PREPARATION AND PROPERTIES OF BISMALEIMIDE RESINS OF AROMATIC SULFONEETHER DIAMINE

Aromatic sulfone ether diamine, bis[4-(4-aminophenoxy)phenyl]sulfone ( SED), was prepared by the nucleophilic aromatic substitution of 4,4'-d ichlorodiphenylsulphone by p-aminophenolate, The reaction was conducte d in the presence of excess potassium carbonate as a weak base, toluen e as the dehydrating agent and N-methylpyrrolidone as the dipolar apro tic solvent. SED showed good solubility in common organic solvents, su ch as dioxan, tetrahydrofuran, butanone and acetone. SED was reacted w ith maleic anhydride to obtain aromatic sulfone ether bismaleimide, bi s[4-(4-maleimidophenoxy)phenyl]sulfone (SEM). The compounds were chara cterized by FTIR and H-1 NMR analysis. Furthermore, copolymer resins o f SED with 4,3'-bismaleimidodiphenyl methane (BMI) and SEM were prepar ed. After curing, crosslinked resins with better thermal stability res ulted. The temperature at maximum rate of weight loss (T-max) and the heat-resistant temperature index (T-i) in air were found to be 426 deg rees C, 208 degrees C and 579 degrees C, 221 degrees C for BMI/SED and SEM/SED resins, respectively. Compared with the corresponding 4,4'-di aminodiphenyl methane (DDM) system, BMI/SED and SEM/SED showed a sligh t decrease in T-max and T-i. SED-modified BMI/amine resin based glass cloth laminates for printed circuit boards showed higher mechanical pr operties than those of the corresponding unmodified system. With SED i nstead of the original amine component in 3-5% weight fraction, the te nsile strength, flexural strength and impact strength of the laminates increased markedly. Meanwhile, the stripping strength and weld resist ance were also improved by the addition of SED.