Optimized high-yield synthesis of chitin nanocrystals from shrimp shell chitin by steam explosion.

This study attempted for the first time to prepare chitin nanocrystals (ChNCs) from shrimp shell chitin using steam explosion (SE) method. Response surface methodology (RSM) approach was used to optimize the SE conditions. Optimum SE conditions to acquire a maximum yield of 76.78 % were acid concentration (2.63 N), time (23.70 min), and chitin to acid ratio (1:22). Transmission electron microscopy (TEM) revealed the ChNCs produced by SE had an irregular spherical shape with an average diameter of 55.70 ± 13.12 nm. FTIR spectra showed ChNCs were slightly different than chitin due to a shift in peak positions to higher wavenumber and higher peak intensities. XRD patterns indicated ChNCs were a typical α-chitin structure. Thermal analysis revealed ChNCs were less thermally stable than chitin. Compared to conventional acid hydrolysis, the SE approach described in this study is simple, fast, easy, and requires less acid concentration and acid quantity, making it more scalable and efficient for synthesizing ChNCs. Furthermore, the characteristics of the ChNCs will shed light on the potential industrial uses for the polymer.

Poly[µ(3)-ß-alanine-aqua-µ(4)-sulfato-dilithium].

The title compound, [Li(2)(SO(4))(C(3)H(7)NO(2))(H(2)O)](n), is a coordination polymer in which the ß-alanine residues remain in the zwitterionic form. The crystal structure consists of corrugated sheets of [LiO(4)] and [SO(4)] tetra-hedra parallel to (010) with the ß-alanine mol-ecules located between the sheets. The two independent Li(+) cations are four-coordinated by O atoms in a distorted tetra-hedral geometry. The crystal structure is formed by stacking of alternate organic and inorganic layers along the a axis. The crystal structure is further stabilized by N-H⋯O hydrogen bonds.