The Study On The Properties Of Ultrasonic Straw Pulp And The Applicability In Papermaking

Ultrasonic pulping technology is a new pulping process with the characteristics of short production processes, significant energy saving and emission reduction, high yield and excellent physical performance. In our paper, the cellulose and lignin of ultrasonic straw pulp were analyzed. The reaction mechanism of ultrasonic pulping technology and the papermaking adaptability were tried to explored. The results are as follows.The strength and optical performance of ultrasonic straw pulp(USP) is similar to reed pulp, and better than APMP. The whiteness, average fiber length, average fiber width, bursting strength, tearing resistance, tensile index and folding are 77.8%ISO,0.754mm,29.5μm,3.08kPa·m2/g,3.98mN·m2/g, 30.49N·m/g and 29 times respectively.The carbonyl group of USP is far lower than ASP, which is one of the reasons for the good witness of USP. The neutral and mild environment of ultrasonic pulping process may decrease the formation of phenolic hydroxyl and quinone groups. The total phenolic hydroxyl content of USP is lower than that in ASP. Due to the more destruction, the traditional alkaline pulping can cause more break of aryl ether linkages and methoxy, which can produce more phenolic hydroxyl. Additionally, the carboxyl group content of USP(0.52 mmol/g) is higher than ASP(0.3 mmol/g).In our paper, the USP and other pulps were used to make the offset paper and newsprint paper. The results are as follows.The optimal conditions of offset paper using USP is as follows. The adding amount of USP, AKD, CPAM, CaCO3 is 50%,0.8%,0.2% and 8.0%～12.0% respectively. The surface sizing consists of CS-1 surface sizing agent, aluminium sulfate(concentration 30%,dosage 2kg/t), oxidize starch(concentration 30%, dosage 2kg/t), and the optimum adding amount is 0.14g/m2. The performance of paper made by USP and aspen chemical pulp through press polishing is as follows:the water absorption, whiteness, opacity, printability, smoothness, tensile index and folding are 34.02g/m2,80.9%ISO,93%,2.8m/s, 38.56s,36.3N·m/g and 18 times respectively. The test value of paper have reached or exceeded the industry standards of offset printing paper.The optimal conditions of newsprint paper using USP is as follows. The adding amount of USP, AKD, CPAM is 80%,0.2% and 0.2% respectively. The surface sizing consists of CS-1 surface sizing agent, aluminium sulfate(concentration 30%,dosage 2kg/t), oxidize starch(concentration 10%,dosage 1.5g/m2), and the optimum adding amount is 0.10g/m2. The performance of paper made by USP and aspen mechanical pulp through press polishing is as follows. The water absorption, whiteness, opacity, printed surface roughness, smoothness, tensile index and tear index are 32.57g/m2,77.5%ISO,89.2%, 5.2μm,27.6s,37.46N·m/g and 4.8 mN·m2/g respectively. The test value of paper have reached or exceeded the industry standards of newsprint paper.In summary, we preliminary think that it shows promising future to replace traditional chemistry wheat straw pulp with ultrasonic wheat straw pulp making offset paper and newsprint paper.