Synthesis of poly(sebacic anhydride): effect of various catalysts on structure and thermal properties

Abstract

The authors investigate the efficiency of various catalysts (22 types, based on oxides, carbonates, chlorides, organometallic compounds, N-heterocyclic carbine based compounds, cadmium acetate and molecular sieves) in the process of poly(sebacic acid) anhydride (PSA) synthesis. Their efficiency was studied utilizing methods that characterize the molecular weight distribution (gel permeation chromatography, GPC), structure (Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), mass spectroscopy (MS)) and thermal properties (differential scanning calorimetry, (DSC), thermogravimetry (TGA)) of the final products. Such structural characterization gave good insight into the resulting polymer structure. Findings reveal the crucial role of catalyst selection in the resulting properties of PSA. The maximum M (w) values reached were found at approximately 280 kg.mol(-1), which in the case of the calcium oxide catalyst was achieved after 60 min of reaction. TGA analyses showed a two-step thermal degradation process for all samples. No significant effect of the catalyst used was observed on polyanhydride thermal stability. However, it was proven that such catalysts do significantly influence the crystallinity of the resulting polyanhydrides.