PAPER making! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® Volume 8, Number 2, 2022
phase volume increased with the concentration of Janus particles increased. In comparison with cationic starch, Janus particles exhibited superior emulsification performance in ASA emulsion. The ASA emulsion stabilized by Janus particles was used as an internal sizing agent for cellulose paper. The results of sizing degree and Cobb 30 showed that the sizing performance of ASA emulsion stabilized by Janus particles was significantly improved. Our study provides a better choice of preparing ASA emulsion for paper sizing and promotes the application of Janus materials in paper industry. “Preparation of cross -linking PVA copolymer modified by DAAM/ADH and application in paper surface sizing”, Kaibin Li, Xiaorui Li, Dan Wang, Baoping Yang, Yihe Liu, Haihua Wang & Yiding Shen, Cellulose (2022). Herein, a novel modified polyvinyl alcohol(DA-IPVA) used as sizing agent was prepared by using diacetone acrylamide(DAAM)/adipic dihydrazide(ADH) as graft monomer and N- (isobutoxymethyl)acrylamide(IBMA) as self-cross-linking monomer. The effect of the amount of DAAM on the properties of emulsion, film and sizing paper was discussed. The surface micro-structure of the sizing paper was characterized by SEM and AFM. The addition of DAAM/ADH and IBMA endowed DA-IPVA with cross-linked active group and increased cross-linking density and hydrophobicity after ADH was added into the emulsion and the cross-linking structure was formed. The enhancing mechanism of surface sizing agent for paper was revealed. The DA-IPVA can be cross-linked on the surface and inside of the paper to form a dense network structure, which improves the bonding force between the fibers. When the mole fraction of DAAM of the cross-linking monomer is 8%, the surface sizing performance of the paper is obviously improved compared with the base paper. The dry and wet strength is increased by 266.5% and 334.3% respectively, and the folding resistance is increased 2946.67%. This study can have a profound impact on the development of the technology of cross-linking surface sizing agent for paper. TESTING “ Determination of the surface charge of lignocellulosic fiber by a derived spectroscopic technique ”, Ning Yan, Yu-Ting Zhang, Xin-Sheng Chai & Zhao-Qing Lu, Cellulose , Vol.29, pp.5547-5556 (2022). This paper proposed a derived spectroscopic technique for determining the surface charge of lignocellulosic fiber. In this method, chitosan quaternary ammonium iodide with higher molecule weight was selected to minimize its interaction with the negative charge inside of fiber pores. It was based on spectroscopically measuring the UV absorbance of I− (the counter ion) in the filtrates from a set of solutions that containing the fixed amount of fibers and the different amount of cationic polymer (from under- to over-saturation). By plotting the derived absorbance at 245nm versus the volume of chitosan addition, a transition point is determined, from which the fiber surface charge can be calculated. The results showed that the present method has a good measurement precision (RSD < 3.24%) and accuracy (relative differences < 3.11%, when compared with the conductivity titration method). It is suitable to be used for determining the surface charge of lignocellulosic fibers. “ Bending behavior and geometrical optimization of five-layered corrugated sandwich panels with equal in-plane principal stiffness ”, A Vakilifard, H Mazaheri & M Shaban, Journal of Composite Materials , online (May 2022). In this work, bending properties of five-layer sandwich panels with corrugated three-layer core are investigated both numerically and experimentally. Sheet metal forming is employed to construct the corrugated core and three-point bending tests are performed to experimentally evaluate the bending behavior of the panels. Besides, reliable finite element model is developed and validated by the experimental results. The results show that the phase difference of
Technical Abstracts
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