Volume 13 Issue 3

Increasing filler content in paper while maintaining paper strength is a continuous need in the paper industry. The bonds between cellulosic fibers and fillers are essential to increase filler level in paper. Besides tensile strength, which traditionally has been used to investigate different fillers on fiber bonding, a new factor, i.e. a filler bondability factor, can be applied in evaluating the mitigation effect of filler addition on fiber bonding. This factor shows its effectiveness in optimizing the key parameters for filler modification and the choice of filler, and it helps to maximize the use of filler in the paper industry.

China is the largest waste paper importing market in the world. Due to more and more demands and awareness of environment/ safety issues, in recent years the Chinese government has implemented a number of new regulations on waste paper importing, for example, prohibiting importing of unsorted waste paper and lowering the foreign (non-paper) content in the imported waste paper from 1.5% to 0.5%. Small-scale (less than 50,000 tons per year capacity) paper mills are not eligible for importing waste paper. These new regulations have had profound impacts on the global waste paper recycling practice and the papermaking industry in China. At the same time, these new regulations bring up new challenges to the global waste paper recycling practices, such as increased labor costs and decreased recycling efficiency.

The bendability of a material can be classified as both a positive and negative characteristic. The classification depends on the intended use of the given material. In the case of materials intended for bending (solid wood), this property is positive; whereas in the case of building materials this property may have a negative effect on the stability and durability of the finished structure. Depending on the use of the material, different characteristics of bendability can be used to describe it. The important characteristics include the force and deflection at the limit of proportionality and at the modulus of rupture. Because the bendability also depends on the material thickness, this characteristic is most often expressed as the ratio of the material thickness to the smallest achievable bent radius. Therefore, an analysis of the minimum curve radius and coefficient of bendability was performed. The bending characteristics were measured for composite materials, which were made of crushed rapeseed stalk and bonded with powder polyester adhesive. The stalks were subjected to different modifications (R, H2O, and NaOH). The results of this work indicated that rapeseed is a prospective raw material for the production of composite materials with specific properties.

To meet the demands for screening sweet potato tubers for bioethanol production, 12 genotypes of sweet potato tubers were collected from Henan, Shandong, Anhui, and Jiangsu Provinces, China. Based on the optimized determination method of the percent dry content, the nutritional composition and fermentation properties were studied. There were differences in the compositions and their correlations among the sweet potato varieties. The results showed that the starch content was weakly correlated with other ingredients, while the percent dry content and fermentable sugars contents had a close correlation with starch content. The percent dry content significantly and positively correlated with the flour and fermentable sugars contents. The percent dry content and starch contents had a significantly positive correlation, with a correlation coefficient that reached 0.96.

This study aimed to analyze the structural and functional diversity of microorganisms inhabiting Paulownia spp. leaves. Next Generation Sequencing (NGS) and Biolog EcoPlates were used to determine microbial diversity. The leaves of Paulownia spp. were taken from two different plantations. Among all the samples, P112_1 was the most abundantly colonized by plant growth promoting bacteria. Overall, the microbial community of the P. elongata × P. fortunei (PB) sample characterized the lowest metabolic activity with the utilization of the carbon sources. All communities used carbohydrates abundantly, whereas amines and amides were used the least. The differences observed may have been due to a variety of factors from composition of the chemicals in the leaf, to the soil type, to the climatic conditions.

Barks from two commercial clones of Eucalyptus urophylla hybrids used by the charcoal industry in Brazil were analyzed, with their polar extracts characterized. Also, tannins were extracted with water and sodium sulfite. The mean bark chemical composition showed 2.6% ash, 16% extractives (89% of which were polar extractives), 1.2% suberin, 18.9% lignin, and 61.4% polysaccharides composed mainly of glucans (glucose 48.3% of bark) and xylans (xylose plus arabinose 10.1% of bark). The polar extracts included high mean contents of total phenolics (380.9 mg GAE / g extract), flavonoids (178.4 mg CE / g extract), and tannins (67.7 mg CE / g extract). The mean antioxidant activity of the extracts was low (53.6 mg Trolox / g of bark extract). The extracts had Stiasny indices of 20% with water and 45% with sodium sulfite solution. The FTIR spectra showed condensed tannin bands characteristic of C=C, C-C, and O-H bonds. The barks of E. urophylla hybrids are a potential source of polar extractives that may represent an important valorization.

