Miscibility and properties of blend membranes of waterborne polyurethane and carboxymethylchitin

We prepared a series of blend membranes by blending waterborne polyurethane (WPU) and carboxymethylchitin (CMCH) in aqueous systems. The effects of CMCH content on the miscibility, morphology, thermal stability, and mechanical properties of the blend membranes were investigated by dilute solution viscometry (DSV), Fourier transform infrared spectroscopy, wide‐angle X‐ray diffraction (WXRD), scanning electron microscopy, dynamic mechanical analysis (DMA), thermogravimetric analysis, ultraviolet (UV) spectroscopy, and tensile testing. The miscibility parameter of the WPU/CMCH aqueous solution obtained by DSV predicted that the blends of WPU and CMCH were miscible or partially miscible. Moreover, the partial miscibility of the blend membranes over the entire composition range were confirmed by FTIR, WXRD, DMA, and UV spectroscopy to support the conclusion from DSV. New hydrogen bonds were formed between CMCH and WPU in the blend membranes, resulting in strong intermolecular interactions. By inducing the CMCH, we improved the tensile strength, thermostability, and organic solvent resistance of the blend membranes significantly. Therefore, this study not only provided a novel way to prepare an environmentally–friendly material but also expanded the application of chitin and CMCH. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1233–1241, 2003     

玻纤表面处理用水性聚氨酯乳液合成与性能研究

采用异佛尔酮二异氰酸酯(IPDI)、聚醚二醇A、聚酯二醇B、亲水单体聚乙二醇PEG1000和二羟甲基丙酸(DMPA)等制备了阴/非离子型水性聚氨酯(WPU).讨论了亲水单体(PEG+DMPA)用量、异氰酸酯指数(R值)、聚醚/聚酯二醇配比等对乳液及胶膜性能的影响,并比较了使用不同表面处理剂的玻纤增强尼龙复合材料的性能....     

Drying of Granular Ceramic Films: I, Effect of Processing Variables on Cracking Behavior

Drying of binder-free granular ceramic films was studied to identify processing variables which affect their cracking behavior. Films were prepared from electrostatically stabilized suspensions of α-alumina in water. A critical cracking thickness (CCT) was determined, above which films would spontaneously crack during drying. The effects of particle size, liquid surface tension, drying rate, dispersion stability, and sedimentation time were evaluated by a statistical design methodology. The CCT for films prepared on glass substrates was used as a measure of the effect of each variable on cracking. The statistically significant variables were particle size, dispersion stability, and sedimentation time. The effect of substrate constraint was also studied by producing films on a Teflon substrate and a pool of liquid Hg. The observations were consistent with a capillary formed tensile stress acting on the entire film rather than differential stress generated by a moisture gradient over the film thickness.     

Morphology and mechanical properties of semi-interpenetrating polymer networks from polyurethane and benzyl konjac glucomannan

A series of semi-interpenetrating polymer network (semi-IPN) films coded as UB from castor oil-based polyurethane (PU) and benzyl konjac glucomannan (B-KGM) were prepared, and they have good or certain miscibility over entire composition range. Morphology, miscibility and properties of the UB films were investigated by using scanning electron microscopy (SEM), differential scanning calorimetry, dynamic mechanical analysis, ultraviolet spectrometer, wide-angle X-ray diffraction and tensile test. The results indicated that the UB films exhibited good miscibility when B-KGM content was lower than 15 wt%, resulting in relatively high light transmittance, breaking elongation and density. With an increase of the B-KGM content from 20 to 80 wt%, a certain degree of phase separation between PU and B-KGM occurred in the UB films. The tensile strength of the films UB increased from 7 to 45 MPa with an increase of B-KGM content from 0 to 80 wt%. By extracting the B-KGM with N, N-dimethylformamide from the semi-IPN, the morphology and phase domain size of the UB films were clearly observed by SEM. A continuous phase and dual-continuous phase model describing the semi-IPN were proposed to illustrate the morphology and its transition.     

