Volume 8 Issue 3

This study investigated a novel route for fast acidogenic fermentation of corn stover through a two-step method. Corn stover was first hydrolyzed by nitric acid, and the hydrolysate was then used for acidogenic fermentation. The results showed that the yields of soluble xylose, arabinose, and glucose in hydrolysate obtained from HNO3 hydrolysis of corn stover at the optimum condition achieved 96.86% of initial xylose, 98.54% of initial arabinose, and 18.58% of initial glucose, respectively. Acidogenic fermentation of hydrolysate proved to be effective, compared to acidogenic fermentation of raw corn stover; the production of volatile fatty acids (VFAs) increased by 54.8%, fermentation time decreased by 50%, and the distribution of VFAs was more suitable for subsequent methanogenic fermentation. This research provided an effective, suitable, and economical method for biogas production from corn stover.

Four different extracts were obtained by extracting Cinnamomum camphora xylem with hot water, methanol, ethyl acetate, and chloroform. Thereafter, wood (Masson pine) was impregnated with these different extracts, and the decay resistance performance of the wood treated with the extracts was studied. The results showed that the mass loss of wood treated with 4% ammoniacal copper quats (ACQ), 4% boric acid, 4% camphor, and extracts made with 10% water, 10% methanol, 10% ethyl acetate, and 10% chloroform were 1.78%, 5.7%, 13.08%, 40.85%, 9.39%, 18.66%, and 21.45%, respectively. The samples impregnated with 4% ACQ, 4% boric acid or 10% methanol extract could meet the demand of degree I (LY/T 1283-2011) for preservation and showed strong resistance to fungal decay. The results from optical microscopy and SEM indicated that treated hyphae (methanol extracts) exhibited an obvious morphological change: the cell wall became rough, and the cell expanded, became twisted, and exhibited uneven growth of hyphae, indicating that the extracts affected the structure and function of the hyphae. The low number of hyphae present within the cell walls revealed that treatment with methanol extracts provided strong resistance to fungal decay.

A novel rosin-based carbamate was prepared by the reaction of N,N-dimethylaminopropylamine with rosin-based cyclic carbonate. Using LiBr in conjunction with ethylene glycol as a catalyst, carbon dioxide was treated with triglycidyl ester of maleopimaric acid to prepare the rosin-based cyclic carbonate. The carbamate was then quaternized to form three rosin-based carbamate group-containing quaternary ammonium salt derivatives. The chemical structures of all new compounds were characterized by IR, 1H NMR, and 13C NMR. The antimicrobial activities of the carbamate and quaternary ammonium salt derivatives were investigated. The bioassay test results showed that all derivatives exhibited strong inhibition against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Bacillus thuringiensis, and Streptomyces microflavus. However, no visible antifungal activity was found against Saccharomyces cerevisiae or Aspergillus niger, except for the activity of the carbamate derivative against S. cerevisiae.

In the present study, batai wood (Paraserianthes moluccana) was impregnated with a combination of styrene, methyl methacrylate, and nanoclay in order to improve compression strength, thermal stability, and surface morphology. Styrene (ST) and methyl methacrylate (MMA) cross-linker introduced a co-polymerization reaction with cellulose in the wood cell wall and produced wood polymer composites (WPCs), as confirmed by Fourier Transform Infrared (FT-IR) Spectroscopy. The mechanical properties of the WPCs were significantly increased compared to the raw wood. Thermal properties of both raw wood and WPCs were evaluated by thermogravimetric analysis (TGA). WPCs exhibited higher thermal stability relative to the raw wood due to the co-polymerization reaction. The surface morphologies of the fracture surface for both the raw wood and WPCs were recorded using scanning electron microscopy (SEM). The SEM micrographs reveal that after polymerization, WPCs show smoother texture and adhesion compared to that of raw wood.

The present work evaluated the potential of the addition of bentonite and feldspar as fillers on the mechanical and physical properties of low-density polyethylene (LDPE)/thermoplastic sago starch (TPSS)/kenaf core fiber (KCF) composites. For this purpose, 3 to15 phr of fillers were incorporated into LDPE/TPSS/KCF composites that were fabricated via a melt-mixing molding system. Results showed that the tensile strength and modulus were improved significantly with the addition of bentonite in comparison with feldspar. Thermal studies confirmed the improvement in thermal stability of composites filled with bentonite as well as feldspar. An increased percentage of water absorption was also observed in these composites compared with the control (LDPE/TPSS/KCF composites) system.

