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Chemistry of cellulose in ionic liquids has been briefly reviewed and, accordingly, the phthalation of chitosan in these ionic solvents has been investigated. Chitosan (K) has been reacted at 100 °C for 4 hours with phthalic anhydride (PA) in ionic liquids 1-butyl-3-methylimidazolium acetate (BMIMAc) and 1-butyl-3-methylimidazolium chloride (BMIMCl) in the presence of bases, pyridine and 1,4-diazobicyclo[2.2.2] octane (DABCO), or the phthalation has been catalyzed by N-bromosuccinimide (NBS). Depending on the nature of the reaction components, the samples were prepared with molar ratios of PA to anhydroglucose unit (PA:K) from 3:1 to 10:1, including molar ratios of bases or catalyst to chitosan, ranging also from 3:1 to 10:1. All the reaction products were soluble in dimethyl sulfoxide and dimethylformamide. Both functional groups of chitosan units, -OH and -NH2 , reacted, resulting in FTIR confirmed products containing esters, amide, and imide functional groups. Heating the isolated phthalated chitosan products to 200 °C led to cyclization with the formation of imide groups and elimination of water. When bases controlled the reactions, the highest degrees of substitution of DABCO product (DS = 0.80) was slightly higher than the highest DC of the reaction products obtained in the presence of pyridine (DS = 0.77). However, the presence of the Nbromosuccinimide catalyst in the system led to an increase of the degree of substitution of the functional groups of chitosan (DS = 1.75), compared with that listed above for the products resulted when the reactions were carried out in the presence of bases. The thermal stability of the chitosan derivatives obtained in the presence of a base depended primarily upon the nature of the counter ion of the ionic liquid. When the reaction was conducted in the acetate ionic liquid BMIMAc, the phthalated chitosan exhibited a lower thermal stability than that of chitosan, while when the chloride ionic liquid BMIMCl was used as solvent, the thermal stability of the phthalated chitosan increased, indicating an interference of the ionic solvents in the mechanisms of reactions. Nevertheless, the thermal behavior of the phthalated products obtained in reactions catalyzed by NBS may be correlated with the increasing degrees of substitution achieved with increased catalyst concentrations: a higher DS resulted in a higher weight loss at higher temperatures.

Ultraviolet (UV), light-activated, self-healing polymers are an emerging technology that was proposed to enhance the elastic behavior of asphalt binder, while improving its self-healing properties. The objective of this study was to evaluate the effects of self-healing polymer on the rheological properties of binder blends prepared with or without recycled asphalt materials. Binder blends were prepared with two different binders (PG 67-22 and PG 70-22M), with or without recycled asphalt materials, and 5% self-healing polymer (Oxetane-substituted Chitosan-Polyurethane). High-Pressure Gel Permeation Chromatography (HP-GPC) results showed an increase in High Molecular Weight (HMW) components in the binder with an increase in stiffness through the addition of recycled materials. A further increase was observed with the addition of self-healing polymer. Fourier Transform Infrared Spectroscopy (FTIR) confirmed High-Pressure Gel Permeation Chromatography (HP-GPC) results with an increase in the carbonyl index. Furthermore, the addition of recycled materials led to an increase in the high-temperature grade and the low-temperature grade of the binder blends, while the self-healing polymer did not have a significant effect on the PG-grade. Overall, the addition of self-healing polymer led to an increase in stiffness and an improvement in the rutting performance, while it did not have a positive effect on low-temperature cracking performance. For unmodified binder (PG 67-22), self-healing polymer incorporation improved the elastic and fatigue cracking properties of the binder. However, when it was added to a polymer-modified binder (PG 70-22M) and/or binder blends containing recycled asphalt materials, the potential of this material was low to negative on the low temperature and fatigue cracking performances.

Halloysite nanotubes (HNTs), naturally occurring and environmental benign clay nanoparticles, have been successfully functionalized with amphiphilic polypeptoid polymers by surface-initiated polymerization methods and investigated as emulsion stabilizers toward oil spill remediation. The hydrophilicity and lipophilicity balance (HLB) of the grafted polypeptoids was shown to affect the wettability of functionalized HNTs and their performance as stabilizers for oil-in-water emulsions. The functionalized HNTs having relatively high hydrophobic content (HLB = 12.0-15.0) afforded the most stable oil-in-water emulsions containing the smallest oil droplet sizes. This has been attributed to the augmented interfacial activities of polypeptoid-functionalized HNTs, resulting in more effective reduction of interfacial tension, enhancement of thermodynamic propensity of the HNT particles to partition at the oil-water interface, and increased emulsion viscosity relative to the pristine HNTs. Cell culture studies have revealed that polypeptoid-functionalized HNTs are noncytotoxic toward Alcanivorax borkumensis, a dominant alkane degrading bacterium found in the ocean after oil spill. Notably, the functionalized HNTs with higher hydrophobic polypeptoid content (HLB = 12.0-14.3) were shown to induce more cell proliferation than either pristine HNTs or those functionalized with less hydrophobic polypeptoids. It was postulated that the functionalized HNTs with higher hydrophobic polypeptoid content may promote the bacterial proliferation by providing larger oil-water interfacial area and better anchoring of bacteria at the interface.

