Improved Adhesion of Waterborne Polyurethanes by Hybridizations

Aqueous polyurethane dispersions based on isophorone diisocyanate (IPDI), poly (tetramethylene adipate) glycol (PTAd), and dimethylolproprionic acid (DMPA) were synthesized by a prepolymer mixing process. Effects of the molecular weight of PTAd and types of hybridizations, viz. blending, semi-interpenetrating polymer network (IPN), and full IPNs with polybutylacrylate have been determined. It was found that thermal, mechanical, and adhesion properties of the polyurethane dispersions increased with increasing molecular weight of polyols.

Regarding the effects of hybridization, full IPNs gave the greatest tensile strength and elongation at break with a fast drying rate, whereas semi-IPNs gave the greatest initial as well as final adhesion, implying that a certain degree of chain mobility would augment the penetrations of adhesive molecules into the soft polyurethane foam substrates.     

水性聚氨酯/聚甲基丙烯酸甲酯杂化乳液的合成

用异佛尔酮二异氰酸酯(IPDI)、聚丙二醇(PPG)和二羟甲丙酸(DMPA)合成了水性聚氨酯分散体(WPU),讨论了PPG摩尔质量,NCO/OH及PPG/DMPA比例对WPU乳液和涂膜性能的影响。以WPU为种子与甲基丙烯酸甲酯进行乳液聚合制备杂化乳液,研究了不同PU/PMMA物质的量比例对杂化乳液及涂膜性能的影响,并采用TEM对WPU及杂化乳液粒子进行了表征。结果表明,在以PPG1000为原料,NCO与OH物质的量比为1.4∶1,PPG与DMPA物质的量比为1∶0.8条件下制备的WPU杂化乳液,随着PMMA比例增加,杂化乳液的稳定性和成膜性变差,聚合物膜断裂伸长率降低,但铅笔硬度、耐水性及耐乙醇性均得到了改善。     

阴离子型水性聚氨酯乳液的合成研究

以甲苯二异氰酸酯(TDI)、聚丙二醇(PPG)、二羟甲基丙酸(DMPA)为原料,制备了阴离子型水性聚氨酯乳液。探讨了温度、DMPA用量、异氰酸基团和羟基的物质的量比、PPG的相对分子质量对其乳液合成的影响,从而得出制备阴离子型水性聚氨酯乳液的较佳配方。     

Waterborne polyurethane dispersions obtained by the acetone process: A study of colloidal features

Waterborne polyurethane (PU) dispersions were prepared from isophorone diisocyanate (IPDI), 2‐bis(hydroxymethyl) propionic acid (DMPA), 1,4‐butane diol (BD), poly(propylene glycol) (PPG), and triethylamine (TEA) by means of phase inversion through the acetone process. Changes in DMPA content, initial PU content in acetone, phase‐inversion temperature, evaporation conditions, and solvent nature were found to have a great impact on dispersion properties. Using a DMPA concentration of 0.30 mmol/g_pol, stable PU dispersions could only be obtained when the initial PU content in acetone was at least 60 wt %, and phase‐inversion temperature was lower than 30°C. However, when increasing the PU content to 75 wt %, stable dispersions were obtained using DMPA concentrations three times lower. Finally, viscosity curves during the water addition step as well as a phase diagram were determined to understand the particle formation mechanism. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of prepolymer structure on the electro-optic performance of polymer dispersed liquid crystals

The effect of prepolymer structure on the electro-optic properties of polymer dispersed liquid crystals (PDLCs) prepared from UV-cured polyurethane acrylates (PUAs) has been studied. Among four types of films with different soft-segment structure, polypropylene glycol (PPG)- and polytetramethyl ether glycol (PTMG)-based PUAs gave lower threshold (V₁₀) and operating (V₉₀) voltages, whereas polycaprolactone diol (PCL)-based PUAs gave higher V₁₀ and V₉₀ voltages. The use of mixed polyol polypropylene glycol/ poly(tetramethylene adipate)diol) (PPG/PTAd) gave an electro-optic response intermediate between the two. Regarding the effect of hard segment type, that from a linear aliphatic diisocyanate (hexamethylene diisocyanate, HDI) gave the lowest V₁₀ and V₉₀ voltages as well as transparent–translucent transition temperature compared with those from cycloaliphatic diisocyanates. This was interpreted in terms of a more flexible nature and hence a lower glass transition temperature of HDI-based PUA. © 1998 SCI.     

