Karakterizacija i odvajanje lignina iz crnog luga dobivenog kraft metodom uz primjenu različitih alkohola

The aim of this study was to investigate the properties of lignin obtained from black liquors of Scots pine (Pinus sylvestris L.) and European aspen (Populus tremula L.) woods cooked by Kraft method. In the study, the cooking process was carried out according to parameters such as: 1/4 of wood/liquor ratio, cooking temperature at (170±2) °C, and cooking time of 90 min. After the cooking process, the black liquor was taken to a beaker from the digester, and lignin was recovered in different ways from the black liquor with methyl alcohol (MeOH) and ethyl alcohol (EtOH). The material properties of the recovered lignin were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), x-ray diffraction (XRD), and thermogravimetric analysis (TGA). Commercial lignin (cml-lignin) was used to compare the properties of lignin obtained from black liquor. SEM images showed that the particle sizes of lignin obtained with EtOH and MeOH were similar. In FT-IR, it was detected that the recovered lignin types have similar functional groups, while some differences were observed in intensities of the peaks. XRD results revealed that all lignin types were found to have a similar structure with the cml-lignin, and that alcohol types used during the recovery process of lignin do not have an important effect on the structural properties of lignin. The TGA results indicated that the thermal stability of recovered lignin has better thermal stability than cml-lignin. The results showed that the recovered lignin was similar to commercial lignin and that it can be recovered from the liquor leftover from Kraft pulping by the method described and used in industry.Cilj rada bio je istražiti svojstva lignina dobivenog od crnog luga drva bijelog bora (Pinus sylvestris L.) i jasike (Populus tremula L.), kuhanoga kraft metodom. Proces kuhanja u ovom je istraživanju proveden uz ove parametre: omjer drva i luga 1 : 4, temperatura kuhanja 170 ± 2 °C, vrijeme kuhanja 90 min. Nakon procesa kuhanja crni je lug premješten iz digestora u čašu te je lignin metilnim alkoholom (MeOH) i etilnim alkoholom (EtOH) na različite načine izdvojen iz crnog luga. Svojstva izdvojenog lignina analizirana su skenirajućim elektronskim mikroskopom (SEM), infracrvenom spektroskopijom s Fourierovom transformacijom (FT-IR), difrakcijom X-zraka (XRD) i termogravimetrijskom analizom (TGA). Za usporedbu svojstava lignina dobivenog iz crnog luga poslužio je komercijalni lignin (cml-lignin). SEM slike pokazale su da su veličine čestica lignina dobivenog uz pomoć EtOH i MeOH bile slične. FT-IR analizom utvrđeno je da izdvojeni tipovi lignina imaju slične funkcionalne grupe te da su se pojavile neke razlike u intenzitetu pikova. Rezultati XRD-a otkrili su da svi tipovi lignina imaju sličnu strukturu kao i cml-lignin i da vrsta alkohola upotrijebljenog tijekom procesa izdvajanja lignina nema bitan učinak na strukturna svojstva lignina. Rezultati TGA analize pokazali su da je toplinska stabilnost izdvojenog lignina bolja od toplinske stabilnosti cml-lignina. Prema rezultatima istraživanja može se zaključiti da je izdvojeni lignin sličan komercijalnom ligninu, da može biti izdvojen iz tekućine koja je preostala od proizvodnje celuloze opisanom kraft metodom te da se može rabiti u industriji

Effects of wood flour on the mechanical, thermal and morphological properties of poly (l-lactic acid)-chitosan biopolymer composites

