Properties of Polyurethane Elastomers with Different Hard/Soft Segment Ratio

Three polyurethane elastomers (PU) containing different hard/soft (h/s) segment ratios were prepared. The PUs were characterized using Gel Permeation Chromatography (GPC), DSC, Wide Angle X-ray Diffraction (WAXD). Dynamic Mechanical Thermal Analysis (DMTA), and Stress-controlled rheometry. The surface properties were evaluated from contact angle measurements. The PUs were used as raw materials for solvent-based adhesives, whose adhesion properties were measured from T-peel tests of solvent-wiped polyvinyl chloride (PVC)/polyurethane adhesive joints. The increase in the amount of h/s segment ratio affected the structure and morphology of the PUs, reducing the degree of phase separation and the extent of the secondary interactions between polymer chains. The h/s segment ratio determined the thermal, mechanical, rheological and adhesion properties of the PUs.     

Properties of Polyurethane Elastomers with Different Hard/Soft Segment Ratio

Three polyurethane elastomers (PU) containing different hard/soft (h/s) segment ratios were prepared. The PUs were characterized using Gel Permeation Chromatography (GPC), DSC, Wide Angle X-ray Diffraction (WAXD). Dynamic Mechanical Thermal Analysis (DMTA), and Stress-controlled rheometry. The surface properties were evaluated from contact angle measurements. The PUs were used as raw materials for solvent-based adhesives, whose adhesion properties were measured from T-peel tests of solvent-wiped polyvinyl chloride (PVC)/polyurethane adhesive joints. The increase in the amount of h/s segment ratio affected the structure and morphology of the PUs, reducing the degree of phase separation and the extent of the secondary interactions between polymer chains. The h/s segment ratio determined the thermal, mechanical, rheological and adhesion properties of the PUs.     

含硫扩链剂改性水性聚氨酯的制备及其性能

以2-巯基乙醇(2-ME)和丙烯酸羟乙酯(HEA)为原料,通过巯基-烯"点击"反应合成了含硫二元醇ME-HEA。并以其为扩链剂,与聚氧化丙烯二醇(PPG)、异佛尔酮二异氰酸酯(IPDI)等合成系列含硫水性聚氨酯(SWPU)。采用纳米粒度仪、红外光谱仪、电子拉力机等对乳液的粒径、胶膜的热性能、力学性能以及耐水性进行了分析。结果表明:随着ME-HEA质量分数的增加,SWPU胶膜的耐热性能和力学性能有明显的提升。当ME-HEA质量分数为4.3%时,乳液粒径为41.7 nm,胶膜拉伸强度和断裂伸长率分别为34.3 MPa和911.2%,在120℃热氧降解处理后的拉伸强度为处理前的拉伸强度的90.09%,有较好的耐热氧降解性能。     

小分子扩链剂对醇溶性聚氨酯性能的影响

采用异佛尔酮二异氰酸酯(IPDI)、聚醚二元醇( N220)以及不同结构的小分子二元醇扩链剂为主要原料,合成了一系列具有不同结构的醇溶性聚氨酯.示差扫描量热和热重测试显示,以一缩二乙二醇为扩链剂的聚氨酯Tg最低,耐热性最差;以乙二醇、1,4-丁二醇、己二醇为扩链剂的聚氨酯Tg依次上升;耐热性能依次降低透射电镜测试表明,...     

Characterization of Thermoplastic Polyurethanes Prepared Using Different Macroglycols

Three polyurethane elastomers (PU_s) were prepared using macroglycols of different nature (varepsilon-polycaprolactone, polyadipate of 1,6-hexanediol) and length of the hydrocarbon chain (polyadipate of 1,4-butanediol, polyadipate of 1,6-hexanediol). The PU_s were characterized using Gel Permeation Chromatography, Differential Scanning Calorimetry, Wide X-ray angle Diffraction, Dynamic Thermal Mechanical Analysis, stress-controlled rheometry and stress-strain experiments. The surface properties were evaluated from contact angle measurements. The PU_s were used as raw materials for solvent-based adhesives, whose adhesion properties were measured from T-peel strength of plasticized poly(vinyl chloride) (PVC)/polyurethane adhesive joints. The use of polyadipate of 1,6-hexanediol produced a polyurethane with high crystallinity (i.e. poor rheological and mechanical properties) and enhanced interactions between soft segments. Low adhesion was obtained in joints produced with this polyurethane and a cohesive failure of the adhesive was produced. The decrease in the polyadipate hydrocarbon chain length decreased the degree of crystallinity between polymer chains, therefore, no reduction in rheological and mechanical properties was obtained; a higher joint strength was also obtained. In this study the best performance was obtained with the polyurethane based on varepsilon-polycaprolactone, presumably because of its higher surface energy and reduced crystallinity. The properties of the polyurethanes prepared in this study were more affected by the characteristics of the macroglycol, and the crystallinity of the polyurethane had a more marked effect on the properties than the degree of phase separation.     

