PAPER making! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL Volume 6, Number 1, 2020 First, compression tests are carried out on nonindentation cartons, one Ǧ line indentation cartons, unclosed rhombus indentation cartons, rhombus indentation cartons, and cross Ǧ indentation cartons to record their maximum compressive force. Second, by comparing the deformation of different cartons, it is found that rhombus indentation and cross Ǧ indentation have the greatest influence on the compressive strength of cartons. Rhombus indentation will enhance the compressive strength of the carton, while cross Ǧ indentation will reduce it. Third, ANSYS Workbench is used to analyze the buckling of cartons, and the maximum compressive force of nonindentation cartons and rhombus indentation cartons is obtained. Finally, through the comparison of the finite element method and experiments, it is concluded that rhombus indentation can improve the compressive strength of cartons, which is of great significance to the industrial production of cartons. PAPER CHEMISTRY Self-assembly of Alkyl Chains of Fatty Acids in Papermaking Systems: A Review of Related Pitch Issues, Hydrophobic Sizing, and pH Effects, Martin A. Hubbe et al, BioResources, Vol.15(2) . This review article considers the role of fatty acids and the mutual association of their long-chain (e.g. C18) alkyl and alkenyl groups in some important aspects of papermaking. In particular, published findings suggest that interactions involving fatty acids present as condensed monolayer films can play a controlling role in pitch deposition problems. Self-association among the tails of fatty acids and their soaps also helps to explain some puzzling aspects of hydrophobic sizing of paper. When fatty acids and their soaps are present as monolayers in papermaking systems, the pH values associated with their dissociation, i.e. their pKa values, tend to be strongly shifted. Mutual association also appears to favor non-equilibrium multilayer structures that are tacky and insoluble, possibly serving as a nucleus for deposition of wood extractives, such, as resins and triglyceride fats, in pulp and paper systems. Paper fillers innovations: From design of particles to preparing filler composites, Shunxi Song et al, BioResources. Vol.15(2) . The increase of filler content in paper is an effective way to reduce production costs and to promote the market competitiveness of paper mills. A shift from natural fillers to synthetic fillers has enabled improvements in the critical properties of paper. Meanwhile, innovations from single particles of filler to filler composites has made it possible to increase the filler content of paper. Among various filler innovations, the design of fiber/filler composites has aroused general attention from industry and academic researchers. However, concerns related to the cost and recyclability of composite fillers remain to be addressed. Studies on ASA emulsion stabilized with anionic polyvinylamine and its evaluation for sizing of different types of paper furnishes, Ashish Kumarab et al, Colloid and Interface Science Communications, Vol.34 . Low stability of cationic starch (CS) stabilized alkenyl succinic anhydride (ASA) emulsion is the main drawback of ASA sizing of paper to impart hydrophobicity. Present communication deals with the study of anionic polyvinylamine (APVAm) stabilized ASA emulsion at different process conditions viz. pH, temperature and pulps viz. mixed hardwood (MHW), bagasse (BBS), recycled (RCL) & fillers. APVAm stabilized ASA emulsion was found to be stable at higher pH and temperature. Sizing was better with BBS pulp followed by RCL and MHW pulps. It was evident from the crystallinity ratios and hydrogen bond energy that BBS pulp had the maximum amorphous region that was translated into lesser chemical requirement to attain same sizing followed by RCL and MHW pulps. The better sizing behaviour with lesser dosage of APVAm stabilized ASA emulsion was observed with unfilled and talc filled paper as compared to ground calcium carbonate and precipitated calcium carbonate filled paper.
Technical Abstracts
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