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Biomass and its interactions for heat generation have received little attention. In this study, the woody biomass materials were Prosopis africana (PA), Harungana madascariences (HM), Vitrllaria paradoxa (VP), and Afzelia africana (AA). The composition (extractives, carbohydrate, and lignin) of the biomass was determined. The biomass was converted to charcoal in a traditional kiln. A thermo-kinetic examination of the charcoal samples was carried out. The kinetic parameters and potential reaction mechanisms involved in the decomposition process were both obtained using the integral (Flynn–Wall Ozawa) isoconversional methods in conjunction with the Coats-Redfern approach. The activation energy profiles for the charcoal samples in oxidizing atmospheres were 548 kJ/mol for AA, 274 kJ/mol for VP, 548 kJ/mol for PA, and 274 kJ/mol for HM. All charcoal samples underwent comprehensive, multi-step, complex reaction pathways for thermal degradation. The charcoal samples exhibit not only great potential for biochemical extraction but also for bioenergy applications. The significant amount of combustion characteristics in the raw biomass and charcoal samples indicates that each type of wood charcoal produced has more fixed carbon, less ash, and less volatile matter, all of which are desirable for the thermo-chemical conversion of biomass for the production of heat. [ABSTRACT FROM AUTHOR]

A composite mixture of wood fiber and sodium silicate (SS) binder has been explored as a viable material for use in additive manufacture of wood based composite materials. Mixtures of 50–60% wood fiber and 50 − 40% SS were explored. The curing behavior of these formulations were examined by differential scanning calorimetry (DSC) and dynamic rheometry. An exothermic curing peak of 83 °C was observed for SS and increased to 153 and 163 °C with the addition of wood fiber. Rheology flow curves showed higher viscosity values for 50/50 blends and lower values for SS. A custom extrusion system was fabricated and 50/50 wet blends were extruded, cured at different temperatures, and characterized for flame retardancy, mechanical, thermal, and water absorption properties. Surface chemistry changes before and after curing were determined by Fourier Transform Infrared (FTIR) spectroscopy. Mechanical properties, determined by three-point bend testing, improved with the addition of the wood fiber but varied with different curing temperatures and thermal stability of the composites increased with curing temperature. This extruded wood-SS composite shows promise for use in additive manufacturing. [ABSTRACT FROM AUTHOR]

This study evaluated the mechanical, thermal, water soak, and rheological properties of mixed plastic waste (MPW) in combination with fibers derived from residual hops bines and coupling agents or dicumyl peroxide (DCP) to form composite materials. Hop bines were pulped to afford individual hop fibers (HF) in 45% yield with 78% carbohydrate content. The MPW comprised mainly of PET, paper, PE and PEVA. Tensile moduli and strength of the formulations ranged between 1.1 and 2.0 GPa and 11 and 14 MPa, respectively. The addition of hops fiber (HF) improved the tensile modulus of the formulations by 40%. Tensile strength was improved by the addition of coupling agents by 11% and this was supported by determining the adhesion factor by dynamic mechanical analysis. However, the addition of DCP resulted in a reduction of tensile properties. The melt properties of the formulations showed shear thinning behavior and followed the power-law model. The water absorption tests for most of the MPW formulations gave an 11% weight gain over 83 d except for the DCP treated composites (14–16%). The fabricated composites can be used in non-structural applications such as (garden trim, siding, pavers, etc.). [ABSTRACT FROM AUTHOR]

There are relatively few long-term studies of wood plastic composite (WPC) performance, especially under harsh sub-tropical conditions. This study examined changes in wood/polymer composition, surface chemistry, and thermal properties of WPC decking with and without a co-extruded cap layer after 8–14 years of above ground outdoor exposure at a sub-tropical site near Hilo, Hawaii. WPC condition was assessed using combinations of destructive and non-destructive (TGA, DSC, and FTIR spectroscopy) methods with WPC wood content determined after chemical digestion. Coextruded WPCs were more resistant to above ground weathering than uncapped materials possibly because the cap layer reduced oxygen availability at the interface between the inner (core) and outer (cap) layer. Moreover, increased vinyl concentrations coupled with lower degrees of crystallinity of the polymer matrix suggested the chain crosslinking and scission reactions occurred simultaneously. Wood components in the cap layer of the coextruded WPCs were less susceptible to weathering due to the encapsulation by plastic. Therefore, the cap layer showed relatively better thermal stability than the uncapped WPCs. [ABSTRACT FROM AUTHOR]

A non-isothermal decomposition of Moringa oleifera husk and Delonix regia seed pod was carried out in an N2 pyrolytic condition with the primary objective of undertaking the kinetics modeling, thermodynamics and thermal performance analyses of the identified samples. Three different isoconversional models, namely, differential Friedman, Flynn–Wall–Ozawa, and Starink techniques were utilized for the deduction of the kinetics data. The thermodynamic parameters were deduced from the kinetic data based on a first-order chemical reaction model. In the kinetics study, a strong correlation (R2 > 0.9) was observed throughout the conversion range for all the kinetic models. The activation energy profiles showed two distinctive regions. In the first region, the average activation energy values were relatively higher—a typical example is in the Flynn–Wall–Ozawa technique—MH (199 kJ/mol) and RP (194 kJ/mol), while in the second region, MH (292 kJ/mol) and RP (234 kJ/mol). It was also demonstrated that the thermal process for the samples experienced endothermic reactions thought the conversion range. In summary, both the kinetic and thermodynamic parameters vary significantly with conversion—underscoring the complexity associated with the thermal conversion of lignocellulosic biomass samples. [ABSTRACT FROM AUTHOR]