Polyurethane microcellular elastomers: 2. Effect of chain extender on the mechanical properties

The influence of ethylene glycol, triethanol amine and a rigid polyol on the tensile strength, elongation at break and tear resistance of a microcellular elastomer (used in RIM technology), have been studied using multiple linear regression analysis. Using the statistical Student-t test, the importance of the above parameters has been established. It has been found that the moulded density has the biggest influence on the tensile strength; so that the tensile strength is increased by the ethylene glycol and rigid polyol content, while triethanol amine reduces it. All the chain extenders studied have a negative influence on the elongation at break. Similarly the moulded density and the ethylene glycol content have a beneficial effect on the tear resistance, while triethanol amine and the rigid polyol reduce this property.     

Synthesis and properties of waterborne polyurethane adhesives: effect of chain extender of ethylene diamine,butanediol, and fluoro-butanediol

Waterborne polyurethane (WBPU) adhesives were prepared using poly(tetramethylene oxide glycol), 4,4’-dicyclohexylmethane diisocyanate (H₁₂MDI), hydrophilic agent dimethylol propionic acid and chain extender of 2,2,3,3-tetrafluoro-1,4-butanediol (TFBD), ethylene diamine (EDA), and 1,4-butanediol. All three chain extenders have been used as single and mixed (different ratio) content during synthesis, and the effect of chain extender and their content to the properties of tensile strength, Young’s modulus, water swelling (%), and adhesive strength was investigated. The adhesive strength value was higher using EDA as a single-chain extender; however, the potentiality of adhesive strength under water was improved using mixed-chain extenders of EDA and TFBD in WBPU adhesives. The maxima potentiality was observed with 6.31 mole% TFBD and 2.10 mole% EDA in WBPU adhesives.     

Low‐modulus siloxane–polyurethanes. Part II. Effect of chain extender structure on properties and morphology

A series of six polyurethanes were prepared to study the effect of silicon chain extender structure on properties and morphology of siloxane–polyurethanes. Polyurethanes were prepared by a two‐step bulk polymerization without a catalyst. The soft segment of the polyurethanes was based on an 80:20 (w/w) mixture of α,ω‐bis(6‐hydroxyethoxypropyl) polydimethylsiloxane (PDMS, MW 966) and poly(hexamethylene) oxide (MW 714). The hard segment was based on 4,4′‐methylenediphenyl diisocyanate (MDI) and a 60:40 molar mixture of 1,4‐butanediol (BDO) and a silicon chain extender. Silicon chain extenders (SCE) investigated were 1,3‐bis(4‐hydroxybutyl)1,1,3,3‐tetramethyldisiloxane (BHTD), 1,3‐bis(3‐hydroxypropyl)1,1,3,3‐tetramethyldisiloxane (BPTD), 1,4‐bis(3‐hydroxypropyl)1,1,3,3‐tetramethyldisilylethylene (HTDE), 1,3‐bis(6‐hydroxyethoxypropyl)1,1,3,3‐tetramethyldisiloxane (BETD). All polyurethanes were clear and transparent with number average molecular weights between 72,000 to 116,000. Incorporation of the silicon chain extender resulted in polyurethanes with low‐modulus and high elongation. This was achieved without significant compromise in ultimate tensile strength in all cases, except BETD. Differential scanning calorimetry (DSC) results showed that the silicon chain extenders did not significantly disrupt the hard segment crystallinity, but exhibited a unique morphological feature where SCE‐based hard segments formed separate domains, which may be the primary reason for achieving low modulus without significant compromise in strength. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1092–1100, 2003     

改性PBT中扩链剂的选用

介绍了在改性PBT中扩链剂的选用。     

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。     

三嗪基含氟扩链剂改性水性聚氨酯的合成

利用三聚氰氯（CC）、八氟戊醇（OFP）和乙醇胺（MEA）间的反应先合成了三嗪基含氟扩链剂CC-F，在此基础上制备出系列三嗪基含氟扩链剂改性水性聚氨酯CC-FPUF。利用FTIR和1HNMR对其结构进行表征，并用DLS、XRD、XPS、SEM、WCA和电子万能试验机探究了CC-FPUF制备中所用CC-F的含量(以CC-F、IPDI、CMA-1044、DMPA、S104、TMP和TEA的总质量为基准，下同）对CC-FPUF的乳液粒径、聚合物形态、胶膜形貌、表面元素组成、疏水性能和力学性能的影响。结果表明，随着CC-F含量的增加，CC-FPUF的乳液粒径、胶膜疏水性能和胶膜拉伸强度均有所增加。当CC-F的含量达到8%（CC-FPUF-8）时，胶膜的水接触角最高达到125.8°，相比不含氟的水性聚氨酯（PU）和CC-FPUF-0（CC-F的含量为0）分别增加了60.9°和34.1°；此时胶膜的拉伸强度最大，相比CC-FPUF-0增加了24.47 MPa。胶膜CC-FPUF-8表现出优异的疏水性能和良好的力学性能。     

