Investigation of solutions and gels of poly(4-methyl-1-pentene) in cyclohexane and decalin by viscosimetry, calorimetry, and x-ray diffraction. A new crystalline form of poly(4-methyl-1-pentane) from gels
Investigation of solutions and gels of poly(4-methyl-1-pentene) in cyclohexane and decalin by viscosimetry, calorimetry, and x-ray diffraction. A new crystalline form of poly(4-methyl-1-pentane) from gels
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DOI：
10.1021/ma50006a048
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发表时间：
1981-09
期刊：
影响因子：
5.5
通讯作者：
S. Aharoni;G. Charlet;G. Delmas
中科院分区：
文献类型：
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作者：
S. Aharoni;G. Charlet;G. Delmas
比较了结晶聚4-甲基-1-戊烯（P4 M1 P）在环己烷（A）和十氢萘（B）中的溶液和凝胶性质。在65 ℃下测量A中的混合热和粘度，在135 ℃下测量B中的粘度。A中的h]（6.5 dL g”！1)和B（2.8 dL g-1）表明聚合物链在两种溶剂中的不同分子状态，特别是B中的统计卷曲和A中可能的螺旋或螺旋缔合。发现在A中无限稀释的P4 M1 P的Aff（溶解）（32 μ g-1）具有与Afi（融合）几乎相同的值。然而，当聚合物体积分数增加并达到高于2= 0.10的15 J g-1的平台时，AH（溶解）降低。这表明具有高内聚性凝胶。在室温下以及在20 - 110 ℃之间的各种温度下，在冷却在125 ℃下制备的溶液后获得的凝胶上溶胀的P4 M1 P上拍摄广角X射线衍射图。B中的凝胶具有与纯结晶聚合物（晶型I）相同的X-射线图案，而在高达100 ℃的温度下在A中观察到新的结晶图案（晶型II）。环己烷或环戊烷凝胶干燥后，II型仍然存在，这是最近在全同立构聚苯乙烯上观察到的特征。新图案的特征在于两个较低的26衍射峰朝向较低角度的位移（26位移= Io）。DSC形式
Comparison is made of solutionand gel properties of crystalline poly (4-methyl-l-pentene)(P4M1P) in cyclohexane (A) and decalin (B). Heats of mixing and viscosities have been measured in A at 65 C and viscosities in B at 135 C. The difference between h] in A (6.5 dL g"! 1) and B (2.8 dL g" 1) points to a different molecular state of the polymer chainin the two solvents, specifically a statistical coil in B and possibly a helix or association of helices in A. Aff (dissolution) of P4M1P at infinite dilution in A (32 J g™ 1) is found to have almost the same value as Afi (fusion). However, AH (dissolution) decreases when the polymer volume fraction increases and reaches a plateau of 15 J g" 1 above 2= 0.10. This is indicative of a highly cohesive gel. Wide-angle X-ray diffraction patterns were taken on P4M1P swollen at room temperature and also at various temperatures between 20 and 110 C on gels obtained after cooling a solution made at 125 C. The gel in B has the same X-ray pattern as the pure crystalline polymer (form I) while a new crystalline pattern (form II) is observed in A up to 100 C. After drying ofthe cyclohexane or cyclopentane gels, form II persists, a feature observed recently on isotactic polystyrene. The new pattern is characterized by a displacement toward lower angles of the two lower 26 diffraction peaks (26 displacement= Io). DSC on form