聚对苯二甲酸丙二醇酯流变性能的研究

采用自制的毛细管流变仪研究了聚对苯二甲酸丙二醇酯 ( PTT)的流变性能。结果表明 :PTT熔体属切力变稀型流体 ,随温度升高或相对分子质量降低 ,其非牛顿指数增大 ,熔体表观粘度对温度的敏感性较大。在 PTT生产中 ,应严格控制纺丝温度 ,通过温度来调节熔体粘度。     

芳砜纶纺丝溶液的流变性能研究

研究了自制的芳砜纶(聚砜酰胺)纺丝溶液的浓度、温度及聚合物的相对分子质量对纺丝溶液的流动曲线、粘流活化能、非牛顿指数和结构黏度指数的影响。结果表明:DMAc溶剂体系低温缩聚的芳砜纶纺丝溶液为切力变稀的非牛顿流体,芳砜纶聚合物相对分子质量增大、溶液浓度升高使纺丝溶液的非牛顿性增加,温度升高使其减小,其中浓度的影响最大。     

芳纶1313纺丝原液的流变性能研究

研究了自制的芳纶1313纺丝溶液的浓度、温度及聚合物的相对分子质量对纺丝溶液的流动曲线、粘流活化能、非牛顿指数和结构黏度指数及松弛时间的影响。结果表明,芳纶1313纺丝溶液为切力变稀的非牛顿流体,芳纶1313聚合物相对分子质量增大、溶液浓度升高使纺丝溶液的非牛顿性增加,温度升高使其减少,其中相对分子质量的影响较其它两个因素为大。     

熔纺聚氨酯流变性能的研究

研究了熔纺聚氨酯熔体的流变性能.结果表明:熔纺聚氨酯熔体为切力变稀流体,随温度升高其非牛顿指数增大,胀大比减小,表观剪切粘度随温度升高下降明显,且低于常规熔纺成纤高聚物,为避免纺丝时产生自重引伸大于喷丝头拉伸比而导致并丝,纺丝温度不应大于210℃;水分存在会导致熔体粘度下降,胀大比减小.     

HDO共聚改性PET的流变性能及可纺性研究

为研究1,6-己二醇(HDO)对共聚酯流变性能以及熔融纺丝性能的影响规律，采用原位合成法制备了不同HDO含量的共聚改性聚对苯二甲酸乙二醇酯(PET)树脂。通过毛细管流变仪考察了共聚酯的流变性能，系统研究了HDO含量对共聚酯熔融纺丝性能的影响规律。结果表明，不同HDO含量的改性PET共聚酯属于典型的切力变稀型非牛顿流体，其流动方式为假塑性流动。共聚酯的黏流活化能随HDO含量的增加而下降，对温度敏感度下降，有利于纺丝；非牛顿指数n随温度的升高而增大，随HDO含量的增加而增大；共聚酯的结构黏度指数Δη随HDO含量增加而下降，说明熔体可纺性和稳定性较好。HDO改性PET共聚酯纤维与PET相比，各项性能指标未见明显差异，可纺性良好。     

聚乳酸(PLA)的流变性能研究

以聚乳酸切片为原料,在不同温度下,利用毛细管流变仪测试其流变性能。流动曲线表明,聚乳酸熔体属于典型的切力变稀型非牛顿流体,其黏流活化能较低,有利于纺丝工艺条件的控制,且熔体结构黏度指数随熔体温度增高而减小,纺丝成纤性得到改善。     

聚碳硅烷可纺性与纺丝工艺探讨

本文研究了聚碳硅烷的特性与其可纺性的关系,并对连续聚碳硅烷原丝制备过程中的纺丝温度、纺丝压力、过滤方式、气流收丝方式与速度等进行了探讨。     

三叶型截面聚碳硅烷纤维的异形度控制

对三叶型截面聚碳硅烷（ＰＣＳ） 纤维的制备工艺及纺丝温度、压力、收丝速度等对纤维异形度的影响进行了研究。结果表明： 纤维异形度随纺丝温度、纺丝压力、收丝速度的升高而降低。熔点低的原料其异形度对压力的变化比高熔点原料更敏感, 软化点高的ＰＣＳ 有利于纺制异形度较大的纤维。     

