Crystalline reduction, surface area enlargement and pore generation of chitin by instant catapult steam explosion

In this study, instant catapult steam explosion (ICSE) was employed for chitin treatment, and the effect of ICSE on the chitin structure was systematically investigated by using a series of analytical techniques including scanning electron microscopy, X-ray diffraction and Brunauer-Emmett-Teller analysis. Due to the powerful seepage force of the steam during ICSE, the crystallinity index of chitin decreased 10.2% in the (1 1 0) plane and 13.3% in the (0 2 0) plane. Significantly larger surface areas (up to 2.5 times greater, 12.69 m²/g at 1.6 MPa) with more and larger pores (up to a 3.5 times larger pore volume, 0.0333 cm³/g at 2.0 MPa) were achieved after ICSE, and numerous lacerated-like pore shapes were observed on the porous surface of chitin. Importantly, the molecular structure of chitin remained intact with no substantial damage to chitin's molecular weight, thermostability and acetylation (∼70%), which ensures the possibility and diversity of further chitin derivatization.