Effect of the ester (R) groups on the controlled/living ATRP cyclopolymerization of alkyl alpha-(hydroxymethyl) acrylate (RHMA) ether dimers

Abstract

Previous cyclopolymerization studies of alkyl α-(hydroxymethyl) acrylate (RHMA) ether dimers showed that they are superior to non-cyclic linear ones due to improved thermal stability and high glass transition temperatures. Cyclopolymerizations of RHMA ether dimers via controlled living ATRP have been formerly investigated in the literature where smaller alkyl groups such as ethyl, n-butyl and tert-butyl and bulkier groups such as; adamantyl and cyclohexyl groups were used as the alkyl group. It was found out that as the bulkiness of the alkyl group (R) increased, cyclization efficiency and polydispersities were improved up to certain size (t-butyl), but became worse when the size was increased further. However, the present study with another bulky group, isobornyl, exhibited polydisperties as low as the ones obtained with smaller t-butyl derivative, indicating that the ATRP process was more controlled than other bulky groups such as adamantyl. In addition to this, smaller isopropyl derivative was also studied and polydisperties was found to be much higher than the monomers with bulkier isobornyl and t-butyl groups, indicating that the ATRP polymerization was less controlled. In this study, CuBr/PMDETA catalyst system was employed and cyclopolymerizations of isobornyl and isopropyl α-(hydroxymethyl) acrylate ether dimers were carried out in xylene. Cyclopolymers of IBHMA and IPHMA ether dimers were employed as macroinitiators in copolymerization studies with t-butyl acrylate comonomer in order to prove the livingness. SEC analysis showed that the cyclopolymers obtained were all living. Fortcoming studies on the physical properties of the cyclopolymers were also carried out and high Tg values and thermal stabilities were investigated.