聚碳硅烷熔融纺丝的动力学模拟

对聚碳硅烷(PCS)熔融纺丝进行动力学模拟，得到了其丝条参数随纺程的变化关系，找出其玻璃化温度，对其纺丝过程的控制有着重要的指导意义。     

干法纺丝制备聚碳硅烷纤维中残留溶剂含量的影响因素

研究了聚碳硅烷纤维纺丝线上残留溶剂含量的影响因素.结果表明:在纺丝线上距离喷丝孔约0.3 m之内,溶剂的挥发主要由对流和闪蒸过程控制,残留溶剂含量呈指数速率减小,且溶剂挥发量约为纺丝线上溶剂挥发总质量的80%～90%;纺丝原液浓度的增大、纺丝甬道温度的升高和纺程的增加有利于残留溶剂含量的降低,而纤维直径的增大则会提高残留溶剂含量.较佳的纺丝条件为:纺丝原液中聚碳硅烷的质量分数为65%～68%,纺程0.3～1.5 m,纺丝甬道温度为室温.     

Shear flow behaviors of poly(p‐phenylene benzobisoxazole) spinning dope

In this study, the shear flow properties of Poly(p‐phenylene benzobisoxazole) (PBO)/poly(phosphoric acid) (PPA) spinning dope were studied by means of capillary rheometer. The effect of shear stress, temperature, PBO concentration, and PBO molecular weight on the apparent viscosity of PBO/PPA dope was discussed. The results showed that the apparent viscosity of the dope decreased with the increase of the shear stress and the temperature. The flow behavior index increased with the increase of temperature, which indicated that the non‐Newtonian behavior of the dope became weaker at high temperature. Moreover, it was also found that at high shear stress, the apparent viscosity of the dope was insensitive to the temperature, PBO molecular weight, and PBO concentration. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

PAN基碳纤维原丝用纺丝溶液的流变性质

为制备适于干 -喷湿纺用PAN(polyacrylonitrile)纺丝溶液 ,选用了较高粘均相对分子质量的PAN ,通过测定纺丝溶液的回转粘度 ,对其流变性能进行了较为详尽的研究。研究结果表明 :粘均相对分子质量为近 2 0万的PAN溶液为切力变稀型流体 ,具非牛顿性。在40～ 80℃的温度范围内 ,浓度为 18%～ 2 0 %的纺丝溶液的临界切变速率为 10 0 9～ 10 1 7。提高纺丝溶液的浓度可使溶液的粘流活化能 (Eη)及结构粘度指数 (Δη)增大、非牛顿指数 (n)减小 ;溶液温度升高则会导致n的增大和Δη的减小     

高等级HDPE管材树脂毛细管流变性能研究

采用单管毛细管流变仪,在不同温度下对高等级高密度聚乙烯(HDPE)管材树脂的熔体流动行为进行了研究,考察了剪切应力(τ<,w>)、剪切速率(γ)、挤出胀大及温度之间的关系.结果表明,高等级HDPE管材树脂熔体的剪切流动基本上服从幂律定律;熔体的表观黏度(η<,a>)对温度的依赖性大致上符合Arrhenius方程;η<,a>随τ<,w>和γ的增加而非线性减小;挤出胀大比随温度的升高而下降,随γ的增加呈非线性增大.     

高密度聚乙烯薄膜流变性能的研究

考察了4种HDPE薄膜料的流变性能。结果表明:4种HDPE薄膜料的熔体均为非牛顿流体,在一定范围内表现为假塑性流体特性,即:表观剪切黏度随剪切速率的增大而降低。HDPE膜料的流动指数随着温度的升高而增大,熔体的非牛顿性减弱。4种薄膜料的黏流活化能随着剪切速率的增大呈升高的趋势。7000F对剪切速率及温度都较为敏感;J50-08对温度敏感,加工时可用温度调节其熔体黏度。在210℃,J50-08的熔体强度最小,加工效率最高;F00952的熔体强度最大而加工效率最低。     

