挤出过程中聚碳酸酯熔体流动特性的研究

应用毛细管流变仪，在温度为１８０￣３１０℃和表观剪切速率为６０￣１０００Ｓ＾－１的条件下，考察了聚碳酸酯（Ｃａｌｉｂｒｅ７００－１０）熔体挤出流动行为及其影响因素。发现，试样熔体的剪切流动大致上服从牛顿流体流动定律，其表观剪切粘度对温度的敏感性相当高，且末端效应十分显著。     

聚丙烯熔体挤出流动性的研究

应用毛细管流变仪，考察了聚丙烯溶体挤出过程中的流动行为及其影响因素，发现熔体的末端效就不太显著，其剪切流动基本上服从幂律；在较低的剪切速率γ下，熔体的剪切稀化特性较为明显；温度对熔体剪切粘度的影响则相对地弱，两者之间的吊Ａｒｒｈｅｎｉｕｓ方程描述。     

高挤出速率下LDPE熔体流动特性的研究

应用Ｒｏｓａｎｄ毛细管流变仪,于高挤出速率下考察了低密度聚乙烯熔体的流动特性。发现：熔体的剪切流动大体上服从幂定律;入口压力降剪切速率或剪切应力的增加而呈非线性函数形式增大;熔体的剪切粘度对温度的依赖性符合Ａｒｒｈｅｎｉｕｓ关系,其温粘性随着剪切强度的增加而有所减弱,此外,当前切速率大于４００ｓ＾－１时可观察到流动曲线的“平台”现象。     

线性低密度聚乙烯熔体挤出流动性的研究

研究了毛细管挤出过程中线性低密度聚乙烯（ＬＬＤＰＥ）熔体的流动行为及其影响因素。结果表明，在较低的温度下，试样的末端压力损失较为明显；试样的流动行为服从指数律，并可观察到流动诱导结晶现象；熔体的剪切粘度对温度的依赖关系大致上符合Ａｒｒｈｅｎｉｕｓ方程。     

聚碳酸酯熔体挤出流动特性的研究

在温度为280～310℃,表观剪切速率为60～900s~(-1)的条件下,应用毛细管流变仪,考察了聚磷酸酯(PC)熔体挤出流动行为及其影响因素。研究表明试样的剪切流动基本上服从牛顿流体流动定律,熔体剪切粘度对温度的敏感性相当同。     

LLDPE熔体挤出流动性的研究

研究了毛细管挤出过程中线性低密度聚乙烯（ＬＬＤＰＥ）熔体的流行行为及其影响因素，结果表明，在较低的温度下，试样的末端压力损失较为明显；试样的流动行为服从指数律，并可观察到流动诱导结晶现象；熔体的剪切粘度对温度的依赖关系大致上符合Ａｒｒｈｅｎｉｕｓ方程。     

聚甲醛熔体挤出流动性能和挤出胀大的研究

应用流动速率仪,在温度170~220℃和载荷1.2~12.5 kg的条件下,考察了剪切速率(γ)、剪切应力(τw)及温度等对聚甲醛熔体流动特性和挤出胀大的影响。结果表明,熔体的剪切流动基本上服从幂律定律;熔体的表观剪切粘度对温度的依赖性大致上符合Arrhenius方程;表观剪切粘度随着γ和τw的增加而非线性减小;挤出胀大比随着温度的升高而近乎线性下降,随着τw和γ的增加而呈非线性增大。     

ABS熔体挤出流变性质的研究

考察了毛细管挤出过程中温度和流动速率对ABS树脂熔体流变行为的影响。结果表明 ,当剪切速率大于 10 3s 1后 ,熔体的剪切流动不服从幂律 ;而剪切粘度对温度的依赖性符合Arrhenius方程 ;入口压力降和入口拉伸应力均随着剪切应力的增加而呈非线性函数形式增大     

PC／TPU共混物的流变性能

用毛细管流变仪研究了聚碳酸酯（ＰＣ）及聚碳酸酯／热塑性聚氨酯弹性体（ＰＣ／ＴＰＵ）共混物的流变性能。实验结果表明：ＰＣ熔体粘度对剪切速率（γ）不敏感，而对温度（Ｔ）敏感。温度升高，ＰＣ粘度降低。加入ＴＰＵ大大改善了共混物的流动性能，使共混物的成型加工变得容易进行。当ＴＰＵ含量为４０份时，共混物的熔体粘度出现一极小值。加入不同第三组分对于降低共混物的熔体粘度效果不同，第三组分Ｅ对共混物有增粘作用     

