WOOD RESEARCH Volume 62, Number 2, 2017
Xiaoshuai Han, Qinqin Zhang, Ren Li, and Junwen Pu

Grafting organic-inorganic compound modifier onto wood cell walls for enhanced mechanical strength in wood composites

The present study describes the possibility to polymerize functional composite modifier within wood cell walls to obtain functional wood composites (FWCs) with poplar wood acting as the base template. The physical and mechanical properties of the composites, including density, bending strength, compressive strength parallel to grain, surface hardness and water uptake, were evaluated. The FWCs were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), Scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD). According to the results, the functional composite modifiers were successfully in situ deposited into the wood structure by kiln drying. The chemical treatment not only significantly improved the physical and mechanical properties of wood, but also provided the wood with better hydrophobic properties. The abbreviations for substances used in this study are: N-wood (natural wood), MD-wood (methylolurea/DMDHEU copolymerization treated wood), FCM-wood (functional composite modifier treated wood).

WOOD RESEARCH Volume 63, Number 6, 2018
Qinqin Zhang, Xiaoshuai Han, and Junwen Pu

Impact of cationic polyacrylamide for a new kind of pulp ultrasonic wheat straw on alkyl ketene dimer sizing

As a new kind of pulp that can protect the environment by conserving wood resources, ultrasonic wheat straw pulp has received increasing attention. It is prepared by the mechanical effect of ultrasound, the effect of cavitation, and thermal effect, and it does not require a large amount of chemical additives. Different pulp methods yield differences in performance. The conventional method of sizing is difficult to achieve the ideal of wheat straw pulp ultrasonic sizing effect. This work examined the effects of additives and surface charge on sizing by studying ultrasonic wheat straw pulp with 0.25% alkyl ketene dimer (AKD) added in the form of
a commercial emulsion without separate retention aids. As a retention aid cationic polyacrylamide (CPAM) contents were prepared and added to fiber suspensions at the wet end of the papermaking process. The relationship between CPAM and the zeta potential of papermaking furnish and sizing degree, the strength properties of the paper sheet, and the factors that affected measuring the zeta potential were investigated. As the CPAM content increased, the surface morphology, the zeta potential and the strength properties of the paper sheet presents a curve.