This study experimentally evaluated wheat straw slurry pipelines. Tests were conducted to determine the particle properties of the biomass mixed in water over time. The saturated particle density of 1,060kg/m3 was reached after 24 hours, while the saturated moisture contents of 78.5% and 79.5% were later reached for particle sizes of 1/8 and 3/4" respectively. A pipeline loop was redesigned to operate with 1/8, 1/4", and 3/4" straw particle slurries at up to 30% wet basis concentrations. The modifications allowed measurements of pressure loss through a length of pipe. These measurements which show the influences of drag reducing fibre suspension. Straw particles added to water lowered the pressure loss, by suppressing turbulence at lower concentrations or higher velocities. Additional straw further improved the result, until the maximum concentration was reached. High concentrations create plugs, increasing the pressure loss. Longer straw particles can further reduce losses, but have lower maximum concentrations. / Engineering Management

Thermoplastic composites using natural fibres are studied intensively and widely used in applications including automotive, packaging, consumer goods and construction. Good balance of mechanical properties, processability and low cost are great advantages of these materials on top of the environmental benefits. Recently, there have been various efforts to amplify the positive effects on the environment by replacing the conventional polymers by bio-derived renewable polymers in the composites. Recent studies conducted from our research group showed competitiveness of plant fibre-thermoplastic composites. Implementing the promising results and experience, a new composite design using renewable polyethylene as the matrix material was studied. This polyethylene is a renewable thermoplastic that was derived from sugar cane ethanol. The objectives of this study were to employ renewable high density polyethylene (HDPE) into composites using wheat straw and flax fibre to extend the range of properties of the HDPE while keeping the amount of renewable content to nearly 100%. The chemical resistance of these materials has not been reported before and it was investigated here by measuring and comparing the properties before and after accelerated chemical ageing. Both wheat straw and flax fibre had two different grades in size. Each of them was compounded with HDPE and additives (antioxidant and coupling agent) in a co-rotating twin screw extruder. The concentrations of fibres were varied from 0 to 30 wt-%. Then, injection molded samples were prepared for measurement of properties: tensile, flexural, impact tests. The effects of reinforcing fibre size were studied first. Both length and aspect ratio were considered. For both types of fibre composites, a general trend was observed. There was no clear evidence of improvements in flexural (strength and modulus) and tensile (strength, percentage elongation at break) properties with respect to the change in fibre size. However, impact (IZOD impact strength, Gardner impact failure energy) properties showed some improvements. This result was due to no substantial difference in size and aspect ratios in post-processed fibres that were actually residing in the matrix. There were remarkable improvements in flexural strength and modulus when the fibre content increased. However, minor decreases in tensile properties were observed. Furthermore, the impact properties were very sensitive to the concentration of fibres. As the fibre concentration went up, there were significant decreases in both IZOD impact strength and Gardner impact failure energy. Chemical resistance of these composites was studied by exposing them in six different chemical solutions (hydrochloric acid, acetic acid, sodium hydroxide, ethyl alcohol, industrial detergent, water) for up to thirty days. The increase in weight and leaching behaviour was observed. As the fibre content increased within the composites, the weight gain was more rapid during chemical ageing. Because there were more fibres exposed on the surface after chemical ageing, it is likely that they contributed to the higher flux of liquids (used for chemical ageing) inside the sample. Among the physical properties, tensile properties were most susceptible to the chemical ageing. One possible reason could be due to the exposed surface area to volume ratio, which was the highest in tensile bars and therefore faster mass transfer taking place into the matrix per volume. Finally, morphological study using scanned electron spectroscopy (SEM) revealed the damage on the surface when exposed to the chemicals. The fibres on the surface had been leached out in the sodium hydroxide solution leaving empty spaces. The fractured surface was also monitored via SEM. Though there was not enough evidence of strong interfacial interactions between the fibre and the polymer, good dispersions were observed.

Cellulose is a potential source of nano-material not only because it possesses excellent mechanical and optical properties, but also because it is environmentally benign. In this study, nanofibres derived from wheat straw, an agriculture residue, was utilized in producing flexible and optically transparent nanocompostie films. The composites were produced using a bi-phase impregnation technique that coats the dried nanofibre films with clear polyurethane acrylate resins using UV radiation induced curing. The nanocomposite films thus produced possess excellent tensile properties (161MPa in strength and 9GPa in Young’s Modulus), superior thermal stability (above 300°C), low coefficient of thermal expansion (8-9ppm/K), good light transparency (80%), excellent flexibility and abrasion resistance. These nanocomposite films are aimed to replace the conventional glass substrates made in batches to a polymer based substrates that can be efficiently produced in a roll-to-roll process for the base of the future flexible flat panel displays.

