Amount Of Char Research Articles

Toward a green economy: Lignin-based hybrid materials as functional additives in flame-retardant polymer coatings

This study describes the combination of unique properties of lignin with TiO2 as an innovative and effective preparation method for high-performance flame-retardant additives that may be utilized as polymer coatings. The use of lignin resulted in numerous advantages including an increased number of functional groups, satisfactory biocompatibility, low toxicity, and high carbon content. The major benefit of lignin is associated with the reduced carbon footprint of the manufactured product. Lignin can be classified as a natural flame-retardant agent owing to the high amount of char formed during combustion. In turn, TiO2 exhibits high chemical stability and low operating costs and is considered a non-toxic and environmentally friendly material. During the experiments, commercial TiO2 in anatase crystallographic form, TiO2 synthesized from titanyl sulfate hydrate, and kraft lignin as well as organic–inorganic hybrid materials composed of these materials were evaluated as functional additives in epoxy-resin-based polymer coatings (Epidian 601) and their properties were investigated in detail. The cone colorimetry test confirmed that the obtained hybrids are effective flame-retardant additives for polymer coatings, with a notable fire hazard reduction observed for samples containing a synergistic system of titanium oxide and lignin. The coating with lignin was the most effective in fire suppression processes. The conducted thermal and mechanical investigations confirmed good performance properties of the coatings indicating thermal resistance up to 360 °C and Shore D hardness in a range of 80.36–86.28°Sh, accordingly. Optical profilometry investigations show that the lignin/TiO2 hybrids exhibit a stable topological surface shape as well as good dispersion and uniformity in the polymer matrix. All the conducted tests allowed confirmation that the presence of functional additives in polymer coatings in the form of lignin and TiO2 can be a promising alternative to non-biodegradable synthetic materials which improve flame-retardant properties.

The Impact of Biomass Composition Variability on the Char Features and Yields Resulted through Thermochemical Processes.

This paper explores the intricate relations between biomass polymeric composition, thermochemical conversion routes, char yields and features in order to advance the knowledge on biomass conversion processes and customize them to meet specific requirements. An exhaustive characterization has been performed for three types of biomasses: (i) spruce bark, a woody primary and secondary residue from forestry and wood processing; (ii) wheat straws-agricultural waste harvest from arable and permanent cropland; and (iii) vine shoots, a woody biomass resulting from vineyard waste. Chemical (proximate and ultimate analysis), biochemical, trace elements, and thermal analyses were performed. Also, Fourier transform infrared spectroscopy, Scanning Electron Microscopy, and thermogravimetric analysis were conducted to establish the compositional and structural characteristics of feedstock. The main polymeric components influence the amount and quality of char. The high hemicellulose content recommends wheat straws as a good candidate especially for hydrothermal carbonization. Cellulose is a primary contributor to char formation during pyrolysis, suggesting that vine shoots may yield higher-quality char compared to that converted from wheat straws. It was shown that the char yield can be predicted and is strongly dependent on the polymeric composition. While in the case of spruce bark and wheat straws, lignin has a major contribution in the char formation, cellulose and secondary lignin are main contributors for vine shoots char.

Biosolid Gasification Performance Prediction Using a Stoichiometric Thermodynamic Model.

The gasification process can recover energy from biosolids produced in wastewater treatment. This paper developed a stoichiometric thermodynamic equilibrium model for biosolid gasification based on the biosolid properties, thermodynamic database, and equilibrium constants. If the calculation result showed that the quantity of char was negative, the quantity of char was put to zero, and the simulation was carried out again. The model was first verified by woody gasification under isothermal conditions, and the influence of a given temperature on biosolid gasification was simulated. The model further investigated the effects of different feedstock types, moisture contents, equivalence ratios, and reaction extensions on the adiabatic temperature, exergy efficiency, and syngas properties under autothermal conditions. The four factors were all the main factors for adiabatic temperature. The exergy efficiency depended more on the operation conditions than on the feedstock type. The H2 concentration of the dry syngas in biosolid gasification exhibited a curve both against the given temperature under isothermal conditions and against the moisture content under autothermal conditions.

