Morphology and mechanical properties of blends of thermoplastic polyurethane and polyolefins

Polyolefins (PO) were melt mixed with thermoplastic polyurethane (TPU) in a 20 : 80 weight ratio with or without compatibilizer containing 0.5 wt % of maleic anhydride. Effects of component viscosities on morphology and on mechanical properties of the blend were studied by scanning electron microscope (SEM), tensile property analysis, and dynamic mechanical analysis (DMA). It was found that the disperse particle size of compatibilizer‐free blends decreased with the decreasing viscosity ratio of the disperse phase to TPU. The efficiency of the compatibilizer in reducing the particle size varied with viscosity ratios of the disperse phase to compatibilizer. However, the particle size did not decrease with the decreasing viscosity ratio monotonically. With lower viscosity ratio, addition of 5 wt % compatibilizer resulted in a greater reduction of particle size and less loss in the tensile properties as compared to the TPU matrix. For the polyethene (PE) that has the lowest viscosity value among all the POs, its size in the blend was stabilized with the addition of compatibilizer and no compatibilization was detected by DMA and by tensile property analysis. The mobility of the disperse phase and compatibilizer and the dispersion competition between them seemed important. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 875–883, 2006     

纯钨MIM黏结剂的优化及其流变性能

为了获得适合纯钨注射成形的黏结剂,通过热力学计算和喂料的流变实验,系统地研究了黏结剂组元的相容性和不同配方的蜡基黏结剂的流变性能,分析了多种因素对喂料黏度的影响,综合评价了不同黏结剂构成的喂料的流变性能,并对喂料进行了SEM观察,结果表明：所选用的黏结剂体系中各组元之间有很好的相容性,当PW与其他组元的质量比大于4时,表现为热力学相容性;由60%PW-10%HDPE-12%PS-13%PP-5%SA组成的黏结剂的流变性能最好,其综合模塑性指数为7.07 m2/N.s.K,SEM结果显示其喂料相当均匀.     

滴丸动力黏度的实验研究

复方丹参滴丸是治疗冠心病等疾病的纯中药固体制剂.在滴丸滴制时,滴丸的动力黏度影响滴丸成品的外观质量,如圆整度、硬度、大小和干裂度等.本文研究复方丹参滴丸制剂的含水率和溶化温度对滴丸动力黏度的影响.通过实验测定和数据分析得出,滴丸制剂的溶化温度在75℃~85℃,滴丸制剂含水率为6%~10%的条件下,滴丸的动力黏度值基本恒定,滴丸的滴制效果最佳.实验结果已经用于制订新的生产工艺,指导实际药品的生产.     

中等浓度含硅铝酸钠溶液深度脱硅过程物理化学性质的研究

通过对脱硅过程中含硅铝酸钠溶液表面张力和黏度的测定,研究脱硅温度、氧化铝浓度、苛性比等因素对溶液的表面张力和黏度的影响.实验结果表明：低温、高浓度、高苛性比的溶液表面张力和黏度较大,反之则较小.通过XRD检测手段对脱硅后的渣相进行分析,用衍射峰与结构的关系解释溶液的表面张力和黏度的变化对硅量指数的影响.     

Dynamic mechanical properties of agricultural residues‐filled polystyrene

Agricultural residues (cotton straw) were added as very small particles to polystyrene (PS) at different weight ratios by using a melt‐mixing technique. The dynamic mechanical tests were performed over a wide range of temperatures and frequencies by using an ARES rheometer (Rheometrics Scientific) operated in the dynamic mode. The dynamic mechanical properties in terms of the storage modulus (G′), loss modulus (G″), compliance moduli, loss tangent, and dynamic viscosity were studied and compared for PS and PS composite. The results showed that the dynamic mechanical moduli and viscosity were found to increase with the addition of cotton straw and rise further with its loading increasing. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 37–40, 2004     

Enhancing thermal and dynamic-mechanical properties of epoxy reinforced by amino-functionalized microcrystalline cellulose

In this study, microcrystalline cellulose (MCC) was chemically modified with 3-(aminopropyl)triethoxysilane and added to epoxy to improve chemical, thermal and dynamic-mechanical characteristics of the composites. The composites were manufactured aided by sonication with 1.0%, 2.5%, or 5.0% wt/wt of untreated MCC or amino-functionalized MCC (MCC-Si). The epoxy/MCC-Si composites showed a decrease in the ─OH band by Fourier-transform infrared spectroscopy, and X-ray diffraction analysis indicated better dispersion. The incorporation of MCC-Si in epoxy resin decreased the heat of reaction, increased activation energy values (E_a) and pre-exponential factor (A), and did not affect thermal degradation. All conversion degree (α) versus temperature curves for the composites showed a sigmoidal shape. MCC-Si composites showed better dynamic-mechanical properties than the MCC counterparts, and the functionalization effect was evidenced in storage modulus (E') and loss modulus (E"). At 2.5% wt/wt of MCC-Si content an increase of 119% in E' at the glassy region, 127% in E' at the rubbery region and 173% in E" was observed compared to the neat resin, whereas the T_g barely changed among samples. Good adhesion between the amino-functionalized MCC and the epoxy matrix was observed at the fracture surface, evidencing that surface modification of MCC improves their chemical interaction.     

丙烯酰胺水溶液聚合反应的研究

探讨了聚乙二醇作为分散剂时丙烯酰胺水溶液聚合体系中单体含量、还原剂用量对聚合物分子量的影响，并探讨了聚合时间与转化率、单体含量与聚合体系粘度之间的关系。结果表明，在保持聚合体系能够流动的前提下，单体含量可提高到２０％，聚合物的分子量可达３００万以上。     

High‐solid‐content emulsions. V. Applications of miniemulsions to high solids and viscosity control

The use of miniemulsions of styrene and butyl acrylate to make high‐solid‐content, low‐viscosity latices was investigated. Products were obtained with solid concentrations greater than 70 wt % and viscosities as low as 350 mPa s at shear rates of 20 s^?1. This was possible with monomodal and bimodal latices. In addition, the compartmentalization of the reactive species in the miniemulsion systems was exploited to produce latices with high solid concentrations, low viscosities, and bimodal molecular weight distributions. This demonstrated a potentially interesting application for this sort of material. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 745–752, 2005     

混炼胶门尼粘度的预测与控制

使用ＭＧＫＪ型密炼机混炼微机监控系统，在ＢＢ２７０型密炼机上预测混炼胶的门尼粘度值，实现了胎面胶门尼粘度值的预测。预测值与实测值的差平均为０８（相对误差１％）。借助预测门尼粘度的数学模型，对排胶点进行控制，使混炼胶门尼粘度的波动范围为－３～＋３。     

α-烯烃磺酸盐、NaCl、NH_4Cl对液体洗涤剂粘度影响的研究

研究了阴离子表面活性剂/非离子表面活性剂复配液体洗涤剂时α 烯烃磺酸盐、NaCl、NH4Cl对其粘度的影响。结果表明:液体洗涤剂中无论是否含有NaCl或NH4Cl,其粘度均随体系中α 烯烃磺酸盐浓度的增加而下降。NaCl或NH4Cl对液体洗涤剂粘度的提高程度与α 烯烃磺酸盐的浓度有关。对以α 烯烃磺酸盐为主体表面活性剂的液体洗涤剂,其粘度的提高与NaCl或NH4Cl的浓度有关。