New insight into the polymerization mechanism of 1,3-dienes cationic polymerization. IV. Mechanism of unsaturation loss in the polymerization of isoprene

Abstract

The mechanism of obtaining a polymer with reduced unsaturation is proposed, which includes the formation of branched structures.

A New Approach toward Investigation of Structure of Terminal Units of Poly(1,3‐Pentadiene) using T2‐Filtered NMR Spectroscopy

“…The similar higher content of head groups as compared to end groups was observed for other "cationic" poly(1,3-diene)s. [17,18,28,42,43] These observations are consistent with the side reaction, which consists in the transfer of growing polymer chain to the double bond of "own" or "alien" macromolecule with the formation of trifunctional branched point and release of the proton. [41] In this case, the obtained branched macromolecule can contain several head groups [41,43,44] and does not contain any chlorine-terminated chain ends due to the absence of termination via ion pair collapse.…”

Synthesizing radiation‐hard polymer and copolymers usinglaccolmonomers extracted from lacquer treetoxicodendron succedaneavia cationic polymerization

“…The COC bond formation was also observed as a minor product in the polymerized material (Scheme ). Possibilities for this observation are macrocyclic compound formation and crosslinking.…”

“…The C O C bond formation was also observed as a minor product in the polymerized material (Scheme 2). Possibilities for this observation are macrocyclic compound formation [15] and crosslinking. Reinvestigation of the samples was carried out after the irradiation process and it was confirmed that the materials were further cured due to gamma radiation without deteriorating (Fig.…”

“…Two hydroxyl groups in the catechol ring which are acidic and has able to form phenoxide anions to react with carbocation species in the side chain. Additionally, formation of macrocyclic compounds is also possible due to phenoxide anions and unsaturated groups ( cis and trans double bonds) in side chain as discussed by Rozentsvet et al . These phenomena were investigated using infrared (IR) and nuclear magnetic resonance (NMR) data for LP and laccol‐styrene copolymers.…”

Environmentally Friendly Radiation Hardd‐Limonene and Laccol Copolymers Synthesized via Cationic Copolymerization

“…Conjugated double bonds (trans) in unsaturated side chain of laccol and terminal double bond in limonene was involved prominently during the chain growth polymerization. Additionally, as explained by Rozentsvet et al [16] macrocyclic compound formation is also possible due to the phenate ions and cis/trans double bonds (unsaturated groups) in the laccol side chain. These phenomena were clearly observed in the infrared and nuclear magnetic resonance (NMR) data obtained for the synthesized copolymers.…”