This paper deals with the results on the mechanical properties (compressive strength parallel to grain, bending and impact bending strength) in the heat-and radiation-polymerized wood-plastic combination of five species. Five species used in these experiments are TOCHI : Aesclus turbinata BLUME, MIZUMEZAKURA : Betura grossa S. et Z., KAKI : Diospyros kaki LINN. var. domestica MAKINO, BUNA : Fagus crenata BLUME, and SUGI : Cryptomeria japonica D. DON. Preparation of the samples are shown in Table 1.
The results obtained are as follows :
(1) The values of the conversion of the heat-and radiation-polymerized wood-plastic combinations are shown in Table 2 (Hard wood) and 3 (Soft wood) for the compressive test parallel to grain and the bending test.
Fig. 1 shows the relation between the value of the conversion and the method of preparation of samples. Table 4 shows the values of the conversion of the heat-and radiation-polymerized wood-plastic combination of SUGI WOOD used for impact bending test.
The values of the conversion of the heat-cured wood-polymer combination were higher than those of the radiation-polymerized wood-plastic combination in all species examined.
(2) The relation between the method of preparation and specific gravity in each sample is shown in Fig. 2. The specific gravity of the heat-and radiation-polymerized wood-plastic combination samples was higher than the specific gravity of the control samples.
(3) The relation between the specific gravity and compressive strength parallel to grain is shown in Fig. 3-7. The compressive strength parallel to grain increased along with the increase of specific gravity.
(4) The relation between bending strength and specific gravity is shown in Fig. 10-13, and the photographs of failure form for each preparation of TOCHI after bending test are shown in Photo. 1.
(5) The relation between impact bending strength and specific gravity is shown in Fig. 16 and 17.