用磺酸型亲水扩链剂制备高固含量聚氨酯乳液

以聚(四氢呋喃-co-氧化丙烯)二醇为软段、异佛尔酮二异氰酸酯为硬段,以1,2-二羟基-3-丙磺酸钠(DHPA)作为亲水扩链剂,用自乳化法合成了一系列稳定的高固含量聚氨酯乳液,分析了DHPA用量对乳液及其胶膜性能的影响。结果表明:所得聚氨酯乳液的粒径呈多元分布,乳胶粒子呈球形;乳液为假塑性流体;随着DHPA用量的增加,乳液平均粒径逐渐减小,粒径分布变窄,固含量不断增大,当DHPA质量分数为7%时,乳液的总固物质量分数可达61%。乳液具有较好的高、低温及贮存稳定性能。随着DHPA用量的增加,聚氨酯乳液胶膜的拉伸强度逐渐增大,扯断伸长率则先增大后减小;当DHPA质量分数为5%时胶膜的综合力学性能最佳;DHPA用量对胶膜的热稳定性没有明显影响。     

Influence of fluorine-containing side chain on the properties of waterborne polyurethane-urea

In order to prepare waterborne polyurethane with excellent water resistance and thermodynamic properties, a series of side chain fluorinated waterborne polyurethane-urea (FWPU-UA) was synthesized with polytetramethylene ether glycol, N-(2-methyl-1,3-propanediol-2′-)-perfluoro-1-butanesulfonyl amine (NPBA), isophorone diisocyanate, and isophoronediamine. With the increase of NPBA content, the weight loss temperature, glass transition temperature, and tensile strength of FWPU-UA were all improved. Gaussian fitting analysis of infrared data and density functional theory simulation proved that the introduction of fluorine side chains increased the interaction of hydrogen bonding in the FWPU-UA. X-ray photoelectron spectroscopy analysis indicated that the aggregation of fluorine atoms on the surface of film were caused by the migration and enrichment of fluorine side chains. Furthermore, the water resistance of polyurethane-urea film could be significantly improved by adding a small amount of NPBA, and the seven-day water absorption rate of polyurethane-urea film was reduced from 30.13% to 12.55%.     

液化MDI基形状记忆聚氨酯扩链剂的选择研究

在选定液化MDI和聚己二酸丁二醇酯(PBAG)软段原料的前提下，采用双酚A(FA)、乙二醇(ED)、1，4-丁二醇(BD)、1，6-己二醇(HD)、一缩乙二醇(DE)扩链剂合成了一系列形状记忆聚氨酯(SMPU)；用FT-IR、DSC对样品的结构进行了分析，并考察了它们的形状记忆性能和力学性能。结果发现，扩链剂对SMPU有一定影响，用FA、ED扩链的SMPU具有较好的微相分离，而DE扩链的具有较好的软段结晶性能；FA、HD的SMPU具有较低的形状回复温度和较快的形状回复速率，HD、DE扩链的则具有较好形状固定性能，FA、DE扩链的SMPU循环使用性能较好；同时FA、HD的SMPU具有较高的弹性模量与力学强度。     

MDI基热塑性聚酯型聚氨酯弹性体性能的研究

以4,4′-苯基甲烷二异氰酸酯（MDI）、聚己二酸丁二醇酯二醇（PBA）、1,4-丁二醇（BDO）为原料,采用一步法合成热塑性聚氨酯弹性体（TPU）。在n（—NCO）/n（—OH）（R值）恒定条件下,研究了PBA相对分子质量、BDO添加量与TPU性能关系,并由红外光谱、热重、X射线衍射分别表征了TPU的结构、热性能和结晶特性。研究发现：R值、BDO量和MDI量恒定时,PBA的相对分子质量越高,TPU的拉伸强度、断裂伸长率均呈增加趋势;R值恒定,以相对分子质量3 000的PBA为原料,TPU的拉伸强度、断裂伸长率均随BDO添加量的增加而增加;TPU的热分解温度高于300℃,结晶特性显著。     

Evaluation of disulfide chain extender effect on the mechanical properties of unsaturated polyurethane‐urea networks

