Júlio César Medina; Dirceu Ciaramello
Engenheiros-agrônomos, Seção de Plantas Fibrosas, Instituto Agronômico
RESUMO
No presente trabalho são apresentados os resultados dos estudos visando conhecer a influência da idade do côlmo sôbre o rendimento e características físico-mecânicas da pasta sódica crua do bambu imperial (Bambusa vulgaris Schrad. var. vittata A. & C. Riv.).
As análises da variância dos dados obtidos revelam que, à exceção da resistência ao estouro, do alongamento e da porosidade, não houve influência da idade dos colmos de 1, 2, 3 e 4 anos sôbre a resistência ao rasgamento, à tração e às duplas dobras.
Do ponto de vista industrial conclui-se que, na colheita do bambual, poderia ser aplicado o sistema de corte arrasante em lugar do corte seletivo de colmos. Resta verificar se, do ponto de vista agrícola, o primeiro sistema não interfere sôbre o vigor e perfilhamento das touceiras.
SUMMARY
The results of a research on the effect of culm age of Bambusa vulgaris var. vittata A. & C. Riv. on the pulp yield and paper qualities are presented.
Culms from 1 to 4 years old were studied. Pulping was made by soda process and a NaOH concentracion of 5% and a dry material to liquor relation of 1/4 were used. Four individual cookings, each one composed of representative samples for each culm age, were made at a maximum temperature of 160ºC during 2 hours, so that the results could he estimated by statistical analysis.
It was found that the effect of culm, age on pulp yield was significative at a level of 5%, but only for the culms 2 years old.
The pulps were worked in a Jokro refiner by steps of 15 minutes, making a series of six beating times. Proof sheets of 60 g. per s. m. of each pulp, were made and submitted to physical tests, including tearing, bursting, tensile and double folding strength, as well as air permeability determination.
Statistical analysis of data showed that no effect on tearing, tensile and double folding strength could be attributed to culm age. In relation to bursting strength, however, the effect was highly significative; paper made of 2 years' old culm had the highest bursting strength, as compared to those of 1 and 4 years' old culms.
The effect of beating time on paper quality was found to be very high. The best beating time for tearing strength was that giving 20 to 30 Schopper Rieggler degrees, but for the other characteristics it was that giving around 70 to 80 S. R. degrees, excepting for double folding in which case 60 to 65º S. R. gave the best results.
In relation to air permeability the pulps showed to be in general of very high porosity. A maximum average time of 114 s. per 100 ml. of air was found for a beating time of 90 minutes corresponding to 78.° S. R., and a minimum of 0.8 for a beating time of 15 minutes corresponding to 18.6.° S. R.
Concluding, a good paper can be made of bamboo pulp, mostly concerning tearing, which can be comparable with unbleached «Kraft» of softwoods.
Texto completo disponível apenas em PDF.
Full text available only in PDF format.
Recebido para publicação a 1.º de junho de 1965.
Influência da idade do côlmo sobre a qualidade papeleira do bambu imperial
Datas de Publicação
-
Publicação nesta coleção
22 Fev 2010 -
Data do Fascículo
1965
