Data/hora: 13/06/2024 17:56:20

Biblioteca(s): 	Embrapa Florestas.	
Data corrente: 	06/06/1995	
Data da última atualização: 	16/03/2009	
Autoria: 	FOELKEL, C. E. B.	
Título: 	Unbleached kraft pulp properties of some the brazilian and U.S. Pines.	
Ano de publicação: 	1973	
Fonte/Imprenta: 	1973.	
Páginas: 	192 f.	
Idioma: 	Inglês	
Notas: 	Thesis (Master of Science) - State University of New York College of Environmental Science and Forestry, Syracuse, New York.	
Conteúdo: 	The purpose of this work was to compare wood characteristics and properties of the pulps obtained from several wood species, four of them growing in Brazil and two in the U.S.A. The four Brazilian pulp woods, namely Araucaria angustifolia, Pinus elliottii var. elliottii, Pinus taeda and Pinus caribaea var. hondurensis, were sampled, analyzed, pulped and tested in that country. The two American pulpwoods, Pinus elliottii var. elliottii (slash pine) and Pinus taeda (loblolly pine) studied in the U.S.A. Fiber measurements, chemical analyses and specific gravity determinations were performed on all samples. The three species of The three species of the genus Pinus from Brazil were young thinned woods and had a large juvenile wood component. The woods were pulped by the kraft process to two different intervals of permanganate number: 16 to 18 and 25 to 30. The objective was to compare pulps of equivalent lignin contents in each interval. The young Brazilian pinewoods were characterized by short fibers, low specific gravity and cellulose content, and high pentosan content. Araucaria angustifolia turned out to have long thick-walled fibers, high specifc gravity and cellulose content, and some what low alcohol benzene solubility and lignin content. The wood of the American slsh pine had longer and thicker-walled fibers, higher specific gravity and lower pentosan content when compared to the wood of loblolly pine. The pulps obtained from Araucaria angustifolia showed high tear strength but low burst and tensile strength. However, the young Brazilian pinewoods produced pulps with relatively high tensile and burst strength. Tear strength was low for Pinus elliottii and Pinus caribaea but high for Pinus taeda. Pinus caribaea pulps had high breaking length and burst factor and required a longer beating time to achieve a given handsheet density. Thesame trend regarding beating time was observed for Araucaria angustifolia pulps. Short-fibered species produced pulps with higher percentage stretch. The main objection to use of the pulps obtained from the young thinned Brazilian woods was the low pulp yield. This important feature leads to an economic problem in using these woods for manufacturing some grades of paper. However, this work demonstrates that kraft pulps from these woods have acceptable strength properties. If wood shortages become more severe, they may be used. The two American southern pine species which were studied gave very strong pulps, but low yields. Comparing the two species, slash pine pulps had higher, breaking lengths and burst factors, while loblolly pine pulps showed higher tear strength and were more easily refined. The effect of K Number on properties and interaction between species and K Number were also successfuly isolated and anlyzed. For all species, pulp yields, beating time and burst factor increased signicantly as a consequece of the increase in the K Number in the ranges which were studied, but the tear factor decreased. Among the Brazilian raw materials, significant effects of interaction between species and K Number were found for total yield (percent of oven- dry wood), beating time and breaking length. For the American woods , these effects were reported for screened yield (percent of oven-dry wood), breaking length and burst factor.	
Palavras-Chave: 	Propriedade.	
Thesagro: 	Polpa.	
Thesaurus Nal: 	Pinus.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Florestas (CNPF)	
Exemplares: 	CNPF - (29916-1) - ADC - TS - -- - TS0027 -  - TS0027 - DIS