Polarized Raman scattering studies of chain orientation in hydrostatically extruded polypropylene
Polarized Raman scattering studies of chain orientation in hydrostatically extruded polypropylene
复制标题
静压挤压聚丙烯链取向的偏振拉曼散射研究
DOI：
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发表时间：
1977
期刊：
影响因子：
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通讯作者：
C. H. Wang
中科院分区：
文献类型：
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作者：
S. Satija;C. H. Wang
利用偏振拉曼散射测量研究了等规聚丙烯单轴流体静压挤出过程中的链取向统计。通过研究1256 cm−1处的CH 2扭曲模，获得了<P2（cosθ）θ和<P4（cosθ）θ的定量结果。函数<P2（cosθ）θ和<P4（cosθ）θ是取向分布函数的二阶和四阶矩，其中θ是链轴和挤出方向之间的角度。聚合物链的排列随着挤出比的增加而增加。发现测量的<P2 λ值与双折射数据很好地一致。首次报道了挤出聚合物的取向有序参数<P_4_1的值。
Polarized Raman scattering measurements have been used to study chain orientation statistics in uniaxial hydrostatically extruded isotactic polypropylene. By investigating the CH2 twisting mode at 1256 cm−1, quantitative results for <P2(cosϑ) ≳ and <P4(cosϑ) ≳ have been obtained. Functions <P2(cosϑ) ≳ and <P4(cosϑ) ≳ are the second and fourth moments of the orientational distribution function, where ϑ is the angle between the chain axis and the direction of extrusion. Alignment of polymer chains has been found to increase with the increase of extrusion ratio. The measured <P2≳ values are found to be in good agreement with the birefringence data. Values of orientational order parameter <P4≳ for an extruded polymer are reported for the first time.