Abstract
Lignocresol was synthesized from Hinoki cypress (Chamaecyparis obtusa) through the phase-separation system with p-cresol and 72% sulfuric acid. Molecular responses of lignocresol for heating were observed at around 160°C. These behaviors were caused by molecular rearrangement associated with the cleavages of benzyl aryl ether linkages. By the alkaline treatment under ordinary pressure at room temperature, benzyl aryl ether linkages with phenolic units are cleaved, and then low molecular lignin fractions are formed. After the alkaline treatment, thermal stability of lignocresol was improved. The glass-transition temperature (Tg) of lignocresol was shifted up by removing the low molecular weight units. The solid-liquid transition temperature was also shifted. These results indicated that the low molecular weight fractions released from lignocresol work as plasticizer. Lignophenols are bio-based thermo plastics, self-providing plasticizer through molecular rearrangement under high energy condition.
