CMP pulps of willows for newsprint part 1: Pulps evaluation.

MONTEOLIVA S., AREA, M.C., FELISSIA, F.E

CELLULOSE CHEMISTRY AND TECHNOLOGY

Romanian Academy

Año: 2007 vol. 41 p. 263 - 272

0576-9787

The pulping characteristics of six Salix clones were investigated by alkaline sulfite chemi-mechanical pulping (CMP). The clones studied were S. babylonica var. Sacramenta, named "American willow", and five hybrids, S. babylonica x S. alba `A 250-33´, `A 131-25´, `A 131-27´ and S. matsudana x S. 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 Ríos 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. Keywords: Salix clones, chemi-mechanical pulps, anatomical properties, chemical properties, pulpproperties