Preparation and Characterization of Liquid Smoke from Wood Sawdust Azadirachta excelsa (Jack) M. Jacobs and its Application as a Natural Rubber Coagulant

Abstract Azadirachta excelsa (Jack) M. Jacobs (AE) sawdust is a waste from the furniture industry that is not utilized and causes environmental problems. AE sawdust that contains cellulose, hemicellulose, and lignin can be used as liquid smoke for various applications. This study aims to perform the production, characterization, and application of liquid smoke as a latex coagulant. AE liquid smoke was produced at ± 300-350 °C by pyrolysis temperature for 6 hours. The yield of AE liquid smoke was 30.59% with characteristic smoke in odor, reddish brown in color, the pH value was 3.58 ± 0.015, specific gravity was 1.08 g/mL, and total organic acid contain was 10.410 ± 0.2%. FTIR spectrum of liquid smoke shown OH, C=O and C-O stretching vibrations of carboxylic acids. The results showed that along with the increase in the concentration of AE liquid smoke that latex coagulation timing was accelerated. Interestingly, at a concentration of 14% AE liquid smoke demonstrated a faster coagulation time than the positive control. The application of AE liquid smoke into the latex was accelerated the coagulation time, removing unpleasant odors from natural rubber, and improving the latex texture but changing the color of natural rubber from white to grey and it might be a substitute for formic acid as a natural rubber latex coagulant.