Facile preparation of bimodal polyethylene with tunable molecular weight distribution from ethylene polymerization catalyzed by binary catalytic system in the presence of diethyl zinc

A series of novel honeycomb films of tri- and octa-arm polystyrene-b-poly(tert-butyl acrylate) star polymers prepared by atom transfer radical polymerization and nitroxide mediated radical polymerization, respectively, have been fabricated. The type of solvents, specifically their miscibility in water is one of essential parameters to construct ordered pore structures. The tri- and octa-arm star polymers yield well-ordered microporous film specifically in 10 to 30 g/L CHCl₃ solution. The contact angle of glass slide substrate (54.57°) is adjusted to 41.06° by plasma treatment and to 12.21° by coating the glass slide with highly hydrophilic hyperbranched polyglycidol. The ordered honeycomb films are created on the hydrophobic substrates, but the ordered films are not formed on the hydrophilic substrates. Microspheres with the diameters ranging from hundreds of nanometers to several micrometers are also obtained by a slight modification of breath figure method.     

Work of Adhesion as a Dominant Factor in Formation of Composition‐Gradient Thermosensitive Gel

By copolymerizing a thermosensitive primary component, N‐isopropylacrylamide (NIPA), and an ionic secondary component, 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) between two substrates of hydrophilic glass and hydrophobic polytetrafluoroethylene (Teflon), a novel composition‐gradient copolymer gel, in which the AMPS content decreases gradually towards Teflon, is prepared. The formation of the composition‐gradient in NIPA‐co‐AMPS gels is discussed in terms of the work of adhesion between a solution and a substrate, i.e., the liquid‐solid interfacial free energy. The work of adhesion is determined from the Young‐Dupré equation on the basis of the measured contact angle and the surface tension in the system consisting of an aqueous solution containing NIPA or AMPS monomers or polymers and glass or Teflon as the substrate. The values of the work of adhesion of AMPS monomer and polymer on Teflon were lower than those on glass. Thus, AMPS remains relatively stable at the glass interface and unstable at the Teflon interface. This repulsion of AMPS due to the hydrophobicity of the Teflon wall generates the composition‐gradient.     

Structure–properties relationship of starch/waterborne polyurethane composites

The blend materials from waterborne polyurethane (WPU)/starch (ST) with different contents (10–90 wt %) were satisfactorily prepared by using the solution casting method. Their miscibility, structure, and properties were investigated by wide‐angle X‐ray diffraction (WAXD), scanning electron microscope (SEM), different scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and the tensile tests, respectively. The results indicated that tensile strength of composite materials not only depended on the starch content, but also related to the microstructure of WPU. The sample WPU2 (1.75 of NCO/OH molar ratio) exhibited hard‐segment order, but WPU1 (1.25 of NCO/OH molar ratio) had no hard‐segment order. The appropriate starch filled into WPU not only decreased the ordered region of soft‐segment matrix, but also hindered the formation of hard‐segment ordered structure. The blend material from 80 wt % WPU1 and 20 wt % starch exhibited better tensile strength (27 MPa), elongation at break (949%), and toughness than others. With an increase of starch content, the WPU matrix with dispersed starch in the blends transited to dual‐phase continuity and then to starch matrix with dispersed WPU. The results suggested that a certain extent of miscibility existed between WPU and starch in the blend materials on the whole composition ratio. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3325–3332, 2003     

醋酸丁酸纤维素与聚丙烯酸乙酯共混体系的研究

通过差热分析和拉伸试验研究了醋酸丁酸纤维素CAB－35－1与聚丙烯酸乙酯（PEA）物理共混、半一互穿网络共混体系的相容性和力学性能，并用扫描电镜观察了共混物的形态。     

Effects of polydimethylsiloxane concentration on properties of polyurethane/polydimethylsiloxane hybrid dispersions

