Abstract: Acid modified polybenzoxazine (PBA-aa) /unsaturated polyester (UPR) blends were prepared by an in situ curing of acid benzoxazine monomer (BA-aa) in the presence of UPR. It was expected that after curing, the PBA-aa/UPR blends would be miscible since the phenolic hydroxyls and acid carbonyl group in the PBA-aa molecular backbone have the potential to form intermolecular hydrogen-bonding interactions with the carbonyls of UPR and thus would fulfil the miscibility of the blends and finally lead to enhance the thermal and mechanical properties. Fourier-transform infrared spectroscopy (FT-IR) conformed that there were intermolecular hydrogen-bonding interactions between PBA-aa and UPR after curing. Thermal properties of the blends have been investigated by using DSC and TGA. Thermal stability of the blends increased with increasing amount of polybenzoxazine in the composition. Fracture morphology study has been done by SEM. The best miscibility effect was achieved for 10 wt% loading level polybenzoxazine in the blend, while at this level of blend mechanical properties were found to be higher. The increase in mechanical properties of the blend indicated improved interfacial interaction between the two discrete phases (polybenzoxazine and unsaturated polyester) induced by the functional groups. The composition having 10 wt% polybenzoxazine and 90 wt% unsaturated polyester resin possesses highest mechanical properties with comparatively higher thermal stability.
 
Keywords: Polybenzoxazine, unsaturated polyester resin, blend, hydrogen bonding

Cite: Atul Dinkar Kamble, Amit Balsing Rajput, Hussein Ali Abed, "Thermosetting Blends of Acid Modified Polybenzoxazine and Unsaturated Polyester: Study on Intermolecular Specific Interactions and Their Thermal, Mech," International Journal of Materials Science and Engineering, Vol. 4, No. 2, pp. 104-112, June 2016. doi: 10.17706/ijmse.2016.4.2.104-112