Volume 14 Issue 4

The aim of this study was to investigate the influence of cellulose sources on the physico-chemical properties of microcrystalline cellulose (MCC) for various applications. The results showed that MCC prepared from non-wood resources including cotton stalk, bamboo, and sisal was comparable to MCC made from wood in α-cellulose content, pH, moisture content, crystallinity index (CrI), and moisture sorption capacity. However, the ash content, polymerization degree, thermal stability, and mechanical properties, including tablet hardness and tensile strength, of MCC were strongly dependent upon the cellulose sources. The crystalline size (002) had no effect on the mechanical properties of the prepared MCC. The order of the obtained mechanical properties was softwood > hardwood > cotton stalk > bamboo > sisal. Compared with the less obvious variation for bamboo and sisal, the tablet hardness for wood and cotton stalk MCC noticeably decreased in correlation with increased MCC particle sizes. In addition, compared to the polycaprolactone (PCL) neat film, the tensile strength and elastic modulus of PCL/MCC films were improved by 16.0% to 42.5% and 62.7% to 82.0%, respectively.

Grape stem is a kind of agricultural and forestry waste. A fundamental understanding of grape stem pyrolysis behavior and kinetics is essential for its efficient thermochemical conversion. Thermogravimetric infrared spectroscopy and pyrolysis gas chromatography-mass spectrometry, combined with two model-free integral methods: Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) were used to investigate the weight loss behavior, the distribution and content of rapid pyrolysis products, the release law of small molecule pyrolysis gases, and the pyrolysis activation energy during pyrolysis. The results showed that the main pyrolysis reaction temperature ranged from 240 °C to 690 °C. The pyrolysis reaction of grape stems at 200 °C to 700 °C was divided into three stages: 0.15 < α < 0.35, 0.35 < α < 0.65, and 0.65 < α < 0.75, which corresponded to the main pyrolysis stages of hemicellulose, cellulose, and lignin, respectively. The products of rapid pyrolysis at 290 °C were mainly composed of acids and sugars, while the products at 355 °C were mainly phenolics. This study aims to provide a theoretical reference for the pyrolysis gasification test of grape stem.

Engineered wood products are becoming more prevalent in the residential and commercial construction industries and need to be regulated by standards that ensure their classification and performance requirements. The applicable standard in Australia for the qualification of glued laminated timber is AS/NZS 1328.1:1998 (2011), last revised in 2011. Confusion exists with the specific interpretation of the testing procedures and subsequent methods used for the delamination process. Two methods currently used for product qualification were compared: one using a drying chamber and the other using a standard laboratory dehydrating oven. The trials conducted in accordance with the standard showed a significant difference in glue line delamination between the two testing methods. This was attributed to the lack of humidity and airflow control within the laboratory dehydrating oven and an incomplete drying of the test samples, resulting in different stresses on the glue line. It is evident that the current standard procedure requires clarification to ensure consistency in the test methods and comparable test results.

Effects of rapid cooling following pyrolysis were studied relative to the properties of activated carbon using different biomass as the raw materials. Coconut shell-based activated carbon (CSAC), bamboo-based activated carbon (BAC), and straw-based activated carbon (WSAC) were activated via high temperature and subsequently rapidly cooled to below minus 150 °C. The results showed that rapid cooling effectively increased the specific surface area, pore volume, and yield of activated carbons. Compared to natural cooling, rapid cooling increased the specific surface area of CSAC from 1076 m2/g to 1484 m2/g, increased the pore volume from 1.46 mL/g to 1.57 mL/g, decreased the average pore size from 2.25 nm to 2.13 nm, and increased the yield from 27.1% to 31.5%. The variation of the properties of activated carbon after rapid cooling using different raw materials and process conditions were studied using orthogonal experiments.

This research presents the anatomical, chemical, and mechanical properties of fibro-vascular bundles (FVBs) from two species of Salacca (snake fruit) frond: Salaccca sumatrana Becc. and Salacca zalacca Gaert (Voss). The anatomical properties were observed in the cross-section by light microscopy and digital microscopy. The anatomical observation focused on the location of the inner and outer vascular system. In the chemical analysis, FVBs were characterized for cellulose, hemicellulose, Klason lignin, and extractive content. Tensile strength and Young’s modulus were investigated, and the structural implications were considered. The FVBs from salacca frond contained vascular tissue in the cross section had new and different vascular type. Generally, the vascular tissue has a wider area than the sclerenchyma tissue. The FVBs of S. sumatrana and S. zalacca contained 41.75 and 44.60 wt% cellulose, 31.36 and 36.39 wt% hemicellulose, and 27.90 and 33.00 wt% lignin, respectively. The hot water solubility and ethanol-toluene solubility of FVBs of S. sumatrana and S. zalacca showed that extractive content were 2.96 wt% and 5.55 wt%; 18.54 wt% and 25.00 wt.%, respectively. As the diameter of FVBs increased, the tensile strength and Young’s modulus decreased. Increased FVB density will directly increase tensile strength and Young’s modulus. Based on the result, it was concluded that the FVBs of salacca type had significantly different properties compared to other palms’ FVBs, and this study confirmed the correlation between the physical and mechanical properties of the FVBs from salacca frond.

