Relating the molecular structure and crystallization behavior of polypropylene

The crystallization behavior of two polypropylene (PP) resins as used for biaxially oriented polypropylene (BOPP) and general injection mold applications, respectively, has been intensively investigated and compared by means of polarized light optical micrography (POM), differential scanning calorimetry (DSC), conventional transmission electron microscopy (TEM), and high resolution transmission electron microscopy (HRTEM). It is found that both molecular weight distribution and isotacticity of polypropylene strongly affect its crystallization characteristics, e.g., the number of crystal nuclei at the initial stage, crystallization dynamics, the morphology, size and perfection of crystals in the final product, and so on. The results indicate an appropriate molecular structure is vital in producing high‐quality BOPP film. Polym. Eng. Sci. 44:1749–1754, 2004. © 2004 Society of Plastics Engineers.     

喷雾干燥器粘壁产生的原因

引言众所周知,喷雾干燥工艺及设备是陶瓷、保护渣、化工、高岭土等行业常用的泥浆干燥设备。不管是哪个行业都或多或少存在喷雾塔体粘壁问题。此问题看似小问题,其实对使用厂会造成诸多不便,同时也造成了能源的浪费,尤其是粘性较大的泥浆原料,此问题尤为突出。     

关于VV6102、VV6106风机振动原因分析及整改措施

通过对VV6102、VV6106风机设计资料和现场测试数据，对两台风机的振动原因作出分析，并提出相应整改建议。     

Analysis of statistical thermodynamic model for binary protein adsorption equilibria on cation exchange adsorbent

A study of nonlinear competitive adsorption equilibria of proteins is of fundamental importance in understanding the behavior of preparative chromatographic separation. This work describes the nonlinear binary protein adsorption equilibria on ion exchangers by the statistical thermodynamic (ST) model. The single-component and binary protein adsorption isotherms of bovine hemoglobin (Hb) and bovine serum albumin (BSA) on SP Sepharose FF were determined by batch adsorption experiments in 0.05 mol/L sodium acetate buffer at three pH values (4.5, 5.0 and 5.5) and three NaCl concentrations (0.05, 0.10 and 0.15 mol/L) at pH 5.0. The ST model was found to depict the effects of pH and ionic strength on the single-component equilibria well, with model parameters depending on the pH and ionic strength. Moreover, the ST model gave acceptable fitting to the binary adsorption data with the fitted single-component model parameters, leading to the estimation of the binary ST model parameter. The effects of pH and ionic strength on the model parameters are reasonably interpreted by the electrostatic and thermodynamic theories. Results demonstrate the availability of the ST model for describing nonlinear competitive protein adsorption equilibria in the presence of two proteins.     

从松节油中高效分离α-蒎烯

设计出一种从松节油中高效分离α-蒎烯的蒸馏-分馏工艺，对工艺条件进行了优化研究，产物经气相色谱-质谱联用测定、红外光谱结构表征，确证为α-蒎烯，纯度为98．76％，收率达到72．92％。     

PF/PU低温固化体系的研究

将端羟基封端和端羧基封端的聚氨酯(PU)预聚物分别与酚醛树脂(PF)复合，加入对甲苯磺酸(PTSA)，在低温下固化，通过对固化体系的参数进行研究，选择的固化条件为：PTSA用量在3．5％，固化温度为80℃。通过扫描电镜对两个体系的复合物进行表征，对两种不同的增韧机理进行讨论。     

海岛型阳离子交换纤维的研究

阐述了海岛型阳离子交换纤维的制备方法,对交联、磺化过程中的硫酸浓度,多聚甲醛的添加量,反应时间,反应温度等对离子交换容量的影响进行了讨论。     

硝基氯苯的分离

本文叙述了根据硝氯苯的物化性质蒸气压方程，设计了采用高效波纹填料的新流程，并与国内外流程装置作比较，指明了新流程和新装置的优点。．     

青酶胺的研究现状及展望

本文详述了青酶胺的性质、应用和研究现状并展望其发展方向。     

预防输氧管道燃烧的措施

概述了输氧管道的燃烧机理，分析了产生燃料的原因及预防措施，并给出了相应的设计规范。