Self-healing products such as hollow fibers filled with a recycling agent present an emerging technology that would enhance an asphalt mixture’s resistance to cracking damage in the long term. The objective of this study was to evaluate the healing efficiency of sodium-alginate fibers containing a recycling agent using asphalt concrete beam specimens. A self-healing experiment was designed and conducted to monitor strength recovery in the damaged specimens using a 3-point bending test during a 6-day healing period under two different environmental curing conditions. In addition, the effects of adding the hollow fibers on the mechanical properties of asphalt mixtures were evaluated by conducting a series of laboratory tests to evaluate the performance against common distress such as permanent deformation, intermediate cracking, and low-temperature cracking. Results of the self-healing experiment test results showed that the addition of sodium-alginate fibers improved the strength recovery of mixtures prepared with unmodified binder. The increase in temperature from 25°C to 50°C during the healing period also resulted in higher strength recovery percentages in all the evaluated mixtures. Furthermore, semi-circular bending test results showed that the addition of fibers enhanced the mechanical properties against fracture at intermediate temperature of mixtures containing recycled asphalt materials.

Sudden Infant Death Syndrome (SIDS) is one of the major reasons for infant death. Millennial parents' growing concern of SIDS has resulted in the springing up demand for health care services, and the invention of wearable baby monitoring systems. The development of wearable electronics and communication technologies has intensified the potential use of wearable technology in healthcare purposes. As infants are vulnerable to sleeping conditions, effective health monitoring using wearable technology can detect unexpected fall of respiratory rate, heart rate, and oxygen level and alleviate parents' anxiety by notifying sudden critical situations. The purpose of this review paper is to explore and summarize recent developments in the field of baby monitoring wearable technology and their functions to acquiring real-time vital signs. Technological breakthroughs in the field of physical biosensors and electronics integrate into textile materials and their applications in monitoring human vital signs such as heart rate, oxygen level, blood pressure, body temperature, and respiratory rate have discussed. A brief introduction to future challenges and recommended considerations during designing baby healthcare wearable technology has also covered.

Fish scales (FS), a byproduct of the fish processing industry, are often discarded carelessly. In this present study, FS were used as a promising bio-sorbent for the removal of anionic acid dyes (acid red 1 (AR1), acid blue 45 (AB45) and acid yellow 127 (AY127)) from the wastewaters of textile coloration. Here, physiochemical characterizations of the FS were investigated by SEM-EDS, TGA and FI-IR analyses, and dye absorption and removal efficiency were evaluated and optimized considering different process parameters such as concentration of initial dye solution, amount of FS used, contact time, FS size, process temperature, additives, stirring and vacuum. SEM images and EDS elemental analyses showed architectural variation and heterogeneous composition of FS at different places. TGA identified the 50% minerals, 33% organic matters and 17% moisture and volatile components. FI-IR evidenced considerable absorption of acid dyes. Process optimization revealed that additives and fine pulverized FS had significant positive and negative impact on the dye removal efficacy, respectively. Temperature and stirring improved dye removal efficiency, and dye absorption by FS was very fast at the beginning and became almost constant after an hour indicating saturation of absorption. The maximum dye absorptions in scales for AR1, AB45, and AY127 were noted as 1.8, 2.7 and 3.4 mg/g, respectively, and removal percentages were 63.5%, 89.3% and 93%. The effects of the process parameters were consistent across all three acid dyes used in this study. Two-way ANOVA model showed that dye type, process parameters and &lsquo, dye type X process parameters&rsquo, interactions had significant effect on the dye removal efficiency.

A new generation of ultraviolet (UV) light-activated, self-healing polymers was evaluated with the aim to enhance the elastic recovery of the binder and to increase its self-healing abilities. This study had three main objectives: (a) to develop an optimized synthesis procedure for producing light-activated self-healing polymers, (b) to examine the thermal stability of the prepared self-healing polymers, and (c) to evaluate the effect of self-healing polymers on the rheological properties of asphalt binder containing binder extracted from recycled asphalt shingles (RAS). Fourier transform infrared (FT-IR) spectroscopy analysis confirmed the successful synthesis of UV-activated polymers in the laboratory. In addition, thermogravimetric analysis showed that the materials produced achieved the required thermal stability at high temperature. Measuring the viscosity of different binder blends with and without RAS and with and without self-healing polymers revealed that the additive decreased the viscosity of the binder blends containing RAS, thereby providing blends with a better workability. Furthermore, rheological results showed that the rutting resistance of the binder blends containing RAS was improved by increasing the percentage of self-healing polymer. Results also showed improved rheological behaviors at low service temperature with 5% self-healing polymer and with exposure to UV light.

This paper presents a new approach for converting lignocelluloses biomass into regenerated cellulose fibers. A major research objective is to examine the effectiveness of nanoparticles as cellulose fillers on improving thermal and mechanical properties of the regenerated cellulose fibers. Pure wood and bagasse cellulose solutions and cellulose/nanoparticle composite solutions were prepared using N-methylmorpholine-N-oxide (NMMO) solvent, and were spun into filament fiber through an extruding device. The thermal analysis methods of TGA and DSC were used for characterizing the solution properties. The regenerated bagasse cellulose fiber was also compared with regenerated wood cellulose fiber and nanoparticle/cellulose fibers in terms of mechanical strength and elongation. Distribution of nanoparticles in the cellulose matrix was evaluated using a method of image analysis for fiber photomicrographs. Tested results indicated that the tensile strength of the regenerated bagasse cellulose fiber was considerably lower than that of the regenerated wood cellulose fiber but the elongation was consistent between these two fibers. The research also revealed that adding a small amount of nanoparticles to fill in the wood cellulose matrix resulted in an increase of the cellulose fiber tensile strength and modulus by 14% and 6% respectively, and a decrease of cellulose glass transition temperature. The nanoparticle distribution in the cellulose matrix was correctly detected by a computing image technique based on a mean shift method.