Self-tapping screws are commonly used to connect critical structural components, such as legs to rails in chair construction, using laminated bamboo lumber (LBL) materials. The loosening of a connection is commonly seen in self-tapping screwed LBL connections before actual breakage of connections happens. The loosening of connections, especially those associated with chair legs, can significantly affect chair stability. Current furniture performance test standards have not address this issue, i.e., the minor loosening of a connection is not treated as a failure in the current standard because of the lack of better understanding the load-rotation-time behavior of various connections subjected to the cyclical loads. The effects of cyclic loading magnitude and orientation on the load-rotation-time behavior of L-shaped, end-to-side, single self-tapping screwed LBL connections were investigated. Results indicated that the Burger and Kelvin models could be used to describe the cyclic and recovery behavior of studied connections. Increasing the cyclic loading magnitude resulted in a decreasing trend for all viscoelastic constants. The most significant decrease in all viscoelastic constants occurred when the cyclic loading magnitude applied to connections increased from 50 to 60% of its corresponding ultimate static resistance loads.

Two kinds of thermoresponsive 2-hydroxy-3-alkoxypropyl hydroxyethyl celluloses (HAPEC) were prepared by grafting butyl and isopropyl glycidyl ethers onto hydroxyethyl celluloses (HEC). The HAPEC was characterized by 1H NMR, 13C NMR, and 2D HSQC NMR. The lower critical solution temperature (LCST) of HAPEC can be tuned by changing the molar substitution (MS). The LCST decreased with the increasing MS of the alkyl chains. The HAPEC concentration, salt concentration, and organic solvent concentration had a marked influence on LCST. In addition, the differences of thermoresponsive properties between the two kinds of HAPECs were investigated. 2-Hydroxy-3-butoxypropyl hydroxyethyl cellulose (HBPEC), which has longer hydrophobic side chains, demonstrated a lower LCST when both HBPEC and 2-hydroxy-3-isopropoxypropyl hydroxyethyl cellulose (HIPEC) possessed similar MS values. HBPEC, which has longer hydrophobic side chains, exhibited thermoresponsive flocculation behavior, and the critical flocculation temperature (CFT) was adjusted in the range from 27.3 to 51.2 °C by changing the molar substitution.

As a great amount of chemicals are employed to carry out the coating process of paper, the wastewater from paper mill making coated products is characterized by high levels of chemical oxygen demand (COD), colour, and total suspended solids (TSS). In this study, wastewater from a paper mill making coated products was treated by a sequencing batch biofilm reactor (SBBR) after a lab-scale coagulation, resulting in COD, colour, and TSS removal efficiencies of 87.7 ± 1.0%, 33.5 ± 5.2%, and 41.4 ± 3.7%, respectively, which exceeded the biological treatment performance in the paper mill. The removal of COD and colour was attributed to the removal of recalcitrant organic matter, and the removal of TSS was attributed to the biofilm.

As the by-product of biomass pyrolysis, wood vinegar (WV) possesses numerous beneficial properties and has been used in many fields. The properties and utilization of WVs are primarily influenced by the type of biomass feedstock and the production techniques. In this paper, WVs were pyrolyzed from fir sawdust waste at 350 to 650 °C to study their growth regulation effect on wheat seed and to investigate the underlying mechanisms. The highest yield of WV was at 450 °C with major components of phenols (37.92%) and acids (24.59%). The concentration of WVs has a major influence on regulation effect, which mainly affected the development of lateral roots. Compared with sterile water (CK), the WV-2 showed the highest seed germination rate and lateral roots growth, which increased nearly 65% and 92%, respectively. The lower concentration of WVs increased the roots vigor (RV) and promoted growth, while the higher concentration increased the content of malondialdehyde (MDA) and inhibited growth. The increased MDA indicated that wheat roots were suffering from oxidative stress. The findings revealed the suitability of WV as growth regulator in sustainable agriculture and also provided an efficient way for biomass waste utilization.

Many academic studies over the years have confirmed that mechano-sorptive (MS) creep is an inherent characteristic of wood. Unlike solid wood, bond lines are introduced into laminated veneer lumber (LVL), creating a laminated structure with different hygroscopicity. What are the effects of these differences on the MS creep of LVL? In this study, three groups of well-matched LVL samples were subjected to four-point bending loading within different relative humidity cycles. For each group, the applied load ranged from 15% to 35% of the short-term fracture load. The results showed that after the first hygroscopic process, LVL showed irreversible expansion (0.11 mm) and a relatively slow moisture adsorption rate. These made it difficult for LVL to show partial creep recovery during the first adsorption process no matter how low the load level was, while solid wood showed partial creep recovery when the load level was ≤ 25%. The following creep behavior of LVL was similar to that of solid wood: partial creep recovery started from the second adsorption stage when a moderate load level was applied.