Investigation of the Chain Transfer Agent Effect on the Polymerization of Vinylidene Fluoride

Abstract

The effect of chain transfer agents (CTAs) ethyl acetate (EA), octyl acetate (OA), and isopropyl alcohol (IPA) on the rate of polymerization of vinylidene fluoride (VDF) in an emulsion polymerization and in solution polymerization in dimethyl carbonate (DMC) initiated by tert-butyl peroxypivalate was investigated. Pressure profiles of the polymerizations were recorded. Solids content and rate of polymerization were calculated by gravimetry; size exclusion chromatography was utilized to evaluate CTA activity, and the produced polymer microstructures were characterized by 1 H and 19 F NMR spectroscopies. It is proposed that the observed reduction in polymerization rate in both systems is due to degradative chain transfer reactions.

Challenges in the Emulsion Co- and Terpolymerization of Vinylidene Fluoride

“…chain transfer 26 , the absence of EA lead to rapid nucleation (peak in temperature profile) and increased VDF uptake, evidenced by presence of crystallinity, higher PC value and the specific IP administered in these experiments (Run 19 had shots added every hour, Run 20 had shots added every 20 minutes).…”

“…Furthermore, greater VDF uptake was noticed, if VAc is added in one-shot (IP2) instead of gradually (IP1), especially evidenced by lower values of T g and higher values of crystallinity. Additionally, the N P have shown to be similar values in which the homogeneous-coagulative nucleation mechanism governs the reaction 26 . The homogeneous-coagulative nucleation mechanism of PVDF emulsion homopolymerization provides an initial preferential addition of VDF units on polymer chain to a point at which, when VAc is added to the reaction media, the expected favored addition of VAc units is hindered, whilst the copolymerization for VDF and VAc is facilitated.…”

“…Similar to the previous runs, a decrease of pressure after VAc injection, and a gradual increase followed by stagnation of pressure throughout the first 60-90 minutes of reaction was noticed ( Figure 13). The presence of EA decreases VDF consumption rate due to degradative chain transfer 26 . Lower VDF incorporation was noticed by the decrease of PC and crystallinity, increase of T g , despite similar N P values (Table 9).…”

Unexpected Radical Telomerisation of Vinylidene Fluoride with 2-Mercaptoethanol

“…The radical telomerisation of VDF was comprehensively studied and reviewed 17 years ago [3]. Several kinetics of radical telomerisation of VDF were achieved from methanol [10], diethyl phosphonate [11], chloroform [12,13], bromotrichloromethane [12,13], carbon tetrachloride [12,13], BrCF 2 CFClBr [14], CF 3 I [15], C 6 F 13 I [16], HCF 2 CF 2 CH 2 I [16], xanthate [17], and iodine monochloride [18], and more recently, isopropanol, ethyl acetate and octyl acetate [19]. In addition, 1-iodoperfluoroalkanes [3,8] have also been successfully involved as efficient CTAs in iodine transfer polymerisation, either in supercritical CO 2 [20] or under photochemical initiation catalysed by Mn 2 (CO) 10 [21,22].…”

“…xanthate [17], and iodine monochloride [18], and more recently, isopropanol, ethyl acetate and octyl acetate [19]. In addition, 1-iodoperfluoroalkanes [3,8] have also been successfully involved as efficient CTAs in iodine transfer polymerisation, either in supercritical CO2 [20] or under photochemical initiation catalysed by Mn2(CO)10 [21,22].…”