Moving Towards Greener Cationic Polymerizations

Indefinitely active aqueous cationic polymerizations, part I: Low cost, recyclable initiator systems

“…Finally, a series of experiments were conducted using the nonionic surfactant IGEPAL ® ( Table 7, entries [8][9][10][11][12][13][14]. Such polymerizations were off-white, tan emulsions that slowly undergo partial phase separation on prolonged standing (Supporting Information S10).…”

“…1789) and the first to use a renewable monomer (i.e., β‐pinene) . It is a commercially important, electrophilic transformation that suffers in terms of sustainability . The drawbacks to this technique are legion: Special handling needed due to moisture‐sensitive carbocation and acid components. Toxic/corrosive substances (e.g., MeCl, TiCl 4 ) are requisite. Low temperatures (T) are necessary for high molecular weight (MW). It is difficult to recycle initiator components (e.g., BF 3 , AlCl 3 ). Few systems retain activity of the initiator system . Bulk polymerization is seldom practiced due to the explosive nature of reaction. …”

“…[6] It is a commercially important, electrophilic transformation that suffers in terms of sustainability. [7,8] The drawbacks to this technique are legion:…”

“…[25,26,[35][36][37][38][39][40] Great effort has been made to synthesize them in a more benign manner. [7,8,19] A counterintuitive approach is to conduct reaction in water. This strategy dates to 1963 with the aqueous polymerization of NVC by electron acceptors (e.g., chloranil).…”

“…[73,74,79] HPAs have been used as initiators of cationic polymerization; [83,86,87,89,[91][92][93][94][95][96][97][98][99][100][101] however, their MW-T profiles are substandard, and they are not cost competitive to traditional LAs (e.g., BF 3 ). [7] As part of earlier investigations on supported methylaluminoxane [7,8,[102][103][104] and heterogeneous PFLA [105] based initiator systems, we also studied activated forms of HPAs as solid acid initiators with limited success. [106] Given our track record of devising aqueous cationic polymerizations, we shifted our attention to water soluble HPAs as the heteropoly anion may exhibit a high enough degree of lipophilicity to transit into a suspended monomer droplet.…”