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本文介绍了由二叔丁基过氧化物作引发剂,在偏氟乙烯(或称1,1-二氟乙烯(VDF))与六氟丙烯(HFP)溶液中进行的自由基共聚,研究了[VDF]o/[HFP]o初始摩尔比从5.0/95.0至85.2/14.8的一系列8个聚合反应。两个共聚单体均在该范围内进行共聚。再者,只有VDF在该条件下可以均聚。这些无规型共聚物的聚合物成分通过19F核磁共振(NMR)光谱进行计算,该测定方法可以将共聚物中各聚合单元进行定量。以Tidwell和Mortimer法对两个共聚单体的竞聚率(ri)进行估算,显示出共聚物中VDF具有较高的结合能力(rHFP=0.12±0.05,rVDF=2.9±0.6,393K)。经计算得到HFP的Alfrey-Price’s Q值和e值分别为0.002(由QVDF=0.008)或0.009(由QVDF=0.015)和+1.44(对eVDF=0.40)或+1.54(对eVDF=0.50),说明HFP是一个电子接受单体。本文也测定了这些含氟共聚物的热性能。除了那些高VDF含量的共聚物之外,其他均为无定形物质。每个产品均只出现一个玻璃化温度(Tg)。同时,从已知的Tg定律,估算了HFP均聚物的玻璃化温度。本文将研究结果与通过文献推断得到的数据进行了比较并进行了讨论。
This article describes the free-radical copolymerization of vinylidene fluoride (or vinylidene fluoride (VDF)) with hexafluoropropylene (HFP) using di-t-butyl peroxide as an initiator. [VDF] o / [HFP] o series of 8 polymerizations with initial molar ratios from 5.0 / 95.0 to 85.2 / 14.8. Both comonomers are copolymerized within this range. Again, only VDF can be homopolymerized under this condition. The polymer composition of these random copolymers was calculated by 19F nuclear magnetic resonance (NMR) spectroscopy, which allowed the quantification of each polymerization unit in the copolymer. The reactivity ratio (ri) of two comonomers was estimated by Tidwell and Mortimer methods and showed that VDF had higher binding capacity (rHFP = 0.12 ± 0.05, rVDF = 2.9 ± 0.6, 393K) in the copolymer. The Alfrey-Price’s Q and e values calculated for HFP were 0.002 (by QVDF = 0.008) or 0.009 (by QVDF = 0.015) and +1.44 (for eVDF = 0.40) or +1.54 (for eVDF = 0.50) HFP is an electron accepting monomer. The thermal properties of these fluorinated copolymers were also determined. Except for those with high VDF content, the others are amorphous. Only one glass transition temperature (Tg) appears for each product. At the same time, the glass transition temperature of the HFP homopolymer was estimated from the known Tg law. This paper compares the results of the study with those obtained through literature inference and discusses them.