Architecture of Star−Block Copolymers Consisting of Triblock Arms via aN,N-Diethyldithiocarbamate-Mediated Living Radical Photo-Polymerization and Application for Nanocomposites by Using as Fillers

Abstract

Highly branched poly(methyl methacrylate) (PMMA) stars were prepared by one-pot approach based on N,N-diethyldithiocarbamate- (DC-) mediated living radical photopolymerization. Soluble alternating hyperbranched microgel formation was initiated fast with preferential consumption of inimer 4-vinylbenzyl N,N-diethyldithiocarbamate (VBDC) and 4,4‘-bismaleimidediphenylmethane (BMIM) in the presence of an excess of methyl methacrylate (MMA). PMMA arms could then grow from DC groups of microgel as macroinitiator. Next, star−block copolymers consisting of diblock arms [(AB) f -DC; arm: PMMA- block-poly(n-butyl methacrylate) (PBMM)] were synthesized by photoinduced atom transfer radical polymerization (ATRP) of n-butyl methacrylate (BMM) initiated by the functionalized PMMA star (A) f -DC in the presence of CuCl/bipyridine (bpy) catalyst. Subsequently, star−block copolymers consisting of triblock arms [(ABA) f -DC; arm = PMMA- block-PBMM- block-PMMA] were synthesized by similar method initiated by (AB) f -DC macroinitiator. It was found from light scattering data that such (AB) f and (ABA) f star−block copolymers (arm number f = 28) not only took spherical shape but also formed a single molecule in solution. We performed the construction of nanocomposites by using these (ABA) f stars as fillers. Free radical polymerization products from the mixture of MMA and (ABA) f star provided transparent fims. It was found from electron microscopy observations that (ABA) f stars distributed molecularly and homogeneously in a PMMA matrix, because such star−block copolymers promoted the ordering strucrure.

Hyperbranched poly(ether sulfone)s: preparation and application to ion-exchange membranes

“…63,64 Hyperbranched polymers are frequently used as the core of core-shell block copolymers, where the shell block is grown from the functional groups of the hyperbranched polymer. [65][66][67] Hyperbranched polymers have also been grown from linear polymers to form diblock, 68 gridlock 69,70 and graft copolymers. 41,71,72 Hyperbranched polymers have also been prepared from one or more oligomeric monomers to yield products that have additional flexibility.…”

One‐Pot Approach to Synthesize Star‐Shaped Polystyrenes via RAFT‐Mediated Radical Copolymerization

“…Subsequently they employed the same method to synthesize star-shaped copolymer with PMMA-block-poly(n-butyl methacrylate)-block-PMMA triblock copolymer arms by this one-pot manner. [26] At the same time, our group has published the one-pot synthesis of star-shaped polystyrene (PS) by ATRP of N-[2-(2-bromoisobutyryloxy)ethyl]maleimide (BiBEMI) with a large excess of St. [27] BiBEMI was preferentially consumed through its copolymerization with St to form a branched intermediate in situ as the multifunctional core which further initiated the homopolymerization of the excessive St to afford a star-shaped PS. In aforementioned two methods, the inimers (initiator-monomers) were necessary and their synthesis made the one-pot method somewhat inconvenient.…”

NMR spectroscopy study on N,N′-bismaleimide-4,4′-diphenylmethane and barbituric acid synthesis reaction mechanism in N,N′-dimethylformamide solvent

“…For the reactant N,N 0 -bismaleimide-4,4 0 -diphenylmethane (MDA-BMI), studies on the selfpolymerization of thermal polymerization and radical polymerization 2 and polymerized with diamine, polyamine, ethyl alcohol, and diphenol have been reported. [2][3][4][5][6][7][8][9][10][11] Studies on the reactant barbituric acid (BTA) molecule have focused on the resonance structures of its electron density distribution calculations and tautomerization properties. [12][13][14][15][16][17][18] Polymerizing BMI with ethylenediamine 7,19 might misguide that the acidity and therefore the active sites of BTA are the amide nitrogen atoms rather than the b-dicarbonyl a-methylene carbon.…”