Integration of thermal plasma with CCUS to valorize sewage sludge

The presented study addresses the threefold challenges namely, sustainable waste valorization of a difficult waste stream, climate change due to CO2 emissions and clean energy crisis and it is a small step forward to achieve SDG-7. A hybrid DC thermal plasma was employed in a pilot scale facility (∼150 kW) to treat sewage sludge in the presence of waste CO2 (according to the concept of CCUS, Carbon Capture Utilization and Storage) to produce syngas and assess the viability to retrieve phosphorus and other valuable materials from the generated ash. An equilibrium model was also developed to enhance the understanding about the dynamics of process. The H2 generation was around 0.5 m3/kg fuel whereas the amount of char produced was negligible (0–0.013 kg/kg fuel) realizing an efficient transformation of carbon. It was promising to find a high amount of P2O5 in the ash retained in the filter (30 wt %) and reactor (9 wt %) as evaluated by XRF. An average value of 97 % was obtained for CCE (carbon conversion efficiency) depicting almost complete carbon conversion. The results are encouraging to valorize sewage sludge under the CCUS scheme to produce clean energy and reclaim valuable nutrients.

A novel integration of plasma gasification melting process with direct carbon fuel cell

As municipal solid waste (MSW) is a low-cost, available, and basically renewable source, energy recovery from MSW is a beneficial technique for reducing fossil fuel usage while also lowering MSW disposal challenges. The current study proposes a novel scheme consisting of plasma gasification melting (PGM) process and direct carbon fuel cell (DCFC) system for converting MSW into high-quality syngas and power. Plasma air and high-temperature steam are employed in the process as gasification agents. The DCFC runs on the pyrolysis char, which is a carbon-rich source and is extracted during the PGM process and sent to the DCFC. The process is simulated in Aspen Plus, and a computational model for estimating the DCFC's output voltage and power is developed in MATLAB. Effects of main operating parameters, including equivalence ratio, steam to biomass ratio, plasma energy ratio, char separation fraction, and fuel cell operating temperature on the system's performance indicators, namely syngas composition, syngas lower heating value, syngas yield, gasification temperature, overall efficiency, and DCFC power output were investigated. By increasing the char separation fraction, more pyrolysis char was extracted and forwarded to the DCFC, which leads to less amount of char entering the gasification section and higher power output through the DCFC. Keeping other parameters constant, at a fuel cell operating temperature of 923 K, the optimal value for char extraction fraction was 0.15, resulting in a 79.5% overall efficiency.

Influence of Selected Parameters on the Product Yields of Broom Weed (Sida acuta) Pyrolysis

Biomass feedstocks have been utilized for the commercial production of a wide range of fuels and chemicals through the pyrolysis process. Broom weed is abundant but it has not been widely used in Nigeria as a means of useful fuel and chemical thereby constituting an environmental menace. This study aimed to determine the effects of selected process parameters on the product yields during the pyrolysis of broom weed in a fixed bed reactor. Broom weed was obtained at the premises of the National Centre for Agricultural Mechanization, Ilorin, Kwara State, Nigeria. 0.1kg of a dried sample of broom weed was loaded into a steel retort, and the retort interior was rendered airtight. The retort was then placed into the furnace chamber and was pyrolysed at 300oC between 10 - 30 minutes at 5 minutes intervals. This was repeated for temperatures of 350, 400, 450, and 500 oC, and in each case, the quantities of char, bio-oil, and gas produced were determined. The average minimum values of the product yielded char, bio-oil, and gas for broom weed were 62.43 wt% at 500 ⁰C, 4.34 wt% at 300 ⁰C and 12.62 wt% at 300 ⁰C, respectively, while the maximum values were 83.37 wt% at 300 ⁰C, 8.80 wt% at 450 ⁰C and 30.96 wt% at 500 ⁰C, respectively. This study showed that pyrolysis of broom weed can serve as a renewable source of energy rather than constituting an environmental menace.

