硬段含量对水性聚氨酯软段结晶性能的影响

以异佛尔酮二异氰酸酯、六亚甲基二异氰酸酯、聚己二酸丁二醇酯为主要原料合成了水性聚氨酯(WPU),通过FT-IR、DSC、XRD、SEM表征手段,研究了硬段含量对软段结晶性及WPU粘结性能的影响。研究表明,随着硬段含量的增加,WPU分子链上氨基甲酸酯键之间的氢键化程度提高,软硬两相相混严重,WPU软段结晶熔融焓变小,熔融温度变低;结晶衍射峰变弱,软段结晶性变差;粘结性能测试表明,在硬段含量较低时,聚氨酯体现出良好的结晶性能,初粘性较好。     

水性聚氨酯的结晶动力学参数及其在鞋用胶黏剂的应用

以聚己二酸1,4-丁二醇酯（PBA）、六亚甲基二异氰酸酯（HDI）和异佛尔酮二异氰酸酯（IPDI）为主要原料,制备了不同软段分子量和不同硬段含量的水性聚氨酯（WPU）乳液。采用DSC技术表征了WPU胶膜在非等温和等温条件下的结晶行为,并以莫志深方程和Avrami方程为模型,对WPU胶膜的结晶行为进行了研究。WPU胶膜的非等温结晶动力学分析结果表明,随着WPU相对结晶度的增加,非等温结晶动力学参数F（T）增大,说明适当提高活化温度可提高WPU胶黏剂的结晶速率和初黏强度;WPU胶膜的等温动力学分析结果表明,不同软段分子量和不同硬段含量的WPU胶膜的等温结晶动力学参数t_1/2与相应WPU胶黏剂的开放时间存在对应关系,即t_1/2较大者,相应WPU胶黏剂的开放时间较长。     

水性聚氨酯的结晶动力学参数及其在鞋用胶黏剂的应用

以聚己二酸1,4-丁二醇酯(PBA)、六亚甲基二异氰酸酯(HDI)和异佛尔酮二异氰酸酯(IPDI)为主要原料,制备了不同软段分子量和不同硬段含量的水性聚氨酯(WPU)乳液。采用DSC技术表征了WPU胶膜在非等温和等温条件下的结晶行为,并以莫志深方程和Avrami方程为模型,对WPU胶膜的结晶行为进行了研究。WPU胶膜的非等温结晶动力学分析结果表明,随着WPU相对结晶度的增加,非等温结晶动力学参数F(T)增大,说明适当提高活化温度可提高WPU胶黏剂的结晶速率和初黏强度;WPU胶膜的等温动力学分析结果表明,不同软段分子量和不同硬段含量的WPU胶膜的等温结晶动力学参数t1/2与相应WPU胶黏剂的开放时间存在对应关系,即t1/2较大者,相应WPU胶黏剂的开放时间较长。     

聚已内酯/聚氨酯共聚热致形状记忆材料的合成与表征

以聚己内酯（PCL）为软段,甲苯2,4-二异氰酸酯（TDI）为硬段,通过预聚合和扩链反应制得含结晶软段的聚氨酯形状记忆材料（SMPU）,通过差热分析、红外分析及X射线衍射对其微结构进行了表征。结果表明,随着硬段含量的增加,SMPU的结晶熔融温度上升,结晶度下降,形状回复率减小,形状固定率始终保持在98 %左右;随着PCL相对分子质量的提高,SMPU的结晶熔融温度减小,结晶度增大,回复响应温度逐渐降低。     

MDI异构体对聚氨酯弹性体微观结构和性能的影响

以聚氧化丙烯二醇(DL-2000)为软段,不同2,4′-异构体含量的二苯基甲烷二异氰酸酯(MDI)和1,4-丁二醇(BDO)为硬段,采用预聚法合成了不同异构体含量的MDI型聚氨酯弹性体。采用FT-IR、DSC和DMA等分析手段对其结构和性能进行了表征。结果表明,随着2,4′-MDI异构体含量的增加,硬段间的氢键结合化程度降低,硬段区聚集结晶的能力也不断下降,硬段趋于均匀分散在连续相软段区中,两相相容性增加,聚氨酯弹性体的T和tanδ大幅度提高。     

硬段含量对MDI型热塑性聚氨酯性能的影响

以4,4'-二苯基甲烷二异氰酸酯(MDI)、聚四亚甲基醚二醇(PTMG)和1,3-丙二醇(PDO)为原料,采用预聚体法合成热塑性聚氨酯(TPU),利用FTIR、DSC及力学性能测试等手段探究了硬段含量对TPU性能的影响。结果表明,硬段含量增加,TPU的氢键化程度、玻璃化转变温度、硬段熔融温度、拉伸强度、撕裂强度、硬度和模量均随之增大,软段结晶熔融温度及断裂伸长率随之减小;在硬段质量分数33%～45%范围内,TPU呈现"海-岛"结构,且随硬段含量增加,微相分离程度逐渐增加。     

