作者机构：
[Chen, Qijie; Yan, Yongxiang] Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha, Hunan Province, 410004, China;[Chen, Fushan] College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, Shandong Province, 266042, China;[Chen, Qijie] State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, Guangdong Province, 510640, China
通讯机构：
[Chen, Q.] H;Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, China
关键词：
Anti-counterfeiting properties;Fluorescent properties;Fluorescent semiconductor nanocrystals;Quantum dots (qds);Special paper
摘要：
Fluorescent semiconductor nanocrystals, also called quantum dots (QDs), have unique electronic and optical properties. One of the most useful features of QDs is that whereas their absorption spectra are broad, their emission spectra are very narrow. Different QDs can emit different wavelengths of visible light under UV excitation. QDs as a fluorescent anti-counterfeiting material have been attracting great interest in the application of specialty papers, such as security paper, banknote paper, packaging paper, etc. An anti-counterfeiting technique using QDs is one of the newest achievements in the anti-counterfeiting field. In the long run, research and development in the area of QDs anti-counterfeiting will surely create many fruitful results.
摘要：
High-yield pulp (HYP) such as bleached chemi-thermo-mechanical pulp (BCTMP) from aspen wood, is now being used in the production of high-quality fine papers, and this is particularly true in China. In this study, the effect of using cationic polymers such as poly-aluminum chloride (PAC), polyethylenimine (PEI), cationic polyacrylamide (CPAM), and poly-(diallyldimethylammonium chloride) (PDADMAC) on Alkenyl Succinic Anhydride (ASA) sizing efficiency in HYP-containing pulp furnish was investigated. The results showed that the addition of only ASA emulsion to the HYP-containing furnish, without any cationic additives, did not yield an appreciable degree of sizing in the paper sheet. PAC (or alum) could improve the ASA sizing efficiency. PEI, PDADMAC, CPAM, and NaHCO3 all improved ASA sizing efficiency in the presence of PAC. The charge density of PEI was important for improving the ASA sizing performance. Also, the sequence of adding the cationic polymer affected the ASA sizing performance.
摘要：
In recent years there has been an increasing interest in using high-yield pulp (HYP) as a partial replacement for hardwood bleached kraft pulp (HWBKP) in the production of high-quality fine papers as a cost-effective way of improving the product performance. This study investigated the substitution of HYP for HWBKP and its effect on the Alkenyl Succinic Anhydride (ASA) sizing performance. The results showed that the substitution of an aspen HYP for HWBKP can increase the ASA sizing performance at a HYP substitution as high as 15 to 20%. The ASA addition sequence has an influence on the ASA sizing performance and first adding ASA to the HYP followed by mixing with kraft pulps was the preferred method. Using precipitated calcium carbonate (PCC) as a paper filler at a dosage of less than 20% can increase the ASA sizing performance due to the contribution of the calcium soap of the hydrolysed ASA. A PCC dosage greater than 20% resulted in a negative impact on the sizing performance. It was also found that different PCC loading sequences can also affect the ASA sizing performance.
关键词：
Dissolved and colloidal substances (DCS);High yield pulp (HYP);Polyamine
摘要：
In recent years High yield pulp (HYP) is being used at an increasing rate to replace bleached hardwood kraft pulp in the manufacturing of high quality paper products. However, HYP has more dissolved and colloidal substances (DCS), when compared with fully bleached kraft pulp. In general these DCS have an anionic character, and they often disturb the papermaking process. In the paper, the effects of high charge density polyamine (PA) single, dual and triple system on DCS control in high yield pulp were studied. The results showed that the DCS control effects of the PA/HCS (high cationic starch)/CPAM (cationic polyacrylamide) triple system were better than the PA/HCS dual system and the PA single system. In the PA/HCS/CPAM triple system, when the dosage of the PA was 0.06% and the dosage was 0.1% and 0.05% for HCS and CPAM, respectively, the zeta potential of pulp increased by a certain degree, drainage property of pulp improved remarkably, the turbidity of the DCS water was near to zero, and the cationic demand of DCS water decreased by 70.8%. The microscope photograph of fibers also confirmed that the polymers in the PA/HCS/CPAM triple system had very good synergetic effects on the removal of DCS in high yield pulp.
摘要：
In recent years, there is an increasing interest in using high-yield pulp (HYP), as a partial replacement for hardwood bleached kraft pulp (HWBKP) in the production of high-quality fine papers as a cost-effective way of improving their product performance. In this study, the ASA sizing behaviour in High-yield pulp containing pulp furnish was investigated. The results showed that the substitution of an aspen HYP for HWBKP can increase the ASA sizing performance at a HYP substitution of up to 15%similar to 20% by the fact that HYP contains more anionic groups (carboxylic and sulfonic groups), which help retain the ASA size and increase the sizing degrees. The ASA sizing was effective in a wide pH range of 6.5 similar to 9.0 which suggest that under the industrial conditions, a good sizing degree can be obtained from ASA sizing when the HYP-containing furnish is used. With the pulp temperature increasing, the ASA sizing efficiency decreased. In the presence of Polyaluminum chloride (PAC), Polyethylenimine (PEI) and poly diallyl-dimethyl ammonium chloride (PDADMAC) had positive effect on improving the ASA sizing efficiency.
关键词：
amphoteric starch;high degree of substitution;AKD sizing;deinked pulp
摘要：
In recent years, recycled fibers have become an important raw material in papermaking industry. With the increasing use of recycled fibers, dissolved and colloidal substances present in pulp have tended to accumulate more and more seriously. It has been found that the Alkyl Ketene Dimer (AKD) sizing in recycled fibers pulp is not as effective as that in the kraft pulp. In this study, we investigated the effect of a new amphoteric starch on AKD sizing efficiency in deinked pulp. The amphoteric starch was prepared by the hemidry process and characterized with a high degree of cationic and anionic substitution. The results showed that this kind of amphoteric starch had a good effect on improving the AKD sizing efficiency. Meanwhile, it can also shorten the AKD curing time. The amphoteric starch had similar good effect as polyamide polyamine epichlorohydrin (PAE), but a better effect than cationic polyacrylamide (CPAM) and cationic starch (CS), on improving the AKD sizing efficiency. The results of scanning electron microphotograph observation support that the amphoteric starch had a good effect on the AKD size retention and improved the AKD sizing efficiency.
关键词：
cationic cyclodextrin;dissolved and colloidal substances;deinked pulp;removal
摘要：
Simultaneous removal of dissolved and colloidal substances (DCS) has been a challenging task. The cationic-modified beta-cyclodextrin (C-CD) nanospheres synthesized in this study, in conjunction with a high substitution cationic starch (HCS) and anionic polyacrylamide (APAM), potentially provide a novel approach to address the problem. The results showed that the DCS control effect of the C-CD/HCS/APAM triple system was better than that of the C-CD/HCS dual system and the single C-CD system in deinked pulp. In the C-CD/HCS/APAM triple system, when the C-CD dosage was 0.9%, HCS was 0.1% and APAM was 0.05%, the zeta potential of pulp began to increase and the drainage property was improved rapidly, the turbidity of DCS water decreased by 92.2%, and the cationic demand of DCS water decreased by 55.4%. Due to the special internal hydrophobic cavities in the C-CD, the conductivity of DCS water can also be decreased by 10% in the triple system. The microscope photograph of fibers also confirmed that the polymers in the C-CD/HCS/APAM triple system had a very good synergetic effect on the removal of DCS in deinked pulp.
