氯磺化聚乙烯流变性能研究

研究氯磺化聚乙烯(CSM)的流变性能，特别是剪切速率、剪切应力和温度对CSM熔体表观粘度的影响。试验结果表明，CSM熔体在试验温度范围内为假塑性流体，随温度的升高其非牛顿性减弱；CSM熔体的表观粘度随表观剪切速率和剪切应力的增大以及温度的升高而降低；剪切应力对CSM的粘流活化能影响不大。     

ABS 在不同入口角圆锥短口模挤出中的流变性能研究

利用毛细管流变仪研究了(丙烯腈/丁二烯/苯乙烯)共聚物(ABS)在不同入口角圆锥短口模挤出中的流变性能,讨论了ABS熔体在长径比为10的不同角度圆锥口模挤出中的流变行为,并测试其非牛顿指数n与稠度系数K。结果表明,ABS的表观粘度随剪切速率的增大而减小,并且在相同的剪切速率下,表观粘度随入口角的增大而增大,但长径比一定时,入口角大时的剪切应力要比入口角小时的剪切应力大;ABS熔体的非牛顿指数n随入口角的增大而减小,而稠度系数K随入口角的增大而增大。     

润滑剂YI对聚氯乙烯塑料流变性能的影响

采用毛细管流变仪，考察润滑剂ＹＩ用量对ＰＶＣ流变性能的影响。实验表明，流体非牛顿指数ｎ＜１，并随ＹＩ用量增加而下降。ＹＩ使ＰＶＣ熔体粘度大幅度减少，在硬质ＰＶＣ中，ＹＩ用量在０．６～１．０ＰＨＲ作用最明显；在软质ＰＶＣ中，当剪切速率γ＞５００ｓ－１时，少量ＹＩ就能使熔体粘度下降。并测定了不同ＹＩ用量ＰＶＣ的流动活化能，随ＹＩ用量增加，Ｅη略有下降，切应力对Ｅη影响不明显     

纺丝用可熔性聚四氟乙烯的流变性能研究

采用毛细管流变仪,对PFA熔体的流变性能进行研究。讨论了温度、剪切速率对纺丝用PFA熔体的非牛顿指数、表观粘度、结构粘度指数等方面的影响。结果表明,PFA熔体非牛顿指数随温度上升而升高。在不同温度下,PFA熔体的粘度均随着剪切速率的增大而减小,表观粘流活化能随剪切速率增加而减小。PFA熔体的结构粘度指数Δη随熔体温度的增高而逐渐减小。     

动态硫化NBR/PFPA热塑性弹性体流变性能的研究

对动态硫化NBR／石油发酵尼龙（PFPA）共混型热塑性弹性体的流变性能进行了研究。结果表明，NBR／PFPA为假塑性流体；表观粘度随剪切速率和剪切应力的增大而减小，随温度升高而降低；粘流活化能随PFPA用量的增大而减小。     

BOPP专用树脂的流变行为研究

利用高压毛细管流变仪,对三种不同BOPP专用树脂的流变性能进行测定,BOPP专用料均表现为剪切应力随剪切速率增加而增加,但增加速率明显减弱,表观粘度随剪切速率增加而减小的特点,具有明显的假塑性的流动行为。通过分析温度、剪切速度和分子量及其分布对树脂的表观粘度的影响,确定不同树脂改善熔体粘度最有效的方法。     

聚苯硫醚的流变性能研究

采用毛细管流变仪研究了纤维级聚苯硫醚(PPS)的流变性能。结果表明,PPS在剪切速率为150～400s~(-1)时,会出现剪切增稠现象;剪切速率在400～1000 s~(-1)时,PPS熔体为假塑性流体,PPS的非牛顿指数随温度的升高而逐渐趋近于1,PPS熔体的表观粘度与温度之间的关系符合Arrhenius方程,PPS熔体的粘流活化能随剪切速率的增大而减小,减小的速度随剪切速率的增大而变慢。     

