Cyanoethylation of several fiber materials and their utilization as adhesive in wood-based panels
This study examines the cyanoethylation and thermoplasticity of several cyanoethylated fiber materials. Cyanoethylated pulps with a degree of substitution of 1.43 have the lowest Vicat softening point. Cyanoethylated poplar with a weight gain of 18.2 % has the lowest melting temperature. Instead of traditional adhesives, cyanoethylated materials can be used to produce wood-based panels because of their good thermoplasticity. Plywood bonded with cyanoethylated pulp has a bonding strength of 2.06 MPa and an average wood failure of 62.7 %. Wheat straw particle board containing 40 % cyanoethylated pulp has an internal bonding strength of 0.49 MPa, a modulus of rupture (MOR) of 33 MPa, and a density between 0.5 and 0.6 g cm−3. Fiberboard containing 40 % cyanoethylated pulp has an internal bonding strength of 0.53 MPa, MOR of 38 MPa, modulus of elasticity of 4,200 MPa, and a density between 0.7 and 0.8 g cm−3. Its swelling in thickness is 41 %.
Mechanical and dielectric properties of cyanoethylated wood
The mechanical properties and dielectric properties of film specimens from cyanoethylated wood (CE-wood) which is a mixture of CE-(cellulose, hemicellulose, and lignin) were investigated and compared with those of cyanoethylated cellulose (CEC). From the dynamic mechanical measurement for CE-wood, it was observed distinctively that the segmental motions of the main chains were restrained by lignin. But these restraints were released with chlorination of CE-wood. The dynamic behavior for chlorinated CE-wood was similar to that for CEC. It was found that the CE-wood was plasticized effectively by blending with cyanoethylated poly(vinyl alcohol) (CE-PVA). The dynamic and static modulus of CE-wood decreased with increasing the CE-PVA fraction in the blended film, and the change of tensile strength at break for the CE-wood polyblends showed a maximum value at the CE-PVA fraction of ca. 40%. It was found that CE-wood which contained lignin showed very high values of dielectric constant comparable to those of CEC which was well known to be a high-performance dielectric materials. These dielectric properties were attributed to the segmental motion of the side chains, and it was tough that the behavior of the side chain was not so much influenced by the lignin as that of the main chain. CE-wood film specimens could be drawn to threefold the initial length in acetone aqueous solution. The degree of orientation measured by optical method increased rapidly at the early stage of drawing. The Young's modulus and the tensile strength at break of the high-drawn specimen increased to as much as three or four times those of the undrawn one, and the elongation at break changed little.
Study on the cationic modification and dyeing of ramie fiber
A modification procedure for ramie fiber using 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHPTAC) as a cationic agent and NaOH as a catalyst was developed in this paper. The morphological and structural transformations of the fiber induced by modification were determined by XRD (XRD), differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA). XRD results show that the crystal structure of the modified fiber was still preserved although its crystallinity was decreased, which was confirmed from the TGA results. The mechanisms for the modification and dyeing of ramie fiber were analyzed, and the optimum modification conditions were determined to be the CHPTAC concentration of 30 g L−1, the NaOH concentration of 15 g L−1, the reaction temperature of 50 °C, and the reaction time of 60 min. The raw and the modified fibers were dyed with C.I. reactive red 2. The K/S values for the cationic modified fiber increased to be three times as high as the unmodified fiber. The dye uptakes increased greatly with an increase in the nitrogen contents up to 0.4% on the modified fibers.