The use of recycled asphalt shingles (RAS) as a partial replacement for petroleum-based virgin asphalt binder has received considerable attention in recent years. The objective of this study is to correlate the molecular structure and corresponding compositional analysis of asphalt binders of conventional asphalt mixtures as well as of mixtures containing RAS and/or reclaimed asphalt pavement (RAP) with their cracking potential at intermediate temperature. Laboratory testing evaluated the molecular composition of asphalt binders obtained from asphalt mixtures evaluated in this study using thin layer chromatograph/FID (Iatroscan) and gel permeation chromatography (GPC). Fracture resistance of laboratory produced mixtures was assessed using the Semi-Circular Bend (SCB) test at intermediate temperature. Molecular fractionation through GPC of RAS samples confirmed the presence of associated asphaltenes in greater concentrations than RAP samples. High concentrations of high molecular weight asphaltenes decreas...

The objective of this study was to evaluate the efficiency of an innovative light-induced self-healing polymers in enhancing the durability of asphalt mixtures and improving its self-healing properties. Mixtures were prepared using two different binders, with and without recycled materials, and self-healing polymer. Results showed that the addition of recycled asphalt material to mixtures prepared with an unmodified binder negatively affected the healing recovery at room temperature. Furthermore, Self-healing properties of the mixtures were improved by increasing the healing temperature. The addition of 5% self-healing polymer to the control mixture, followed by UV light exposure resulted in an increase in self-healing properties of the mixtures prepared with PG 67-22 binder. Semi-Circular Bending (SCB) test results showed that the incorporation of self-healing polymer and 48 h of UV light exposure improved the cracking resistance. Loaded-Wheel Test (LWT) results showed that the self-healing polymer caused an increase in the rut depth of the samples prepared with an unmodified binder. However, the final rut depth was less than the acceptable rutting performance. Thermal-Stress Restrained Specimen Test (TSRST) test results showed that self-healing polymer improved the low temperature cracking performance of the mixtures.

Self-healing products such as hollow-fibers filled with an asphalt rejuvenator present an emerging technology that would enhance an asphalt mixture’s resistance to cracking damage. The objective of this study was to evaluate the rejuvenating efficiency of sodium-alginate fibers containing a rejuvenator product using asphalt binder blends containing extracted binder from recycled materials. The effects of adding extracted binder from recycled materials and sodium-alginate fibers on asphalt binder blends were evaluated by conducting a series of chemical and binder tests. HP-GPC and FTIR test results showed that the addition of fibers in blends containing recycled materials resulted in an increase in the HMW/LMW ratios. Some of the added polymeric fibers are thought to have increased the HMW fraction, thus leading to increase in the HMW/LMW ratio. The increase of the HMW fraction suggests that some of the fibers, which are polymers, caused the increase in the HMW/LMW ratios. MSCR test results showed that a binder blend with extracted binder from recycled materials and sodium-alginate fibers would have less rutting susceptibility than a conventional virgin binder would.

Covalent polymeric networks composed of imine cross-linkages have been prepared by condensation polymerization of poly(ethylene glycol) bis(3-aminopropyl) with 1,3,5-triformylbenzene with an equal molar ratio of amine and aldehyde functionalities in organic solvents with varying polarity and in neat condition. The polymer networks exhibit malleability and self-healing characteristics. Rheological measurements revealed that longer reaction time is required to reach the gel point (i.e., crossover of G′ and G″) in polar solvents than in nonpolar solvents. The malleability of the solvent-swelled polymer network is also strongly dependent on the solvent polarity. Polymer gels in polar solvents are more malleable than those in nonpolar solvents, as supported by the dynamic mechanical analysis. These results are consistent with faster dynamic imine bond exchange in the polar solvents relative to the nonpolar solvents, thus requiring higher functionality conversion to form an elastic network in the polar solvent ...

The use of recycled asphalt shingles (RAS) as a partial replacement for petroleum-based virgin asphalt binder has received considerable attention in recent years. The objective of this study is to correlate the molecular structure of asphalt binders of conventional asphalt mixtures as well as of mixtures containing RAS with their cracking potential at intermediate temperature. Laboratory testing evaluated the molecular composition of asphalt binders obtained from asphalt mixtures evaluated in this study using gel permeation chromatography (GPC), extent of ageing using Fourier Transform Infrared spectroscopy, and fracture resistance of laboratory produced mixtures using the Semi-Circular Bending test at intermediate temperature. Molecular fractionation through GPC of RAS samples confirmed the presence of associated asphaltenes in greater concentrations than recycled asphalt pavement samples. High concentrations of high-molecular-weight asphaltenes decrease the fracture resistance of the asphalt mixtures. T...

Microencapsulation of rejuvenators was introduced as a new approach to increase the efficiency of rejuvenators toward improving the self-healing rate of asphalt pavement. This study had two...

Self-healing products such as microcapsules filled with an asphalt rejuvenator present an emerging technology that would allow asphalt mixtures to resist cracking damage caused by vehicular...