The aim of this paper was to investigate the effects of wood flour on the mechanical, morphological and thermal properties of poly (L-lactic acid) (PLA)-chitosan biopolymer composites produced by compression molding. The composites were characterized by a combination of mechanical properties, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The addition of chitosan to PLA matrix reduced the tensile strength from 57.1 MPa for pure PLA to 34.3 MPa for 5% chitosan and 11.5 MPa for 10% chitosan, and the flexure strength from 72.3 MPa for pure PLLA to 30.4 MPa for 5% chitosan and 24.6 MPa for 10% chitosan. The change trend in the young’s modulus was found to be similar as compare with the tensile strength. However, the flexure modulus generally increased with the addition of the chitosan as comparison with pure PLA. The mechanical properties of the PLA-chitosan blends with wood flour were found to be lower than theirs of the pure PLA. According to SEM images, some holes and small voids at various diameters on the fractured section of the all composites were seen. Tonset, T10%, T50%, T85% of the pure PLA decreased with the addition of both chitosan and wood flour. Thermal stability of the PLA-chitosan blends was determined to be better than the PLA-chitosan composites with wood flour

Retrospective comparison of flot and modified dcf as first-line chemotherapy in metastatic gastric adenocarcinoma

Background: The aim of our study was to compare the efficacy and the safety of the FLOT and the modified DCF (mDCF) regimens in patients with metastatic gastric (GC) and gastroesophageal junction (GEJ) adenocarcinoma as first-line treatment. Methods: The medical records of 72 patients were retrospectively reviewed. Survivals and hematological adverse events of the patients were examined. Factors affecting survivals were analyzed in univariate analysis. A multivariate analysis was performed with the factors contributing to survivals in univariate analysis. Results: The median PFS (mPFS) was 10.1 months (95% CI, 6.8-13.4) in the FLOT arm (n = 33) and 7.4 months (95% CI, 9.1-21.6) in the mDCF arm (n = 39) (p = 0.041). The median OS (mOS) was 12.9 months (95% CI, 9.7-16.1) in the FLOT arm and 15.4 months (95% CI, 9.1-21.6) in the mDCF arm (p = 0.622). It was found that all grade neutropenia was 51.3% vs. 72.7% (p = 0.063), febrile neutropenia was 8.3% vs. 6.3% (p = 0.743), and thrombocytopenia was 48.7% vs. 51.5% (p = 0.813) in the FLOT and mDCF arms, respectively. Anemia was 59% in the FLOT arm and 100% in the mDCF arm (p < 0.001). Grade 3-4 anemia was 7.7% in the FLOT arm and 24.2% in the mDCF arm (p = 0.052). Discussion: It was shown that the mPFS was significantly increased in the FLOT arm compared to the mDCF arm as the first-line treatment in patients with metastatic GC and GEJC. Hematological adverse events were more favorable in the FLOT arm than in the mDCF arm

CHANGES IN THE CHEMICAL STRUCTURE OF THERMALLY TREATED WOOD

Changes in the chemical structure of hornbeam and uludag fir woods during thermal treatment were investigated at three temperatures (170, 190, and 210 oC) and three durations (4, 8, and 12 hours). After thermal treatment, the extents of degradation in the chemical structure of the samples were determined, and the effects on the chemical composition of hornbeam wood and uludag fir wood were investigated. The data obtained were analyzed using variance analysis, and Tukey’s test was used to determine the changes in the chemical structure of uludag fir and hornbeam woods. The results showed that heating wood permanently changes several of its chemical structures and that the changes are mainly caused by thermal degradation of wood polymers. It was found that decreasing of the cellulose and holocelluloses ratio had a favorable effect on the interaction of the wood with moisture. According to the obtained results, hornbeam wood is affected more than uludag fir wood. For each wood, the maximum decreases of holocellulose and α-cellulose were found at 210oC for 12 hours, and the maximum increase of lignin occurred at the same treatment combination

Lamine Kayın Panellerin Fiziksel ve Mekanik Özellikleri Üzerine Lif Dolgulu Epoksi Tutkallarının Etkisi