Flame retardancy and toughness of epoxy resin induced by a star-shaped flame retardant containing P/Si/B

A star-shaped flame retardant containing Si/P/B (SiFAD) was synthesized and used to regulate the performance of epoxy (EP). The SiFAD modifies the flame retardancy, toughness and transparency of EP. The EP containing 6 wt% SiFAD displays a UL-94 V0 rating and a limiting oxygen index (LOI) of 34.7 vol%. The SiFAD promotes the early degradation of EP, increases the amount of char formed at high temperature, and improves the flame retardancy through the combined actions of gas phase and condensed phase. The tensile and impact strength of EP are both improved, especially the impact strength of EP containing 4 wt% SiFAD is 15.8 kJ/m2, which is 139% more than that of EP. The SiFAD in EP constructs high free volume through bridge effect, thus improves the impact strength of EP. In addition, microphase separation is produced in EP composites which is so small that the EP composites keep good transparency.

Preparation of nitrogen-containing compounds and nitrogen-doped biochar via nitrogen-rich pyrolysis coupled with ammonia source impregnation

Using lignocellulose to produce nitrogen-rich bio-oil and nitrogen-doped biochar in the presence of nitrogen-carrying bodies has become a research hotspot in recent years for high-value conversion and utilization of biomass. Different nitrogen carriers significantly influence biomass pyrolysis and conversion process and products. In this study, a new strategy for the preparation of both nitrogen-rich bio-oil (high-value N-containing compounds (NCCs)) and N-doped biochar by ammonia impregnation treatment coupled with Zeolite Socony Mobil Five (HZSM-5) via N-enriched pyrolysis was proposed. The influence of amine type (formamide, urea, melamine and dicyandiamide) and concentration on the product content, distribution, properties and evolution mechanism was also explored. The results showed that the amine treatment significantly reduced the activation energy (from 23.71 kJ/mol to 12.35–20.82 kJ/mol) and N content (from 7.42% to 6.05–7.29%) due to destruction of the crystalline phase and amine volatilization but increased the amount of char formed (from 18.15% to 21.47–24.06%). The amino groups derived from four different ammonia sources (formamide, urea, melamine and dicyandiamide) reacted with biomass-derived O-containing compounds to form pyridinic- and graphitic-like biochar due to NH3 etching and activation, and the enhanced adsorption capacities decreased in the order melamine (107.95 m2/g) > urea (96.84 m2/g) > dicyandiamide (79.46 m2/g) > formamide (74.12 m2/g) > biochar (35.63 m2/g)) due to the higher specific surface areas, pore volumes, graphitization degrees and enrichment of the O/N-containing functional groups. Additionally, higher concentrations of formamide coupled with the HZSM-5 catalyst noticeably boosted the NCCs content and pyrrole selectivity. The maximum NCCs content and pyrrole selectivity were 82.97% and 52.45%, respectively, and these were obtained via catalytic pyrolysis with HZSM-5 when the formamide concentration was 15%. Furthermore, formamide preferentially generated NCCSs and pyrroles via the Maillard reaction, and urea facilitated amine formation. This research provides useful background knowledge and a novel process for transformation and recovering high value-added NCCs products by N-rich pyrolysis of ammonia impregnated biomass.

In Situ P-Modified Hybrid Silica–Epoxy Nanocomposites via a Green Hydrolytic Sol–Gel Route for Flame-Retardant Applications