Herein, we report the investigation of sodium deoxycholate (NaDC)/TRIS-based hydrogels as delivery vehicles for a broad range of applications. Three hydrogel formulations were chosen for unique rheological behaviors that suggest a change in internal hydrogel structure with the application of a shear force. In this work, we compare solute release from sheared and non-sheared hydrogels in order to explore the effect of shear force on structure and release kinetics. It was found that the application of a shear force, in addition to changes in temperature, drug solubility, drug concentration, and hydrogel formulation each affected the amount of solute ultimately released from a hydrogel system. Moreover, the use of the inherent chirality of the hydrogel network for enantio-preferential drug release was also explored. We show significant enantio-preference in the release of model drugs tryptophan and ibuprofen from the hydrogel network. Furthermore, hydrophobic domains within the hydrogel network were exploited to enable ibuprofen loading at ten times the maximum water solubility. Retention of enantio-preference was observed at this higher ibuprofen concentration. Cyclodextrin modification to the hydrogel matrix allowed for enantio-preferential inversion which is an unprecedented observation.

A series of partially hydrolyzed polyacrylamide/cellulose nanocrystal (HPAM/CNC) nanocomposite hydrogels with various amounts of CNCs were used to remove methylene blue (MB) dye from an aqueous solution. The effects of three preparation variables (i.e., HPAM anionicity, content of CNCs, and pH value of prepared solution) on swelling properties and equilibrium adsorption were studied systematically. The results showed that improved swelling properties and enhanced MB adsorption capacity were acquired by raising HPAM anionicity, by increasing CNC’s content up to 20 wt.%, and by decreasing pH value of solution. The optimum HPAM/CNC nanocomposite hydrogels had an adsorption efficiency of more than 90%. MB adsorption kinetics followed the pseudo-second-order and Elovich models. The adsorption isotherms of nanocomposite hydrogels could be described very well by the Langmuir equation. A possible adsorption mechanism was inferred based on the results of adsorption kinetics and isotherms to show the synergistic effect of HPAM and CNCs.

Ground tyre rubber (GTR) has been employed to modify asphalt binders used in hot-mix asphalt construction since the early 1960s. Proper formulation of GTR-modified asphalt binders provides for substantial improvement in performance over conventional asphalt binders, while providing an outlet for disposal of waste tyres. Physical characteristics of GTR are considered to be vital to the final performance of the asphalt paving mixture, with some state agencies specifying chemical composition requirements for GTR used in binder modification. Adequate analysis and understanding of the functional polymer content, polymer available in GTR to improve asphalt binder properties, and other chemical characteristics of GTR remain lacking. Thermogravimetric analysis (TGA) is a method used to measure the change in mass of a material measured as a function of temperature or time facilitating acquisition of information on properties of the material and its composition. This paper introduces an instrumental TGA method to a...

A new strength test method for asphalt mixture at low temperatures is presented in this paper. The method uses a modified bending beam Rheometer (BBR), capable of applying loads at different rates. Two major factors, that can significantly affect strength, were analysed: cooling medium and specimen size. Similar strength values were obtained in air and potassium acetate and significantly lower values were obtained in ethanol. Preliminary investigation with sodium fluorescein (FL) indicates the fluorescing marker diffused in mixtures when ethanol was used. The failure distributions of BBR mixture beams and of larger beams (LBs) were analysed using histogram testing and size effect theory. Different Weibull moduli were obtained for BBR and for the LB, which indicates that BBR beams may be too small to capture the representative volume element of the material.

Objective To evaluate aqueous humor viscosity in the raptor, dog, cat, and horse, with a primary focus on the barred owl (Strix varia). Animals studied Twenty-six raptors, ten dogs, three cats, and one horse. Procedure Animals were euthanized for reasons unrelated to this study. Immediately, after horizontal and vertical corneal dimensions were measured, and anterior chamber paracentesis was performed to quantify anterior chamber volume and obtain aqueous humor samples for viscosity analysis. Dynamic aqueous humor viscosity was measured using a dynamic shear rheometer (AR 1000 TA Instruments, New Castle, DE, USA) at 20 °C. Statistical analysis included descriptive statistics, unpaired t-tests, and Tukey's test to evaluate the mean ± standard deviation for corneal diameter, anterior chamber volume, and aqueous humor viscosity amongst groups and calculation of Spearman's coefficient for correlation analyses. Results The mean aqueous humor viscosity in the barred owl was 14.1 centipoise (cP) ± 9, cat 4.4 cP ± 0.2, and dog 2.9 cP ± 1.3. The aqueous humor viscosity for the horse was 1 cP. Conclusions Of the animals evaluated in this study, the raptor aqueous humor was the most viscous. The aqueous humor of the barred owl is significantly more viscous than the dog (P

In the present article, the commercial value of fish scales (FS), one of the most discarded fish wastes, has been identified by discovering their gelation capability. Fish scales of different physical forms were applied for the removal of dyes (acid red 1 (AR1), acid blue 45 (AB45), and acid yellow 127 (AY127)) from textile dye solution by absorption process. An astounding phenomenon, gelation of the treated solution, was noticed when it was aged for a certain period. The absorption of dye by FS was confirmed and quantified by FT-IR and UV-visible spectroscopy analyses, respectively. Process optimization revealed that pristine FS showed better gelation efficacy compared to pulverized FS. The gelation process was successful only when the dye solution contained acid and salt. As most of the textile effluents contain acids and salts in the discarded dye solution, this gelation process implies an obvious indication of the saving process and chemical cost in textile waste treatment. The jellified wastewater was characterized by exploring the rheological properties. Based on these analyses, potential application areas have been discussed.

