Hinoki cypress (Chamaecyparis obtusa) -lignophenol (p-cresol type, HCLC) has been directly synthesized from lignocellulosics through the phase-separation system composed of concentrated acids and phenols under mild conditions. Thermal responses of HCLC were estimated by FT -IR, GPC, UV-Vis, TMA, TG, DSC and 1 H-NMR. The HCLC annealed up to 180 °C have large molecular weight distribution estimated by GPC. The results showed both de-polymerization through the cleavage of unstable C 1 -aryl ethers and polymerization through attacks of adjacent phenolic units to resulting reactive points on C 1 occurred in the same time on the molecules. Although an exothermal peak of HCLC was• detected by DSC, HCLC annealed up to 200 °C, exothermal peaks were vanished with focusing of the Mw to about 4 000. These heat resistant materials with new conjugated structures, which were produced by eliminations of aliphatic hydroxyl groups, held recycle designs. In fact, HCLC annealed up to 300 °C, the Mw were focused to 1 000-2 500 by phenol switching under alkaline conditions at 140-170 °C. Thus annealed HCLC over 200 °C kept particular structures of lignophenol, especially both grafting p-cresol and C 2 -0-aryl type linkages without random thermal decompositions.
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