Vibrações ultra-sônicas: uma tecnologia alternativa ao refino da celulose branqueada kraft de eucalipto / An alternative technology to the refining of the bleached kraft pulp in eucalyptus

AUTOR(ES)

Rogério Peixoto Silva

DATA DE PUBLICAÇÃO

2002

RESUMO

Some technological conditions were studied at laboratory level, so allowing to evaluate the application of the ultrasonic vibrations upon the bleached pulp in eucalyptus as a refining form, as well as their effects on the development of the paper properties. Initially some preliminary tests were accomplished in order to verify either the best time and the potency of the ultrasonic waves to be applied on the eucalyptus pulp. Following, it was tried to optimize the consistence conditions and the mass pH in such a way to provide a higher increment in quality of the paper. After optimizing these conditions, the experimental study was implemented in order to evaluate the properties of the paper, as well ass the possible morphological, physical and chemistry alterations in the fibers. It was found that the eucalyptus pulp suffered an effect similar to that of the conventional mechanic refining, therefore increasing the resistance of the paper. The properties of the paper were developed on an optimized way, when the ultrasound waves were applied at the maximum potency of the equipment (190 W), for thirty minutes, at a mass consistence of 3% and pH 8.0. A better result was attained when, under these optimized conditions, the eucalyptus pulp was sonificated after the mechanical refining, since the same tensile index was reached with a lower energy consumption of the PFI refiner. Comparing the effects of this technology with those of the mechanical refining, it is concluded that the ultrasound provides a better development of the paper properties, besides causing no deleterious effects on the fibers such as the cutoffs and fines. Thus, under the technological viewpoint, the application of the ultrasound is viable as a refine technology. However, this technology has a need for the availability of higher power-loaded equipments that would allow to reduce the time of the pulp ultrasonification.

ASSUNTO(S)

paper properties eucalipto tecnologia de celulose e papel aplicações industriais celulose propriedades ultrasound waves pulp eucalyptus ondas ultra-sônicas papel industrial applications

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