Current culture methods based on monocultures under phototrophic regimes are prone to contamination, predation, and collapse. Native cultures of multiple species are adapted to the local conditions and are more robust against contamination and predation. Growth, lipid and biomass productivity of a Louisiana native coculture of microalgae (Chlorella vulgaris) and cyanobacteria (Leptolyngbya sp.) in heterotrophic and mixotrophic regimes were investigated. Dextrose and sodium acetate at C:N ratios of 15:1 and 30:1 under heterotrophic (dark) and mixotrophic (400 μmol m−2 s−1) regimes were compared with autotrophic controls. The carbon source and C:N ratio impacted growth and biomass productivity. Mixotrophic cultures with sodium acetate (C:N 15:1) resulted in the highest mean biomass productivity (156 g m−3 d−1) and neutral lipid productivity (24.07 g m−3 d−1). The maximum net specific growth rate (U) was higher (0.97 d−1) in mixotrophic cultures with dextrose (C:N 15:1) but could not be sustained resulting in lower total biomass than in mixotrophic cultures with acetate (C:N 15:1), with a U of 0.67 d−1. The ability of the Louisiana coculture to use organic carbon for biomass and lipid production makes it a viable feedstock for biofuels and bioproducts.

The presence of bulk water and the resistant cell walls significantly limit the efficiency of lipid extraction from microalgal biomass paste. Current methods to rupture the cell walls (i.e. grinding after freeze-drying, osmotic shock, sonication) are energy intensive and time consuming. Due to their high surface energy concentration and high surface to volume ratio, silver nanoparticles can enhanced the cell wall rupture to increase the extraction efficiency of cell components. In this study, silver nanofibers were added as enhancers for the Folch’s extraction method and microwave assisted extraction of lipids from wet biomass paste (water content of 80.9%). Nanofibers concentrations of 0–1000 μg g−1 were tested. Two solvent:biomass ratios were tested in the Folch’s extraction method. Two temperatures (70 and 90 °C) and three treatment times (2, 5 and 10 min) were compared in the microwave assisted extraction. The results showed that the extraction efficiency increased with increased concentration of the nanofibers in the range tested. At concentrations of 1000 μg g−1 silver nanofibers (w/w based on the solvent and biomass solution) the efficiency of lipid extraction increased by ∼30% and 50% for the Folch’s and microwave assisted lipid extraction respectively. Treatment with AgNO3 in the same concentration as the nanofibers did not improve the extraction compared with no silver or nanofibers addition. The extraction method affected the lipid fatty acids profile. The Folch’s extraction with no silver nanofibers resulted in proportionally higher short chain saturated fatty acids, but lower lipid extraction. The microwave assisted lipid extraction provides the best results considering fatty acid profile, treatment time, solvent use and lipid extraction efficiency.

Bis-ketal-protected diethyl galactarate was condensed with different diamines to prepare sugar-based polyamides. Ketal-protected polyamides, which are soluble in organic solvents, were deprotected with 90% trifluoroacetic acid to yield water insoluble materials. FTIR, NMR, GPC, MALDI-TOF, ESI and TGA techniques were used to characterize the structure and the properties of these biodegradable materials. D-galactaric acid-based polyamides are complex mixtures of cyclic and linear structures. High molecular weight linear polymer formation was limited by competitive cyclization reactions. The percentage of cyclization was highly dependent on the nature of the diamine used. Polycondensation with linear aliphatic diamines favored the formation of macrocycles, identified by MALDI-TOF and ESI.

Blends of chitosan and cellulose were successfully produced using 1-butyl-3-methylimidazolium acetate (BMIMAc) as solvent media. Films were prepared from the blends by manually spreading the solution on a flat surface and precipitating the polymers in a mixture of methanol and water. To prevent the shrinkage of films, most of the absorbed water was removed by freeze drying under vacuum. Films prepared from the polymeric solutions were investigated by means of FT-IR, TGA, X-ray diffraction and SEM measurements. The shifting of the bands corresponding to -NH and CO groups of chitosan (FT-IR), the absence of the diffraction peaks at 2θ=10.7 and 14.9° (XRD), the increased Ea for thermal decomposition for all the polymeric blends (MTGA), and the presence of an apparent homogeneous structure with no phase separation of the two polymers (SEM) provide evidence for the miscibility between chitosan and cellulose in the solid state.

Microstructures of sodium deoxycholate hydrogels were observed to be altered considerably in the presence of variable tris(hydroxymethyl)aminomethane (TRIS) concentrations. These observations were confirmed by use of X-ray diffraction, polarized optical microscopy, rheology, and differential scanning calorimetry measurements. Our studies reveal enhanced gel crystallinity and rigidity with increasing TRIS concentration. The tunable hydrogel microstructures obtained under various conditions have been successfully utilized as templates to synthesize cyanine based fluorescent nanoGUMBOS (nanoparticles from a Group of Uniform Materials Based on Organic Salts). A systematic variation in size (70–200 nm), with relatively low polydispersity and tunable spectral properties of [HMT][AOT] nanoGUMBOS, was achieved by use of these modified hydrogels. The gel microstructures are observed to direct the size, as well as molecular self-assembly of the nanomaterials, thereby tuning their spectral properties. These modified hydrogels were also found to possess other interesting properties such as variable morphologies ranging from fibrous to spherullites, variable degrees of crystallinity, rigidity, optical activity, and release profiles which can be exploited for a multitude of applications. Hence, this study demonstrates a novel method for modification of sodium deoxycholate hydrogels, their applications as templates for nanomaterials synthesis, as well as their potential applications in biotechnology and drug delivery.

