Volume 5 Issue 3

A series of 4- alkyoxybenzoyloxypropyl cellulose (ABPC-n) samples was synthesized via the esterification of hydroxypropyl cellulose (HPC) with 4-alkoxybenzoic acid bearing different numbers of carbon atoms. The molecular structure of the ABPC-n was confirmed by Fourier transform infrared (FT-IR) spectroscopy and 1H NMR spectroscopy. The liquid crystalline (LC) phases and transitions behaviors were investigated using differential scanning calorimetry (DSC), polarized light microscopy (PLM), and refractometry. It was found that the glass transition (Tg) and clearing (Tc) temperatures decrease with increase of the alkoxy chain length. It was observed that the derivatives with an odd number of carbon atoms are non-mesomorphic. This series of ABPC-n polymers exhibit characteristic features of cholesteric LC phases between their glass transition and isotropization temperatures.

A study has been carried out to evaluate physical and flexural properties of composites made by areca fibers with a randomly distributed orientation of fibers. The extracted areca fibers from the areca husk were alkali treated with potassium hydroxide (KOH) to get better interfacial bonding between fiber and matrix. Then composites were developed by means of a compression molding technique with varying process parameters, such as fiber condition (untreated and alkali treated), and fiber loading percentages (50% and 60% by weight). The developed areca fiber reinforced composites were then characterized by physical and flexural tests. The results show that flexural strength increases with increase in the fiber loading percentage. Compared to untreated fiber, significant change in flexural strength has been observed for treated areca fiber reinforcement.

The objective of this research was to investigate the utilization of olive mill sludge (OMS) as an alternative to wood in the manufacture of the medium density fiberboard (MDF). The MDF panels were manufactured using standardized procedures that simulated industrial production at the laboratory. Six panel types were made from various mixtures of hardwood fiber/dried OMS flour, 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 (by weight) percents, respectively. With increasing OMS flour content, the flexural properties of the panels, modulus of rupture and modulus of elasticity, decreased by 31.0% and 29.2% as compared to panels without OMS flour, respectively. However, the water resistance was improved by the addition of the OMS flour up to 20 wt % content. For example, the thickness swelling and water absorption values of the panels containing 20% OMS flour were 17.3% and 59.5%, while they were found for the panels without OMS flour as 21.5% and 75.6%, respectively. The findings obtained in the study showed that the OMS was capable of serving as lignocellulosic raw material in the manufacture of the MDF.

Experimental laminated veneer lumbers (LVLs) from rotary peeled I-214 (Populus x Euramericana) and two Populus deltoides I-77/51andS.307-26 fast growing hybrid poplar clones were manufactured with a melamine urea formaldehyde (MUF) adhesive successfully. Two Populus deltoides clones that are grown in Turkey were used for the first time in LVLs manufacturing. The results showed that clone types affected physical and mechanical properties of LVLs. Populus deltoides clones had better physical and mechanical properties compared to Populus x Euramericana clonedue to their higher density and fiber length values. S.307-26 clone had the highest and I-214 had the lowest properties among three hybrid poplar clones. The physical and mechanical properties of LVLs were higher than those of solid woods. This increase may be due to compaction factor (densification), manufacturing techniques, and the use of adhesives. The degree of contribution of solid wood properties to the LVLs’ properties was explained by using a contribution factor. Two Populus deltoides clones were found to be more suitable for LVLs manufacturing compared to Populus x Euramericana clone.

In the present study, classical statistical tool Response Surface Methodology (RSM) was adopted for the optimization of process variables in the bioconversion of pretreated sugarcane bagasse into ethanol by cellulase and Candida wickerhamii MTCC 3013 based on Central Composite Design (CCD) experiments. A 23 five level CCD with central and axial points was used to develop a statistical model for the optimization of process variables such as incubation temperature (25 – 45°) X1, pH (5.0 – 7.0) X2,and fermentation time (24 – 120 h) X3. Data obtained from RSM on ethanol production were subjected to analysis of variance (ANOVA) and analyzed using a second-order polynomial equation, and isoresponse contour plots were used to study the interactions among three relevant variables. Maximum response for ethanol production was obtained when applying the optimum values for temperature (33°C), pH (5.7), and fermentation time (104 h). Maximum ethanol concentration (4.28 g/l) was obtained from 50 g/l pretreated sugarcane bagasse at the optimized process conditions in aerobic batch fermentation. Various kinetic models such as Modified Logistic model, Modified Logistic incorporated Leudeking – Piret model, and Modified Logistic incorporated Modified Leudeking – Piret model were evaluated and the constants were predicted.

Sodium titanate nanobelt was synthesized by treating titanium dioxide hydrothermally in concentrated sodium hydroxide solution. The product was characterized by SEM analysis and zeta potential measurement. It served as a microparticle to constitute a microparticle retention system with cationic polyacrylamide (CPAM), while the microparticle system was employed to induce the flocculation of kaolin clay. The flocculation behavior of kaolin clay in such a system was investigated by using a photometric dispersion analyzer connected with a dynamic drainage jar. It was found that the sodium titanate nanobelt carried negative charges and had a lower zeta potential at higher pH. It gave a large synergistic flocculation effect with CPAM at a very low dosage, and showed higher flocculation effect with CPAM under neutral and weak alkaline conditions. A suitably high shear level was helpful for the re-flocculation of clay by sodium titanate nanobelt. The clay flocculation induced by CPAM/titanate nanobelt system demonstrated high shear resistance and also generated dense flocs.

The aim of this study was to evaluate effects of chemical pretreatment and storage on non-wood pulping and on pulp quality. The processes studied were hot water treatment followed by alkaline peroxide bleaching or soda cooking. The results showed that it is possible to store wheat straw outside for at least one year without significant changes in the raw material chemical composition and without adverse effects on the resulting pulp quality. The results are significant to the industry using non-woods to ensure the availability and the quality of the raw-material throughout the year in spite of the short harvesting time.

Pitch-related deposition has been a significant issue in paper mills that produce wood-containing paper grades. A component analysis showed that a mill deposit sample was a mixture of wood resin, fiber, metal cations, and other inorganics. Based on the differential scanning calorimeter (DSC) method, some critical parameters, including pH, metal cations, and their interactions, on the thermal stability of pitch-related deposits were studied. The valency of metal cations determined the ability of capturing pitch the formation of deposits. Trivalent Al3+ or Fe3+ ions had much stronger effects than divalent Ca2+, Mg2+, or Mn2+. It was also found that a higher pH and trivalent Al3+ or Fe3+ increased the thermal stability of deposits formed in colloidal pitch solutions.

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.

A centrifugal method has been modified and applied to the assessment of water retention value (WRV) in cellulosic materials. Microcrystalline cellulose (MCC), small particles/fibrils isolated from MCC using high-pressure homogenizer, and pulp fibers saturated in water were centrifuged at different speeds and times with filter paper and/or a membrane acting as the filter in the WRV measurement setup. As centrifugal speed, time, and filter pore-size increased, lower WRVs were obtained. Smaller MCC particles/fibrils retained more water than the as-received MCC and pulp fibers. The results are useful for WRV measurements of cellulosic materials, especially for microfibrillated cellulose and small cellulosic fibrils.