Search

Paper has been used in the field of hygiene for centuries. Tissue papers have low grammage, creped or non-creped surface, and consisting of one or more layers from virgin papers. Toilet paper, which has an important area of use, comes at the beginning of the tissue papers divided into various product groups. Its use has increased even more with the effect of the coronavirus pandemic. Increasing use of toilet paper causes clogging in sewers as solid waste. Because an important and large part of the sewage is composed of cellulosic structures. Therefore, the disintegration of toilet paper is an important issue. The main properties of toilet paper are characterized by grammage, thickness, polymerization degree, softness and wet tensile strength. This study, it was aimed to determine the relationship between the degree of polymerization, thickness, grammage, softness and wet tension strength of toilet papers, which accumulate in the sewer pipes and cause clogging, and their disintegration in tap water and pure water at environment of different pH levels. A great level and positive linear relationship was found between grammage and in disintegration pH9. It was determined a low level and positive relationship with wet tensile strength in disintegration tap water.

This work has been conducted to investigate the effect of accelerated ageing on the filler-free (control) handsheets and the ones having Precipitated Calcium Carbonate (PCC) and Zeolite (Clinoptilolite) fillers. The diagnosis approach of this work has been based on the use of the techniques of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray diffraction (XRD). The FT-IR technique has allowed identifying the changes in cellulose components of handsheets. Likewise, the XRD technique has provided to diagnose the changes in crystallinity of the handsheets and fillers. The results found out that PCC and Zeolite fillers could be easily added to the structure of the paper network by changing various experimental variables. The loss of C−O functional groups and the formation of carbonyl groups in handsheets has been analysed by accelerated ageing. The spectroscopy results confirmed that usage of zeolite filler has a retarding and structurally improving effect on the glycosidic linkages. Recent findings have been provided new insights into the role of the synergistic effect of the combination of PCC and zeolite fillers in the decelerating of certain ageing mechanism.

WOS:000616046900069 This study aimed to determine the influence of prehydrolysis of wood chips on the kraft pulping of Populus x euramericana. Optimum cooking conditions were determined by evaluating different alkali concentrations and cooking periods. Xylanase was used to hydrolyze chips before cooking. Prehydrolysis process increased the yield and viscosity of pulp. Consequently, the mechanical properties of paper changed remarkably. In contrast, the optical properties of the unbleached kraft pulp declined due to lignin content. The authors thank The Scientific and Technological Research Council of Turkey (Grant No. TUBITAK-COST110O558) for their support.

The choice of the filler type for paper materials has been a qualitative discussion. The mineral precipitated calcium carbonate (PCC) is used in considerable quantities in the pulp and paper industry as filler. However, alternative filler materials have been researched for improving the properties of paper. In this work, a domestic zeolite (clinoptilolite) filler was used separately and mixed with precipitated calcium carbonate (PCC) fillers. Indeed, the objective of our approach was to explore the structural and mechanical properties of handsheets having filler content affected as a function of accelerated ageing. The results confirmed that the mixed furnish of zeolite and PCC fillers provides positive and synergistic effect on the mechanical properties of ageing handsheets at the low content.

Biokraft pulping of aspen has been investigated. Wood chips were treated with CZ-3 and FP 90031-sp strains of white-rot fungus Ceriporiopsis subvermispora for 2 weeks. Afterwards, bleachability of the pulps in peroxide stage was evaluated. Two commercial xylanase enzymes were used for bleaching. Xylanase pre-treatment of pulps increased their ISO brightness properties by approximately 10%. Biokraft pulps were beaten more easily in comparison to the control kraft pulps. Meanwhile, a significant difference due to the fungal or enzymatic pre-treatments was not found in tensile or bursting strength properties of pulps. A strength correlation was found between freeness and alkaline solubility (S18) for pulps at equal beating conditions.

The present study determines the characteristics of bleaching and beating of annual plants and agricultural waste, which constitute important raw material potential for the pulp and paper industry in Turkey. It also examines the effects of this process on several paper properties. Firstly, chemical contents are determined for each raw material and then evaluated for use in the pulp and paper industry. All raw materials studied are found to be suitable for use in the pulp and paper industry, according to the determined chemical content. Secondly, pulp with different properties is obtained and subsequently pretreated with the enzyme xylanase. It is then bleached using the elementary chlorine-free (ECF) method, utilizing the DEpD bleaching sequence, which is both easy to apply and highly effective. The bleaching behavior of each material is then determined. The highest ISO brightness value of 98.3% is obtained using soda-AQ pulps deriving from rye straw. This is followed by wheat straw (92.0%), reed (88.6%), corn stalks (87.6%), and rice straw (87.5%). Each unbleached pulp sample is beaten at a constant 3000 revolutions PFI (9000 rev. for hemp), and changes in freeness properties are determined. The hardest material to beat is hemp fibers, followed by reed, rye, corn, and cotton stalks. The best beatable pulps are rice straw, tobacco, wheat, sunflower, and barley stalks. Paper sheets from both unbleached and bleached pulps are tested.