Aerobic biodegradation of polyhydroxybutyrate (PHB) was investigated. Mass loss experiments were performed to determine degradation kinetics. Tributyl citrate was blended with some test samples to determine the impact of a natural plasticizer on biodegradation. Effects of biodegradation in the physical, chemical, thermal, and mechanical properties of the materials tested were determined. Plates of different thicknesses (0.24, 1.2, 3.5, and 5.0 mm) were degraded to determine the effect of initial mass:initial surface area ratio on degradation rates. The mass:initial surface area is proportional to the plate thickness. PHB biodegradation rates obtained are dependent on the mass:surface area ratio. Temperature affects the relation of degradation rate to initial mass:initial surface area. PHB in plates up to a thickness of 3.5 mm can degrade completely in compost. Plates with an initial mass:initial surface area ratio of

The thermal decomposition mechanism of raw and treated bagasse fibers was modeled with three parallel independent first-order reactions. The kinetic parameters and pseudo components which best fit the experimental dynamic pyrolysis rate of bagasse was determined by means of the Matlab program using the least-square method. The calculated rate of thermal decomposition for each bagasse sample was consistent with experimental pyrolysis rate very well. A method was adopted to calculate the contents of cellulose, hemicelluloses, and lignin for bagasse fiber based on the dynamic pyrolysis model. The calculated contents of the untreated bagasse fiber agreed very well with some reported values from the literature. The effect of treatment conditions on the bagasse fiber compositions was also studied. From the three-dimensional plot for each of the three components, it could be observed that bagasse fibers treated under the intermediate alkaline condition could achieve the higher content of cellulose.

The main objective of this study was to establish the relationship between asphalt binder deformation properties at intermediate and low temperatures, its molecular compositions, and mix performance. To achieve this objective, nine straight binders obtained from two asphalt suppliers were tested using the ductility and the direct tensile tests. To assess the results of these tests, selected asphalt binders were evaluated using high pressure gel permeation chromatography (HP-GPC), differential scanning calorimetry (DSC), and dynamic mechanical analysis. Measurements showed that an inverse correlation exists between binder ductility at intermediate temperatures and failure strain at low temperatures. In other words, a binder that provides high ductility at intermediate temperatures would be characterized by poor elongation properties at low temperatures. This trend was related to the binder molecular compositions as characterized by HP-GPC. An increase in the binder content of low molecular weight results in an increase in its ductility at intermediate temperatures. However, an increase in paraffinic maltene content results in the binder tending to crystallize at higher temperatures as it approaches the glassy region. This was confirmed through DSC measurements, which showed that an increase in crystalline fractions may have a negative impact on the binder stiffness at low temperatures. In general, physical properties of the binder can be strongly linked to its molecular constituents. In addition, there was a positive correlation between the binder ductility and the measured tensile strength of the mixture as well as its strain at failure. Using a binder with a high ductility resulted in a mixture with greater indirect tensile strength and a stronger ability to resist cracking at intermediate temperatures.

Anaerobic biodegradation in sewage sludge of polyhydroxybutyrate (PHB) was investigated. Evolved gaseous carbon was measured to assess biodegradability according to ASTM D5210. Mass-loss experiments were performed to determine degradation kinetics. Changes in the polymer properties were investigated. The impact of a natural plasticizer [tributyl citrate (TBC)] on biodegradation was determined. Polylactic acid was also biodegraded for comparison. Melt-pressed plates of PHB (with thicknesses of 0.24, 0.5, 1.2, 3.5, and 5.0 mm) were biodegraded to investigate the relationship between initial mass:initial surface area ratios and decay rates. Scanning electron microscopy micrographs of degraded specimens were recorded for visual illustration of the degradation process. A relationship between initial mass:initial surface area and degradation rates indicates that the thickness and surface area of the material affect its degradation. The degradation rates were impacted by the sewage sludge activity. TBC additive hindered PHB's rate of degradation. Thermal properties, molecular bonding, and molecular weight measured by differential scanning calorimetry, Fourier transform infrared, and size exclusion chromatography, respectively, were only slightly affected by biodegradation, indicating that recycling PHB will not affect its performance.

This contribution describes the preparation and characterization of PEO/montmorillonite nanocomposite gels and films containing various lithium and sodium salts. The objective is to understand how the size and diffusion abilities of different ionic species added to these systems alter the crystallinity of the polymer, and affect the mechanical properties and ionic conductivities of the solid nanocomposites. The network strength of the polymer/clay dispersions influences decisively the crystallinity of the PEO chains and the final layered texture of the solid films. The characteristics of films were investigated using a combination of techniques, such as DSC, DMA, DEA, SEM, SAXS and XRD.

The aim of the present contribution is to understand how ionic strength, brought by the addition of salt to laponite/PEO nanocomposite dispersions, influences the texture and adhesion characteristics at nano- and microscales in multilayered nanocomposite films prepared from such dispersions. At the nano-scale, SAXS and XRD measurements indicated that the clay platelets orient parallel to the film plane and that the polymer chains intercalate the clay platelets regardless of salt addition. A gradual transition from an agglomerated structure, containing polymer-rich and clay-rich domains, to a fine-balanced structure with smaller distinct details without excess PEO was observed, via AFM, on the exposed edges of cryo-microtomed films with increasing ionic strength.

