THE RELATION BETWEEN THE CURING CONDITION S AND MECHANICAL-PROPERTIESOF POLYAMINOBISMALEIMIDE

Polyaminobismaleimide oligomer was cured at various curing temperature s and curing times. The relation between the curing conditions and str uctural characteristics of the resulting polymers have been investigat ed by means of IR, DTA, TG, TMA, tensile properties, and dynamic visco elasticity measurements. The IR adsorption peaks centered at 690 and 8 20 cm-1 decreased in intensity with increasing curing temperature and curing time. Because the bands are assigned to the double bond of the maleimide ring, the degree of curing may be estimated from the band in tensities. As the degree of curing increased, the thermal expansion de creased regularly. The dynamic viscoelasticity in the temperature rang e of 200 approximately 300-degrees-C varied with the curing level. The E' value decreased considerably from 200-degrees-C and then recovered up to 300-degrees-C. This variation in E' decreased gradually at high er curing temperatures and longer curing times. The alpha relaxation p eak of slightly cured polymer seen in E' - and tan delta-temperature c urves decreased in height and shifted to higher temperatures with incr easing curing degree. A linear relationship exists between the plot of the curing temperature and the logarithm of curing time with point of disappearance of the alpha relaxation peak. The initial increase in t he strength and elongation at break of the film cured at 240-degrees-C was followed by a decrease at curing time longer than 960 min.