Improvement of Thermal Behavior of Rattan by Lignosulphonate Impregnation Treatment

Abstract

Lignin derived from black liquor has a lot of potentials, particularly in its thermal stability, for making value-added chemicals. The purpose of this study was to determine the effect of washing frequency during hydrochloric acid lignin isolation on the properties of eucalyptus kraft lignin. To improve its thermal characteristics and enable its usage as an additive flame retardant, the isolated lignin was synthesized into lignosulphonate. The lignin produced by 3× and 5× washing treatments had a purity of 85.88 and 92.85%, respectively. An FTIR analysis indicated that lignosulphonate was successfully synthesized from isolated lignin after 3× and 5× washing treatments, as the S=O bond was detected at around 627 cm−1. The lignosulphonate exhibited a purity of 71.89 and 67.21%, respectively. Thermal gravimetry and differential scanning calorimetry analysis revealed that the lignin and lignosulphonate after 3× and 5× washing treatments had a char residue of 44, 42, 32, and 48%, respectively. Glass transition temperatures (Tg) of 141, 147, 129, and 174 °C were observed. According to the findings, washing frequency increases lignin purity and Tg, thereby improving the thermal properties of lignosulphonate. Furthermore, the flammability of rattan impregnated with lignosulphonate was V-0 in the UL-94 vertical burning test.