Organoborazines. III. Homo‐ and copolymerization of p‐vinylphenylcyclotriborazines

Abstract

The polymerization and copolymerization with styrene of a series of unsymmetrically B‐p‐vinylphenyl‐N‐methyl and N‐phenyl borazines [R3(R2)2B3N3(R1)3; R1 = methyl, phenyl, R2 = methyl phenyl, R3 = p‐vinylphenyl] has been studied. The polymerization of these monomers yielded both tractable and crosslinked materials. The polymers obtained were characterized by 1H‐ and 13C‐NMR spectroscopy, elemental analysis, gel permeation chromatography, and thermogravimeteric analysis. The reactivity ratios for the copolymerization reaction were calculated by the Mortimer‐Tidwell method.

Well-Defined Boron-Containing Polymeric Lewis Acids

“…Side-chain organoboron polymers have been prepared from organoboron monomers using a variety of polymerization techniques including standard free radical polymerization, metathesis polymerization, and Ziegler−Natta polymerization . Alternatively, organic polymers or resins can be modified in a postpolymerization modification step.…”

Mixed substituent poly[(vinyloxy)cyclotriphosphazenes]

“…(11). Only the strongly nucleophilic triflouroethoxide ion was able to replace all of the chlorine atoms in 4.…”

“…[7][8][9] Polymers with cyclophosphazene substituents were first prepared in our laboratories and have received the most attention. Related systems with cycloborazines 10,11 and cyclothiaphosphazenes 12 have also been reported. The electronic effect of the phosphazene on the olefin substituent 9 leads to a very reactive propagating radical leading to chain transfer and related problems so most systems have an insulating group between the olefin and the phosphorus center.…”

Preparation of Organoboron Block Copolymers via ATRP of Silicon and Boron-Functionalized Monomers

“…The method of choice usually is standard free radical polymerization due to the reasonably good compatibility with boron−carbon bonds and the relatively straightforward synthetic procedures involved. Thus, heat-induced or AIBN (2,2‘-azobis(2-methylpropionitrile)) initiated free radical polymerization has been applied to the homo- and copolymerization of olefins containing boronic acid and boronic ester, , borazine, and polyborane and carborane moieties. Ring-opening metathesis polymerization (ROMP) , and Ziegler−Natta techniques , have also commonly been employed, and the latter are especially useful for the polymerization of more highly reactive and more strongly Lewis acidic organoboron species.…”