Study of rheological property of nylon‐1212 with Haake Rheometer

Rheological properties of nylon‐1212 have been studied by means of Haake Rheometer. The effect of shear rate and temperature on the apparent vicosity of nylon‐1212 was discussed. A correlation of non‐Newtonian index with the temperature was obtained. The results showed that the apparent viscosity decreases with the increase of the temperature. With increasing shear rate, shear thinning of nylon‐1212 was observed clearly. From the relation of the temperature dependence of the polymer, we obtained the viscous flow activation energy. We conclude that the apparent viscosity is sensitive to temperature at lower shear stress because of higher viscous flow activation energy, and the temperature affect on the apparent viscosity becomes weaker at higher shear stress because of lower viscous flow activation energy. We have investigated the creep and elastic recovery of nylon‐1212. A creep test was carried out to define the linear viscoelastic range as 1.0 and 5.0 Pa for 195 and 190°C nylon‐1212 melts, respectively. A time‐dependent response was found for the creep and recovery phases at a lower applied shear stress. However, at higher shear stress, the creep and recovery phases were time‐independent. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 379–385, 2003     

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。     

A Survey of Rheological Properties of One-Component Epoxy Adhesives

Flow characteristics of seven commercially available one-component epoxy adhesive pastes were measured using a controlled shear stress rheometer and a controlled shear rate rheometer over a temperature range from 5°C to 60°C. Combining data obtained from both controlled rate and controlled stress experiments over a wide range of shear rates, we observed Newtonian flow (shear stress proportional to shear rate) at very low shear rates, a plateau “shear thinning” region at intermediate shear rates, and a second region of linear dependence of shear stress on shear rate at high shear rates. The adhesive pastes exhibited a very broad range of rheological behavior. Two flow parameters important to adhesive application technology, the plastic viscosity and the apparent yield stress, were measured for each adhesive. The plastic viscosity ranged from 11.6 to 329.5 Pa. s; the apparent yield stress ranged from 56.2 to 413 Pa. The temperature dependence of the rheological parameters of the epoxy adhesive pastes was also determined. The results are reported as the activation energies, E_η and E_σ, of plastic viscosity and apparent yield stress, respectively. The apparent yield stress of each adhesive paste was much less sensitive to changes in temperature than was the plastic viscosity. This suggests that the processing characteristics are likely to show qualitative as well as quantitative changes with temperature.     

纤维素/硅酸钠纺丝原液流变性能的研究

采用旋转流变仪对不同阻燃剂添加量的粘胶共混纺丝原液的流变性能进行了研究。结果表明,添加阻燃剂的粘胶共混原液为切力变稀型流体。随着温度升高,粘胶混合原液的粘度降低,温度在50℃以后有凝胶现象,粘度急剧增大。与普通粘胶纺丝原液相比,加入阻燃剂后的粘胶混合原液非牛顿指数n和结构粘度△η、粘流活化能△Eη等流变参数没有较大的变化,纤维素/硅酸钠纺丝原液符合纺丝要求。     

A Survey of Rheological Properties of One-Component Epoxy Adhesives

Flow characteristics of seven commercially available one-component epoxy adhesive pastes were measured using a controlled shear stress rheometer and a controlled shear rate rheometer over a temperature range from 5°C to 60°C. Combining data obtained from both controlled rate and controlled stress experiments over a wide range of shear rates, we observed Newtonian flow (shear stress proportional to shear rate) at very low shear rates, a plateau “shear thinning” region at intermediate shear rates, and a second region of linear dependence of shear stress on shear rate at high shear rates. The adhesive pastes exhibited a very broad range of rheological behavior. Two flow parameters important to adhesive application technology, the plastic viscosity and the apparent yield stress, were measured for each adhesive. The plastic viscosity ranged from 11.6 to 329.5 Pa. s; the apparent yield stress ranged from 56.2 to 413 Pa. The temperature dependence of the rheological parameters of the epoxy adhesive pastes was also determined. The results are reported as the activation energies, E_η and E_σ , of plastic viscosity and apparent yield stress, respectively. The apparent yield stress of each adhesive paste was much less sensitive to changes in temperature than was the plastic viscosity. This suggests that the processing characteristics are likely to show qualitative as well as quantitative changes with temperature.     

PP/玻璃微珠复合材料的流变性能

制备了聚丙烯/玻璃微珠复合材料,在温度为175～225℃和载荷为1.2～12.5kg的条件下,应用熔体流动速率仪考察了填料粒径、剪切速率、载荷及温度等对复合材料熔体流变特性的影响。结果表明:熔体的剪切流动服从幂律定律;熔体的表观黏度对温度的依赖性符合Arrhenius方程;表观黏度随剪切速率和剪切应力的增加而下降;挤出胀大比随温度的升高而下降,随剪切应力和剪切速率的增大而增大。在此基础上,预测了第一法向应力差,发现其随剪切速率的增大而增大。