolymers of blocks with a tendency toward immiscibility, some microphase separation within the soft segment domains of the polyurethane polymers might be expected. The soft segment T_g is highest where properties are maximized, suggesting changes in phase mixing. © 1992 John Wiley & Sons, Inc.     

Shape memory effect of poly(L‐lactide)‐ based polyurethanes with different hard segments

A series of biodegradable polylactide‐based polyurethanes (PLAUs) were synthesized using PLA diol (M_n = 3200) as soft segment, 4,4′‐diphenylmethane diisocyanate (MDI), 2,4‐toluene diisocyanate (TDI), and isophorone diisocyanate (IPDI) as hard segment, and 1,4‐butanediol as chain extender. The structures and properties of these PLAUs were studied using infrared spectroscopy, differential scanning calorimetry, tensile testing, and thermomechanical analysis. Among them, the MDI‐based PLAU has the highest T_g, maximum tensile strength, and restoration force, the TDI‐based PLAU has the lowest T_g, and the IPDI‐based PLAU has the highest tensile modulus and elongation at break. They are all amorphous. The shape recovery of the three PLAUs is almost complete in a tensile elongation of 150% or a twofold compression. They can keep their temporary shape easily at room temperature (20 °C). More importantly, they can deform and recover at a temperature below their T_g values. Therefore, by selecting the appropriate hard segment and adjusting the ratio of hard to soft segments, they can meet different practical demands for shape memory medical devices. Copyright © 2007 Society of Chemical Industry     

Nanoclay-tethered shape memory polyurethane nanocomposites

The study investigated shape memory properties of nanoclay-tethered polyurethane nanocomposites. Polyurethanes based on polycaprolactone (PCL) diol, methylene diisocyanate, and butane diol and their nanocomposites of reactive nanoclay were prepared by bulk polymerization in an internal mixer and the values of shape fixity and shape recovery stress were determined as function of clay content. The melting point of the crystalline soft segment was used as the transition temperature to actuate the shape memory actions. It was seen that clay particles exfoliated well in the polymer, decreased the crystallinity of the soft segment phase, and promoted phase mixing between the hard and soft segment phases. Nevertheless, the soft segment crystallinity was enough and in some cases increased due to stretching to exhibit excellent shape fixity and shape recovery ratio. A 20% increase in the magnitude of shape recovery stress was obtained with the addition of 1 wt% nanoclay. The room temperature tensile properties were seen to depend on the competing influence of reduced soft segment crystallinity and the clay content. However, the tensile modulus measured at temperatures above the melting point of the soft segment crystals showed continued increases with clay content.     

酸化处理对碳纳米管改性聚氨酯性能的影响

近年来,碳纳米管以其优异的性能引起了极大的关注,从而广泛用于改性聚合物材料。采用浓硫酸和浓硝酸的混合酸对多壁碳纳米管进行酸化处理,并采用原位聚合法制备了碳纳米管改性聚氨酯材料,研究了碳纳米管的酸化处理对材料力学性能和热稳定性的影响。结果表明,碳纳米管的加入使得聚氨酯材料的拉伸强度和弹性模量升高,断裂伸长率减小,提高了聚氨酯材料的热稳定性,而且经过酸化的碳纳米管对聚氨酯材料的改性要比未酸化碳纳米管对聚氨酯材料的改性效果更为显著。     

Microphase-separated structure and mechanical properties of norbornane diisocyanate-based polyurethanes

Norbornane diisocyanate (NBDI: 2,5(2,6)-bis(isocyanatomethyl)bicyclo[2.2.1]heptane) is a new commercialized diisocyanate. NBDI-based polyurethane elastomers (PUEs) were prepared from poly(oxytetramethylene) glycol (PTMG), NBDI and 1,4-butanediol (BD) by a prepolymer method. Microphase-separated structure and mechanical properties of the NBDI-based PUEs were compared with general aliphatic and cycloaliphatic diisocyanate-based PUEs. The diisocyanates used were isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate (HMDI) and 1,6-hexamethylene diisocyanate (HDI). Regular polyurethanes were also prepared as hard segment models from each isocyanate and BD to understand the feature of each hard segment chain. The HDI-based PUE showed the largest Young's modulus and tensile strength in the four PUEs due to the ability of crystallization of the hard segment component and the strongest microphase separation. HMDI has both properties of aliphatic and cycloaliphatic diisocyanates because of its high symmetrical chemical structure compared with NBDI and IPDI. On the other hand, the NBDI- and IPDI-based PUEs have an inclination to phase mixing, leading to decreased Young's modulus and tensile strength. The NBDI-based PUE exhibited better thermal properties at high temperatures due to stiff structure of NBDI.