Design of thermosetting polymeric systems based on benzoxazines modified with maleic anhydride

E.GILBERT; G. MORALES; M. SPONTÓN; D. ESTENOZ

JOURNAL OF APPLIED POLYMER SCIENCE

JOHN WILEY & SONS INC

Lugar: New York; Año: 2018

0021-8995

A novel benzoxazine (BzPFA) with carboxylic acid groups in its structure was synthesized in a two-step process. First,BzPOH monomer was obtained from bisphenol A, paraformaldehyde, and ethanolamine with an initial molar ratio 1:4:2. Then,BzPOH was reacted with maleic anhydride using a stoichiometric 1:1 ratio of oxazine ring: maleic anhydride to produce a mixture ofoligomeric species named BzPFA. The products were characterized by nuclear magnetic resonance, size-exclusion chromatography,and Fourier transform infrared spectroscopy. BzPFA presented a weight-average molecular weight of 50,000 g mol21. Mixtures of thenovel precursor and the conventional benzoxazine based on bisphenol A (BzBA) (60:40 and 40:60 weight ratios) were prepared andthree different curing conditions were considered in order to study the effect of BzPFA on curing and final properties. Blends exhibitedimproved properties respect to BzBA even at relatively low curing temperatures. These results can be associated to the networkcrosslinked by ester bonds that promotes a high rigidity