A cyanate ester resin used for preparing a long storage period, excellent mechanical and long-lasting antibacterial carbon fibre prepreg

To address dry cracking, powder shedding, poor layup, and bacterial degradation after long-term storage of existing carbon fibre/cyanate ester (CE) prepreg, a “thermally triggered bifunctional” catalyst system of Benzoquinone-Dibenzothiazole disulfide-Sulfur (MT) and a toughening agent Diallyl bisphenol A were used to regulate the gelation reaction of Bisphenol A CE and Novolac CE resin system and enhance the initial adhesion as well as antibacterial property of its carbon fibre prepregs. A certain amount of the resulting resin system is applied to the flattened surfaces of unidirectional T800 CF bundles at 90 °C, and a scraper is used to uniformly spread the resin over the CF bundles to ensure effective impregnation. The resin undergoes a gelation reaction for 50 min, forming a prepreg with resin content of approximately 40 wt % and a crosslinking degree of 10−15%. The prepreg is stored at −18∼25 °C to achieve polymerisation inhibition and demonstrate storage stability, while at 160 °C, “rapid curing” can be achieved. When the prepreg is refrigerated at −18 °C for 400 days and then subjected to a 180° peel test, it maintains good tackiness and shows no powder shedding or degradation. The interlaminar shear strength and flexural strength of the prepreg composites are 83.6 MPa and 2106.0 MPa, respectively. Furthermore, the catalytic prepreg and its composites exhibit long-lasting antibacterial activity of over 97% against thermotolerant coliform bacteria and Enterococcus faecalis. This research provides a significant application potential in the field of aerospace composite materials.