Cationic polymerization of bis(1‐alkylvinyl)benzenes and related monomers, 2. Controlled syntheses of 1,1,3‐trimethyl substituted polyindanes

Abstract

1,1,3‐Trimethyl substituted polyindanes were synthesized in the presence of Brønsted acids (H2SO4, CF3COOH) or Lewis acids (BCl3, AlCl3) using 1,4‐diisopropenylbenzene (1), 1,4‐bis(1‐hydroxy‐1‐methylethyl)benzene (2) or 1,4‐bis(1‐chloro‐1‐methylethyl)benzene (3) as monomers. The effects of experimental conditions on yields, molar masses and polymer structure were studied in detail with respect to monomer and initiator used, their concentrations, reaction time and experimental procedure. It was shown, that polymerization temperatures above the ceiling temperature and low monomer concentrations favour the formation of indane units. However, in particular the uniformity of the polymer structure is sensitive to the experimental conditions, mainly to the initiator and to the procedure used. DSC measurements on the polymers proved the remarkable heat‐resistance of polyindanes (Tdec. ≥ 450°C; Tg ≈ 210°C). The thermal properties were related to the polymer structure and were compared with those of some commercial polymers.

Cationic Polymerization of Phenyl Vinyl Ethers: Investigations of the Propagation Mechanism, the Living Polymerization of Ortho-Substituted Derivatives, and the Step-Growth Polymerization of Divinyl Derivatives

“…Specifically, divinyloxy­benzenes can potentially be polymerized via a step-growth mechanism, as shown in Scheme B. The polymerization of 1,4-diisopropenyl­benzene was reported to proceed in a similar manner via indanyl ring formation. , However, unlike the case of 1,4-diisopropenyl­benzene, the cleavage of the sec -benzylic ether moiety by a Lewis acid catalyst, which occurred in the polymerization of PhVE (Scheme A), potentially occurs as a side reaction in the polymerization of divinyl­oxybenzenes. Therefore, reaction conditions that are suitable for the formation of chromane-type structures but unsuitable for sec -benzylic ether cleavage are required for the successful polymerization of divinyloxybenzenes.…”

Poly(ether‐ketone)s with indan structure elements

“…All indan containing poly(ether-ketone)s synthesized so far are completely amorphous and thus form clear films. The glass transition temperatures are increased by about 20-30 K if the indan structure element is present, no matter whether the polymer was synthesized from a monomer containing only one isomeric indan structure element (3,Sindanylene) or from a mixture of two monomers containing different isomeric indan systems (3,Sindanylene and 3,. Due to the amorphous nature of the polymers, they are dissolved by a number of organic solvents including CHCl,, THF, DMAc, NMP, and dimethyl sulfoxide (DMSO) at room temperature to give solutions with a polymer content of at least 20% by weight.…”

Poly(ether ketone)s with cyclohexyl‐substituted indan groups in the main chain

“…While most polyindans described so far were amorphous". 13 bulky trimethylsubstituted indan moiety (polymers 5 ) results in increased glass transition temperatures of about 20 "C. The introduction of two cyclohexyl groups into the indan system in place of methyl groups results in a further considerable increase of the glass transition temperature of about 45-50°C between polymers 3a-i and 5a-i. This is due to the reduced chain mobility caused by the increased bulkiness of the indan moiety.…”