Infrared (IR) drying of paper in a pilot scale has been investigated by several researchers in the past [1–3]. Both high-intensity electric heating and medium-intensity gas heating are now being used industrially either to preheat wet... more
Infrared (IR) drying of paper in a pilot scale has been investigated by several researchers in the past [1–3]. Both high-intensity electric heating and medium-intensity gas heating are now being used industrially either to preheat wet paper before conventional steam drying [1] or as a moisture-profile corrector just before paper sizing press [2]. Our own investigation [3] on the use
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Cellulose nanofibers (diameter=10-70 nm) were produced using chemical treatments (alkali treatment and bleaching) and high pressure homogenization from de-pectinated sugar beet pulp (DSBP). Chemical analysis and Fourier transform infrared... more
Cellulose nanofibers (diameter=10-70 nm) were produced using chemical treatments (alkali treatment and bleaching) and high pressure homogenization from de-pectinated sugar beet pulp (DSBP). Chemical analysis and Fourier transform infrared spectroscopy (FTIR) indicated that the chemical treatments greatly removed the hemicellulose and lignin from the DSBP and significantly increased the cellulose content. The crystallinity of the cellulose nanofibers increased from 35.67% to 69.62% after alkali treatment and bleaching. The thermal degradation temperature of DSBP cellulose nanofibers was 271.7 °C which was found to be 47.3 °C higher than that of the untreated DSBP. The DSBP cellulose nanofibers can be preferably used as reinforcement in the biocomposite material at high temperature.
Research Interests: Materials Science, Chemistry, Organic Chemistry, Nanofibers, Scanning Electron Microscopy, and 14 moreMorphology, Medicine, Cellulose, Nanofiber, Lignin, Crystallinity, Thermogravimetry, X ray diffraction, Fourier transform infrared spectroscopy, Food Sciences, Hemicellulose, Pectins, Beta Vulgaris, and Carbohydrate Polymers
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Microbial modification of starch with Ophiostoma spp . was investigated, with the purpose of developing a novel packaging material for the food or pharmaceutical industries. Various starch sources, such as tapioca, potato, corn, rice and... more
Microbial modification of starch with Ophiostoma spp . was investigated, with the purpose of developing a novel packaging material for the food or pharmaceutical industries. Various starch sources, such as tapioca, potato, corn, rice and amylopectin were tested as raw materials. The initial screening demonstrated that tapioca and potato starch had better performance for biopolymer production. The yield was about 85%. Preliminary characterization of the modified biopolymer was also conducted. Following microbial conversion, the percentage of molecules with at least a Mw of 10M Daltons increased from 25% to 89% after 3 days, confirming that the modification increased the weight of the starch polymer. Fourier Transform Infrared (FT-IR) revealed changes in the chemical structure of the starch after the modification. Both pure starches and the modified biopolymers were cast into films and tested for mechanical properties. The tensile tests showed that after treatment with the fungus, the...
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Because of their wide abundance, their renewable and environmentally benign nature, and their outstanding mechanical properties, a great deal of attention has been paid recently to cellulosic nanofibrillar structures as components in... more
Because of their wide abundance, their renewable and environmentally benign nature, and their outstanding mechanical properties, a great deal of attention has been paid recently to cellulosic nanofibrillar structures as components in nanocomposites. A first major challenge has been to find efficient ways to liberate cellulosic fibrils from different source materials, including wood, agricultural residues, or bacterial cellulose. A second major challenge has involved the lack of compatibility of cellulosic surfaces with a variety of plastic materials. The water-swellable nature of cellulose, especially in its non-crystalline regions, also can be a concern in various composite materials. This review of recent work shows that considerable progress has been achieved in addressing these issues and that there is potential to use cellulosic nano-components in a wide range of high-tech applications.
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Tea polyphenols have received much attention from the pharmaceutical and food industries owing to their extraordinary antioxidant and antibacterial characteristics. However, tea polyphenols are very unstable to processing and storage,... more
Tea polyphenols have received much attention from the pharmaceutical and food industries owing to their extraordinary antioxidant and antibacterial characteristics. However, tea polyphenols are very unstable to processing and storage, since they are sensitive to the environmental factors like temperature, light and pH. Therefore, the effective application of tea polyphenols requires a protective mechanism to maintain its activity. The utilization of compounded tea polyphenols, instead of raw materials, can potentially help to improve their stability. This review focuses on the summarization of the compounding technologies for tea polyphenols, including physical technologies, chemical-interfacial technologies and nano-scale compounding technologies. Of which, the emerging nanocellulose bio-carrier, as a promising technology, is particularly proposed.