A series of waterborne polyurethane (WPU) derived from isophorone isocyanate and poly(tetramethylene glycol) were modified by hydroxyl‐terminated polydimethylsiloxane (HPMS). The solutions were then cast into films named as PUHS. Rheological behavior of the emulsions were studied using Rheometer and morphology was studied with transmission electron microscope. Meanwhile, the casting films were prepared from the WPU/HPMS hybrid dispersions, and their glass transition behavior, miscibility, water resistance, and medium resistance were studied with differential scanning calorimeter (DSC), wide‐angle X‐ray diffraction (WAXD), and so on. The results revealed that the emulsions' particle size decreases with increasing HPMS content and the particles are more easily affixed to each other when the HPMS content is more than 15%, and emulsions are endowed with pseudoplasticity and thixotropy. WAXD and DSC figures manifested that the casting films all exhibited a certain degree of miscibility. The degrees of crystallinity (x_c) decreased with increasing HPMS content, and the PUHS films were almost amorphous. It is noticed that water and medium absorption increased in the HPMS/PU compared to pure PU, which demonstrate that the membrane surfaces have excellent water and chemical medium repellency. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5538–5544, 2006     

Preparation and characterization of high solid content cationic waterborne polyurethane with core-shell structures

In this study, core-shell structured cationic waterborne polyurethane (WPU) dispersions with high solid content were prepared. To this end, prepolymer A was synthesized from polytetramethylene ether glycol (PTMG), isophorone diisocyanate (IPDI), castor oil (CO) and 1,4-butanediol (BDO) without integration of the hydrophilic groups. Prepolymer B with hydrophilic groups was prepared from PTMG, IPDI, CO, BDO and N-methyldiethanol amine (MDEA). WPU dispersion with a core-shell structure could be generated by mixing, neutralizing, and emulsifying of the prepolymer A and the prepolymer B. The results indicated that the generation of WPU dispersions through this technique exhibited a milky appearance while the pH values range from 5.30 to 5.60. The optimal combination of prepolymer A and prepolymer B (at a ratio of 5:5) resulted in a dispersion with the highest solid content (50.4%), lowest viscosity (69 mPa·s), and narrowest particle size distribution. As the proportion of prepolymer A to prepolymer B decreases, the tensile strength of WPU film reduces while the elongation at break and glass transition temperature increases. Moreover, initially the contact angle with water was decreased instead of increase. However, modifications in a ratio of prepolymer A and B was not showed any significant impact on the thermal stability performance of the WPU films.     

Synthesis and characterizations of waterborne polyurethane modified with 3-aminopropyltriethoxysilane

Waterborne polyurethane (WPU) was prepared by the reaction of isophorone isocyanate (IPDI), polyether polyol (PTMG1000), dimethylol propionic acid (DMPA), and trimethylol propane (TMP) and 3-aminopropyltriethoxysilane (APTES) as coupling agent. The films of the WPU were prepared by casting emulsions on Teflon surfaces. The structure of the polyurethane (PU) was characterized by Fourier transform infrared spectrometer (FT-IR), thermogravimetry (TG), X-ray diffraction (XRD), and differential scanning calorimeter (DSC). The mechanical properties and solvent absorption of the cast films were also measured quantificationally. FT-IR indicates that –NH₂ of APTES reacted with –NCO of PU prepolymer. TG analysis indicates that APTES can improve thermal stability of PU. XRD and DSC show that crystallinity of PU decreased with the increase of w(APTES). It was found that greater mechanical properties of WPU were obtained when chemical networks were formed between PU and APTES. As the mass fraction of APTES increases from 0% to 10%, water absorption decreased from 17% to 8%, ethanol absorption decreased from 46% to 30%. The particle size increases with increase of w(APTES).     

Miscibility and properties of blend materials from waterborne polyurethane and carboxymethyl konjac glucomannan

We prepared composite materials by blending waterborne polyurethane (WPU) and carboxymethyl konjac glucomannan (CMKGM) with CMKGM content from 15 to 80 wt % in an aqueous system. The structures and properties of the blend materials were characterized by FTIR, dynamic mechanical analysis, ultraviolet spectroscopy, scanning electron microscopy, wide‐angle X‐ray diffraction, thermogravimetric analysis, and tensile testing. The results indicated that the blend sheet with 80 wt % CMKGM exhibited good miscibility and higher tensile strength (89.1 MPa) than that of both WPU (3.2 MPa) and CMKGM (56.4 MPa) sheets. Moreover, with an increase of CMKGM content, the tensile strength, Young's modulus, and thermal stability increased significantly, attributed to intermolecular hydrogen bonding between CMKGM and WPU. Based on the experimental results, the blend materials have good, or a certain degree of, miscibility over the whole range of composition ratio of WPU to CMKGM. In addition, the blend materials exhibited organic solvent resistance. This work not only provided a simple method to prepare environmentally friendly materials, but also expanded the application of CMKGM. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 77–83, 2004     

