Absorption of low molecular weight solutes into polyurethane in supercritical carbon dioxide

Absorption of a series of low molecular weight solutes into polyurethane was investigated in supercritical carbon dioxide with different conditions. The effect on the amount of solutes absorbed in polyurethane due to these factors such as pressure, temperature, absorption time, decompression time, the character of solutes, and the amount of cosolvent was examined by a gravimetric method. The absorption mechanism was discussed. The desorption of solutes in polyurethane showed a dependence on the logarithm of time. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3162–3168, 2000     

硬质聚氨酯泡沫塑料模塑成型压力研究

采用正交实验,初步探索了模具温度、原料温度、催化剂用量、发泡剂用量、匀泡剂用量、异氰酸酯指数对硬质聚氨酯泡沫塑料模塑成型时发泡压力的影响规律。在此基础上,进一步研究了当密度不同时,发泡剂对发泡压力的影响,并采用回归分析的方法获得了硬质聚氨酯泡沫塑料模型成型发泡压力（y）、泡沫塑料模腔内发泡密度（x‘）和发泡剂的用量（x）三者之间的数学关系,结果为y=(1.2181x‘-0.0991)x 0.2975x‘-0.0966。     

降低TMP-TDI加成物中游离TDI含量的研究

以甲苯二异氰酸酯(TDI)、三羟甲基丙烷(TMP)为原料,采用化学合成法合成了低游离TDI含量的双组分聚氨酯用固化剂。结果表明:当n(—NCO)/n(—OH)为1.9,催化剂质量分数为0.1%,催化剂加入温度为55℃时,合成了游离TDI含量为0.90%(质量分数)的TMP-TDI加成物,配漆试验表明产品性能优异。     

非异氰酸酯路线合成聚羟氨酯的研究

由非异氰酸酯路线合成聚氨酯,避免使用有毒、难运输和贮存的异氰酸酯,是聚氨酯的绿色合成路线,属于高分子合成化学的前沿课题。本文报道了一种由双环碳酸酯与二元胺加成聚合制备聚羟氨酯的新路线,其中双环碳酸酯是由含双环氧基团的环氧树脂与二氧化碳(CO 2)在双金属氰化络合物与季铵盐组成的二元催化剂催化下高效偶合反应得到。双环碳酸酯在季铵盐催化下与二元胺加成聚合,得到聚羟氨酯。由此提供了一条以环氧树脂、C O2和二元胺为原料合成聚羟氨酯的新途径。     

Water‐blown soy polyol based polyurethane foams modified by cellulosic materials obtained from different sources

This article deals with the effect of cellulosic fiber from commercially available writing paper, bleached kraft pulp, and commercially available rice flour on the foaming of polyurethane based on polyol derived from soy bean oil. The presence of cellulosic materials was observed to have a notable influence on the density of the foams. Changes in the density of different foams were correlated with possible chemical structures generated in the presence of the fiber and were analyzed by Fourier transform infrared spectroscopy and thermogravimetric analysis. Furthermore, differential scanning calorimetry analysis was performed to lend support to possible changes in foaming behavior in the presence of refined fiber. Scanning electron microscopy observations were in line with the observation of structures generated in the presence of cellulosic fibers from different sources. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of polyethylene–octene elastomer foams by compression molding

To produce polyethylene–octene elastomer foams with compression molding, the influences of various activators on the thermal decomposition temperature of the chemical blowing agent azodicarbonamide were investigated with thermogravimetric analysis, which showed that the decomposition temperature of azodicarbonamide could be effectively reduced by the addition of zinc oxide/zinc stearate. The results of a moving die rheometer suggested that the vulcanization and blowing curves were influenced by the content of azodicarbonamide and temperature, and the optimum temperature was about 170°C. The morphology and physical properties of the microcellular polyethylene–octene elastomer were studied. The results indicated that the amount of azodicarbonamide and the processing temperature played important roles in the cell morphology and physical properties of polyethylene–octene elastomer foams. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

基于醇胺固定-释放二氧化碳原理的聚氨酯泡沫绿色制备

通过二乙醇胺（DEA）和二氧化碳反应制得一种氨基甲酸铵化合物（DEAC）。DEAC初始分解温度约为54℃,二氧化碳含量14.6%。将不同份数的DEAC作为反应型发泡剂添加到硬质聚氨酯发泡体系中制备泡沫材料,得到密度为90~150 kg·m^-3,压缩强度为0.02~1.65 MPa性能良好的泡沫材料。DEA在火力发电厂作为二氧化碳吸收剂以减少二氧化碳排放。因此,DEAC可以来源于火力发电厂的副产物,成本低廉。本研究为硬质聚氨酯泡沫的制备提供了一种新型的绿色、环保、经济的方法。     