Flame retardance of epoxy resins is usually imparted using suitable additives and/or properly modified curing agents. Herein, via a two-step green synthetic procedure, the chemical modification of the epoxy matrix with reactive silicon and phosphorus precursors is explored to obtain nanocomposites with intrinsic flame-retardant features. Nanoscale phase separation occurs in the first step, forming an inverse micelle system in which polar nanodomains act as nanoreactors for the hydrolysis of silanes (Si precursors), giving rise to silica lamellar nanocrystals (SLNCs). In the second step, inside the silica nanodomains, the formation of stable Si–O–P bonds occurs because the reactivity of phosphoric acid (P precursor) with the oxirane rings of the polymer chain is balanced by its tendency to diffuse into polar nanodomains. Intriguingly, the use of phosphoric acid alone in epoxy composite manufacturing leads to a wormlike morphology of the network, whereas its addition in the presence of silanes results in the formation of SLNCs with a thinner interlayer distance. The morphology of the hybrid Si/P–epoxy nanocomposites, comprising organic and inorganic co-continuous phases, can confer, through a prevalent mechanism in the condensed phase, interesting flame-retardant performances, namely, the absence of dripping during vertical burning tests, the formation of a large amount of coherent char after combustion, and a remarkable reduction (up to 27.7%) in the peak of heat release rate. The above characteristics make these nanostructured hybrid materials very promising for the manufacturing of epoxy systems with enhanced fire behavior (e.g., coatings, sealants, matrices for reinforced composites), even containing a low amount of specific flame retardants and thus keeping good viscoelastic properties.

Making hybrid mixture explosions a common case

Explosions of gas-dust hybrid mixtures have long been considered as particular cases encountered in specific industrial contexts. However, it should be reminded that during the explosion of an organic powder, the presence of a hybrid mixture composed of the dust itself and its pyrolysis gases is compulsory. On these premises, an experimental study to determine the role of cellulose pyrolysis products (gaseous, condensable and solid) on the global phenomenon is presented. Hybrid mixture explosion tests were exploited to carry out the investigation. The G-G furnace and the 20 L sphere were employed. Several experimental strategies were chosen to demonstrate the impact of pyrolysis reaction on the explosion of organic powders: i) the fuel equivalence ratio of the reactive mixture (case 1), or ii) the mass of reactants (case 2) were respectively kept constant, iii) the effects of water vapor, char and tar were tested. They were next compared to identify the most suitable one. The two first experimental approaches lead to significantly different results: only case 2 keeps the maximum explosion pressure almost constant, but maximum rate of pressure rises and deflagration index greatly decrease when the pyrolysis gases concentration decreases, which highlights the importance of the pyrolysis reaction on the explosion kinetics. It should also be stressed that the maximum explosion severity is not obtained for the pure gases but when a small dust content is added. The same evolution is observed when a small amount of char is introduced to pyrolysis gases, which underlines the influence of the radiative transfer. Adding small amounts of tar to cellulose tends to increase its explosion severity. However, this impact is less than that generated by the addition of pyrolysis gases.

Numerical investigations of biomass pyrolysis with partial oxidation in a drop tube reactor

This study relates to 2D numerical calculations of fast pyrolysis with partial oxidation of pine and pine bark in a drop-tube reactor at 550 °C. Numerical studies were supported by experiments using thermogravimetric analysis of pine, pine bark, and pure lignin. The study involved 3 atm of pyrolysis: pure nitrogen, 95% nitrogen/5% oxygen, and 90% nitrogen/10% oxygen v/v. Numerical calculations were performed using Euler–Lagrange multiphase theory. According to the results, it was possible to linearly reduce the amount of char from 49% to 34% for pine and from 57% to 36% for pine bark, as the oxygen content in the carrier gas increased from 0 to 10% v/v. Furthermore, the addition of oxygen decreased the required energy for pyrolysis from 1.55 to 1.1 MJ/kg for pine and from 1.6 to 1.1 MJ/kg for pine bark at the maximum considered oxygen content. Simultaneously, owing to the increasing oxygen content in the carrier gas, gaseous products were promoted, and the mass ratio of CO to CO2 was almost the same for all cases and was approximately 0.6.