PA1010／MGEPR共混物的流变性能研究

以尼龙1010（PA1010）为基体,以马来酸酐接枝乙丙橡胶（MGEPR）为增韧剂,采用Brabender PLE331型塑化仪制备了PA1010／MGEPR共混增韧尼龙材料,测试了PA1010／MGEPR共混物的表观粘度、非牛顿指数和粘液活化能等流变能数,并重点讨论了其流变性能。实验结果表明：共混物的表观粘度随温度升高而降低;粘流活化能随剪切速率的增而而减小。共混物熔体的表观粘度随剪切速率和剪切应力的增大而降低,非牛顿指数n小于1,符合假塑性流体流动规律。     

氢氧化镁阻燃EVAC的流变性能研究

采用熔融共混法制备了Mg(OH)2阻燃乙烯-乙酸乙烯酯塑料(EVAC),并采用毛细管流变仪对其流变性能进行了研究。讨论了温度、剪切速率和剪切应力对熔体表观黏度的影响;研究了黏流活化能与剪切速率的变化规律。结果表明,熔体的表观黏度随温度的升高而降低,随剪切速率和剪切应力的增大而减小;黏流活化能随剪切速率的增大而降低。其非牛顿指数小于1,说明Mg(OH)2阻燃EVAC为假塑性流体。当剪切应力无限小时,由Spencer-Dillon公式外推得到阻燃EVAC的零切黏度。     

高聚合度PVC改性电缆料的研制

本文介绍采用不同改性剂对高聚合度ＰＶＣ进行改制造橡胶类改性热塑性电缆料，考察了塑化温度、改性剂、增塑化温度为１７５℃；丁腈胶Ｎ－４１是ＰＶＣ的良好改性剂；当ＣａＣＯ３用量为３０份，ＤＯＰ用量为６５－７５份（均以ＰＶＣ／Ｎ－４１为９０／１０，共计１００）时，可制得性能良好的改性电缆料。     

Calcium stearate–stearic acid as lubricants for rigid poly(vinyl chloride) (PVC). Capillary rheometer measurements and extrusion properties

Capillary rheometer measurements show that stearic acid can be characterized as a normal lubricant. If the content of stearic acid is increased in rigid PVC formulations, the melt viscosity will decrease. This leads to a corresponding increase of shear rate and volumetric flow rate. The influence of calcium stearate is opposite to the normal characteristic of a lubricant. Increasing amounts of calcium stearate lead to an increased melt viscosity and a decreased shear rate and volumetric flow rate. In the extrusion of rigid PVC, the apparent “lubricating” effect of calcium stearate is probably due to the increased friction with resulting heat evolution and higher mass temperature, leading to a decreased viscosity of the plastic melt. This is in agreement with the results of the extrusion experiments. Both mass temperature and power consumption decrease when stearic acid is added and increase when calcium stearate is added to the formulation.     

The significance of capillary rheology testing temperature for predicting PVC extrudability

A rheological investigation of the saturated fatty acids as lubricants for PVC was made in a Sieglaff-McKelvey rheometer over a wide temperature range. Results reveal that with an increase in carbon chain, fatty acids became more effective in reducing the melt viscosity of PVC. It was also discovered that the maximum viscosity variation due to these materials was observed at 350°F. At test temperatures of 400°F and above, no major viscosity differences were observed. Furthermore, the changes in the melt viscosity were more pronounced at shear rates less than 200 sec^?1. The usefulness of the measured viscosity variations at the critical test temperature of 350°F was shown by extrusion. An excellent correlation between the apparent melt viscosity and extrusion melt temperature was found. The criticalness of the test temperature in assessing the effect of lubricants on PVC flow is discussed.     

Rheological properties of calcium silicate‐filled isotactic polypropylene

The melt rheological behavior of calcium silicate‐filled isotactic polypropylene, with filler volume contents of 0–17.8%, was determined at 493 K. The composites followed the power law in shear stress versus shear rate variations and were shear thinning. Initially, apparent melt viscosity decreased until a critical filler volume content of 8.5% was reached. However, on further increase in calcium silicate concentration, apparent melt viscosity increased. Melt elasticity also showed an initial decrease until 8.5% filler content was reached and then an increase beyond this filler content. Surface treatment of calcium silicate with a titanate coupling agent, LICA 38, modified the rheological properties because of the plasticizing/lubricating effect of LICA 38. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1511–1518, 2003     

