Polymers with Side Chain N‐Alkoxy Pyridinium Ions as Precursors for Photoinduced Grafting and Modification Processes

Abstract

A combination of NMP and photoinitiated polymerization is suggested as a new strategy for the synthesis of graft copolymers. First, P(S‐co‐CMS) copolymer backbones with different chloromethyl content are prepared by NMP. The chloro functions are then converted into photosensitive 4‐phenyl pyridinium‐N‐oxide ion functions. Finally, these photoactive polymers are irradiated in the presence of MMA to obtain the graft copolymers. They and their precursors at various stages are characterized by spectroscopy and GPC. It is demonstrated that the irradiation of photoactive polymers in the presence of a hydrogen donors such as THF facilitates the conversion of pyridinium ions to hydroxyl groups.

Diethoxy‐azobis(pyridinium) Salt as Photoinitiator for Cationic Polymerization: Towards Wavelength Tunability by Cis–Trans Isomerization

“…Previously we introduced another generic class of photoinitiators, namely N-alkoxy pyridinium salts, [20][21][22][23][24][25] which are useful for cationic, free radical, and zwitterionic polymerizations. Upon photolysis, these salts undergo cleavage of the nitrogen-oxygen bond to form radical cations and alkoxy radicals and initiate the respective polymerizations independently [22,26] or concurrently.…”

Synthesis of Block Copolymers Based on Polyethylene by Thermally Induced Controlled Radical Polymerization Using Mn2(CO)10

“…[ 8 ] This way, many block copolymers of structurally different monomers with high level of control over molar weight and dispersity can successfully be prepared. [ 9 ] Although not fully controlled, light induced polymerization processes [ 10 ] also offer an alternative route to prepare block [ 11 ] and graft copolymers [ 12 ] as they can be conducted at low temperatures, especially at room temperature minimizing side reactions. Moreover, initiating sites can be generated at defi nite positions in the macromolecule by taking advantage of the selective absorptivity of certain chromophoric groups leading…”

Graft polymer growth using tandem photoinduced photoinitiator-free CuAAC/ATRP

“…56 Chloromethyl styrene (CMS) and styrene in a 1 : 1 ratio were reacted with 1,1′azobis(cyclohexanecarbonitrile) VAZO as the radical source, mediated by TEMPO, at a temperature of 120°C for 28 h to yield the copolymer in 16% conversion with M n = 14 200 g mol −1 and M w /M n = 1.7. 56 Chloromethyl styrene (CMS) and styrene in a 1 : 1 ratio were reacted with 1,1′azobis(cyclohexanecarbonitrile) VAZO as the radical source, mediated by TEMPO, at a temperature of 120°C for 28 h to yield the copolymer in 16% conversion with M n = 14 200 g mol −1 and M w /M n = 1.7.…”