according to the method described in f p glatz and r mulhaup high performance polymers 1993 5 213 or reacting diaminodiphenylsulfone with maleic anhydride according to the method described in b s rao r sireesha and a r pasala polym int 2005 54 1103 specific examples will described in the following synthesis examples certain bismaleimide of formula ii such as 4 4 u2032 diaminodiphenylmethane bismaleimide ch 2 bmi is commercially available 4 4 u2032 diaminodiphenylsulfide bismaleimide s bmi corresponding to x representing u2014 s u2014 in the formula ii was synthesized by reacting 4 4 u2032 diaminodiphenylsulfide with maleic anhydride according to the method described in f p glatz and r mulhaup high performance polymers 1993 5 213 mp 187 u00b0 c 4 4 u2032 diaminodiphenylsulfone bismaleimide so 2 bmi corresponding to x representing u2014 so 2 u2014 in the formula ii was synthesized by reacting 4 4 u2032 diaminodiphenylsulfone with maleic anhydride according to the method described in b s rao r sireesha and a r pasala polym int 2005 54 1103 mp 252 u00b0 c 4 4 u2032 diamino diphenylmethane bismaleimide ch 2 bmi corresponding to x representing u2014 ch 2 u2014 in the formula ii 2s 3r 1 4 dimercaptobutane 2 3 diol dt oh and 4 4 u2032 thiobisbenzenethiol dt s were received from commercial sources and were used as received to a 250 ml three neck round bottomed flask equipped with addition tube and purged with nitrogen gas an acetone solution 100 ml containing 9 44 g 96 28 mmol of maleic anhydride was added.