Cyclopolymerization XXIII. Design of Unconjugated Dienes with High Polymerizability Using Functional Groups with No Homopolymerization Tendency and Synthesis of Completely Cyclized Polymers Therefrom: Radical Polymerizations of N-Substituted N-Allyl-2-(methoxycarbonyl)allylamines

Abstract

ABSTRACT:N-Substituted N-allyl-2-(methoxycarbonyl)allylamines (SAMC) were synthesized and polymerized to establish a methodology for designing unconjugated dienes with not only a high cyclization tendency but also high polymerizability. The N-substituents investigated were methyl, propyl, tert-butyl, and phenyl groups. Detailed examination of the properties of the unconjugated dienes reported so far indicated the use of functional groups with a higher conjugative nature together with no homopolymerization tendency to be essential to achieve this purpose. SAMC were designed since oc-substituted acrylates have a considerably higher conjugative nature, even if they do not have homopolymerization tendencies. In fact, conjugation between C=C and C=O double bonds of the acryloyl groups of SAMC and N-substituted N-propyl-2-(methoxycarbonyl)-allylamines (SPMC), one of the monofunctional counterparts of SAMC, were found to be considerably effective. No detectable homopolymer could be obtained from SPMC. It is well known that ally! compounds, the other monofunctional counterparts of SAMC, have extremely lower polymerization tendencies. SAMC were converted to completely cyclized polymers by use of a radical initiator with a high polymerization rate, especially in the case of methyl and propyl derivatives. Their polymerizabilities were correlated with the conjugative nature of C = C and C = 0 double bonds of their acryloyl groups, except for the phenyl derivative. ESR studies on the methyl derivative suggested that its polymerization initiates through the acryloyl group.

Recent advances to decrease shrinkage stress and enhance mechanical properties in free radical polymerization: a review

“…Thus, several non-conjugated diene-based cyclopolymerizable monomers (CPMs) have been designed and examined. [91][92][93] CPM reactivity varies with reaction environment (e.g. temperature) and type of groups adjacent to the reactive double bonds.…”

Stereospecific anionic polymerization of chiral benzyl ?-[(1-phenylethoxy)methyl]acrylate

“…It has been reported that bulky ␣-substituents greatly reduce radical polymerizability of ␣-(alkoxymethyl)acrylates. 2,[16][17][18] However, the anionic polymerization with n-BuLi in toluene at −78°C proceeded in better polymer yields (entries 2, 5, and 7). Although highly enantiomer-selective polymerization of racemic ␣-methylbenzyl methacrylate (MBMA) using the cHexMgBr-(−)-Sp complex has been accomplished, 19,20 the complex gave a polymer of low optical activity ([␣] 25 365 = −4°) in 60% yield in the polymerization of rac-BPEMA (entry 3), and recovered monomer was nearly racemic, indicating that little enantiomer selection took place in this system, and the anionic polymerization mechanism of BPEMA was different from that of MBMA.…”

Photopolymerization of difunctional cyclopolymerizable monomers with low shrinkage behavior

“…The reason behind this is the increased reactivity of the formed radical, which additionally prefers intramolecular cyclization reactions due to steric effects. Furthermore, the monoene counterparts of these ester‐activated compounds are also known to have no or low polymerization tendency, contributing to their reactivity‐enhancing properties 18,21,22 …”

“…Since non-activated diallyl-compounds 14,15 show a low degree of polymerization, electron-withdrawing groups are introduced in the vicinity of the unsaturated group to enhance both overall reactivity and cyclization tendency. 12 Some representative examples for this strategy are dimethacrylamides, 16 methacrylic anhydrides, 17 ester-activated diallylamides, 18 and aromatically activated allylic anhydrides. 19 Interestingly, dimethacrylamides generate completely cyclized polymer backbones upon polymerization.…”

“…Furthermore, the monoene counterparts of these ester-activated compounds are also known to have no or low polymerization tendency, contributing to their reactivity-enhancing properties. 18,21,22 Difunctional monomers based on 1,6-diene functionalities have already proven their suitability as CPMs. 3,4 Within the field of light-induced radical cyclopolymerization, these difunctional monomers have been investigated only recently.…”