Termoset bir polimer olan epoksi, birçok alanda kullanımı olan bir materyaldir. Suya, aside ve alkaliye direnci çok yüksek, zamanla direnç özelliğini kaybetmez ve bu yüzden birçok materyalin ya da kompozitin hazırlanmasında kullanılabilmektedir. Özellikle yüzey kaplamalarında ve yüzey özelliklerinin iyileştirilmesinde farklı katkı maddeleriyle birlikte kullanılabilmektedir. Bu çalışmada; lamine kayın panellerin fiziksel, mekanik ve yüzey morfolojisi üzerine Mikrofibril selüloz (MFC), Nanofibril selüloz (NFC), pamuk (C) ve α–selüloz (AC) katkılı epoksi tutkalının etkileri araştırılmıştır. Lamine malzemeler 5 katmanlı olarak Doğu kayını (Fagus orientalis) odunu kullanılarak yapılmıştır. Analiz sonuçlarına göre epoksi’ye eklenen farklı katkı maddelerinin, lamine malzemelerin yoğunluk değerlerini kısmen yükselttiği belirlenmiştir. Yoğunluk değerlerine göre tam kuru rutubette NFC ilaveli lamine kompozitlerin yoğunluğu 0.70 gr/cm³, hava kurusu rutubette MFC’li kompozitlerin 0.74 gr/cm³ ve %100 rutubette ise kontrol örneklerinde 0.90 gr/cm³ olarak belirlenmiştir. Elde edilen mekanik özelliklere bakıldığında sırasıyla en yüksek eğilme direnci, MFC içeren kompozitlerde 118,5 MPa; eğilmede elastikiyet modülü ve basınç direnci ise C’li numunelerde 9385 MPa ve 66.81 MPa Olarak belirlenmiştir. Elektron mikroskobu yardımıyla yapılan yüzey analizlerinde ise katkı maddelerinin yüzeyde tutunmayı artırarak mekanik özellikleri yükselttiği belirlenmiştir

Surface properties of mdf coated with calcite/cla y and effects of fire retardants on these properties

The coating of wood and wood panel surfaces basically serves for surface protection and its surface can be improved at various user areas. Different application methods are used for the coating of MDF surface. Th ese are methods such as curtain coating, spraying, rolling, knife, etc. In this study, suitability of pigment coating method instead of the traditional surface coating methods used for coating MDF panels and the effects of fi re retardants on surface properties of MDF coated by the best appropriate coating mixture was investigated. Calcite and clay were used as coating pigment and latex, urea formaldehyde, and melamine formaldehyde were used as adhesive. Coating/adhesive mixture obtained was applied to MDF panels with knives. Before the analysis, test samples were put to condition room and they were kept in there for 1 week. According to the results obtained, the best appropriate coating material was found as calcite. 22% concentrated melamine formaldehyde as adhesive and 0.25 mm as coating thickness was determined better than other combinations. Borax, boric acid and zinc borate as fi re retardant were added to calcite /melamine formaldehyde with 22% mixture. So, the effects of fi re retardant on surface characterization were determined. Surface properties of coated MDF panels tested were found lower than standard requirements except for abrasion resistance

The density, compression strength and surface hardness of heat treated hornbeam (Carpinus betulus ) wood

The heat treatment of wood is an environment-friendly method for wood preservation. The heat treatment process only uses steam and heat, and no chemicals or agents are applied to the material during the process. Tests have shown no harmful emissions are apparent when working with the ma-terial. This process improves wood’s resistance to decay and its dimensional stability. In this study, the density, compression strength and hardness of heat treated hornbeam (Carpinus betulus L.) wood were investigated. Wood specimens that had been conditioned at 65% relative humidity and 20 ºC were subjected to heat treatment at 170, 190, and 210 ºC for 4, 8, and 12 hrs. After heat treatment, compression strength and hardness were determined according to TS 2595 and TS 2479. The results showed that the decreases of compression strength and hardness were related to the extent of density loss. Both compression strength and hardness decreased with the increasing temperatures and durations of the heat treatment. While the maximum density loss observed was 16.12% at 210 ºC and 12 hour, at these heat-treatment conditions, the compression strength approximately decreased 30% and hardness values in tangential, radial, and longitudinal directions approximately decreased by 55%, 54%, and 38%, respectively. Hence, it was concluded that there might be a relationship between changes of these wood properties.