水性聚氨酯胶粘剂的合成

以甲苯二异氰酸酯(TDI)、聚醚二元醇(PPG)和亲水单体二羟甲基丙酸(DMPA)为主要原料合成了水性聚氨酯胶粘剂。用红外光谱对合成产物结构进行表征,研究了分散工艺和配方对性能的影响。研究发现,将预聚体加入到溶有三乙胺的水中,成盐和分散同步进行,能获得性能更好的分散体。确定-NCO和-OH的摩尔比为1.6,DMPA和PPG的摩尔比为1时性能比较理想。     

阴离子型水性聚氨酯的合成与性能研究

以甲苯二异氰酸酯(TDI)、聚丙二醇醚(PPG-220)和二羟甲基丙酸(DMPA)为原料制备了阴离子型水性PU乳液,研究了DMPA用量、n(NCO)／n(OH)值、交联剂TMP用量对水性PU乳液与涂膜性能的影响,得出了制备阴离子型水性PU的最佳配方。     

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。     

The Effect of Glycol Type,Glycol Mixture,and Isocyanate/Glycol Ratio on Flexural Properties of Oil Palm Empty Fruit Bunch-Polyurethane Composites

Abstract

Oil palm empty fruit bunch (EFB)-polyurethane (PU) composites were produced. The effects of the isocyanate (NCO)/glycol (OH) ratio, glycol type, and mixtures (polyethylene glycol PEG 400 (M _w 400) and polypropylene glycol PPG 400 (M _w 400)) on the flexural properties were investigated. The NCO/OH ratio had a significant effect on the flexural properties of the EFB-PU composites. Composites made with PEG 200 exhibited higher flexural properties than with PEG 400 and PPG 400. The flexural properties were also found to be influenced by the PPG 400/PEG 400 ratio.     

金属交联型水性聚氨酯乳液的合成

用甲苯二异氰酸酯、聚丙二醇、二羟甲基丙酸等为原料，以锆化合物作交联荆合成金属交联型水性聚氨酯乳液。考察了交联剂用量，NCO／OH值及固含量对乳液粘度及吸水率等性能的影响。实验结果表明：锆盐交联剂用量为0．64％时，乳胶膜的吸水率最低。     

Aqueous dispersion of polyurethane anionomers from H12MDI/IPDI,PCL, BD,and DMPA

Polyurethane anionomer dispersions were prepared from hydrogenated diphenylmethane diisocyanate (H₁₂MDI) or isophorone diisocyanate (JPDI), poly(caprolactone) (PCL) diol, 1,4-butane diol (BD), and dimethylolpropionic acid (DMPA). Upon neutralization of the DMPA with triethylamine (TEA), the NCO-terminated polyurethane (PU) ionomers were self-emulsified by adding water, followed by chain extension using triethylenetetramine (TETA) in aqueous media. Polyurethanes from H₁₂MDI showed coarser dispersion and better tensile properties over those from IPDI. Polyurethanes prepared by the one-shot method had better dispersion and tensile properties over those by the two-shot method. When some of the PCL diol was replaced by DMPA or BD, tensile strength increased and ductility decreased due mainly to the increased chain rigidity and intermolecular forces. © 1994 John Wiley & Sons, Inc.     