HDI/IPDI对水性聚氨酯及胶膜性能的影响

采用预聚体分散法制备了一系列固含量为50%的水性聚氨酯(WPU),并通过傅里叶红外光谱(FT-IR)、粒径分析仪、X射线衍射(XRD)、差示扫描量热分析(DSC)、拉力试验机等仪器进行表征,研究了HDI/IPDI摩尔比对WPU的乳液性能和胶膜结晶性能、力学性能、耐水性能,以及基材EVA/PVC粘接性能的影响,分析了不同摩尔比的HDI/IPDI和粘接时间与WPU胶黏剂对EVA/PVC粘接性能的关系。研究发现,随着HDI/IPDI摩尔比增加,水性聚氨酯的乳液性能、软硬段的结晶性都得到提高,而胶膜拉伸强度呈先增大后减小的趋势,断裂伸长率则先减小后增大。所有WPU胶膜都有很好耐水性,胶膜吸水率都在5.0%（质量）以下。粘接实验结果表明,WPU胶黏剂对EVA/PVC具有优异的粘接性能,24 h后可对基材产生界面破坏,随着HDI/IPDI摩尔比增加,胶黏剂的粘接强度增大。当HDI/IPDI=7∶1时,水性聚氨酯的综合性能最好。     

基于紫外光辐照改性自组装单层膜图案化表面的铁酸铋薄膜制备与表征

采用自组装单层膜(self-assembled monolayers,SAMs)技术在玻璃基板表面制备了十八烷基三氯硅烷(octadecyltrichlorosilane,OTS)-SAMs,将OTS-SAMs基体在光掩膜覆盖下用紫外光进行刻蚀,得到含有亲水性和疏水性区域的模板,利用液相沉积法在OTS-SAMs模板表面制备了铁酸铋(BiFeO3)图案化薄膜。通过接触角仪、原子力显微镜、X射线衍射、扫描电镜、X射线能谱仪等测试手段对OTS膜和BiFeO3薄膜进行表征。结果表明:以OTS为模板利用液相沉积法制备出边缘轮廓清晰、粗糙度较小,与基板结合力较强,条纹宽度为10～20μm的BiFeO3图案化薄膜。     

脂肪族水性聚氨酯的制备及性能研究

以异佛尔酮二异氰酸酯(IPDI)和聚醚二醇(PPG)为主要原料、二羟甲基丙酸(DMPA)为亲水扩链剂和乙二胺(EDA)为小分子扩链剂,采用预聚体分散法制备出一种水性聚氨酯(WPU)乳液。考察了n(-NCO)∶n(-OH)比例、EDA扩链方式等对WPU稳定性、玻璃化转变温度、力学性能和耐水性等影响。结果表明:将EDA先溶于水中,采用乳化与扩链同时进行的工艺,并且当n(-NCO)∶n(-OH)=1.5∶1时,WPU乳液稳定性好、粒径(14 nm)较小且分布较窄,WPU胶膜的力学性能(拉伸强度为3.683 MPa、断裂伸长率为347%)和耐水性(吸水率为19.7%)俱佳。     

葡萄糖改性水性聚氨酯的合成与表征

采用预聚体合成法,以二羟甲基丙酸（DMPA）、葡萄糖（PG）为亲水扩连剂和交联剂制备一种水性聚氨酯乳液。利用FTIR对胶膜结构进行表征,证实葡萄糖已引入聚氨酯主链。TG分析得出PG改性后的聚氨酯胶膜热稳定性增强。研究了PG用量对该聚氨酯胶膜力学性能的影响,结果表明：随着PG用量的增加,胶膜力学强度得到改善。当PG的用量由0增加至4.68%时,断裂伸长率从529.9%降至276.4%,拉伸强度从10.9 MPa增加至24.2 MPa。     

