共查询到20条相似文献,搜索用时 93 毫秒
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在探讨塑料熔体粘度模型的基础上,根据塑料熔体在注射成型过程中的流动特点,讨论了一种能够在加工温度和压力条件下,剪切速率在l0~10^3s^-1的变化范围内,相当精确地描述高聚物流变特性的拈度模型。重点讨论了模型的参数拟合和适用范围,为注射模具设计和成型模拟提供了科学依据。 相似文献
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在塑料熔体的发泡成型过程中,熔体的粘度是基本的流变性能之一,粘度影响到气泡的成核和长大,是制定发泡成型工艺和原料配方即设计发泡机头的重要依据,带有发泡剂的塑料熔体的粘度是温度、剪切速率和熔所含发泡剂种类、浓度及分布状态等的函数,对含有化学发泡 以CO2为发泡剂的泡沫塑料熔体粘度分别进行了探讨,介绍了相应的计算公式,分析了其影响因素 。 相似文献
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用毛细管流变仪测定并研究了热塑性丁苯三嵌段共聚物(SBS)/蒙脱土纳米复合材料的熔体的稳态剪切流变行为,研究结果表明:温度和压力一定的条件下,加入一定量的改性蒙脱土可以降低熔体的粘度;在较低的剪切速率下,即出现剪切变稀现象;在高剪切速率下,粘度对剪切速率的敏感性是降低的,改性蒙脱土加入量对熔体的剪切粘度影响较小,主要是由基体材料所决定的;随温度的升高熔体粘度对剪切速率的敏感性是降低的。采用转矩流变仪对材料的加工性能进行研究,发现复合材料的加工性能基本上保持了纯SBS的加工性能。 相似文献
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聚丙烯剪切流变测试与分析 总被引:1,自引:0,他引:1
在不同温度和剪切速率下,利用高压毛细管流变仪测试聚丙烯流变性能。结果表明,聚丙烯属于典型的剪切变稀型非牛顿流体,其粘流活化能较低,熔体粘度对温度敏感度低。 相似文献
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以Oldroyd共旋转B模型为基础,从理论上推导了尼龙拉伸流动模型,建立了针对尼龙熔体的拉伸流动本构方程,研究了尼龙6及其尼龙610共混物的熔体拉伸流动行为.结果表明,尼龙共混物的拉伸黏度与剪切速率的平方和拉伸速率之比呈现拟合关系,根据试验数据拟合得到了拉伸黏度对剪切速率的平方和拉伸速率之比的经验公式.并且通过数据拟合发现,尼龙6和尼龙610共混物的拉伸应力与参数t存在较好的幂律拟合关系. 相似文献
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剪切稀化悬浮体触变性的研究 总被引:5,自引:0,他引:5
假设在剪切状态下结构参数变化的速率服从一级动力学关系,在此基础上导出适用于剪切稀化悬浮体的数学模型。该模型能够定量表征悬浮体非定态的流认性能(如触变性),并可求得悬浮体系的材料函数,进而可以推一态的流变性能(如剪切粘度)。用二氧化钛水浆及泥石流触变环的实验数据拟合触变环,求取模型参数,模型预示的定态剪切粘度与实验值吻合良好。 相似文献
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应用Bohlin高级流变仪,在温度190~290℃及剪切速率10-2~102s-1试验条件下测景聚丙烯(PP)熔体、聚全氟乙丙烯(FEP)及其共混物熔体的剪切粘度.研究发现,PP和FEP/PP共混物熔体剪切粘度对温度的依赖性均符合Arre-hnius方程.在剪切速率极低的范围内,PP熔体的剪切粘度对剪切速率的变化不敏感.而FEP/PP共混物熔体则具有明显的剪切变稀特性.当PP的质量分数(wpp)不大于10%时,FEP/PP共混物熔体的剪切粘度随着PP含量的增加而大幅度下"降;随着wpp的进一步增加,剪切粘度摹本上随着Wpp的增加而线性缓慢下降. 相似文献
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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。 相似文献
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D. G. Gordeev L. F. Gudarenko M. V. Zhernokletov V. G. Kudel’kin M. A. Mochalov 《Combustion, Explosion, and Shock Waves》2008,44(2):177-189
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.
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Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 2, pp. 61–75, March–April, 2008. 相似文献
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Jorge Marcelo Romero Soledad Bustillo Hugo Enrique Ramirez Maisuls Nelly Lidia Jorge Manuel Eduardo Gómez Vara Eduardo Alberto Castro Alicia H. Jubert 《International journal of molecular sciences》2007,8(7):688-694
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. 相似文献
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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%. 相似文献
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醋酸纤维素取代基分布与性质的关系 总被引:9,自引:0,他引:9
分析了以吡啶为溶剂的醋酸纤维素的13C-NMR核磁共振谱,得出了三种不同位置羟基的取代度。结合X—射线和DSC分析,初步说明具有相同取代度但未经水解和经过水解的醋酸纤维素(CA) 性质上的差异是由于三个羟基上的取代度分布不同及消晶程度差异所致。 相似文献