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Comparison of reinforced oxygen delignification methods for old corrugated board (OCC) fibres

Koç B. O., Gümüşkaya E., Erişir E., Peşman E., Kirci H.

Drewno : prace naukowe, doniesienia, komunikaty

2017

vol. 60, nr 199

47--64

The present work focuses on the effects of sodium percarbonate and hydrogen peroxide as reinforcing agents for the oxygen delignification of old corrugated container paper (OCC). The chemical and crystalline structure, physical and mechanical properties and the optical properties were investigated in OCC papers delignified using reinforced oxygen delignification methods. The relative degradation rates were determined at 4.02% for oxygen delignification reinforced with sodium percarbonate and 0.62% for oxygen delignification reinforced with hydrogen peroxide at a 2% alkali charge. The results showed that paper sheet properties following oxygen delignification reinforced with hydrogen peroxide were better than for those following oxygen delignification reinforced with sodium percarbonate and pure sodium percarbonate. It was determined that the whiteness value was higher following oxygen delignification reinforced with sodium percarbonate rather than any of the other reinforcing agents, while the highest ISO brightness value was found following oxygen delignification reinforced with hydrogen peroxide.

Alkaline sulphite pulping of Caucasian spruce (Picea orientalis L.) chips with additions of NaBH4 and Ethanol

Erişir E., Gümüşkaya E., Kirci H., Misir N.

Drewno : prace naukowe, doniesienia, komunikaty

2015

vol. 58, nr 194

89--102

The study determined and compared the yield, viscosity, and chemical and physical properties of the pulps obtained as a result of Alkaline Sulfite–Anthraquinone (AS-AQ) pulping of Caucasian spruce wood with and without the addition of sodium borohydride (ASAB process) and ethanol (ASAE). It was found that the addition of ethanol to the AS-AQ pulping had a favourable influence on the screened yield and kappa number of the pulps. The addition of NaBH4 to the AS-AQ pulping in general also had a favourable influence on these pulps’ indices, provided that the amount added was not higher than 1–2% and the time of pulping was 180 mins. The higher yield of the ASAE pulps resulted from the higher retention of both cellulose and hemicelluloses, while the higher yield of ASAB pulps resulted from the higher retention of hemicelluloses and lignin. Regarding the AS-AQ pulping conditions, a distinct negative effect of modification on the viscosity of the pulps was observed in the case of the NaBH4 a additions to this pulping process. The viscosity reduction was, however, lower with extended pulping time. The static strength properties (tensile index and burst index) of the ASAB and ASAE pulps were in general lower than the AS-AQ pulps. In the case of the tear index, the tendency was similar. The addition of ethanol and especially NaBH4 to the AS-AQ pulping had a distinctly unfavourable influence on the whiteness and brightness of the pulps.