A concept is outlined for the production of materials/commodities from a polluting waste. A preliminary evaluation is presented for a proposed integrated dairy farm manure management system consisting of a two-stage anaerobic digester coupled with a polyhydroxyalkanoate reactor, algae cultivation system (ACS) and a biomass treatment system, such as fast-pyrolysis or hydrothermal liquefaction, to sequester carbon, nitrogen and phosphorus into value-added products (e.g., bioplastics, biogas, fertilizer, soil amendment and livestock bedding) rather than releasing them into the environment. Mass flows through the system are presented for a 10,000-cow dairy. The integrated manure treatment system can reduce the amount of nitrogen and phosphorus released from the manure by 50.9% and 38.1%, respectively. Without an ACS, the reduction drops to 19% and 27%, respectively. Greenhouse gas emissions can potentially be reduced by 44,200 MT CO2e/year over the referenced open lot dairy. [ABSTRACT FROM AUTHOR]

This study investigated weathering effects on polyvinyl chloride (PVC) based wood plastic composites (WPC), with a focus on the color and structure that is attributed to the material composition. It is directed towards quantifying the main chemical modifications, such as carbonyl and vinyl groups which are formed during weathering. These composites were subjected to three weathering regimes: exterior, accelerated xenon-arc, and accelerated UVA. The change in color was monitored using colorimetry. Fourier transform infrared spectroscopy was used to identify and quantify the chemical modifications (carbonyl formation and vinyl propagation) due to weathering. Additionally, scanning electron microscopy was employed to observe the physical morphological changes that occurred. The results showed that exterior and accelerated xenon-arc and UVA weathering regimes increased the degree of lightness, total color change, carbonyl concentration, and wood loss on the surfaces of the weathered composites. The increased carbonyl concentration during weathering implied that degradation had occurred by oxidation process. Also, oxidation and lignin (from the wood) degradation influenced the color (lightness) of PVC based WPC upon weathering. [ABSTRACT FROM AUTHOR]

The effects of weathering on the constituents of wood and polymer matrix behavior in wood plastic composites (WPCs) were investigated. WPCs were produced from pine, extractives-free pine, and pine holocellulose fibers (60%) together with HDPE (40%). These composites were subjected to xenon-arc accelerated and outside weathering for a total of 1200 h and 120 days, respectively. The color and chemical changes that occurred on the surface of the WPCs were analyzed using a set of analytical techniques. For pine and extractive-free pine filled composites, the results showed that the total color change, lightness, and oxidation increased, while the lignin content decreased. In addition, the weight average molecular weight ( Mw) and number average molecular weight ( Mn) of extracted HDPE decreased with an increase in exposure time of the composites. However, HDPE crystallinity increased with longer exposure time. Lightness of holocellulose-based WPC changed the least while the change in its HDPE crystallinity was not significant compared to the other composite types. Therefore, holocellulose-based WPC may be preferred for applications where color stability is of high priority. [ABSTRACT FROM AUTHOR]

Tracheid and sclereid differentiation was induced in callus cultures of Pinus radiata D. Don by culturing on a basal medium containing activated charcoal but no phytohormones; sclereids differentiated in callus derived from xylem strips, but not in callus derived from hypocotyl segments. The tracheids differentiated in hypocotyl-derived callus had helical, scalariform, reticulated or pitted secondary cell-wall patterns, but those differentiated in xylem-derived callus had a reticulate or pitted pattern. The thickened tracheid and sclereid walls contained lignin as indicated by the red colour reaction given with phloroglucinol-HCI. The presence of lignin in the cell walls of differentiated callus was confirmed using pyrolysis gas chromatography- mass spectrometry by the detection of phenylpropanoid components derived from lignin. Lignin was also detected using solid-state 13C cross-polarisation/magic-angle spinning nuclear magnetic resonance spectroscopy and quantified as thioglycolic acid lignin. Monosaccharide analyses of the cell walls isolated from differentiated and undifferentiated calli showed that the cell walls of the differentiated calli contained higher proportions of glucose and mannose, consistent with the presence of greater proportions of gluco- and/or galactoglucomannans in the secondary cell walls of the differentiated cells. A protocol for the stable transformation of undifferentiated, xylem-derived cultures was successfully developed. Transgenic cell lines were established following Biolistic particle bombardment with a plasmid containing the coding region of the nptII gene and the coding region of the cad gene from P. radiata. Expression of the nptII gene in transgenic lines was confirmed by an NPTII-enzyme-linked immunosorbent assay. The overexpression of cad in the transgenic lines resulted in a down-regulation of cinnamyl alcohol dehydrogenase (EC 1.1.1.195) expression. [ABSTRACT FROM AUTHOR]