Perfluoroalkyl end-functionalized polystyrene show lower glass transition temperatures. DSC and optical transmission studies

摘要

A series of polystyrenes (10-30k) end-functionalized with perfluoroalkyl (RF = C7F16, C10F21 and C13F27) groups were synthesized by atom transfer radical polymerization (ATRP) of styrene initiated by RF functionalized initiators and studied using optical transmission, differential scanning calorimetry and thermogravimetric analysis. Large decreases (= 40-50%) in optical transmission of the C13F27 end functionalized PS were observed compared with the non-functionalized isobaric PS consistent with the formation of large RF domains. This association increases with RF concentration and length with the latter being especially significant. A melting endotherm attributed to semi-crystalline perfluorocarbon domains was seen only for a low MW(10k) C13F27 end functionalized sample. Interestingly, compared with the matching PS, the glass transition temperatures of the RF-PS polymers were found to decrease by as much as 15 degrees C and with the RF lengths having the larger effects. (c) 2018 Elsevier Ltd. All rights reserved.