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Although there is a growing interest in utilizing nanocellulose fibres (NCFs) based composites for achieving a higher sustainability, mechanical performance of these composites is limited due to the poor compatibility between fibre... more
Although there is a growing interest in utilizing nanocellulose fibres (NCFs) based composites for achieving a higher sustainability, mechanical performance of these composites is limited due to the poor compatibility between fibre reinforcement and polymer matrices. Here we developed a bio-nanocomposite with an enhanced fibre/resin interface using a hybrid-toughened epoxy. A strong reinforcing effect of NCFs was achieved, demonstrating an increase up to 88% in tensile strength and 298% in tensile modulus as compared to neat petro-based P-epoxy. The toughness of neat P-epoxy was improved by 84% with the addition of 10wt% bio-based E-epoxy monomers, which also mitigated the amount of usage of bisphenol A (BPA). The morphological analyses showed that the hybrid epoxy improved the resin penetration and fibre distribution significantly in the resulting composites. Thus, our findings demonstrated the promise of developing sustainable and high performance epoxy composites combing NCFs with a hybrid petro-based and bio-based epoxy resin system.
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In order to broaden the applications of bio-epoxy resins in high performance sector, an understanding of thermal behavior of these environmentally-friendly biopolymers is essential. This study investigates the thermal degradation... more
In order to broaden the applications of bio-epoxy resins in high performance sector, an understanding of thermal behavior of these environmentally-friendly biopolymers is essential. This study investigates the thermal degradation mechanism of a bio-epoxy resin (E-epoxy) derived from bark extractives in comparison with a petroleum-based epoxy resin. The thermogravimetric analysis (TGA) results show that the activation energy of E-epoxy varied significantly with the extent of degradation indicating a multistage degradation mechanism involving a variety of compounds. According to Fourier transform infrared spectroscopy (FTIR) analysis, the dehydration and crosslinking reactions occurred at low temperatures, while the Claisen chain rearrangement and chain–scission reactions dominated at high temperatures. The pyrolysis-gas chromatography–mass spectrometry (Py-GC/MS) results show that a significant amount of methyl abieta-8,11,13-trien-18-oate, diethyl phthalate, 2,2-isopropylidenebis(3,5-dimethylbenzofuran), and epimanool were detected in the bio-epoxy resins. The newly proposed degradation mechanism of bio-epoxy resins based on structural illustration through FTIR and Py-GC/MS can provide guidance for design of high performance bio-based epoxies.
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The floatability of flexo ink dispersions mixed with imprinted TMP fibres was investigated as a function of pulp consistency, aeration rate and mixing intensity. Flotation efficiency was assessed from turbidimetric and thermogravimetric... more
The floatability of flexo ink dispersions mixed with imprinted TMP fibres was investigated as a function of pulp consistency, aeration rate and mixing intensity. Flotation efficiency was assessed from turbidimetric and thermogravimetric measurements of carbon black concentration in pulp filtrates and flotation froths, respectively. Pulp consistency had the most detrimental effect on the flotation efficiency of flexo ink particles. An increase in impeller speed and/or air flow rate during flotation slightly improved the flotation efficiency. Our results suggest that fibres affect the formation and growth of flexographic ink-calcium soap aggregates but not their break-up.
ABSTRACT The process optimization for production of a tough hybrid biocomposite through Long Fibre Thermoplastic Direct compounding and molding process (LFT-D) was investigated with an ultimate goal of high impact strength. High shear... more
ABSTRACT The process optimization for production of a tough hybrid biocomposite through Long Fibre Thermoplastic Direct compounding and molding process (LFT-D) was investigated with an ultimate goal of high impact strength. High shear mixing -Twin screw extrusion- and low shear mixing -single screw extrusion- methods were used for the production of tough hybrid composites. The optimum operating condition was found to be the twin screw extrusion at which feeder to motor speed ratio was 1:10 without breaker and die while feeding the GF before the vent at 100 rpm. The hybrid composite produced accordingly had well dispersed fibres with GF content of 20 wt%, the average length of 2.3 mm, and impact strength of 130 J/m. It can be concluded that toughness was influenced by fibre concentration, length and dispersion.