Graphene oxide (GO) was synthesized from graphite and also produced from waste materials, such as coconut shell, rice husk, and bagasse. The GO obtained from pure graphite was compared with graphite made from Indonesian biomass (coconut shell, rice husk, and bagasse) that had its silica content removed. The characterization of GO was with X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, and Raman spectroscopy. The XRD images showed the formation of the GO and graphite from various angles and revealed that the chemical reaction had an important role in the formation of the GO particles. This was confirmed by the FTIR and Raman spectra, where the presence of various oxygen functional groups was identified. The FTIR spectra showed that the GO had some functionals oxygen groups within its structure.

In this study, the optimization of formamidine sulfinic acid (FAS) and hydrogen peroxide (P) bleaching stages of pre-bleached blue, red, yellow, green, and mixed colored office papers was investigated. The FAS was performed as a strong color stripping reagent on blue and green colored samples. However, due to reduced amine compounds FAS was not found to be effective on the red colored samples. In contrast, effective results were obtained with hydrogen peroxide on the red and yellow colored samples. These results showed that the two reagents must be used together in a sequence. Therefore, in this study, FASP and PFAS bleaching sequences were also investigated and the optical properties (absorbance (k/s) spectra, CIE L*a*b* color values, and ISO brightness) of these sequences were compared. The color differences (CIE ΔE) of FASP and PFAS bleaching sequences of the mixed colored samples were calculated as 18.2% and 16.1%, respectively. The FASP bleaching sequence was determined to be more effective than the PFAS sequence for the bleaching of all samples. As a result, this study showed that FAS, a strong reducing agent, and hydrogen peroxide, an effective oxidative decolorizer, can be used together to obtain white writing papers from waste direct dye colored office papers.

Changes in the air permeability and density profiles of 12-mm-thick oriented strand board (OSB) specimens were evaluated in relation to changes in their moisture content. The test methodology consisted of the simulation of real conditions that may occur during construction. Using a water bath, the OSB moisture content was increased from 10% to 17%, and the consequent changes in the air permeability and vertical density profile (VDP) were analyzed. The air permeability and VDP were then reanalyzed after acclimatization of the OSB to a balanced moisture content at 60% relative air humidity and 11.4 °C. After wetting the boards with an initial moisture content of 10% for 2 h and naturally re-drying them in laboratory conditions, an average increase of 11.7% in air permeability was observed. The increase in air permeability was 5.6% with a pressure difference of 50 Pa. After redrying, the boards showed a 1.1% lower average density and 14.5% lower maximum density in the surface layers. From the results, it followed that even the short-term effects of water and the related increase in moisture content of the OSB had a negative impact on the air permeability and VDP.

Camelina sativa is a cool-season oil seed crop that has been proven to produce various biofuels. The present study investigated the technical possibilities of using whole camelina biomass as a model feedstock in a biorefinery. This investigation examined the possibilities of using camelina seeds as a source of oil for biodiesel, sugars for ethanol, and meal for one-portfolio products. The camelina harvest residues (straw) can serve as the main source for green sugars. This study found that the energy input for the whole biorefinery process was 25.1 MJ/L ethanol, while the energy output was 54.3 MJ/L ethanol. The net energy ratio of 2.16 MJ/L ethanol was found to be competitive with other energy crops. The process was environmentally friendly, and it reduced greenhouse gas emissions by 40% if the produced biodiesel replaced petroleum diesel. The seed meals and glycerin were found to be a good source of revenue as high value-added products and can provide an additional revenue of $1/kg of produced oil.