Cellulose is a potential source of nano-material not only because it possesses excellent mechanical and optical properties, but also because it is environmentally benign. In this study, nanofibres derived from wheat straw, an agriculture residue, was utilized in producing flexible and optically transparent nanocompostie films. The composites were produced using a bi-phase impregnation technique that coats the dried nanofibre films with clear polyurethane acrylate resins using UV radiation induced curing. The nanocomposite films thus produced possess excellent tensile properties (161MPa in strength and 9GPa in Young’s Modulus), superior thermal stability (above 300°C), low coefficient of thermal expansion (8-9ppm/K), good light transparency (80%), excellent flexibility and abrasion resistance. These nanocomposite films are aimed to replace the conventional glass substrates made in batches to a polymer based substrates that can be efficiently produced in a roll-to-roll process for the base of the future flexible flat panel displays.

When two or more individual materials combine to form a new material with improved characteristics, a composite is created. The two major components in a thermoplastic composite are the polymer, such as polypropylene (PP), and the filler, such as minerals like calcium carbonate and talc, or agricultural crop by-products like wheat straw, soy hull and soy stems. The main advantages of using agricultural fillers (AgFillers) in polypropylene are cost reduction and modulus improvement, without drastically increasing the specific gravity of the composite. These properties can be further enhanced by subjecting the composite to the bulk orientation process, in which the polymer chains align to give superior strength to the material, while the presence of polar AgFillers contributes to a reduction in material density. The objective of this research was to systematically study the relationships between the components and properties of AgFiller-PP composites, and their contributions to property modifications. Three types of AgFillers, wheat straw (WS), soy hulls (SH) and soy stems (SS) were studied, along with two PP types, virgin PP (vPP) and recycled PP (rPP), and mixtures of the two PP types. Non-oriented composites with a composition ratio of 40 wt% AgFiller to 60 wt% PP were tested for their morphology, chemical, thermal, rheological and mechanical properties. Similar properties of oriented composites with 20 wt% wheat straw filler and 80 wt% PP were also examined. The type of AgFiller was found to play a significant role in determining the rheological and mechanical properties of non-oriented AgFiller-PP composites. Scanning electron microscopy (SEM) showed that AgFillers had the tendancy to align lengthwise when subjected to the extrusion process. Depending on the fiber alignment within the filler with respect to the lengthwise direction of the filler, each AgFiller contributed differently to the composites’ properties. Stem-based AgFillers like WS and SS had fiber alignment parallel to the lengthwise direction, and the composites created had higher viscosity and higher flexural modulus. On the other hand, shell-based AgFillers like SH had fiber alignment perpendicular to the filler’s length, and were found to have less contribution to viscosity increase. Fourier transform Infrared (FTIR) spectroscopy using attenuated total reflectance (ATR) technique showed that a skin layer of PP congregated on the surface of all the non-oriented AgFiller-PP composites, regardless of the AgFiller used. The main contribution of PP polymer type was to the rheological properties of non oriented AgFiller-PP composites. The presence of rPP also appeared to slightly improve the immiscibility between polar AgFillers and nonpolar PP polymer, according to SEM image analysis. The viscosity of the composites decreased linearly with increasing amount of rPP, because the rPP tested had significantly lower viscosity than the vPP chosen. No statistically significant conclusions could be drawn on the mechanical property changes due to large experimental variance that existed in the data. Bulk orientation of AgFiller-PP composites was shown to provide significant reduction in the material’s density as well as improvement in physical properties. Experimental results of oriented wheat straw-PP composites showed that wheat straw was highly comparable, perhaps even more superior, to wood fibers as filler for oriented PP composites. The ability to produce oriented wheat straw-PP composites using the same technology and conditions as producing oriented wood-plastic composites affirmed the feasibility for commercialization of oriented wheat straw-PP composites, and by means contributing to setting a milestone in the scientific research of AgFiller-thermoplastic biocomposites.