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The incorporation of a phase modifier, as is well known in the case of elasto-plastic blends, leads to an improvement of mechanical properties and brittleness character for PRP-EVA blends. Similarly, the influence of a cocuring agent and... more
The incorporation of a phase modifier, as is well known in the case of elasto-plastic blends, leads to an improvement of mechanical properties and brittleness character for PRP-EVA blends. Similarly, the influence of a cocuring agent and a phase modifier on NR-PRP blends also improved the mechanical properties. Although the modification of the PRP-EVA blend has very little influence on glass transition temperatures, the NR-PRP blends show a measurable shift in their glass-transition temperatures. It is demonstrated that strong interaction occurs between the elastic and plastic components of the blends. Further, it has been shown that this interaction is responsible for improved properties of the blends over that of the pure polymer components.
The effects of the addition of interface modifiers on the structure and properties of wood fiber-filled polypropylene (PP) have been studied. Although an increase in the wood fiber loading reduces the overall cost of composites, the... more
The effects of the addition of interface modifiers on the structure and properties of wood fiber-filled polypropylene (PP) have been studied. Although an increase in the wood fiber loading reduces the overall cost of composites, the mechanical properties of such composites are very poor in the absence of a suitable interface modifier. The poor mechanical and thermal properties of the unmodified composite are attributed to increased heterogeneity induced in the system with increased concentration of wood fiber. A significant improvement in tensile strength and thermal resistance of these composites in the presence of a suitable interface modifier such as maleated polypropylene, itaconic anhydride, or bismaleimide-modified polypropylene is due to the improved dispersity of wood fibers in the polypropylene matrix as well as to the development of a stable interface effected by chemical interaction. In general, all modifiers are found to affect the crystallinity of PP in composites, and an improvement of tensile strength is marked by a lowering of crystallinity of PP.
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Hemp (émph{Cannabis Sativ L}.) is an important lignocellulosic raw material for the manufacture of cost-effective environmentally friendly composite materials. From an earlier experiment it was found that when hemp bast fibers were heated... more
Hemp (émph{Cannabis Sativ L}.) is an important lignocellulosic raw material for the manufacture of cost-effective environmentally friendly composite materials. From an earlier experiment it was found that when hemp bast fibers were heated between 160∘C and 260∘C, there was softening of lignin leading to opening of fibers and the preliminary observations showed that heat treatment at 220∘C in an inert environment seemed to provide enough fiber without affecting the associated tissues of the fibers. However, these heat treated fibers need to be separated by mechanical action. For this experiment, hemp fibers were given heat treatment in an enclosed vessel in a nitrogen environment at 220∘C for 30 min and then they were ball milled. It was found that there was further opening of fibers upon ball milling of the heated fibers and the total number of fibers increased for the equal weight of fibers. It was not possible to find strength properties of shorter length fibers; however, the results from shorter clamping length indirectly indicated that these fibers were of higher strength. The ball milled fibers also contained copious amount of fines which must be removed before using the fibers for composite manufacturing.
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Hemp (émph{Cannabis Sativ L}.) is an important lignocellulosic raw material for the manufacture of cost-effective environmentally friendly composite materials. From an earlier experiment it was found that when hemp bast fibers were heated... more
Hemp (émph{Cannabis Sativ L}.) is an important lignocellulosic raw material for the manufacture of cost-effective environmentally friendly composite materials. From an earlier experiment it was found that when hemp bast fibers were heated between 160∘C and 260∘C, there was softening of lignin leading to opening of fibers and the preliminary observations showed that heat treatment at 220∘C in an inert environment seemed to provide enough fiber without affecting the associated tissues of the fibers. However, these heat treated fibers need to be separated by mechanical action. For this experiment, hemp fibers were given heat treatment in an enclosed vessel in a nitrogen environment at 220∘C for 30 min and then they were ball milled. It was found that there was further opening of fibers upon ball milling of the heated fibers and the total number of fibers increased for the equal weight of fibers. It was not possible to find strength properties of shorter length fibers; however, the resu...
