Graft copolymerization of poly(ethylene terephthalate) (PET) to cellulose was attempted via esterification of cellulose with benzoyl chloride and terephthaloyl dichloride. The esterification of cellulose was performed in 8wt% LiCl/DMAc under reflux in N2 at 100°C using pyridine as basic catalyst. Cellulose benzoate terephtalate (CBT), further transformed to chloride form using thionyl chloride, was reacted with ethylene glycol and terephthaloyl dichloride in THF under reflux in N2 at 50°C using pyridine as basic catalyst. Formation of CBT and PET-grafted cellulose (PET-C) was suggested from FTIR spectra. PET-C showed melting transitions between 150 to 190°C and formed mesophase, in spite of the possible remaining of free PET chains.
Warm color distributed on lumber surface is one of the most important visual characteristics of wood, and would affect aesthetics of various wood products. The objective of this study is to characterize the wooden colors quantitatively by imaging spectroscopy. Twelve different specimens of coated and uncoated fancy veneer overlaid plywood of six species were prepared. These surfaces were scanned by the imaging spectroscope system, and color values of metric lightness (L*), chroma (C*) and hue (H°) were measured in every pixel. Resolution of the image was approximately 0.20mm /pixel. Results were summarized as follows. (1) In comparison with the same species, the coated specimen became darker than the uncoated specimen, because spectral reflectance in the visible light of the coated was lower than the uncoated. And by the coating, decrement of the reflectance of dark spots in the surface, for example latewood, tended to be greater than light spots such as earlywood. (2) Histograms of L*, C* and H° were constructed by counting every pixel. By the coating, peak positions of L* and C* histograms shifted to lower (darker) and upper (more saturated) sides, respectively. (3) Multi-resolution contrast analysis (MRCA) was applied to images with the three color attributes, and revealed that the color difference, especially contrast of the lightness and the chroma, were enlarged by the coating.
Wood flour (WF) was converted not only to carrier matrix for in situ synthesis of iron oxide nanoparticles but also to thermoplastic material by combination of anionic functionalization and benzylation. A sequence of procedure for the in situ synthesis of iron oxides includes ferrous ion-absorption of the chemically modified WF, precipitation of ferrous hydroxide by an alkaline treatment, and oxidation of the ferrous hydroxide. To facilitate the ferrous ion-absorption, we performed the anionic functionalization of WF via carboxymethylation or maleylation. The benzylation was expected to be favorable for improving thermoplasticity of the products. FT-IR spectroscopy revealed that the original hydroxyl groups were considerably substituted by the etherification and/or esterification. A successful incorporation of iron oxide particles (synthetic ferrites) into the anionically funcionalized WF matrix was confirmed by redox titrimetry. However, maleyl moieties incorporated after benzylation were largely hydrolyzed by the alkaline treatment for the in situ synthesis of iron oxides, which gave rise to an elution of ferric contents simultaneous with its formation. Such an elution could be prevented in part by the introduction of maleyl groups preceding benzylation. By means of the adequate set of chemical modifications, the original WF was transformed into a thermoplastic material. Actually, it was possible to mold the modified WF samples into a film form at a relatively low temperature of 140°C, even after the in situ synthesis of iron oxide. Magnetometry measurements revealed that the magnetic woody composite showed superparamagnetism (SPM) at room temperature. The unique magnetic character can be generally observed when the magnetic particles as dispersoid are loaded into the matrix on a scale of less than a few tens of nanometers. The formation of iron oxide nanoparticles was supported by field emission scanning electron microscopy and X-ray diffractometry. The observation of SPM may be of significance in the perceptibility to an external magnetic stimulus only on demand and without energy loss.
The observed values of bending properties (MOR or MOE) for sandwich panels with veneer as the faces and various oriented fiberboards as the core were compared with the ideal values estimated by properties of veneer or various oriented fiberboards. The results showed that the bending stress was applied mainly to the face veneers, the shearing stress was applied mainly to the core fiberboards. The result in relation to the agreement between observed and calculated value was divided into the two cases. One was a rough agreement between observed and calculated value of MOR or MOE. The other was that the observed value was lower than estimated one. When shear modulus of fiberboard as the core was estimated, that of the former was larger and that of the later was smaller.
The observed values of dimensional stabilities(thickness swelling (TS) or linear expansion (LE)) for sandwich panels with veneer or paper as the faces and various oriented fiberboards as the core were compared with the values calculated by the properties of veneer, paper or various oriented fiberboards. As a result, observed TS or LE values agreed basically well with calculated ones , however, it was important for calculated value of higher precision to consider the effect of adhesive properties between face and core. Dimensional stabilities of sandwich panel could be estimated by the properties of face and core materials of composites. If face material had high Young's modulus and great dimensional stabilities like the veneer in fiber direction with the poor dimensional stabilities of core material, sandwich panel would have great dimensional stabilities.
In this research, joint strength of glued laminated timber (glulam) of karamatsu (Larix kaempferi) connected by large finger joint (LFJ) whose finger length was 52mm was estimated using results of tensile and bending strength of LF-jointed laminae. Adequate end-pressure of the LFJ with resorcinol resin adhesive was obtained to be 2 - 5 MPa by the linear portion of relation between load and displacement observed in the inserting compressing test. Using an equation for predicting the modulus of rupture (MOR) for glulam derived by Komatsu, 5th percentile lower limit value of bending strength of glulam connected by LFJ of 120mm width were estimated by observed tensile and bending strength of LF-jointed laminae of 30mm thick and 120mm width. And joint strength of several cross section size glulam connected by LFJ, 120 × 120, 120 × 180 and 120 × 300mm, were obtained by bending test. As a result, observed minimum joint strength on each section size were higher than the estimated MORs. Moreover, good agreement was obtained between estimated MOR curve and estimating strength by size factor for larger cross section size.
It is the aim of this study to evaluate the surviving strength of bending or full compression of wood damaged by bio-deterioration. The bending or the full compression performance of the Sugi and Todomatsu specimens damaged by termite attack or brown-rot fungal attack was evaluated, and the threshold value ensuring the standard strength was also investigated. As the results, we suggested that penetration depth of 25mm in the case of Pilodyn®, regardless of the wood species and the type of bio-deterioration, was appropriate as the threshold value in this research. It was also suggested that the enough residual strength was not obtained in the case of the ultrasonic velocity of below 5000m/s for the longitudinal direction in the bending test. But it was difficult to decide the threshold value using the ultrasonic velocity for the tangential direction in the full compression test.