Rice husk constitutes the largest by-product of the rice milling industry. Numerous research studies have been conducted on the utilization of rice husk powder (RHP), but research on incorporating RHP into natural rubber latex foam (NRLF) is lacking. The purpose of this study was to use RHP as a filler for NRLF. A compression test was performed on RHP-filled NRLFs, and they were compared with the control NRLF. The compression set increased, while the recovery percentage decreased, as RHP loading increased. The stress versus strain curve showed increasing stress with increasing RHP loading. The increase in thermal stability and decreased (Qf/Qg) value of RHP-filled NRLFs indicated good interaction between RHP and NRLF. RHP incorporation can contribute to NRLF industries with environmentally friendly products such as mattresses and cushioning materials by lowering costs.

This work aims to develop a new ionic liquid, used as an aprotic green ä solvent, to dissolve kraft lignin from black liquor. The kraft lignin was extracted through precipitation with carbon dioxide at atmospheric pressure. 1,8-Diazabicyclo[5.4.0]undec-7-ene-based ionic liquids were obtained by quaternization of the nitrogen atom with a hydrogen atom or an alkyl chain. The yields of the synthesis of the ionic liquids varied between 76 and 80%. Dissolving experiments were carried out using the lignin isolated from the black liquor of a kraft process. Up to 20% (w/w) of the lignin can be dissolved in butyl-1,8 diazabicyclo[5.4.0] undec-7-enium chloride ([DBUC4]+[Cl-]), hexyl-1,8 diazabicyclo[5.4.0] undec-7-enium chloride [DBUC6]+[Cl-], and octyl-1,8 diazabicyclo[5.4.0] undec-7-enium chloride [DBUC8]+[Cl-]. The time it takes to dissolve the lignin in these three liquids shows that its solubility is influenced mostly by the nature of the cations. The lignin solubility was reduced in relation to the increased length of the grafted carbon chain. The thermogravimetric analysis (TGA) showed these liquids can be used as lignin solvents from room temperature up to 300 °C (onset of degradation). Steric exclusion chromatography showed a slight decrease (6%) in the molecular weight of the lignin dissolved in these ionic liquids.

This article reports the results of temperature measurements carried out on 50-mm-thick Norway spruce (Picea abies [L.] Karst) wood samples exposed to infrared (IR) radiation. The varied property with respect to the optimization of the drying technology was the initial moisture content of samples. During the experiments, temperature profiles were registered on the surface and in the core of the samples under controlled technological conditions. Based on our osmotic approach, the variability in the curves was interpreted with respect to the stagnation temperature below the fiber saturation point (FSP). We conclude that the amount of liquid water necessary for osmosis must still be available locally in the core. With decreasing initial average moisture content, the time interval of the osmotic process also decreases. In this context our results support the hypothesis that the presence of free water in the wood tissue is necessary for the osmotic mechanism even if the average moisture content falls below the FSP.

Homogenous chemical modification of ball-milled eucalyptus wood with palmitoyl chloride was investigated using a dimethyl sulfoxide/N-methylimidazole solvent system at room temperature. The parameters were optimized, including the reaction time and the dosage of palmitoyl chloride. The results indicated that prolonging the reaction time from 15 min to 120 min resulted in an increase in the weight percentage gain (WPG) of eucalyptus from 9.5 to 22.8%, while a further increase of the reaction time to 180 min led to an increase in WPG of 19.3%. An increase of the mass ratio of palmitoyl chloride-to-wood from 1:2 to 5:1 resulted in an improvement of WPG from 8.7 to 46.0%, while a further increase of the mass ratio of palmitoyl chloride-to-wood to 6:1 led to a decrease in WPG (39.7%). The physico-chemical properties of the esterified wood were investigated with FT-IR and CP/MAS 13C-NMR spectroscopies. The results indicated that the palmitoyl ester group was successfully attached to the eucalyptus. The esterification of lignin and carbohydrates occurred at room temperature and the thermal stability of eucalyptus increased after esterification.

The overall aim of the research was to better understand the influence of raw material characteristics on the quality of decorative veneer, to identify phenotypes of oak and sessile oak valuable for veneer use, and to promote quality in relationship with sustainable development of Romania’s forests. This paper describes specific aspects regarding wood defects and quality conditions imposed on raw materials for veneer slicing. The experiments focused on identifying and analyzing defects in oak veneer found in six regions from Romania. Taking into account the dimensional and quality requirements, and obtaining a sufficient quantity of decorative oak veneer, Pareto diagrams corresponding to each region were created. The Pareto analysis allowed for a hierarchy of main defects and also enabled adequate decision-making for improving the quality of the studied products in accordance with specific international standards. Also, by knowing the types of defects, decisions can be made to conserve natural resources and to utilize wood resources by sustainable reuse of waste.