EPDM橡胶的流变特性实验研究

为了研究橡胶熔体流变性能对其加工成型的影响，利用毛细管流变仪对三元乙丙橡胶（EPDM）的流变特性进行了实验研究。实验结果表明：EPDM橡胶在毛细管挤出时，剪切速率对剪切应力、剪切粘度和挤出胀大的影响最大；挤出温度对三者有一定的影响；在长径比相同时，毛细管半径对剪切应力和剪切粘度几乎没有影响，但对挤出胀大影响较大。     

定向碳纳米管/高密度聚乙烯复合材料体系流变行为的研究

对定向碳纳米管进行酸化处理以后，采用机械共混法制备了定向碳纳米管／高密度聚乙烯复合材料，利用毛细管流变仪研究了高密度聚乙烯和定向碳纳米管／高密度聚乙烯复合材料的流变行为．讨论了剪切应力、剪切速率、温度以及定向碳纳米管的加入对体系流变行为的影响。结果表明：高密度聚乙烯和定向碳纳米管／高密度聚乙烯复合材料都属于假塑性流体．高密度聚乙烯的非牛顿性要大于定向碳纳米管／高密度聚乙烯复合材料；随剪切速率和剪切应力的增大及温度的升高．熔体表现粘度均减小；随着定向碳纳米管含量的增加，定向碳纳米管／高密度聚乙烯复合材料的表观粘度先减小后增大。     

The rheological properties of vinyl chloride–vinyl acetate copolymers

Copolymers of vinyl chloride–vinyl acetate have been prepared with different vinyl acetate contents and molecular weights and under different polymerization conditions. A rheological study of these copolymers indicates that they behave in some ways like externally plasticized PVC. For instance, as the vinyl acetate content increases, the melt viscosity decreases, the flow activation energy decreases, and the copolymer becomes more Newtonian. However, the critical shear rate for melt fracture increases, resembling the addition of elastic polymers to PVC. An increase in copolymer molecular weight has a similar effect on the rheological behavior as in PVC, except that the flow activation energy is observed to increase rather than decrease. Decreasing the polymerization temperature affects the flow properties of the copolymer, probably due to changes in degree of branching and crystallinity. A copolymer made by the delayed addition of vinyl chloride, having a more random structure than one made by the conventional batch method, exhibited quite different flow behavior. It had a lower melt viscosity, higher critical shear rate, and lower flow activation energy.     

Rheological behaviour of copoly(ethylene/octene) elastomer compunds: Effect of blowing agent and precipitated CaCO3 filler

Abstract

An experimental study of the rheological behaviour of ethylene/octene copolymer compounds in extrusion containing blowing agent has been carried out. The cell morphology development was studied using scanning electron microscopy. Rheological properties of unfilled and precipitated CaCO₃ filled systems with various blowing agents, extrusion temperatures, and shear rates were studied using a capillary rheometer. The total extrusion pressure, apparent shear stress, apparent viscosity, and die swell of the unfilled and CaCO₃ filled compounds were also determined and the effect of blowing agent on the rheological properties of the compounds studied. It was observed that there is reduction of stress and viscosity with blowing agent loading. Incorporation of blowing agent led to decreased shear thinning behaviour resulting in an increase in the power law index. The viscosity reduction factor of the unfilled compound was found to be dependent on the concentration of blowing agent, the shear rate, and the temperature.     

八种ABS树脂的流变性能比较研究

用熔体流动速率仪测定了8种ABS树脂的熔体质量流动速率，并用毛细管流变仪对8种ABS树脂流变性能进行了研究。结果表明，1、7、8号样的流动性最好；8种树脂的非牛顿指数n都小于1，属于假塑性流体；同时8种ABS树脂的表观黏度随剪切速率、剪切应力的增加而降低，当剪切速率、剪切应力足够高时，它们对8种ABS树脂表观黏度的影响趋于一致。     

PVC/EVA共混物的研究

本文研究了混炼温度和时间对PVC/EVA共混物抗冲性能的影响,发现加入聚乙烯,共混体系的抗冲击强度能进一步提高.用TEM观察了PVC/EVA的形态结构,采用Brabender塑化仪和毛细管流变仪研究了共混物的塑化和熔体流变行为.通过计算机对实验结果进行二元线性回归,建立了共混物的熔体粘度与剪切应力和温度相关联的数学模型.