Preparation of soluble microgel by the copolymerization of methylmethacrylate with p‐divinylbenzene in the presence of tetrabromomethane

Abstract

Various types of soluble crosslinked polymers obtained from the copolymerization of methylmethacrylate (MMA) and p‐divinylbenzene (p‐DVB) in the presence of a transfer agent (CBr4) have been discussed in relation to the variation of the structure during the reaction time. When [p‐DVB]/[MMA] = 1.49 × 10−3 and [CBr4]/[MMA] = 1.28 × 10−4, only linear polymers (primary polymer; Mn = 1.0 × 105) with pendant vinyl groups are formed intially. Considerable branched structure is attained in rather large polymers (Mn = 2.5 × 105), but the number of pendant double bonds is not enough to reach the gelation. As the concentration of the transfer agent becomes high, the intermolecular crosslinking is depressed, and the formed polymers contain loops and short chains. At [p – DVB]/[MMA] = 7.43 × 10−3 and [CBr4]/[MMA] = 1.28 × 10−3, the shape of polymer with the same Mn became compact gradually with increasing reaction time. These results are considered to be useful for the preparation of soluble crosslinked polymer with controlled structure.

Nanoparticles from a controlled polymerization process

“…Additional synthesis techniques for nanoparticle preparation include sonochemical processing, cavitation processing, microemulsion processing, 1,2 and precipitation polymerization. 3 Only recently the synthesis of nanostructured materials from block copolymers 4−6 was reported. Researchers have succeeded in the preparation of block copolymer nanostructures from a variety of polymers like polystyrene, poly(2-cinamoylethylmethacrylate), poly(acrylic acid), poly(t-butyl acrylate), and polyisoprene.…”

Microgels-Intramolecularly Crossünked Macromolecules with a Globular Structure

“…Chen et al synthesized microgels by copolymerization of 1,4-DVB and MM A in the presence of a chain transfer agent (CBr 4 ) [214]. They showed that when the concentration of the chain transfer agent becomes high, the intermolecular crosslinking is depressed and microgels are formed.…”

Preparation of Soluble Poly(methyl methacrylate–p-divinylbenzene) in the Presence of Tetrabromomethane

“…The overall conversion was determined by gravimetric measurement, and also calculated from the consumed amounts of M and D determined by high performance liquid chromatography (Japan Spectroscopic Co., Ltd. TRI ROTAR-II). The absorbance of the pendant double bond of each sample, as described in the previous paper, 5 was measured at 292 nm by Hitachi 124 Spectrophotometer. The absolute quantity of the pendant double bond was determined for several samples by iodine monochloride addition to the vinyl group and successive titration of excess iodine monochloride.…”

“…From the absorbance and absolute value of PV, the molar extinction function was determined and was used to obtain the content of the vinyl group in other samDetails of this method have been reported in a previous paper. 5 From the values of D, M, and PV at various reaction times and from eq 6 and 7, rM and r were calculated.…”

“…5 Methods for preparing soluble intramolecularly crosslinked copolymers (microgels) by the copolymerization of monomer with divinyl compound have been reported in many papers. 1 -4 In the solution copolymerization of styrene with divinylbenzene containing a transfer agent (diphenyl disufide), "breaks" are introduced in the propagation and the microgel can be generated with very high conversion and high concentration (74% conversion, 35 g/ 100 ml polymer concn).…”