Pretreatment of hemp pulp with xylanase was investigated. Unbleached hemp pulp was treated with commercial xylanase, and then bleached with hydrogen peroxide. Control pulp bleached with out xylanase was compared with xylanase bleached pulp. Application of xylanase was found to have a positive effect on followed peroxide stage in terms of low kappa number and high brightness of pulp.

This paper presents the results of trials to evaluate the color-stripping behaviour of offset printing colors and the effect of coating on deinking performance. Oil-based four-color inks were separately printed as base printing on coated and uncoated white poster paper, and then extensive pulping and deinking processes were carried out. Standard offset printings were conducted on paper samples using cyan, magenta, yellow, and black colors (CMYK), and the effects of deinking efficiency on the removal of each color were analysed. The pulps were made at Micro-Maelstrom Laboratory Pulper at specified conditions with and without bleaching agents. Formamidin sulfinic acid and hydrogen peroxide formulation were used as reductive and oxidative bleaching agents, respectively. Flotation deinking and thickening of pulp were practiced using Degussa flotation and thickening cell. The changes in the optical properties, such as brightness, whiteness, and color value (CIE L, a b) of deinked pulp were determined. It was found that optical properties of color-stripped pulps from coated papers were better than that of uncoated office papers. However, yield was quite low in coated papers since fillers were lost during flotation process. Cyan color was found to be the most difficult one in four main color printing inks stripping out in the deinking process.

Pretreatments of wheat straw with two dif erent lignin­degrading fungal cultures ­ Ceriporiopsis subvesmispora and Phlebia subserialis­ were carried out and their ef ects on soda­AQ and kraft­AQ pulping were studied. After two weeks of bio­treatment of the wheat straw, both fungus were found to be suitable for bio­chemical pulping. The fungal pretreatment decreased the kappa number by as much as 24% and the unbleached pulp brightness increased by about 7% at a constant yield. Furthermore, the bio­pretreatment increased the brightness of the fully bleached pulp by about 1 ISO% point. This can apparently reduce the amount of the chemicals used in the bleaching process. The results on the sugar analysis of the pulps showed that in terms of carbohydrate composition, there were no significant dif erences between the bio­treated and control pulps. However, the strength properties of the un­bleached and bleached chemical straw pulps decreased slightly after the fungal pretreatment. This is dif erent from reported results that the strength properties of mechanical pulps were improved after the fungal pre­treatment. There was no dif erence of the two white­rot fungal species, Ceriporiopsis subvesmispora and Phlebia subserialis in term of their ef ect on the strength properties.

Heat treatment is often applied to some wood species to improve dimensional stability. This study evaluated the effect of heat treatment on some physical and mechanical properties and colour of Eucalyptus wood ( Eucalyptus camaldulensis Dehn.), which has industrially high usage potential and large plantations in Turkey. Wood specimens from Tarsus, Turkey were subjected to heat treatment in varying temperatures and durations. After the heat treatment, hardness, swelling, ovendry density, and colour change of the wood specimens were tested in comparison with untreated specimens. The results showed that density, swelling, and hardness decreased with increasing treatment temperature and durations while heat treatment made the colour of the wood specimens darker.

Sap- and heartwood extracts obtained by successive extractions with cyclohexane, chloroform, ethanol and hot water from J. foetidissima and J. oxycedrus were tested for their antifungal activity by using the agar plate method. Generally, the extractive substances of heartwoods soluble in nonpolar or slightly polar solvents show higher activities, whereas the extract fractions with higher polarity also seem to possess notable inhibition in case of sapwoods.

The pretreatment of soda-anthraquinone (AQ) wheat straw Pulp with Purified endo-(1,4)-beta-xylanase was studied. Different xylanase dosages (0, 2, 20 and 100 IUg(-1)) were applied to the Pull) before ail ECF (Elemental Chlorine Free) bleaching sequence. The fiber characteristics, brightness stability and strength properties of the obtained pulps were determined. The results showed that the fiber characteristics were not significantly affected by the enzyme pretreatment. Oil the other hand, the xylanase pretreatment lowered the strength properties of the pulp. A slight improvement in lignin removal was observed, thus improving pulp bleachability, the results agreeing with those obtained oil wood pulps. Furthermore, higher paper brightness stability was obtained by the xylanase pretreatment, explained by the removal of the metal ions from the Pulp samples.