CMP PULPS OF WILLOWS FOR NEWSPRINT.I.PULP EVALUATION

摘要

The pulping characteristics of six Salix clones were investigated by alkaline sulfite chemimechanical pulping(CMP).The clones studied were S.babylonica var.Sacramento,named"American willow",and five hybrids,S.babylonicaXS.alba'A 250-33','A 131-25','A 131-27'and S.matsudanaXS.alba'A 13-44','NZ 26992',implanted in 2 culture sites in Argentina.The sampling sites included a floodable place in the Paranaense Delta,the Entre Rios province,and a continental site in the Buenos Aires province.Following wood characterization,12 alkaline sulfite pulps were prepared under the following conditions:pre-vaporization,impregnation with 2.6% o.d.NaOH and 2.6% o.d.Na2SO3,liquor/wood ratio of 5.5/1,80°C;40 minutes,and refining with a target value of 50-55 ~oSR(post-screening).Generally,the pulp properties,analyzed for their posible use in newsprint,varied significantly between clones and sites.American willow(tear strength:3.20 mNm2/g,tensile:28.2 Nm/g and opacity:98.6%),250-33(tear strength:4.03 mNm2/g;tensile:26.8 Nm/g;opacity:98.6%)and 26992(torn:3.51 mNm2/g;traction:27.6 Nm/g;opacity:98.5%),all from the Delta site,were the predominant ones.If pulp whiteness was generally higher in the Continental site(reaching 50% ISO),the sample from the Delta site evidenced higher mechanical strength.