Silikon Yağının Bakteriyel Selüloz Üretiminde Verime Olan Etkisi

Bu çalışmada, CAS kayıt numarası 63148-58-3 olan silikon yağı kullanılarak bakteriyel selüloz (BC) üretiminde verime olan etkisi incelenmiş ve bazı özelliklerine bakılarak literatür ile karşılaştırılmıştır. Bu amaçla, hazırlanan Hestrin ve Schramm (HS) ortamına Gluconacetobacter hansenii (Kontrol-BC) ve Gluconacetobacter hansenii + Silikon (Silikon-BC) yağı ilave edilerek 14 gün bekletilmiştir. Oluşan BC tabakalarının morfolojik özellikleri SEM ile incelenmiştır.  Su tutma kapasitesi Kontrol-BC ve Silikon-BC için sırasıyla; 68,31 ve 173,82 katı olarak bulunmuştur. Selüloz verimleri ise sırasıyla Kontrol-BC’de 1,054 g/l ve Silikon-BC de ise 1,234 g/l olarak belirlenmiştir. Diğer taraftan, FTIR ve TGA analizleri de yapılarak karşılaştırılmış ve benzer yapıda oldukları görülmüştür. XRD analizi sonuçlarına göre Silikon-BC ilaveli örneklerin kristalinitesinin kontrol örneğine göre daha yüksek olduğu belirlenmiştir. Bu sonuçlara göre, silikon yağının selüloz verimi üzerinde olumlu etkisi olduğu saptanmıştır

Cannabinoid Receptors Are Not Involved in Antinociception Induced by Systemic Diclofenac in Mice

DergiPark: 700217tmsjAims: It has been long suspected that the cannabinoid system participates in the antinociceptive effects of nonsteroidal anti-inflammatory drugs. We studied the possible effects of cannabinoid receptor antagonism on diclofenac-induced antinociceptionin the writhing test in mice. Methods: In our study, male BALB/c mice, weighing 20-30 g, were used. Writhing responses wereproduced by intraperitoneal injection of 0.6% acetic acid. Different doses of diclofenac (3, 10, 30 mg/kg, i.p.) were tested, thenthe influence of AM-251 (1 mg/kg, i.p.), a cannabinoid CB1 receptor antagonist and AM-630 (3 mg/kg, i.p.), a cannabinoidCB2 receptor antagonist on the antinociceptive effects of diclofenac was studied. Results: Diclofenac administration elicited asignificant, dose-dependent antinociceptive response; however, neither the cannabinoid CB1 receptor antagonist AM-251 northe cannabinoid CB2 receptor antagonist AM-630 had any influence on the antinociceptive effect of diclofenac. Conclusion:Iinhibition of cannabinoid receptors does not contribute to the antinociceptive action of systemic diclofenac. Further studiesare needed to explain the antinociceptive mechanism of diclofenac. Keywords: AM-251, AM-630, antinociception, cannabinoidreceptors, diclofena

The bending and tension strength of furniture joints bonded with polyvinyl acetate nanocomposites

Furniture is the general name given for the portable equipment used in various human activities such as seating, working and relaxing. They can be a product of design and is considered a form of decorative art. They can widely be manufactured with different adhesives. Biodegradable and biobased adhesives which have no toxic compounds and non-dangerous elements have been selected since the furniture is generally benefited in interior locations. Meanwhile, polyvinyl acetate (PVAc) is a thermoplastic polymer which is widely used in the furniture industry. In this study, tension and bending strength of the furniture joints bonded with polyvinyl acetate adhesives filled with nano-TiO2 and nano-SiO2 were investigated. Three materials; oak (Quercus robur) wood, beech (Fagus orientalis) wood and plywood made with beech veneers were selected, and the joints were prepared by mortise and tenon joints. The results showed that the maximum value for the tension strength and bending strength were obtained to beech wood and oak wood in 2% addition of nano-SiO2 fillers. The minimum values for the tension and bending strength nano-SiO2 were found to plywood and 4% loading