Using Functionalized Fines To Improve The Bonding Property Of High Yield Pulp Fiber

High yield pulp(HYP)fiber is widely used in many kinds of paper and paperboard,due to its unique advantages.However,the main drawback of this type fiber associated with weak inter-fiber bonding properties limits its extended application in proportion and fields.Improving the bonding property of HYP without sacrifice of many advantages is severely concerned by many papermaking scientists.In this work,the functional fines were prepared by compounding the fines with cationic polyacrylamide(CPAM).The functional fines were used to improve the inter-fiber bonding properties of HYP,and to maintain the bulk property at the same time.Firstly,the physical properties of fractional aspen P-RC APMP fibers were analyzed,and the fiber fraction of P30/R50 was chosenas raw materials for this experiment.The effect of different fines addition on the properties of handsheet was analyzed.The result showed that the HYP fines have less effect on the improvement of tensile strength of HYP fiber,rather than the chemical pulp fines.However,the addition of HYP fines showed less sacrifice of bulk of HYP network.Then,the functional fines were prepared by compounding the HYP fines with CPAM.The functional fines were added into the suspension with HYP long fiber to prepare the handsheet.The retention value of the fines and the physical properties of handsheet were evaluated,respectively.The result showed that the functional fines were easier to be retained into the HYP fiber network.Also,the retention value increased with the increase of CPAM dosage used for functionalization.The result obtained by testing the physical properties of handsheet shows that the addition of primary fines improves the tensile strength of handsheet finitely,although it can effectively maintain the network buk.Adding CPAM can effectively improve the tensile strength of handsheet,whereas it decreases the bulk sharply.In comparison,adding functional fines into the suspension with HYP fiber can not only improve the tensile strength of fiber network,but also maintain the bulk property.As the functional fines with dosage of 15%+1%(fines+CPAM)was added in to the suspension,the tensile strength of handsheet increased by 79.2%from primary handsheet without addition of any additives,and the bulk of handsheet decreased only by 2.5%.The fines undergone the functionalization can capitalize the synergistic effect of CPAM and fines on improving the performance of HYP fiber network.Finally,the functional chemical pulp fines and HYP fines were respectively prepared,and the different effects of functional chemical pulp fines and HYP fines on the improvement of HYP fiber network performance were comparactively studied.The result shows that the functional chemical pulp fines improves the tensile strength of HYP handsheet more remarkable than the functional HYP fines,but the bulk of paper reduce more than the functional HYP fines.