Melt compounding of different grades of polystyrene with organoclay. Part 2: Rheological properties
Melt compounding of different grades of polystyrene with organoclay. Part 2: Rheological properties
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DOI：
10.1002/pen.20099
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发表时间：
2004-06
影响因子：
3.2
通讯作者：
S. Tanoue;L. Utracki;A. García-rejón;P. Sammut;M. Ton-That;I. Pesneau;M. Kamal;Jørgen LYNGAAE-JØRGENSEN-Jørg
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文献类型：
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作者：
S. Tanoue;L. Utracki;A. García-rejón;P. Sammut;M. Ton-That;I. Pesneau;M. Kamal;Jørgen LYNGAAE-JØRGENSEN-Jørg
以三种不同相对分子质量的聚苯乙烯为原料，制备了聚苯乙烯基纳米复合材料。该树脂在同向旋转双螺杆挤出机中与0~10wt%的商用有机粘土熔融复合。由于热氧化降解，分散程度较差。测定了PNC在动态剪切、稳态剪切和拉伸流动条件下的流变性能。在粘粒含量较高的情况下，动态应变扫描表明，随着应变的增加，土体的储能模数和损失模数不断减小。为了表征这种非线性粘弹性行为，应用了傅立叶变换流变学。低应变频率扫描表明，随着有机粘土含量的增加，材料的储能模数和损耗模数增大。提取的零剪切粘度数据用于计算特性粘度，进而计算分散体的长径比。尽管存在非线性粘弹性行为，但在整个浓度范围内都观察到了时间-温度叠加现象。水平和垂直位移因子几乎与有机粘土含量和PS的相对分子质量无关。为了比较，我们还用溶液法制备了PNC。获得了高度的分散度，反映在长径比：p=269，与熔融复合PNC计算的p=16相比。
Polystyrene-based nanocomposites (PNC) were prepared using three grades of polystyrene (different molecular weights). The resin was melt-compounded with 0 to 10 wt% of commercial organoclay in a co-rotating twin-screw extruder. Owing to thermo-oxidative degradation the degree of dispersion was poor. The rheological properties of PNC were determined under dynamic and steady state shear as well as under extensional flow conditions. At the higher clay content, dynamic strain sweep demonstrated that the storage and loss moduli decrease continuously with an increase of strain. To characterize this nonlinear viscoelastic behavior, the Fourier-transform rheology was applied. The low strain frequency sweep showed that the storage and loss moduli increase with organoclay content. The extracted zero-shear viscosity data were used to calculate the intrinsic viscosity and then the aspect ratio of dispersions. In spite of nonlinear viscoelastic behavior, the time-temperature superposition was observed in the full range of concentration. The horizontal and vertical shift factors were found to be almost independent of organoclay content and molecular weight of PS. For comparison, PNC was also prepared by the solution method. A high degree of dispersion was obtained, reflected in the aspect ratio: p = 269, to be compared with p = 16 calculated for the melt-compounded PNC.