化学交联对PPDI基聚碳酸酯型聚氨酯结构和性能的影响

用熔融预聚物法合成了以对苯二异氰酸酯（PPDI）、1,4-丁二醇（BDO）以及三羟甲基丙烷（TMP）为硬段,聚碳酸酯二醇（PCD）为软段的PPDI基聚碳酸酯型聚氨酯弹性体（PCU）,研究了交联剂TMP用量对其结构与性能的影响。结果表明,随着TMP含量的增加,拉伸强度和断裂伸长率显著提高,并伴随压缩永久变形的明显下降;随着交联密度增加,羰基的有序氢键化程度由23 %下降至5 %,软段相的玻璃化温度由-33 ℃升高到-17 ℃,表明PCU中软硬段相之间的微相分离程度减小;当TMP含量小于40 %时,PPDI基PCU具有良好的耐热性和动态性能。     

聚碳酸酯二醇型热塑性聚氨酯弹性体的制备与性能

以聚碳酸酯二醇(PCDL)为软段、4,4'-二苯基甲烷二异氰酸酯(MDI)/1,6-己二醇(HG)为硬段,经两步法制备了不同硬段含量的PCDL型热塑性聚氨酯弹性体,即聚碳酸酯聚氨酯(PCU); 考察了硬段含量对PCU的力学性能、结晶性能、流变性能及耐热性能的影响。结果表明,随着硬段含量的增加,PCU的拉伸强度、定伸应力及邵尔A硬度均增大,扯断伸长率减小,当硬段质量分数为40%时,PCU的拉伸强度高达28.82 MPa,300%定伸应力为21.46 MPa,扯断伸长率为382%,邵尔A硬度为85。随着硬段含量的增加,PCU的结晶能力增强,耐热性能提高。PCU具有典型的假塑性流体特征。     

硬段对热塑性聚氨酯弹性体结构及性能的影响

以实验室自制聚己二酸乙二醇酯二醇PEA为软段,二苯基甲烷-4,4’二异氰酸酯(MDI)为硬段,分别采用乙二醇(EG、1,4-丁二醇)、BOD和1,6-己二醇、HG为扩链剂,经预聚体法合成了硬段不同的聚氨酯弹性体。研究了硬段结构和硬段含量对弹性体硬度及力学性能的影响。采用旋转流变仪研究了弹性体在降温条件下的非等温结晶过程。结果表明,当硬段含量相同时,BDO-TPU结晶性能最好,拉伸强度最大;HG-TPU断裂伸长率最好。在BDO-TPU体系中,随硬段含量增加,材料硬度和强度增加,伸长率减小;结晶起始温度逐渐增大,结晶性能增强。     

硬段对聚碳酸酯二醇型水性聚氨酯性能的影响

以聚碳酸酯二醇(PCDL)为软段、二羟甲基丙酸(DMPA)为亲水扩链剂、异佛尔酮二异氰酸酯(IPDI)和六亚甲基二异氰酸酯(HDI)为硬段,采用预聚体法合成了水性聚氨酯(WPU)。研究结果表明:随着n(HDI)∶n(IPDI)比例的增加,WPU的黏度、断裂伸长率增大,耐水性和耐乙醇性提高;当n(HDI)∶n(IPDI)=1.0∶1时,WPU的综合性能相对较好,其热稳定性和结晶性能得到明显改善。     

聚醚型聚氨酯的氢键、微相分离及性能

用本体一步法合成了5种不同硬段含量(11.0％～46.9％)的二苯甲烷-4,4′-二异氰酸酯/环氧乙烷封端型聚环氧丙烷聚醚/乙二醇的聚醚型聚氨酯,并借助于IR,DSC,DMS和材料试验机等手段对该聚氨酯的氢键、微相分离及力学性能进行了表征。结果表明:随着硬段含量的增加,其>NH与微区中的>C=O的氢键化程度逐渐提高,软段微区中—O—的氢键化程度逐渐降低;微相分离程度逐渐提高;拉伸强度及硬度随之增加,扯断伸长率在硬段含量40％左右出现极大值。     

