Self‐condensing atom transfer radical polymerization of inimers of different reactivity ratios with styrene and the thermal properties of poly(2,6‐dimethyl‐1, 4‐phenylene oxide)/branched polystyrene blends

Abstract

Although the self-condensing atom transfer radical polymerization (SCATRP) of inimers with typical comonomers has been extensively performed, there have been few reports to correlate the reactivity ratio with the growth of the molecular weights (MWs) and the development of branched structures. Thus, the SCATRP of inimers of different reactivity ratios, namely, 4-chloromethylstyrene (CMS) and maleimide (MI) inimers, with a large excess of styrene (St) were carried out, respectively, to examine the effect. The conversion and MW were monitored by gas chromatography, gel permeation chromatography, and multiangle laser light scattering. The results suggested that CMS merely functioned as an initiator for St at the early stage; this led to linear macroinimers, which underwent SCATRP and gave rise to randomly branched polystyrene (PS) only at high conversion. The MI inimers formed charge-transfer complexes with St and underwent the SCATRP to result in hyperbranched copolymers at first; this initiated the atom transfer radical polymerization of St and led to star-shaped PS. With the objective of improving the processability and melt fluidity, the physical properties of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) blends with linear, randomly branched, and starshaped PS were compared. In comparison with those with linear PS, the PPO/branched PS blends exhibited a higher glass-transition temperature, a higher melt flow index, and a comparable thermal stability because of the spherical architecture of the branched PS.

Functional Polymers with Controlled Microstructure Based on Styrene and N ‐Substituted Maleimides

“…N-(4-Hydroxyphenyl) maleimide, N-(4-(α-chloropropionyloxy)]phenyl maleimide, and N-(4-(α-bromopropionyloxy)]phenyl maleimide were copolymerized with styrene under RAFT conditions to form alternating copolymers used as precursor of graft copolymers prepared by polymerization of styrene from the ATRP initiators present on the copolymer backbone [65]. Hyperbranched polymers were prepared by self-condensing vinyl polymerization (SCVP) under ATRP conditions of styrene in the presence of N-[2-(2-bromoisobutyryloxy)ethyl] maleimide [66], N-(4-α-bromobutyryloxy phenyl) maleimide [67][68][69], N-[4-(α-chloropropionyloxy)]phenyl maleimide [69], or N-[4-(α-bromopropionyloxy)] phenyl maleimide [69] as inimer. The use of an excess of styrene favored the consumption of the N-[2-(2-bromoisobutyryloxy)ethyl] maleimide to form a core of the corresponding copolymer and the formation of polystyrene branches from this core [66].…”

Synthesis of Hyperbranched Multiarm Star Block Copolymers and Their Application as a Drug‐Delivery System

“…Li et al . reported the graft polymerization of the hyperbranched poly(2‐((bromobutyryl)oxy)ethyl acrylate) onto the exterior surface of mesoporous silica nanoparticles (MSNs) by the surface‐initiated self‐condensing atom transfer radical vinyl polymerization . The core‐shell nanostructure may have potential applications in biomedicine and biotechnology due to a large amount of the terminal functional groups of the hyperbranched polymers.…”