Search

Kraft method, the most widely used method in pulp production, causes to various environmental problems. Therefore, environmentally friendly pulp production methods have been investigated. In recent years, environmentally friendly deep eutectic solvents (DESs) as cooking liquor have been investigated. In this study, the possibilities of using a ternary DES (TDES) in pulp production from Scots pine (Pinus sylvestris L.) chips were investigated. TDES constituents were choline chloride (ChCl), lactic acid (LA), and glycerol (G). The effects of cooking temperature (145 °C and 155 °C) and cooking time (3 h, 3.5 h, and 4 h) on pulp and paper properties in TDES pulping were investigated. For comparison, kraft pulp from Scots pine was produced with conditions of 18% active alkali, 25% sulfidity, 155 °C cooking temperature, and 3.5 h cooking time. The highest lignin removal was obtained from TDES3 pulping conditions (155 °C and 4 h) with 76.0%. Lignin removal in the kraft pulp was 67.8%. TDES pulps were more quickly beaten to the target freeness level of 25°SR (the times for TDES3 and kraft pulps were 90 sec and 1350 sec, respectively.). Crystallinity index (CrI) values of kraft pulp and TDES3 pulp were 70.7% and 68.0%, respectively. TDES6 pulp had the highest pulp strength. But, the strength properties of all TDES pulps had lower than kraft pulp. TDES pulping can be a greener alternative to kraft pulping. • The pulp production using TDES from Scots pine was accomplished successfully. • The longer cooking time at 155 °C caused significant changes in fiber morphology. • Some properties of TDES pulps were comparable to those of the kraft pulps. • TDES pulping conditions had a significant effect on the pulp and paper properties. • TDES pulps more quickly reached to target freeness level. [ABSTRACT FROM AUTHOR]

Abstract: The results of characterization for four different vine shoot varieties, grown using two different methods, revealed no significant differences in composition among vine varieties or between growing methods. The holocellulose content of vine shoots (67.14%) is lower than those of other non-wood raw materials (e.g. wheat straw, sunflower stalks, cotton stalks, etc.), but similar to those of pine and higher to those of olive trimmings. On the other hand, their lignin content (20.27%) is similar to those of eucalyptus and the non-wood raw materials. Also, their contents in cold-water, hot-water and 1% soda solubles, and ethanol–benzene extractables, are higher than for pine and eucalyptus. Soda, kraft, ethanol and ethylene–glycol pulping processes have low yields (29–47%) relative to the pulping processes applied to olive trimmings and wheat straw. Kraft pulp is that exhibiting the best properties, including a higher α-cellulose content (73.74%) than pulp from wheat straw or olive trimmings, but a higher lignin content (17.18%). Also, kraft pulp provides paper with the highest breaking length, burst index and tear index (viz. 1316m, 1.63kN/g and 1.59mNm2/g, respectively); these values, which are intermediate among those for olive trimmings, wheat straw and sunflower seeds, are low and can be substantially improved by appropriate refining of the pulp. [Copyright &y& Elsevier]