Preparation and Characterization of Liquid Rubber-modified Polybenzoxazine

Abstract

Alloying polybenzoxazine with liquid rubber was studied in order to overcome its brittleness. We used three kinds of liquid rubber having different functional groups at the chain-end, which are amino, carboxyl and methoxyl groups, namely ATBN, CTBN and ETBN, respectively, to examine the effect of liquid rubber terminal groups on the polymerization of a typical benzoxazine monomer, F-a, and the compatibility with the polybenzoxazine, PF-a. DSC analysis revealed that ATBN and CTBN were effective modifier for lowering the onset temperature of the ring-opening polymerization of F-a. PFa/ATBN hybrid films exhibited high homogeneity throughout wide range of weight ratios of ATBN due to acid-base interaction between the phenolic groups of PF-a and the amino terminal groups of ATBN as confirmed by SEM. Viscoelastic measurement of the hybrids revealed improvement in toughness for the hybrids having low content of ATBN. Moreover, increase of the glass transition temperature of the polybenzoxazine was observed by the hybridization with ATBN. Thermogravimetric analyses revealed that the addition of liquid rubber also enhanced the thermal stability of the polybenzoxazine.

Significant Improvement on Polybenzoxazine Toughness Achieved by Amine/Benzoxazine Copolymerization‐Induced Phase Separation

“…Blending with other materials such as liquid rubber and thermoplastic has been reported to effectively improve the toughness of various polybenzoxazine‐based materials. These modifiers usually induce phase separated structures, which are able to change crack direction and absorb impact energy, leading to improved toughening properties when compared to the pure polybenzoxazine resin synthesized via a bulk polymerization.…”

Research Progress in Toughening Modification of Polybenzoxazine

“…The micro-cracks are generated at the interface and consume external force to prevent the extension of the cracks, to achieve the purpose of toughening. [35] Reactive liquid rubbers, such as epoxy terminated nitrile rubber (ETBN), [36] amino terminated nitrile rubber (ATBN), [17,37] vinyl terminated nitrile rubber (VTBN), [38] hydroxyl terminated nitrile rubber (HTBN), [39] carboxyl terminated nitrile rubber (CTBN) [40] (Scheme 3, Table 1), have attracted much attention due to their high elasticity and selective reactive end groups. Grishchuk et al [36] used ETBN as a modifier to strengthen the benzoxazine/epoxy (BOZ/EP) blend system.…”

Improvement of aldehyde‐functional polybenzoxazine processability and mechanical properties achieved by 5‐aminoindole/benzoxazine copolymerization

“…Blending with other polymers such as liquid rubber 14 and thermoplastic resins [15][16][17] has been reported to effectively improve the toughness of various polybenzoxazine resins. Phase-separated structures were induced, while the impact energy was absorbed and the toughening properties of polymers were improved.…”