Processability and mechanical properties of bisbenzoxazine modified by the cardanol-based aromatic diamine benzoxazine

Abstract

To improve the processability and toughness of bisbenzoxazine, a series of cardanol-based aromatic diamine benzoxazine (BZ-Xc) monomers were synthesized from cardanol, formaldehyde aqueous solution and aromatic diamines with different bridging groups such as -CH 2 -, -O-and -SO 2 -. The curing behavior, viscosity, thermal and mechanical properties of 4,4′-diaminodiphenylmethane (DDM)-based bisbenzoxazine (BM) and BZ-Xc copolymers were studied systematically. The results demonstrate that the plasticizing effect and flexibility of the alkyl side chain on BZ-Xc significantly reduced the melting viscosity of BM/BZ-Xc blends and improved the toughness of the copolymers. At the same time, the heat-resistant and mechanical properties of the copolymers were retained, because of the bifunctional structure of BZ-Xc. Moreover, the melting viscosity, glass transition temperature and curing temperature of the corresponding copolymers were increased as the result of rigidity and electron-withdrawing effects of the -SO 2 -bridging group compared to others.

Polybenzoxazines: new players in the bio-based polymer arena

“…group as reported in the literature. 13 Cardanol has also been combined with other amines such as aniline [14][15][16][17] (Bz2, Scheme 2), allylamine 18 (Bz3), ethanolamine (Bz4) and a series of aromatic 19,20 and aliphatic diamines 21 such as 4,4′-diaminodiphenylmethane (DDM) (Bz5 with X = -CH 2 -) and isophorone diamine (Bz7) to yield different benzoxazines with a broad range of applications. Additionally, cardanol-furfural phenolic resins were also used to prepare oligomeric benzoxazine precursors (Bz8).…”

Development of Halogen Free Sustainable Polybenzoxazine Matrices and Composites for Flame Retardant Applications

“…However, solutions can be provided by either physical blending with flame retardants or by chemical modification. Several research groups attempted to solve these issues by designing multi amine precursors [63,64] or by introducing, silica/silicon, phosphorus, boron, and furan [52,[65][66][67][68][69][70].…”

Research Progress in Toughening Modification of Polybenzoxazine

“…On the other hand, design and synthesize benzoxazine group terminated molecules can also be used for improving the toughness or for modification of other kinds of thermoset resins. These benzoxazines can be divided into four categories according to their molecular structures: (1) small molecule benzoxazines, [15,23,24] (2) main chain benzoxazines, [25][26][27][28][29] (3) side chain benzoxazines, [30,31] (4) telechelic benzoxazine. [32][33][34] Scheme 2.…”

“…Unfortunately, because of the monofunctional structure of cardanol-based benzoxazine, the thermal properties of the blends are usually reduced. Gu et al [24] synthesized a series of cardanol and improve the toughness of the copolymer. When the addition amount of BZ-Xc is 10%, the impact strength of the BM/BZ-Mc, BM/BZ-Oc, BM/BZ-Sc system reaches 31.8, 30.9, and 30.1 J•m -2 respectively, which is significantly improved compared with 17.3 J•m -2 of pristine poly (BM).…”