FTIR, 1H‐NMR spectra,and thermal characterization of water‐based polyurethane/acrylic hybrids

Polyurethane (PU) polymer was synthesized following a prepolymer mixing process, by polyaddition of isophorone diisocyanate (IPDI), poly(propylene glycol) (PPG), 2‐hydroxyethyl methacrylate (HEMA), and 2,2‐bis(hydroxymethyl)propionic acid (DMPA). The PU anionomer having 2‐ethoxymethacrylate terminal groups was dispersed in water by prior neutralization of carboxylic acid groups of DMPA with triethylamine (TEA), chain extended with hydrazine (HZM) in water and a dispersion polymerization with methyl methacrylate/n‐butyl acrylate/acrylic acid mixture was performed. The above polymerization reactions lead to the formation of PU/acrylic hybrids having a chemical bond between PU and acrylic moieties. Acrylic content was varied from 0 to 50 wt % and samples were purified to eliminate oligomers and impurities before characterization. The FTIR and ¹H‐NMR spectra of these purified hybrid samples were obtained and bands and peaks assignments were discussed. Thermal properties (DSC and TGA) were also discussed. Breaking hydrogen bonds is the main reason for changes in properties with increasing acrylic content. Particle size data of dispersions is also presented and discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Mesomorphic polyblends of poly(p-phenylene terephthalamide) and poly(4,4′-terephthanilide adipamide)

A simultaneous dissolution of two lyotropic polyamides, poly(p-phenylene terephthalamide) (PPTA) and poly(4,4′-terephthanilidc adipamide) (PTAd), in a concentrated H₂SO₄ (1 to 1.5% wt) produced an isotropic single phase solution. The crystallinity of PPTA/PTAd blends confirmed formation of a mesomorphic polyblend to the molecular level. With increasing concentration, solutions of these PPTA/PTAd blends in 100% H₂SO₄ showed a sequential phase change typical of a single lyotropic polymer. Further, the ternary solution exhibited a wider biphase range than both binary solutions of PPTA/100% H₂SO₄ and PTAd/100% H₂SO₄. Dry-jet wet spinning of anisetropic solution of this ternary composition with a PTAd weight fraction less than 0.5 enabled us to obtain PPTA/PTAd blend fibers. Including a PTAd weight fraction of 0.1-0.15 reduced both the orientation angle and fibrillation. The particular blend fiber with a PTAd weight fraction of 0.15 exhibited a synergistic effect on the mechanical properties.     

Structure–property study of polyurethane anionomers based on various polyols and diisocyanates

Polyurethane (PU) anionomers were prepared as aqueous dispersions using dimethylol propionic acid (DMPA) as the stabilizing moiety. The principal diols used were polytetrahydrofuran of molecular weight 1000 (PTHF1000) and cyclohexane dimethanol (CHDM). The diisocyanates used in this study were isophorone diisocyanate (IPDI), hydrogenated methylene bisphenylene diisocyanate (H₁₂MDI), tetramethylene xylene diisocyanate (TMXDI), hexamethylene diisocyanate (HDI), and a 50 : 50 blend of IPDI and HDI. All these samples were neutralized using triethylamine (TEA) and chain-extended using hydrazine monohydrate. The dispersions were prepared at a NCO/OH ratio of 2 so that a comparison of their structure–property relationships could be made with respect to their mechanical and viscoelastic properties and solvent resistance. Also, two further samples were prepared of similar composition to the IPDI-based sample, but using poly (propylene glycol), PPG1000, and PTHF2000 polyols. The effects on the structure and properties of the PPG1000 and the higher molecular weight PTHF sample were compared with the PTHF1000 sample. Dynamic mechanical thermal analysis, tensile testing, solvent spot, and swelling studies were employed for the characterization of these materials. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2035–2044, 1997     

Synthesis and molecular weight determination of urethane-based anionomers

Summary Anionomer prepolymers based on poly(propylene oxide) (PPG), 4,4-dicyclohexylmethane diisocyanate (H₁₂MDI) and dimethylol propionic acid (DMPA) were synthesized in bulk. The molecular weight of the prepolymers was determined by vapour pressure osmometry (VPO) and gel permeation chromatography (GPC).     