When two or more individual materials combine to form a new material with improved characteristics, a composite is created. The two major components in a thermoplastic composite are the polymer, such as polypropylene (PP), and the filler, such as minerals like calcium carbonate and talc, or agricultural crop by-products like wheat straw, soy hull and soy stems. The main advantages of using agricultural fillers (AgFillers) in polypropylene are cost reduction and modulus improvement, without drastically increasing the specific gravity of the composite. These properties can be further enhanced by subjecting the composite to the bulk orientation process, in which the polymer chains align to give superior strength to the material, while the presence of polar AgFillers contributes to a reduction in material density. The objective of this research was to systematically study the relationships between the components and properties of AgFiller-PP composites, and their contributions to property modifications. Three types of AgFillers, wheat straw (WS), soy hulls (SH) and soy stems (SS) were studied, along with two PP types, virgin PP (vPP) and recycled PP (rPP), and mixtures of the two PP types. Non-oriented composites with a composition ratio of 40 wt% AgFiller to 60 wt% PP were tested for their morphology, chemical, thermal, rheological and mechanical properties. Similar properties of oriented composites with 20 wt% wheat straw filler and 80 wt% PP were also examined. The type of AgFiller was found to play a significant role in determining the rheological and mechanical properties of non-oriented AgFiller-PP composites. Scanning electron microscopy (SEM) showed that AgFillers had the tendancy to align lengthwise when subjected to the extrusion process. Depending on the fiber alignment within the filler with respect to the lengthwise direction of the filler, each AgFiller contributed differently to the composites’ properties. Stem-based AgFillers like WS and SS had fiber alignment parallel to the lengthwise direction, and the composites created had higher viscosity and higher flexural modulus. On the other hand, shell-based AgFillers like SH had fiber alignment perpendicular to the filler’s length, and were found to have less contribution to viscosity increase. Fourier transform Infrared (FTIR) spectroscopy using attenuated total reflectance (ATR) technique showed that a skin layer of PP congregated on the surface of all the non-oriented AgFiller-PP composites, regardless of the AgFiller used. The main contribution of PP polymer type was to the rheological properties of non oriented AgFiller-PP composites. The presence of rPP also appeared to slightly improve the immiscibility between polar AgFillers and nonpolar PP polymer, according to SEM image analysis. The viscosity of the composites decreased linearly with increasing amount of rPP, because the rPP tested had significantly lower viscosity than the vPP chosen. No statistically significant conclusions could be drawn on the mechanical property changes due to large experimental variance that existed in the data. Bulk orientation of AgFiller-PP composites was shown to provide significant reduction in the material’s density as well as improvement in physical properties. Experimental results of oriented wheat straw-PP composites showed that wheat straw was highly comparable, perhaps even more superior, to wood fibers as filler for oriented PP composites. The ability to produce oriented wheat straw-PP composites using the same technology and conditions as producing oriented wood-plastic composites affirmed the feasibility for commercialization of oriented wheat straw-PP composites, and by means contributing to setting a milestone in the scientific research of AgFiller-thermoplastic biocomposites.

The focus of this study was to determine the effects of pretreatment of wheat straw by superheated steam (SS) alone or in combination with boiling water (BW) on biomass structure and yields of fermentation products (cell mass and fermentation end-products) by Clostridium thermocellum. Different cultivars of wheat straw were ground to a particle size less than 355 µm, and exposed to the following methods of pretreatment: i) 15 min soaking in 119 °C boiling water under absolute pressure of 193 kPa, followed by processing with SS at atmospheric pressure at different temperatures and retention times; ii) 15 min processing with SS at atmospheric pressure; and iii) 15 min soaking in 119 °C boiling water under absolute pressure of 193 kPa. Processing with SS was conducted at a variety of temperatures in the range of 180-220 °C. The severity of pretreatment was expressed through a treatment severity factor as a measure of harshness of treatment. Pretreatment combinations of boiling water with superheated steam at different retention times inside the SS chamber were also investigated. Wheat straw samples were then used as substrates in fermentation reactions with C. thermocellum. The most noticeable effects on biomass structure and fermentation were observed at the highest severity factor of 6.5, corresponding to 15 min pretreatment with boiling water followed by 15 min treatment with SS at 220˚C. This pretreatment provided the maximum increase in percentage of contribution of amorphous cellulose (% CAC), and the highest fermentation yield in terms of hydrogen, carbon dioxide, and ethanol production. / October 2015

No description available.