硬段含量对水性聚氨酯性能的影响

以聚酯多元醇、二羟甲基丙酸(DMPA)、甲苯二异氰酸酯(TDI)和1,4-丁二醇(BDO)为主要原料,合成了阴离子型WPU(水性聚氨酯),并着重探讨了聚氨酯(PU)分子链中硬段含量对其性能的影响。结果表明:随着PU分子链中硬段含量的不断增加,硬段的Tg(玻璃化转变温度)上升,但软段的Tg呈先升后降态势,WPU的外观由半透明泛蓝光转变为乳白色不透明(稳定性变差),并且WPU的黏度、耐水性和T型剥离强度均呈先升后降态势;当WPU中w(硬段)=22.79%时,相应WPU的综合性能相对最好,用其胶接聚酰胺(PA)/聚丙烯(PP)复合薄膜的T型剥离强度达到0.488 kN/m。     

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。     

Preparation of waterborne polyurethane adhesives based on macromolecular-diols containing different diisocyanate

ABSTRACT

Three different macromolecular diols were synthesized by the reaction of Poly(1,4-butanediol adipate) diol (PBA) and diisocyanate (Isophorone diisocyanate (IPDI), Hexamethylene diisocyanate (HDI) and Methylene-bis(4-cyclohexylisocyanate)(HMDI)) at the ratio of 2:1. Based on these macromolecular diols, waterborne polyurethane (WPU) adhesives were prepared. The structure and molecular weights of the WPU were characterized by Nuclear magnetic resonance spectroscopy (¹H NMR), Fourier Transform Infrared Spectroscopy (FTIR) and Gel permeation chromatography (GPC) respectively. Furthermore, the hydrogen bonding interaction of WPU were analyzed by the deconvolution FTIR spectra. The results showed that the hydrogen bonded NH was increased when carbamate was in the soft segment. The crystallinity of WPU was tested by X-ray diffraction (XRD) and Differential scanning calorimetry (DSC). The results showed that the crystallinity of WPU2 (HDI) and WPU3 (HMDI) were enhanced, especially for WPU2. Meanwhile, the Tg,s as well as the mechanical strength, storage modulus, the contact angle and thermo-stability were increased with the introduced carbamate into soft segment. The T-peel tests of plasticized PVC/WPU/plasticized PVC joints and lap-shear tests of wood/WPU adhesive/wood joints were carried out. The results indicated that the carbamate in the soft segment could significantly enhance the adhesion of WPU at an appropriate activation temperature.     

Self-healing supramolecular waterborne polyurethane dispersions with quadruple hydrogen bonds in main chain

A facile method for preparing supramolecular waterborne polyurethane (WPU) based on quadruple hydrogen bonds (4H-WPU) is reported. Herein, 4H-WPU with quadruple hydrogen bonds in main chain were synthesized by poly (1,4-buthylene-neopentylene adipate glycol) as soft segment, 2-ureido-4[1H]-pyrimidinone (UPy) functionalized monomer, isophorone diisocyanate, 2,2-Bis(hydroxymethyl)propionic acid (hydrophilic monomer), isophorondiamine, triethylamine (neutralizer), and monoethanolamine (blocking agent) as hard segment. The molecular weight of 4H-WPU was controlled around 18,000 consistently. The properties of 4H-WPU with different content of hydrophilic group, hard segment, and UPy units were characterized and the results could provide the reference for preparing supramolecular WPU with high mechanical and self-healing performance while maintaining dispersion stability. The tensile strength of 4H-WPU was 10 times of the blank sample. The healing time of scratched 4H-WPU film was inversely proportional to the content of UPy- functionalized monomer and the shortest healing time is 2.5 hr at 80°C. Mechanical performance of healed films can be restored to more than 90%.     

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.     

Polyurethane elastomers based on molecular weight advanced poly(ethylene ether carbonate) polyols. III. Effects of diisocyanate modified diols

A series of diisocyanate-modified, molecular weight advanced poly(ethylene ether carbonate) diols has been prepared, characterized, and formulated into polyurethane elastomers using a prepolymer process. Properties were compared to a polyurethane elastomer control in which the only variable was the diisocyanate modification. The diisocyanate modification produces polymers with increased modulus (445–730% at 25°C), improved tensile strength and hardness properties and reduced (improved) coefficients of linear thermal expansion, while still passing the notched Izod impact test. The tensile strength at break increases with increasing number of urethane moieties in the soft segment and the elongation at break also increases. The plaques studied appear to have a three-phase morphology—a soft segment continuous phase containing amorphous hard segment, an amorphous hard segment phase plasticized by about 11% of the soft segment material, and a crystalline hard segment. The polymers based on the diisocyanate modified polyols are significantly more phase mixed than the control due to the increased amount of hard segment-soft segment interactions taking place. The improved properties of the polymers made with the modified polyols are due to their higher hydrogen bonding protential which gives more physically crosslinked polymers.     

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.