Phosphorus-containing Polysulfones - A Comparative Study

Abstract

A comparative study of the influence of 2-(10-oxo-10H-9-oxa-10 λ5-phosphaphenanthrene10-yl)-benzene-1,4-diol (DOPO-HQ) and 2-(2,8-dimethyl-10-oxo-10H-10 λ5-phenoxaphosphine-10-yl)benzene-1,4-diol (DPPO-HQ) on their ability to form polysulfones (PSU) with 4,4′ -difluorodiphenylsulfone (DFDPS) as well as the properties of the aromatic phosphorus-containing polysulfones (P-PSU) is reported. These properties are also compared to bisphenol A-based polysulfone. Both diols have the phosphorus unit as substituent and differ in the number of oxygen atoms within the environment of the phosphorus changing from DOPO-HQ (phosphinate structure, Ar2 OP(=O)) to DPPO-HQ (phosphine oxide structure, Ar3PO). The nucleophilic aromatic polycondensation was carried out successfully using both phosphorus-containing aromatic diols instead of bisphenol A and was followed by ATR-FTIR in-line monitoring. The use of DPPO-HQ decreased the number of side reactions and enhanced slightly the molecular weight. The thermal stability of DPPO-HQ-based PSU is slightly better than DOPO-HQ-based PSU. Thermal decomposition schemes for PSU and for both P-PSUs are proposed based on thermogravimetric analysis and Pyrolysis GC-MS results.