抄録
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 1H-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 C1-aryl ethers and polymerization through attacks of adjacent phenolic units to resulting reactive points on C1 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 C2-O-aryl type linkages without random thermal decompositions.
