To obtain thermosets with high performance, a 1,5-naphthalenediamine (NDA)-based benzoxazine (NB) is successfully synthesized and used as a novel hardener for diglycidyl ether of bisphenol-A (DGEBA). The structure of NB is confirmed by FT-IR and NMR. The curing behaviors of NB and NB/DGEBA are studied by non-isothermal DSC, and the properties of the resulting thermosets are measured by DMA and TGA. The results show that NB’s thermoset has excellent thermal–mechanical property, thermal stability, and flame retardancy, with storage modulus at 30 °C ( \( E^{{\prime }} \) ) of 2.4 GPa, 10% weight loss temperature ( T 10% ) of 366 °C, glass transition temperature ( T g ) of 279 °C, and char yield at 800 °C in nitrogen (CY) of 60.6%. NB-cured DGEBA possesses better stiffness, thermal stability, flame retardancy, and high-temperature resistance than NDA-cured DGEBA, as indicated by the 1.2 GPa higher \( E^{{\prime }} \) , 11 °C higher T 10% , 21% higher CY, and 50 °C higher T g .
High efficient dispersant that meanwhile possesses additional functions is highly desirable for the fabrication of graphene-based composite. In this paper, a new reactive dispersant, multi-silanols grafted naphthalenediamine (MSiND), is synthesized, which shows superiority compared with conventional dispersants. It can not only stabilize graphene in water at a high concentration of up to 16 mg mL −1 , but also simultaneously be applicable for ethanol medium, in which the graphene concentration can be as high as 12 mg mL −1 at the weight ratio of 1:1 (MSiND:graphene). The dispersion is compatible with multi-matrixes and affinity to various substrates. In addition, MSiND exhibits excellent reactivity due to the existence of high-density silanol groups. Tough graphene coatings are constructed on glass slides and non-woven fabric simply by direct painting and dip-coating. Moreover, with the assistance of MSiND, graphene-doped phase-change coatings on hydrophobic non-woven fabric (e.g., functional mask) are prepared via the spray method. The composite coatings show enhanced mechanical strength and excellent energy storage performance, exhibiting great potential in heat preservation and thermotherapy.
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