Effect of a graphene-APP composite aerogel coating on the polyester fabric for outstanding flammability

Catalytic charring is an important way to realize flame retardant modification of polymer, especially for carbonaceous polymers. In this paper, graphene aerogel (GA) as a new carbon carrier, and ammonium polyphosphate (APP) as catalyst, an efficient integrated composite aerogel (GA-APP) is constructed and in situ grown on the surface of polyester fabric by the hydrothermal reduction method. The flame retardancy and mechanism of GA-APP has been investigated in detail by limiting oxygen index (LOI), x-ray photoelectron spectroscopy (XPS), thermogravimetry-infrared (TG-IR) and cone calorimeter (CONE) method. The results showed that, with the addition of 26 % GA-APP powder, the LOI value of GA-APP/PET fabric is 34.1 %, and the vertical combustion test passed B1 grade. GA-APP flame retardant significantly reduced the peak heat release rate, total heat release, total smoke production and smoke rate of PET fabric through the synergistic effect of GA and APP. The char residual amount of GA-APP/PET fabric increased to 91.5 % after the combustion during the CONE test. GA-APP mainly played the role of agglomerative flame retardant by changing the char structure and char quantity, which can function the stronger barrier effect and inhibit the combustion reaction. The dense and carbon layer with high thermal stability formed under the synergistic action of GA-APP. This layer can isolate heat transfer, flame retardant and smoke suppression during PET fabric combustion.

Valorization of industrial waste lignin via pyrolysis in the presence of additives: Formation, characterization, and application of fuel valued bio-oil and activated char

The annual production of over 50 million tonnes of industrial waste kraft lignin and scant utilization invites environmental concern. To explore the potential of simultaneously produced bio-oil and modified char (Activated char), lignin from industrial effluents was subjected to pyrolytic degradation at 380 °C using various additives, viz., H3BO3, ZnCl2, and KOH yielding encouraging quantities of bio-oils besides substantial quantities of char. Quantitative and qualitative analyses of gaseous products (by GC-TCD) indicated a mixture of CO, CO2, H2, and methane, with some variation in volumetric composition suggesting potential for gaseous fuel/syngas. Gaseous products obtained in the presence of H3BO3 have the highest methane percentage. The bio-oils obtained in the presence of H3BO3, ZnCl2, KOH, and only pure lignin under otherwise similar conditions were respectively 37%, 21%, 27%, and 11 wt%. In all cases, mainly bio-oils contain phenols, cyclic esters, and carboxylic acids, as indicated by GC-MS analysis. Elemental (C, H, O) Analyses of bio-oils obtained in the presence of (H3BO3, ZnCl2, and KOH) indicated decreasing oxygen content compared to original lignin, suggesting their prima facie potential to lead to fuel additives/supplements. Similarly, the Char obtained in the presence of H3BO3, ZnCl2, KOH, and only pure lignin were respectively, 40%, 53%, 48%, and 33 wt% with a high calorific value. Char obtained from KOH application demonstrated good uptake of Carbofuran (pesticide) from the aqueous solution. Less modified, cost-effective activated char was characterized using FTIR, TG-DTA, XRD, SEM, and BET-BJH, indicating 188.798 m2/g; this explores the role of KOH to form a microporous structure. Pseudo-second-order kinetics explain chemisorption to be dominant in the adsorption process. Thus, pyrolysis at selected temperatures/additives/and further treatments provides a much better way to utilize industrial waste lignin.

Development of Intumescent Flame Retardant for Polypropylene: Bio-epoxy Resin Microencapsulated Ammonium-polyphosphate

As polypropylene (PP) has no charring ability on its own due to the lack of hydroxyl functional groups, the flame retardant system needs the addition of carbonizing agent in a relatively great amount. Ammonium-polyphosphate (APP), a conventional flame retardant additive was modified by microencapsulation with a sorbitol-based bioepoxy resin shell to create an intumescent flame retardant system with enhanced charring ability for PP. The flame retardant efficiency of the microencapsulated additive, which contains all the components needed in an effective intumescent flame retardant system, was evaluated in PP matrix at different loadings.When compared to the physical mixture of the component, the microencapsuated form of APP (MCAPP) was found to have improved flame retardant efficiency in PP. The LOI values of the MCAPP containing PP samples increased by 8–11 V/V% besides achieved V-0 classification according to the UL94 test. During cone calorimeter tests, the burning intensity was reduced (peak of heat release rate decreased by 20–35% and shifted in time), increased amount of charred residue was obtained, and based on the calculated Flame Retardancy Index (FRI) “Excellent” fire performance was achieved when MCAPP was used. The improved flame retardant performance is attributed to the effective interaction between the APP core and the readily available carbonizing shell, which promoted the formation of increased amount of char accompanied with improved heat protecting and barrier efficiency.