挤出过程中HDPE流动特性及结晶行为的研究

$ 用毛细管流变仪,考察了挤出过程中HDPE熔体的流变行为。实验发现,当温度接近试样熔点时,熔体在较低的表观剪切速率(γ_a)下,易产生流动诱导结晶现象,表现为入口压力降(或剪切应力)突然增大;当γ_a大于发生该现象的临界值后,试样的流动服从幂律;试样熔体粘度对温度的依赖关系符合Arrhenius方程。     

乙烯酮(双乙烯酮)下游产品废水的治理技术

乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。     

几种乙炔加压设备性能的比较

阐述并比较了几种加压设备在乙炔加压清净过程中的性能和特点。     

三种煤样燃烧热的测定

本文通过三个厂家提供的三种煤样燃烧热的测定,由测定结果综合得出3号煤样燃烧最完全、燃烧热也最大,是三个煤样中最好的一种。     

Semi-empirical equation of state of metals. Equation of state of aluminum

A semi-empirical equation of state for metals is described. Its capabilities are demonstrated by the example of the equation of state for aluminum. New experimental data are presented on the location of the isentrope of aluminum for unloading from the state at p = 229.71 GPa on the shock adiabat to an aerogel (SiO₂) of density 0.08 g/cm³. __________ Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 2, pp. 61–75, March–April, 2008.     

水泥水化热测定方法综述

水泥水化热是中、低热水泥和核电工程用水泥的一项关键的技术指标。全球范围内测定水泥水化热的方法有溶解法、直接法/半绝热法、等温传导量热法三种。本文总结了中、美、欧相关方法标准,对其测试原理、仪器设备、试验过程等方面进行了比对,并对其在领域的应用做了简单的概括。     

小议汽车涂装工艺设计对涂装成本的影响

论述了涂装工艺设计对涂装设备投资、涂装生产成本的影响。     

Measurement of the gradient of viscosity with composition of mixtures of non-ideal gases

A perturbation viscometer is a differential capillary viscometer that measures the logarithmic viscosity gradient of the viscosity-composition curve for gas mixtures. Measurements are made at different gas mixture compositions. Integration of the logarithmic viscosity gradients measured over the full composition range gives the mixture viscosity relative to the viscosity of one of the pure components of the gas mixture. This method is attractive because, for measurements of equal precision, integration of the gradients is potentially an order of magnitude more precise than measurement of the viscosities directly. It can also work at high and low temperatures and perhaps high pressures.The perturbation viscometer has been used to make measurements on ideal gas mixtures at ambient and elevated temperatures. The situation is more complicated when the gas mixtures are non-ideal. Extra effects due to density differences, molar volume change on mixing and differential thermal expansion may be measured in addition to the desired viscosity change producing systematic errors in the results. Thus, a more sophisticated apparatus is required. The standard perturbation viscometer has been modified to separate out the extra effects to permit measurement of the true change in viscosity. In addition, the theoretical operation of the modified apparatus has been revised to account for the design changes to permit calculation of the viscosity-composition profiles from the results.The apparatus has been tested using helium-HFC-125 mixtures and two new viscosity-composition profiles are presented for these mixtures at 23 and . Internal consistency tests have been used to confirm that the data produced are of high quality with an estimated uncertainty in the viscosity ratio data at of 0.9% and at of 1.5%.     

Calorimetric and Computational Study of Enthalpy of Formation of Diperoxide of Cyclohexanone

A thermochemical rather simple experimental technique is applied to determine the enthalpy of formation of Diperoxide of ciclohexanone. The study is complemented with suitable theoretical calculations at the semiempirical and ab initio levels. A particular satisfactory agreement between both ways is found for the ab initio calculation at the 6–311G basis This set level. Some possible extensions of the present procedure are pointed out.     

塔设备改造选型的分析

就当前扩产增容中塔设备设计和改造时板式塔和填料塔的选型问题加以分析。在评述目前国内常用的几种塔板和新型填料之后，着重介绍一种新型塔板（导向梯形浮阀塔板）和一种新型填料（波环填料——乾隆帕克）。     

Effect of degree of deacetylation of chitin on the properties of chitin crystallites

In the present article, chitin from crab shell was systematically deacetylated using a NaOH treatment with control of the reaction time. The degree of deacetylation, monitored using solid-state NMR, revealed that the reaction was pseudo-first order. Based on this, swollen and NaOH-saturated particles are proposed as the reaction system. The weight loss of the partially saponified and neutralized samples after HCl hydrolysis increased linearly with the degree of deacetylation. The crystallinity of the samples was found to increase after acid hydrolysis. According to conductimetric titration, the surface charge density of the crystallites, after acid hydrolysis, was found to increase with base treatment time. The effect of surface charge on the formation of a chiral nematic phase, due to the rodlike nature of the crystallites, was explored. These results show that because the contribution of charged particles to the ionic strength was significant the double layer compression was affected, especially since the surface charge density was close to the Manning limit. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:373–380, 1997