2SiO₃ on the properties of the resultant pulp and the residual H₂O₂ content were investigated in this study. The results showed that the obtained P-RC APMP has 15.4% increase in bulk but opacity and strength properties decreased after replacing 50% NaOH with MgO. Compared with the pulp adding DTPA， bulk of the pulp without DTPA reduced by 6.5%. However， the tensile index， burst index and tear index increased by 6.6%， 4.4% and 6.6%， respectively. Moreover， the opacity increased by 10.3%， and the brightness had no significant change （only 0.57% increased）. The residual H₂O₂ content was 3.55 g/L at the end of bleaching， which was decreased by 5.1%. Therefore， if the property of bulk was not regarded as most important， using MgO as the alkaline source to replace 50% NaOH in the HC stage of P-RC APMP could also replace the chelating agent DTPA at the same time， thereby the need for metal ion chelating agents was eliminated.]]> 2021/7/27 0:00:00 ZHANG Bo,LIU Xin,WU Kaili,WANG Xiaodi,ZHANG Fangdong,LIU Wei,HOU Qingxi 2true 2 were copolymerized to obtain nano TiO₂ composite fluorescent whitening emulsion （FBs-TiO₂）， which was used for paper surface coating. The results showed that FBs-TiO₂ was successfully prepared and had better stability. The whiteness increased from 67.2% to 87.2%， the tensile strength was enhanced from 3.12 kN/m to 4.87 kN/m， the tearing strength was increased from 13.8 mN·m²/g to 17.4 mN·m²/g after FBs-TiO₂ was coated on paper surface， the PC value decreased from 10.40 to 6.66 after 48 hours of UV aging. It was indicated that the FBs-TiO₂ not only improved the whiteness of paper and inhibit the yellowing of paper， but also significantly enhanced the surface strength and mechanical properties of paper. It was a papermaking additive with positive performance.]]> 2021/7/27 0:00:00 ZHANG Guanghua,WANG Zhe,GUO Mingyuan,NI Meile,HAN Xiaoqian,TONG Xin,WANG Yanmeng,FENG Pengchao 1true