The influence of size and surface area of two different types of clay on the structure and characteristics of PEO/clay nanocomposites in the form of multilayered films is discussed. To search for new synergistic properties and/or improve the properties of nanocomposite films already known, we study polymer nanocomposites that have laponite as well as montmorillonite incorporated. While DSC measurements showed that higher laponite amounts gradually suppress the crystallinity of PEO in the nanocomposite, XRD measurements provided evidence that higher montmorillonite amounts ensure an improved final orientation of the clay platelets, parallel to the plane of the multilayered film.

The present contribution describes the preparation and characterization of polymer–clay nanocomposite gels and films containing poly(ethylene oxide) and various ratios of Laponite and Montmorillonite. The aim is to understand how clays with different chemistry, sizes and surface areas interact with each other and affect the structure and characteristics of polymer based nanocomposites in the form of both gels and multilayered films. The rheological behavior of the gels is compared to the spreading process during sample preparation and the resulting film structures and properties are analyzed. While gradually replacing Laponite clay with equivalent amounts of Montmorillonite clay decreases the viscosity of the resulting gels, we observed that the progressive increase of the Montmorillonite percent in the samples leads to a gradual increase of the storage and loss moduli in the multilayered films. At the nano-scale, SAXS and XRD measurements on films indicated that the clay platelets orient parallel to the film plane and that the polymer chains intercalate between silicate galleries. Thermal analysis shows that the polymer crystallinity can be controlled by combination and variation of different clays.

The purpose of the present contribution is to provide an efficient method that would help to quantify the orientational levels occurring in polymer/clay dispersions subjected to elongational flow. The extent of internal orientation developed in salt containing montmorillonite/ poly(ethylene oxide) gels is investigated, combining shear and elongational rheology methods. Entropic changes indicate that the strength of the transient network present in each gel affects the orientational ability of clay particles and polymer chains. We found that an increased Hencky strain of the hyperbolic die leads to a higher variation of the calculated entropy of the material.

Changes in melting points, enthalpy, and specific heat capacity of catfish visceral oil at each step of the purification process were studied. Melting points of −46.2 to 21.2 °C for crude oil, −45.9 to 11.5 °C for degummed oil, −44.3 to 11.4 °C for neutralized oil, −47.1 to 9.9 °C for bleached oil and −52.3 to 8.0 °C for deodorized oil were observed. Enthalpy (kJ/kg) was 74.1 for crude oil, 74.7 for degummed oil, 75.1 for neutralized oil, 79.3 for bleached oil, and 84.3 for deodorized oil. The specific heat capacities at 20 °C for crude, degummed, neutralized, bleached, and deodorized oils were 1.69, 1.96, 1.97, 1.91, and 1.83 kJ/kg °C, respectively.

Hemp fiber is a strong natural fiber similar to flax, kenaf, and ramie, possessing very good fiber quality and physical properties of strength, durability, and absorbency. Hemp fiber has been increasingly used for making nonwoven composites that are ideal for the production of biobased auto interior parts. This paper studies the physical properties of a hemp/polypropylene composite and compares these properties with those of a kenaf/polypropylene composite, a ramie/polypropylene composite, and a bagasse/polypropylene composite. The hemp/polypropylene nonwoven was produced by carding and needle-punching techniques and was thermo-bonded to form a hemp composite. Tensile and bending properties were measured using an Instron tensile tester. Dynamic mechanical properties were tested using a DMS instrument. The thermal property was analyzed using a TG instrument. A preliminary study on the ability of the hemp fiber composite to resist termite attack was also conducted. In comparison, the hemp composite...

We report the synthesis and characterization of amino acid ester based chiral ionic liquids, derived from L- and D-alanine tert butyl ester chloride. The synthesis was accomplished via an anion metathesis reaction between commercially available L- and D-alanine tert butyl ester chloride using a variety of counterions such as lithium bis (trifluoromethane) sulfonimide, silver nitrate, silver lactate, and silver tetrafluoroborate. Both enantiomeric forms were obtained as confirmed by bands of opposite sign in the circular dichroism spectra. The L- and D-alanine tert butyl ester bis (trifluoromethane) sulfonimide were obtained as liquids at room temperature and intriguingly exhibited the highest thermal stability (up to 263 degrees C). In addition, the ionic liquids demonstrated enantiomeric recognition ability as evidenced by splitting of racemic Mosher's sodium salt signal using a liquid state (19)F nuclear magnetic resonance (NMR) and fluorescence spectroscopy. The L- and D-alanine tert butyl ester chloride resulted in solid salts with nitrate, lactate, and tetrafluoroborate anions. This illustrates the previously observed tunability of ionic liquid synthesis, resulting in ionic liquids of varying properties as a function of varying the anion.