4‐Aminophenyl disulfide and bis(4‐aminophenyl)methane chain extenders containing hydroxyl‐terminated polybutadiene‐based polyurethane‐ureas are prepared one‐shot to explore the effect of the chain extender structure on the elastomers mechanical properties. However, the results revealed that the participation of the disulfide chain extender in side reactions like thiol‐ene and proton abstraction prevented disulfide metathesis reaction due to decomposing chain extender in the polyurethane‐urea matrix. Also, these side reactions improved the phase mixing via chemical crosslinking between polyurethane‐ureas soft and hard segments, too. Tensile test results showed higher stress strength of the elastomers in the presence of the disulfide chain extender in comparison with the nondisulfide bond containing elastomers. This result was in agreement with the observed result in dynamical mechanical analysis. Dynamic mechanical analysis results established that the absence of the disulfide bond in the polyurethane‐urea matrix led to the higher viscous modulus. The swelling test revealed chemical crosslinking increased in the presence of the disulfide bond. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46309.     

Synthesis of triazole ring‐containing pentol chain extender and its effect on the properties of hyperbranched polyurethane‐urea coatings

This article describes the synthesis and property evaluation of different hyperbranched polyurethane‐urea (HBPUU) coatings based on a newly synthesized triazole ring‐based pentol chain extender. For this initially, the chain extender was synthesized using acetylene azide click reaction and the structure of the intermediate compounds were confirmed by ¹H‐, ¹³C‐NMR, FTIR, and ESI‐mass spectrometry. In the further steps, the required HBPUU coatings were prepared by a systematic three‐step reaction process. In the first step, a isocyanate terminated prepolymer resin was synthesized at NCO/OH ratio of 1.2 : 1, while the second and third step involves the partially chain extension followed by moisture curing. The excess NCO content in the prepolymer was calculated by standard dibutylamine titration method and partially (10, 20, 30, 50, and 70% of the excess NCO content) chain extended with the pentol chain extender and remaining was moisture cured. The structure property relation of different HBPUU coating films were analyzed by FTIR peak deconvulation technique using Gaussian curve fitting procedure while, their viscoelastic and thermo‐mechanical properties were measured by dynamic mechanical thermal analysis, thermo gravimetric analysis, differential scanning calorimetric, and universal testing machine instruments. These results showed that thermal stability, glass transition temperature (T_g), elongation at break increases but the storage and tensile modulus decreases with increasing the percent loading of the triazole chain extender. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation and characterization of one-component polyurethane powder adhesives by the solution polymerization technology

A new technology integrating the synthesis and granulation was adopted to prepare the one-component polyurethane powder adhesives (PPAs) by the solution polymerization. The influence of R_total, neutralization, and types of dispersion solution on the properties of PPAs was investigated. It was found that the initial melting temperature increased and storage stability decreased with increasing R_total. The neutralization reaction between the carboxylic group and amino group made the reduction of the sizing temperature and the increase of the T-peel adhesion strength. The granulation behaviors of the polyurethane (PU) prepolymer under different dispersion solutions showed that the PU prepolymer can be effectively blocked by the 20–30 wt % NaHSO₃ or n-butyl alcohol. Furthermore, the blocked polymers formed small particles with the ideal sizing temperature and peel strength. The excellent adhesive property and thermal stability of PPAs could meet the requirements of the industrial gluing in the fields of packaging, lining, and footwear. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47898.     

扩链剂对含氟聚氨酯乳液性能的影响

采用预聚体分散法合成含氟聚氨酯乳液，分析了扩链剂种类及含量对乳液性能的影响。研究发现不同的扩链剂对含氟聚氨酯乳液的稳定性有不同的影响，而对于同一种扩链剂因其含量的不同对乳液性能影响也有差异。     

Syntheses and properties of polyurethanes containing side‐chain azobenzene groups

Polymers containing azobenzene groups have the characteristic reaction of photo‐induced cis–trans isomerism. The study of new materials for optical information storage has prompted making use of these photo‐isomerizations. In this study, we report the syntheses and properties of four different polyurethanes (DR‐PUns) containing azobenzene groups in the side‐chains. The structurally similar polyurethanes (DR‐PUns) were synthesized by the polycondensation reaction of Disperse Red 19 (DR 19) and four different diisocyanates in dimethylformamide. By introducing of DR 19 into the polymer, we obtained polymers containing a photochromic group in the side‐chain. The weight‐average molecular weights of the DR‐PUns were in the range 5500–12 900. The T_gs of the DR‐PUns range from 119.5 °C to 157.0 °C, depending on the structure of the diisocyanate. Optical properties and solubilities of the polyurethanes were compared. The diffraction efficiencies of films were measured as a function of the reaction time. Typically, the diffraction efficiencies of the DR‐PU1 film prepared from toluene 2,4‐diisocyanate were observed up to a level of 0.25%. For the DR‐PU1 film, the effect of the intensity of the induced laser beam on the diffraction efficiency is also discussed. © 2003 Society of Chemical Industry