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The foamability of thermoplastic vulcanizate (TPV) has been investigated in a customized foaming system using carbon dioxide (CO2) and nitrogen (N2) as a physical blowing agent. TPV or dynamic vulcanizate is a special class of... more
The foamability of thermoplastic vulcanizate (TPV) has been investigated in a customized foaming system using carbon dioxide (CO2) and nitrogen (N2) as a physical blowing agent. TPV or dynamic vulcanizate is a special class of thermoplastic elastomer that is produced by technological blending of a rubber and a thermoplastic simultaneously. The rubbery part was dynamically cured in a thermoplastic matrix. The influence of blowing agent content and the processing conditions on the expansion behaviour, the cell-number density and the foam structure are discussed. The TPV foam with N2 produced a uniform and fine cell structure with a smooth surface, indicating that N2 could be a very good physical blowing agent for TPV material.
ABSTRACT Secondary sludge (SS) and mixed sludge (MS) from a Canadian paper mill were characterized, and investigated for extracellular polymeric substances (EPS) to explore the potential opportunity for value added utilization of waste... more
ABSTRACT Secondary sludge (SS) and mixed sludge (MS) from a Canadian paper mill were characterized, and investigated for extracellular polymeric substances (EPS) to explore the potential opportunity for value added utilization of waste paper sludge as wood adhesive. After basic characterization which showed the availability of significant amount of organic matter, further study of wood adhesive extenders were carried out through extraction of EPS by using 4000g centrifugation, a physical control method, and a chemical extraction technique involving formaldehyde and sodium hydroxide reagents. Gravimetric analysis showed the chemical extraction technique as being efficient method by yielding up to 5 times more EPS compared to physical control method. SS sludge, as anticipated, contained significantly high amount of EPS compared to MS. Fourier transform infrared spectrometry (FTIR) studies on extracted EPS confirmed the presence of key functional groups related to potential adhesions like protein, glucose, lignin, and carbohydrates. The polymeric nature of EPS was further diagnosed through calorimetric studies.
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... mechanical properties from the wheat straw and soya hulls were produced for potential use as reinforcement fibers in composite applications. The main goal of the present work is to produce and characterize the bio-nanocomposites from... more
... mechanical properties from the wheat straw and soya hulls were produced for potential use as reinforcement fibers in composite applications. The main goal of the present work is to produce and characterize the bio-nanocomposites from wheat straw nanofibers and ... Materials. ...
Research Interests: Engineering, Scanning Electron Microscopy, Morphology, Nanofiber, Nanocomposite, and 10 moreComposite Material, Glass Transition, Thermal Stability, Differential Thermal Analysis, Thermogravimetric Analysis, Wheat Straw, Thermal Properties, Tensile Strength, Tensile Test, and Dynamic Mechanical Analysis
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ABSTRACT The effect of extraction of wood components on wood anatomy and cellulose crystallinity was studied using X-ray computed microtomography (micro CT) and X-ray crystallography. Micro CT of the xylem vessels of birch wood samples... more
ABSTRACT The effect of extraction of wood components on wood anatomy and cellulose crystallinity was studied using X-ray computed microtomography (micro CT) and X-ray crystallography. Micro CT of the xylem vessels of birch wood samples was used for the quantitative determination of the wood porosity after conventional and microwave extraction. The method was also used as an indirect means for the determination of temperature generated inside the fibers. Original porosity of birch wood was 18.5 ± 1.5%, and porosity increased with both extractions. The increase in wood porosity after 10 minutes of microwave extraction was double that of wood after conventional method of extraction at 90°C for two hours (42% vs. 26%), indicating a sudden rupture of the wood structure due to the volumetric heating effect produced by the microwave heating. Comparison of porosities of the conventionally extracted samples at different temperatures for the same duration indicated that the temperature generated inside the fibers during 10 minutes of microwave extraction is around 120°C. Crystallinity of cellulose did not change after both extractions, suggesting that the extraction did not affect the strength of the fibers. © 2013 Copyright Taylor and Francis Group, LLC.
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ABSTRACT The permeability of hemp fibre mats used in a resin transfer moulding process were computed from the measured mould filling time, using a simplified mathematical approach. This approach could be applied because of the simple... more
ABSTRACT The permeability of hemp fibre mats used in a resin transfer moulding process were computed from the measured mould filling time, using a simplified mathematical approach. This approach could be applied because of the simple geometry of the mould and because a certain number of assumptions were made The permeability values obtained were found to decrease with increasing fibre content. In addition the hemp fibre permeability was found to be an order of magnitude lower than the value for glass fibre at a fibre content of 19 vol%. This preliminary work shows the importance of studying the permeability of natural fibre systems in order to provide the data necessary for the proper design of industrial moulds.