非异氰酸酯聚氨酯发展近况

非异氰酸酯聚氨酯(NIPU)的特殊分子结构,赋予其材料比传统聚氨酯(PU)更独特的性能,并促使20世纪90年代研发热潮,发展较快.简述了传统PU生产和制品呈现的问题、NIPU市场发展概况及其性能特征、NIPU合成方法发展沿革及合成反应机理;举例说明典型和杂化NIPU的几种其体合成方法,并介绍其主要应用领域.     

CO2/N2 separation ability and structural characteristics of poly(butadiene‐co‐acrylonitrile)‐based polyurethanes and hydrogenated nitrile rubbers

Two families of rubbery polymers, commercial hydrogenated nitrile rubbers and synthesized poly(acrylonitrile‐co‐butadiene)‐based polyurethanes with different amount of nitrile groups were studied as CO₂ selective membrane materials. The polymers were characterized by the techniques of FTIR, gel permeation chromatography, WAXD, and differential scanning calorimetry. The permeabilities of pure CO₂ and N₂ were measured using constant pressure/variable volume method at a feed pressure of 6 atm. With a higher amount of polar nitrile group within a given family of polymers, the permeability coefficient (P) was found to decrease, while the permselectivity (α) of these membranes was found to increase. The trade‐off between both transport parameters was less severe for the polyurethanes, which also showed much higher permeabilites. The results obtained were also discussed with respect to the polymer structure, and some relationships were found between P and T_g values. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

液体CO2作发泡剂的聚氨酯软泡生产工艺及设备

介绍了以液体二氧化碳作物理发泡剂生产软质聚氨酯泡沫的生产工艺、技术特点及其设备;并对新工艺与传统工艺在产品性价方面进行了比较。     

二氧化碳高压发泡聚氨酯模塑生产成套设备

介绍了采用二氧化碳作发泡剂替代CFC-11的聚氨酯泡沫发泡新工艺路线，以及相应开发的二氧化碳高压发泡成套设备的用途及构成要点。     

Synthesis and properties of thermoplastic expandable microspheres: The relation between crosslinking density and expandable property

A set of thermoplastic expandable microspheres was investigated with respect to their crosslinking density and expandable property. The crosslinking efficiencies of dipentaerythritol hexaacrylate in a set of thermoplastic expandable microspheres were measured. As expandable properties, expansion curves were measured by using a thermomechanical analyzer, and they also were shown by measuring the change of thickness of the coated compound consisting of ethylene–vinyl acetate copolymer resin emulsion and CaCO₃ with thermoplastic microspheres on paper. In view of the expansion ratio and heat resistance, as crosslinking density, a swelling ratio of about 20–25 is needed to achieve optimum expansion without collapse and rupture of microspheres. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 505–512, 2004     

Effects of the chemical structure on the heat resistance of thermoplastic expandable microspheres

The effects of various additional non‐nitrile‐containing monomers on the heat resistance of thermoplastic expandable microspheres containing acrylonitrile and methacrylonitrile were investigated to determine the correlation between the chemical structure and expandable properties. Thermoplastic expandable microspheres were synthesized by suspension polymerization, with acrylonitrile and methacrylonitrile as the main ingredients and seven kinds of methacrylic acid derivatives, methacrylic acid, and acrylic acid as non‐nitrile‐containing monomers. The expandable properties, that is, the maximum expansion temperature, the expansion start temperature, and the maximum dimension change, were measured with thermomechanical analysis. For the development of heat‐resistant microspheres, polymer structures with smaller functional free volumes, higher glass‐transition temperatures, and higher cohesive energy densities, such as methyl acrylic acid, were applied as non‐nitrile‐containing monomers. Molecular structures such as ? COOH groups with strong electrostatic interactions and hydrogen‐bonding forces were found to be suitable for high heat resistance. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1306–1312, 2005     

Effects of the properties of blowing agents on the processing and performance of extruded starch acetate

