Dynamic mechanical and thermal properties of copolymer from o-allylphenol and 4,4'-diaminodiphenyl methane-based benzoxazine and bisphenol-A type novolac epoxy resin

Benzoxazine/epoxy copolymers were prepared by solution blending bis(4-(8-allyl-2H-benzo[e][1,3]oxazin-3(4H)-yl)phenyl)methane (oAP-ddm) with bisphenol-A type novolac epoxy resin (bis-ANER), followed by thermally polymerization of the blend. The copolymerization behavior of oAP-ddm/bis-ANER was investigated by Fourier transform infrared spectroscopy and differential scanning calorimetry (DSC). With the increasing of bis-ANER fraction, the exothermic peak in DSC curve changes from one to two overlapped peaks, and the second peak shifts to higher temperatures. Dynamic mechanical analysis results show that a single peak appears in each tan delta curve of the oAP-ddm/bis-ANER copolymers. With the bis-ANER content increasing, the storage modulus and the peak temperature of tan delta peak increase, whereas the tan delta peak height decreases. Thermogravimetric analysis results indicate that the onset temperatures of mass loss and the char yields at 800 A degrees C of the oAP-ddm/bis-ANER copolymers decrease with the increase of bis-ANER content.