Kinetic modelling of pyrolysis of cellulose using CPD model: effect of salt

In this work, effect of salt on cellulose pyrolysis behaviour using chemical percolation devolatilization (CPD) model has been investigated. The distributed activation energy model (DAEM) has been used to determine the kinetics of pure and NaCl-loaded cellulose pyrolysis in a thermogravimetric analyser (TGA). A number of these experiments were performed for a range of heating rates (5–100 °C min−1) and for different concentrations of NaCl in cellulose (0.25–2 mass/%) which showed a pronounced effect of salt on the primary pyrolysis reactions of cellulose. These data were then used in a two-component DAEM to calculate the kinetic parameters for the chemical percolation devolatilization model (CPD) for both pure and NaCl-loaded cellulose. The optimized kinetic parameters for the pure and NaCl-loaded cellulose were used in the CPD model, and the product yield was predicted. The CPD predictions showed that the fraction of gases and char in the pyrolysis products increased in the presence of salt. The amount of char for pure cellulose was 6.97% which increased to 16.4% in the presence of 0.25% NaCl. The amount of gases produced as a result of pure cellulose pyrolysis was 9.63% and this amount increased with addition of NaCl to 22.85% and then further increases with an increase in NaCl concentration. Amount of tar produced for pure cellulose was 83.4%, and this amount reduced to 60.7% with addition of 0.25% NaCl. The presence of NaCl accelerates cellulose decomposition and favours the formation of gases and char.

Synergistic effect of chitosan derivative and DOPO for simultaneous improvement of flame retardancy and mechanical property of epoxy resin

In this work, the effects of a chitosan-based derivative (CSA), DOPO (9, 10-dihydro-9-oxa-10- phosphaphenanthreene-10-oxide) and CSA-DOPO additives on the flammable properties of EP (epoxy resin) composites were systematically studied, where CSA was synthesized by a facile condensation between chitosan (CS) and 9-anthralaldehyde. The mass ratio of CS and 9-anthralaldehyde in CSA was determined by elemental analysis and theoretical calculation. Under the 8% addition in EP, EP/2.66%/5.34%DOPO sample was the only one passing the UL-94 V-0 rating and exhibiting the highest LOI value of 36.4%. The cone calorimeter test (CC) showed that the total smoke emission value and the peak heat release rate of the EP/2.66%/5.34%DOPO decreased by 36.0% and 61.9%, and the residual char amount increased by 151%, respectively, when compared with EP. Moreover, the incorporation of CSA/DOPO effectively improved the flexural strength by 52.3%. According to the results obtained from Py-GC/MS analyses for EP and EP/2.66%CSA/5.34%DOPO samples, together with Raman spectra, XPS (X-ray photoelectron spectra) for their char residues, and the real time FTIR (Fourier-transform infrared) spectra at different pyrolysis temperatures and cone calorimeters, it was proposed that CSA/DOPO played roles in both gaseous and condensed phases, and the synergistic effect of CSA and DOPO significantly improved the flame retardancy and mechanical strength of EP. Graphical abstract

Copper Rich Composite Materials Based on Carboxylic Cation Exchangers and Their Thermal Transformation.

