Resource Utilization And Ionization Modification Of Secondary Starch From The Recycling Process Of Old Corrugated Cardboard Paper

Generally,the mechanical strength and stiffness of old corrugated cardboard?OCC?waste paper are decreased after multiple recycling procedures.Enzymatic starch,which is extensively used in the surface sizing of paper making,accumulates after dissolving from the fibers and is transformed into pollutant during the OCC re-pulping process.Starch is the ideal nutrient which will boost the growth of microorganism and increase the COD value of waste water,and it will seriously pollute the production system and cause the waste of precious starch resources.The simulant secondary starch in the recycled OCC waste paper was obtained in a sequence of surface sizing via starch,drying and dissolving.The dissolution process and physicochemical properties of the secondary starch were analyzed.On this basis,the secondary starch was ion-modified by hydrogen peroxide?H₂O₂?and 3-chloro-2-hydroxypropyl trimethyl ammonium chloride?CTA?as chemical reagents.It was used in papermaking system to test the retention and the effect on paper properties.The results show that in the dissolution process of secondary starch,the dissolution rate increased with the increase of temperature,time and shear force.The dissolution rate is fast in the early stage and tends to be gentle in the later stage.The starch modified by H₂O₂ can be adsorbed onto the pulp fibers under the bridging effect of CPAM.The increased oxidation degree resulted in an increased retention rate for the modified starch.When the slurry system is 70?,the contact time at 50 s and the CPAM dosage is 0.01%,the retention rate of secondary starch increases to 52.4%.Cationic starch which modified by CTA can be retained directly on the fiber,which can get the highest substitution degree under the condition of 10%CTA dosage modification.When the slurry system is 70?,contact time is 50 s,secondary starch retention rate increased to 56.7%.The modified secondary starch was reused in the papermaking system,the results showed that the construction of the retention and filtration system had a positive effect on the retention effect,and the addition of modified starch could enhance the strength of the paper.In the retention and filtration system of anion starch/CPAM/attapulgite,when the attapulgite content is more than1.0%,the physical properties of the paper are adversely affected.CPAM can improve the disadvantages of cationic starch single component retention and filtration system in a certain degree,and further improve the wet part characteristics and physical properties of the paper.The retention rate of anionic starch on the surface of fiber and the enhancement of paper property are slightly inferior,but it has advantages in economic benefit and reducing secondary pollution.Whatever,the pathway we presented here has a substantial impact on high value utilization of the waste starch,reducing the production cost and promoting clean production.