Thermal decomposition of polyurethane pressure-sensitive adhesives dispersions

The thermal degradation of polyurethane pressure-sensitive adhesives (PSAs) at temperature 600 °C was investigated by the application of pyrolysis-gas chromatography technique. The present study was undertaken in order to determine the key thermal degradation products of polyurethane PSA based on isophorone diisocyanate (IPDI), polypropylene glycol (PPG), hydroxylated polybutadiene (HTPB), dimethylolpropionic acid (DMPA) and to elucidate the mechanism of the polyurethane PSAs pyrolysis.     

PUA／PVC复合乳液树脂的制备及表征

采用甲苯二异氰酸酯（TDI）、聚醚（PPG）和二羟甲基丙酸（DMPA）合成了自乳化阴离子水性聚氨酯（PU），以此为种子制备了聚氨酯／聚丙烯酸酯（PUA）复合乳液，接着在高压釜中进行氯乙烯原位接枝共聚，制备了聚氨酯／聚丙烯酸酯／聚氯乙烯（PUA／PVC）复合乳液树脂。采用激光粒度分析仪、透射电镜、动态热力学分析仪对复合材料的形态及动态力学性能进行了研究。结果表明：PUA／PVC复合胶乳粒子具有多核壳“海岛型”复合结构，经原位改性的PVC复合材料中的PUA橡胶相具有高度均匀的分散性。     

Polyurethane–urea anionomer dispersions. I

Polyurethane–urea anionomer dispersions with different stoichiometric DMPA/polyol and NCO/OH ratios were preapred from poly(oxypropylene)glycol, toluene diisocyanate (TDI), dimethylolpropionic acid (DMPA), and ethylenediamine (EDA). The dispersion-cast films were prepared and characterized by mechanical properties, dynamic mechanical analysis (DMA), and differential scanning calorimetry (DSC). Increasing the hard-segment content by either increasing the DMPA/polyol or the NCO/OH ratios affects the glass transition temperature (T_g) of the soft segments. © 1994 John Wiley & Sons, Inc.     

水性紫外光固化超支化聚氨酯的制备

以聚环氧丙烷二醇醚(PPG1000)、季戊四醇、2,2-二羟甲基丙酸(DMPA)和异佛尔酮二异氛酸酯(IPDI)为主要聚合单体,甲基丙烯酸羚乙酯(HEMA)为封端剂,合成了超支化紫外光固化水性聚氨醋树脂.研究了各组分用量对涂膜性能的影响,确定了较佳工艺条件,并用红外光谱和核磁共振谱对该超支化聚氨醋树脂的结构进行了表征....     

Effect of Poly(dimethylsiloxane) Content on the Properties of Water-Borne Poly(urethane-urea)s Containing MDI

Low photo- and water-resistance is often cited as the problem of MDI-based WBPU. This study addressed this problem. Water-borne poly(urethane-urea)s (WBPUs) were synthesized using a pre-polymer mixing process from 4,4'-methylenebis(phenyl isocyanate)(MDI)/4,4-dicyclohexylmethyl diisocyanate (H₁₂MDI) (15/85 mole %)/dimethylol propionic acid (DMPA)/ethylene diamine (EDA)/triethylamine (TEA) with different poly(propylene glycol) (PPG, M _n = 2000)/hydroxyl terminated poly(dimethylsiloxane) (PDMS, M _n = ～550) molar ratios. This study highlights the effect of PDMS content on the inherent viscosity, hydrogen-bonding, storage modulus, tan δ peak intensity, tensile modulus/strength, elongation (%) at break, water swelling (%), contact angle, and the yellowness index of WBPUs containing MDI. The mechanical properties (strength/modulus), water-resistance and photo-resistance of WBPUs containing MDI increased significantly in proportion to the PDMS content. These results indicate the potential for using multi-performance WBPU with PDPS for WBPU coatings.