The effect of a cupric deposit (Cu2+, CuO) on the thermal decomposition of carboxylic cation exchangers (CCEs) is not known, and such studies may have practical significance. CCEs have a very high ion exchange capacity, so an exceptionally large amount of CuO (which is a catalyst) can be precipitated inside them. Two CCEs, macroreticular (Amberlite IRC50) and gel-like (Amberlite IRC86), served as a polymeric support to obtain copper-rich hybrid ion exchangers. Composites with CuO particles inside a polyacrylic matrix (up to 35.0 wt% Cu) were obtained. Thermal analyses under air and under N2 were performed for CCEs in the H+ and Cu2+ form with and without a CuO deposit. The results of sixteen experiments are discussed based on the TG/DTG curves and XRD patterns of the solid residues. Under air, the cupric deposit shifted the particular transformations and the ultimate polymeric matter decomposition (combustion) toward lower temperatures (even about 100–150 °C). Under N2, the reduction of the cupric deposit to metallic copper took place. Unique composite materials enriched in carbonaceous matter were obtained, as the products of polymeric matrix decomposition (free radicals and hydrogen) created an additional amount of carbon char due to the utilization of a certain amount of hydrogen to reduce Cu (II) to Cu0.

Ignition and Charring of PVC-Based Electric Cables

The ignition of four different PVC-based electric cables was studied using cone calorimeter and the influence of the charring phenomenon on ignition was investigated. The thermophysical and optical properties of the sheaths before decomposition were measured. The kinetics of charring was studied by photogrammetry. It was shown that charring occurs for three cables before ignition at heat flux lower than 45 kW/m2. The lower is the heat flux, the higher is the char amount at ignition. In spite of the char formation, it was observed that the time-to-ignition of the cables can be properly calculated using the well-known Quintiere’s equation, considering an apparent temperature of ignition. This apparent temperature at ignition was found in the range 312°C to 349°C for the four electric cables.

Recovery of Carbon Fibre from Waste Prepreg via Microwave Pyrolysis.

Management of waste from carbon fibre composites has become a significant societal issue as the application of composite grows across many industries. In this study, carbon fibres (CF) were successfully recovered from cured carbon fibre/epoxy (CF/EP) prepreg under microwave pyrolysis at 450, 550 and 650 °C followed by oxidation of any residual char. The recovered fibres were investigated for their tensile properties, surface morphologies and the elements/functional groups presented on the surface. The chemical compositions of gaseous and oil pyrolysis products were also analysed. The microwave pyrolysis effectively pyrolyzed the epoxy (EP) resin. Char residue remained on the fibre surface and the amount of char reduced as the pyrolysis temperature increased. Compared to virgin fibres, the recovered fibre suffered from a strength reduction by less than 20%, and this reduction could be mitigated by reducing the pyrolysis temperature. The surface of recovered fibre remained clean and smooth, while the profile of elements and functional groups at the surface were similar to those of virgin fibres. The main gaseous products were CO, H2, CO2 and CH4, whilst the liquid product stream included phenolic and aromatic compounds.

Growth, nutritive value and dry matter degradability of three tepbrosia species

Two trials were carried out to evaluate the potential of Tephrosia bracteolata (TB), Tephrosia candido (TC) and Tephrosia linearis (TL) for animal feed. In an 18 week growth experiment, Tephrosia species differed (P<0.05) in leur number (LN) and stein height (SH). TB and TL had apparent (P<0.05) earh and persisten growth than TC until wecks 12-18 when they retarded in growth of the commencement of flowering. 7C however, increased geometrically in LN and SH. There were significant (P<0.50) differences among the species in diy matter (DM) and acid detergent fibre (ADF). The DM, CP, NDF, 4DF, EE and ash range from 30-41.8, 24-26.5, 62.5 68.5, 45.8-48.4, 2.3-26 and 5.6-6.2% respectively. Calcium and sodium were highest (P<0.05) in TB and 72 species were not significantly (P<P.05) different in degradation char amount of crude protein (10-14.81%) was released in the 3 Tephrosia species. As a result of rapid growth, high nutritive values and easily degradable nutrients of Tephrosia shrubs, ruminants could benefit immensely from the plants.