NEW POLYMER SYNTHESIS 99 - HYPERBRANCHED POLY(ESTER-IMIDE)S DERIVED FROM 4,5-DICHLOROPHTHALIC ACID

A new trifunctional monomer was prepared from ethyl-4-(4,5-dichloropht halimido) benzoate and 4-mercaptophenol. The phenolic OH groups were a cetylated,and the carboxylic group was silylated to reduce the melting temperature. A successful homopolycondensation yielding a completely soluble hyperbranched poly(ester-imide) was only obtained when the sil ylated monomer was used. This branching monomer was polycondensed with a difunctional imide monomer to yield co(polyester-imide)s having a v ariable degree of branching. Furthermore, copolycondensations with 3-a cetoxybenzoic acid or 3,5-bisacetoxybenzoic acid (and their trimethyls ilyl esters) were studied. The composition of the resulting copolyeste rs were checked by elemental analyses and H-1 NMR spectra. The glass t ransition temperatures (TgS) showed a systematic variation between the values of the parent homopolyesters.