Preparation and crosslinking of oligoesterified woods based on phthalic anhydride and glycidyl methacrylate

Summary

Oligoesterification reaction of wood with phthalic anhydride and glycidyl methacrylate (GMA) was investigated. The reaction proceeded smoothly at 90°C. The products obtained consisted of acetone-insoluble and soluble parts. The insoluble parts were novel oligoesterified woods with oligoester chains having methacrylate double bonds. The soluble parts were viscous liquids consisting mainly of free oligoesters not linked with the wood matrix, and contained small amounts of GMA and oligoesterified wood components which were dissolved out. The products (the oligoesterified wood-containing mixtures), when subjected to hotpressing, gave plasticized crosslinked wood boards whose surfaces are smooth, glossy, and plasticlike. In this case, plasticization of wood components and thermal polymerization of the methacrylate double bonds in the oligoester chains occurred simultaneously even in the absence of radical initiator. The soluble parts worked as a plasticizer for the wood components. The crosslinked wood boards exhibited outstanding properties in tensile strength (∼ca. 700 kg/cm²), flexural strength (ca. 900–1030 kg/cm²), and Rockwell hardness (ca. 120).