Thermoplastic composites using natural fibres are studied intensively and widely used in applications including automotive, packaging, consumer goods and construction. Good balance of mechanical properties, processability and low cost are great advantages of these materials on top of the environmental benefits. Recently, there have been various efforts to amplify the positive effects on the environment by replacing the conventional polymers by bio-derived renewable polymers in the composites. Recent studies conducted from our research group showed competitiveness of plant fibre-thermoplastic composites. Implementing the promising results and experience, a new composite design using renewable polyethylene as the matrix material was studied. This polyethylene is a renewable thermoplastic that was derived from sugar cane ethanol. The objectives of this study were to employ renewable high density polyethylene (HDPE) into composites using wheat straw and flax fibre to extend the range of properties of the HDPE while keeping the amount of renewable content to nearly 100%. The chemical resistance of these materials has not been reported before and it was investigated here by measuring and comparing the properties before and after accelerated chemical ageing. Both wheat straw and flax fibre had two different grades in size. Each of them was compounded with HDPE and additives (antioxidant and coupling agent) in a co-rotating twin screw extruder. The concentrations of fibres were varied from 0 to 30 wt-%. Then, injection molded samples were prepared for measurement of properties: tensile, flexural, impact tests. The effects of reinforcing fibre size were studied first. Both length and aspect ratio were considered. For both types of fibre composites, a general trend was observed. There was no clear evidence of improvements in flexural (strength and modulus) and tensile (strength, percentage elongation at break) properties with respect to the change in fibre size. However, impact (IZOD impact strength, Gardner impact failure energy) properties showed some improvements. This result was due to no substantial difference in size and aspect ratios in post-processed fibres that were actually residing in the matrix. There were remarkable improvements in flexural strength and modulus when the fibre content increased. However, minor decreases in tensile properties were observed. Furthermore, the impact properties were very sensitive to the concentration of fibres. As the fibre concentration went up, there were significant decreases in both IZOD impact strength and Gardner impact failure energy. Chemical resistance of these composites was studied by exposing them in six different chemical solutions (hydrochloric acid, acetic acid, sodium hydroxide, ethyl alcohol, industrial detergent, water) for up to thirty days. The increase in weight and leaching behaviour was observed. As the fibre content increased within the composites, the weight gain was more rapid during chemical ageing. Because there were more fibres exposed on the surface after chemical ageing, it is likely that they contributed to the higher flux of liquids (used for chemical ageing) inside the sample. Among the physical properties, tensile properties were most susceptible to the chemical ageing. One possible reason could be due to the exposed surface area to volume ratio, which was the highest in tensile bars and therefore faster mass transfer taking place into the matrix per volume. Finally, morphological study using scanned electron spectroscopy (SEM) revealed the damage on the surface when exposed to the chemicals. The fibres on the surface had been leached out in the sodium hydroxide solution leaving empty spaces. The fractured surface was also monitored via SEM. Though there was not enough evidence of strong interfacial interactions between the fibre and the polymer, good dispersions were observed.

Many agricultural biogas stations process predominantly phytomass specifically grown for power engineering purposes as a primary raw material. This results in gradual increase of maize proportion in sowing sequences at the exclusion of traditional area-specific crops, which presents various potential negative effects. The aim of study is to evaluate the substitution of maize with wheat straw in the anaerobic fermentation process from the biotechnological and economic viewpoint. For this purpose, wheat straw pellets were pretreated using the high-pressure extruder in compliance with UV CZ 21314 at different runtime parameters. Cumulative methane (CH4) production in quarter-mode operation simulation, based on the extrusion pressure, cycle duration and fermentation temperature, was the main evaluation criteria. Optimal run time parameters were derived from the approximation ? extrusion pressure 1,35 MPa, reaction time 210 s, in order to achieve maximal CH4 production at mesophilic fermentation temperature (38 °C). For fermentation temperature 48 °C, optimal pressure 1,25 MPa and cycle duration 180 s were approximated. The discount rate of Net Present Value (NPV) was established as a main comparative criterion considering overall executive, legislative and technological aspects of analyzed biological effects. Based on these findings suggest, wheat straw extrusion is interesting, unconventional and profitable technology in the field of biogas production.