Thermoplasticization of wood.

摘要

A study of converting wood into thermoplastic materials was undertaken to develop a new technique in the utilization of wood wastes. Thermoplasticization of wood was based on chemical modification of wood polymeric components. The introduction of chemicals into the inherent structure of wood cell walls resulted in meltable wood.; In this investigation, thermoplasticization of wood was carried out by means of benzylation, hydroxypropylation and hydroxybutylation. Various reaction parameters, such as alkalinity of reaction media, reaction temperature and time, and usage of chemicals were considered to produce thermoplasticized wood with different weight gain.; The chemical structure of the thermoplasticized woods was analyzed by using FTIR, DSC, TGA and x-ray crystallography. The dynamic mechanical properties were studied by using DMTA. The morphology of the melted wood was examined by means of SEM. Mechanical and physical properties of the products were also evaluated.; Experimental data showed that preswelling and reaction temperature had critical effects on all three etherification reactions. Lignin in the wood inhibited benzylation and prevented hydroxyalkylated wood from dissolving in water. Although extractives brought about little effect on benzylation and hydroxyalkylation of southern yellow pine, different species showed some variations in reaction rates.; The thermoplasticized woods exhibited good melting properties and were readily molded or extruded into block or film materials. A wide range of glass transition temperatures from 66 to 280{dollar}spcirc{dollar}C for the thermoplasticized woods essentially depended upon the weight gain. The molded products exhibited acceptable mechanical strength for structural engineering applications. The relations of properties and structure for the thermoplasticized woods were discussed.