The extrusion of polysaccharide‐based polymers, such as starch acetate, is quite different from that of ordinary synthetic polymers. To understand how the physiochemical properties of blowing agents affect plasticization and expansion processes, starch acetate was extruded with water, ethanol, and ethyl acetate. The studied properties and factors were the evaporation rate, surface tension, boiling point, solubility index, latent heat of vaporization of blowing agents, extrusion temperature, and nucleating‐ and blowing‐agent concentrations. The properties of the blowing agents and operating conditions affected the solubility of the matrix polymer, the nucleation process, and cell growth, which affected the foam density and specific volume. A high temperature increased the cell density and specific volume when water and ethanol were used because a high temperature increased the solubility of starch acetate in water and ethanol and promoted nucleation. Ethyl acetate already had high solvency to starch acetate and a high evaporation rate. A high temperature reduced the melting strength, thereby reducing the cell density and specific volume. Water evaporation was greater, despite a high latent heat of evaporation (hr) and boiling point, than the average volumes of ethanol and ethyl acetate that evaporated. The blowing‐agent efficiency was a function of the solvency, blowing‐agent evaporation rate, and operating conditions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1880–1890, 2005     

Solid solubility of antilipemic agents and micronization of gemfibrozil in supercritical carbon dioxide

The solid solubilities of three antilipemic agents of clofibric acid, fenofibrate and gemfibrozil in supercritical carbon dioxide were measured using a semi-flow apparatus. The experimental data were taken at three isotherms of 308.2, 318.2 and 328.2 K, with pressure range from 10 to 22 MPa. These measured solid solubilities were correlated by the semi-empirical models of Mendez-Santiago-Teja and Chrastil. A solution model was also employed to fit the measured data. The absolute average deviation in solid solubility from semi-empirical models was 3-7%, and that from the solution model was 4-8%. The measured data satisfied the self-consistency test, and the optimally fitted parameters were reported.Gemfibrozil of the above antilipemic agents had high ranking among the best-selling generic drugs. It was then micronized using the rapid expansion of supercritical solution (RESS) method in this study. The particle size of gemfibrozil was micronized from its original 14.3 to 5.8 μm. It was also demonstrated that the dissolution rate of micronized gemfibrozil in a simulated intestinal fluid was enhanced by 5.5 times compared to that of the original compound.     

冰箱用环戊烷发泡体系组合聚醚的研制

通过对泡沫稳定剂和国产聚醚的筛选 ,研制的HY5 10 6环戊烷组合聚醚具有不分层、流动性优良及泡孔细腻等特点。它用于冰箱的保温层 ,其泡沫的主要性能指标为 :平均芯密度35 .6kg/m3,最大芯密度差 1.6kg/m3,10 %压缩强度 170kPa ,导热系数 0 .0 191W/ (m·K) ,低温尺寸稳定性 0 .2 1%。结果表明 ,HY5 10 6环戊烷组合聚醚完全能满足家电等产品的生产要求     

聚氨酯泡沫塑料工业氯氟烃发泡剂替代技术进展

叙述了聚氨酯泡沫塑料行业中发泡剂替代工作进展状况,分别介绍了国际上硬质泡沫和软质泡沫生产中的主要替代技术。     

Mechanical properties and antibacterial activity of peroxide‐cured silicone rubber foams

Silicone rubber (SR) foams were prepared by the peroxide curing of a silicone compound with 2,4‐dichlorobenzoyl peroxide (DCBP), di‐t‐butyl peroxide (DTBP), or 2,5‐dimethyl‐2,5‐di(t‐butylperoxy) hexane (DBPH) in the presence of 2,2′‐azobisisobutyronitrile (AIBN) as a blowing agent. The cells were formed in the foam as a result of nitrogen produced by the decomposition of AIBN during the foaming process. The cell size, hardness, and tensile properties of the SR foams were examined as a function of the peroxide concentration. When the peroxide concentration increased, the hardness and tensile strength of the SR foams increased, whereas the cell size and elongation at break decreased. The antibacterial activity of the prepared foams was also evaluated via their effects on Staphylococcus aureus and Escherichia coli. The peroxide‐cured SR foams had antibacterial activity because a toxic residue was generated by the peroxide decomposition. The foam prepared by the AIBN/DCBP system showed more antibacterial activity than the AIBN/DBPH and AIBN/DTBP ones. However, after postcuring at 250°C for 2 h, the antibacterial activity of the SR foams significantly decreased. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008