不同合成工艺制备的脂肪族水性聚氨酯的性能研究

采用异佛尔酮二异氰酸酯（IPDI）、聚己二酸丁二醇酯二醇（PBA）、二羟甲基丙酸（DM-PA）、乙二胺（EDA）等为主要原料,以4种不同的合成工艺制备了固体质量分数大于40％的高固含量水性聚氨酯（WPU）乳液,考察了4种不同合成方式所制备WPU的稳定性、粘度、粒径、耐水性能及力学性能等。结果表明,以不同合成方式所制备的固体质量分数大于40％的WPU均具有较佳的稳定性,乳液的粒径均小于0．51μm,所制备的WPU胶膜具有较高的力学性能,拉伸强度均高于30MPa,其中以方法4所制备的WPU综合性能最佳,拉伸强度达到44．52MPa,断裂伸长率达到770％,吸水率为22．92％。     

Bio-based waterborne polyurethane structural color films with high stability

In recent years, structural colors derived from photonic crystals (PCs) with a periodically ordered nanostructure are gorgeous and iridescent, but once their structure is destroyed, they will fade. In this work, the feasibility of the application of bio-based waterborne polyurethanes (WPU) in structural color films was explored. The structural stability of PCs is enhanced bio-based WPU as a kind of green product, which can replace solvent polyurethane one. A tung oil polyol (TOP) is fabricated by one-step method with simple purification process and used to prepare waterborne polyurethane dispersions (WPUD). More introduction of TOP into the WPUD may help improve tensile strength and hydrophobic capability. It shows excellent mechanical properties with 16.8 MPa in tensile strength and water contact angle 109.5°. The SEM images confirmed that bio-based WPU is more conducive to the self-assembly of silica particles than traditional WPU.     

双酚A环氧树脂改性水性聚氨酯的合成及性能研究

以环氧树脂(EP)、异佛尔酮二异氰酸酯(IPDI)、聚酯二元醇和二羟甲基丙酸(DMPA)等为原料,合成了一系列不同EP含量的水性聚氨酯(WPU)分散体,讨论了EP、亲水基团含量对EP改性WPU分散体的储存稳定性、胶膜力学性能等影响。结果表明:当u(EP)≤3%、w(羧基)=1.6%时,EP改性WPU分散体及其胶膜的综合性能良好;利用WPU中残留的-NCO与EP中羟基反应,使EP被包覆在PU链段中,乳化后EP可稳定存在于WPU中,并且具储存稳定性、耐水性、耐溶剂性及力学性能等俱佳。     

Preparation and characterization of soy protein plastics plasticized with waterborne polyurethane

Utilizing anionic waterborne polyurethane (WPU) as a plasticizer, for the first time, we prepared new soy protein isolate (SPI) plastics. The WPU was prepared by using the emulsion‐extending‐chain method, and mixed with soy protein in aqueous dispersion. The mixture was cast, cured, pickled and hot‐pressed to form SPI plastics plasticized with WPU. The plastics sheets were characterized by infrared spectroscopy, scanning electron microscopy, ultraviolet spectrophotometry and wide‐angle X‐ray diffraction, and their properties were measured by using dynamic mechanical analysis, differential scanning calorimetry and tensile testing. The results revealed that SPI plastics plasticized with WPU possess good mechanical properties, such as a tensile strength (σ_b) of 7–19 MPa, water resistance (σ_b(wet)/σ_b(dry) = 0.4–0.5), optical transmittance and thermal stability, because of the good miscibility and strong interaction between WPU and SPI. With an increase of WPU content from 20 to 50 wt%, the elongation at break (ε_b) value of the sheets increased from 50 up to 150 %, and is much higher than that of the pure SPI sheet. WPU as a plasticizer can play an important role in improving the properties of SPI plastics. Copyright © 2004 Society of Chemical Industry