Periodic patterns resembling spirals were observed to form spontaneously upon unassisted cooling of d-glucaric acid- and d-galactaric acid-based polyamide solutions in N-methyl-N-morpholine oxide (NMMO) monohydrate. Similar observations were made in d-galactaric acid-based polyamide/ionic liquid (IL) solutions. The morphologies were investigated by optical, polarized light and confocal microscopy assays to reveal pattern details. Differential scanning calorimetry was used to monitor solution thermal behavior. Small- and wide-angle X-ray scattering data reflected the complex and heterogeneous nature of the self-organized patterns. Factors such as concentration and temperature were found to influence spiral dimensions and geometry. The distance between rings followed a first-order exponential decay as a function of polymer concentration. Fourier-Transform Infrared Microspectroscopy analysis of spirals pointed to H-bonding between the solvent and the pendant hydroxyl groups of the glucose units from the polymer backbone. Tests on self-organization into spirals of ketal-protected d-galactaric acid polyamides in NMMO monohydrate confirmed the importance of the monosaccharide's pendant free hydroxyl groups on the formation of these patterns. Rheology performed on d-galactaric-based polyamides at high concentration in NMMO monohydrate solution revealed the optimum conditions necessary to process these materials as fibers by spinning. The self-organization of these sugar-based polyamides mimics certain biological materials.

A novel route to fabricate low-cost porous carbon nanofibers (CNFs) using biomass tar, polyacrylonitrile (PAN), and silver nanoparticles has been demonstrated through electrospinning and subsequent stabilization and carbonization processes. The continuous electrospun nanofibers had average diameters ranging from 392 to 903 nm. The addition of biomass tar resulted in increased fiber diameters, reduced thermal stabilities, and slowed cyclization reactions of PAN in the as-spun nanofibers. After stabilization and carbonization, the resultant CNFs showed more uniformly sized and reduced average diameters (226-507 nm) compared to as-spun nanofibers. The CNFs exhibited high specific surface area (400 m(2)/g) and microporosity, attributed to the combined effects of phase separations of the tar and PAN and thermal decompositions of tar components. These pore characteristics increased the exposures and contacts of silver nanoparticles to the bacteria including Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, leading to excellent antimicrobial performances of as-spun nanofibers and CNFs. A new strategy is thus provided for utilizing biomass tar as a low-cost precursor to prepare functional CNFs and reduce environmental pollutions associated with direct disposal of tar as an industrial waste.

In the present study, sodium deoxycholate (NaDC) was used to produce gelation of tris(hydroxymethyl)amino-methane (TRIS) solutions above, below, and near the pKa of NaDC, respectively, which yielded a neutral gelator, a charged gelator, and a mixture of each. Impacts of ionic interactions on gel formation were studied in detail and showed that pH can be used to modify many hydrogel properties including sol-gel temperature, crystallinity, and mechanical strength. Several formulations yielded a unique rheological finding of two stable regions of elastic modulus. The release of a small molecule has been investigated under different hydrogel conditions and at variable shear rate, suggesting utility as a drug-delivery vehicle. It was also observed that pH modification of the hydrogels affected nanoparticle formation. Nanoparticles derived from a Group of Uniform Materials Based on Organic Salts (nanoGUMBOS), specifically cyanine-based NIR dyes, were templated within the hydrogel network for potential applications in tissue imaging. These nanoGUMBOS were found to be size-tunable, although material-dependent. Further understanding of NaDC/TRIS gelation has broadened the tunability and multidimensional applications of these tailored hydrogel systems.

The structures and thermal properties of a series of nanocomposite poly(ethylene oxide)/Laponite films have been investigated by differential calorimetric and thermal analysis and complemented by microscopy and X-ray diffraction experiments. The crystalline structures of the nanocomposite multilayered films can be tuned by controlling the composition, polymer Mw and the water content. We study the concentration, polymer Mw and humidity dependence of polymer crystallinity in selected nanocomposite multilayered films. Results show that the exact sample preparation and history are important in controlling structure and properties and in developing new materials. Complementary microscopy is used to monitor the structural changes.

The process of manufacturing an activated carbon nonwoven made by cotton fiber was investigated. The study was focused on cotton nonwoven formation, carbonization, activation, and characterization of the activated carbon nonwoven. Pyrolysis of the cotton carbonization was analyzed using TGA. There was a considerable decrease in weight loss in the region between 250°C to 400°C and the proper carbonized temperature was 400°C. The SEM examination indicated that the surface area of cotton fiber was increased significantly because the inside hollow of cotton fiber was widely opened and some small agglomerated particles were gasified after activation. Absorbability of the activated carbon nonwoven was evaluated using an instrument of inverse gas chromatography. Dispersive surface energy, specific free energy, and total surface energy all indicated this trend: Carbonized Cotton > Activated Cotton > Raw Cotton. The activated carbon nonwoven exhibited the potential for use as high adsorbent and absorbent materials. They are light weight and bulky, advantageous in protective clothing applications and other consumer and industrial applications.

The use of cellulosic fibers, such as cotton, kenaf, ramie, jute, flax, and bagasse, in the manufacturing of nonwoven composites for a variety of automotive parts, such as headliners, wall panels, and trunk liners, can significantly enhance their ‘end of life’ biodegradability and also improve their thermal insulation properties. Currently, automotive nonwovens are made from synthetic, petro-based polymer materials that are not biodegradable, thus creating significant environmental problems. Three different sets of ‘sandwich-type’ nonwoven materials are manufactured by layering the cellulosic webs, with recycled thermoplastic synthetic fibers and/or using readily biodegradable binders such as polyvinyl alcohol (PVA) and Eastar Biocopolymer (EBC). A ‘steady state’ heat flow meter is used for the evaluation of the thermal insulation properties of these biodegradable, low-cost nonwoven composites. The results show that the thermal insulation properties of cellulosic-based nonwoven composite materials vary significantly, depending on the type of the vegetable fibers, the ratios of the cellulosic to synthetic fibers, the nature and quantity of the binder, the design, and the resulting bulk density of the composites.

The isothermal and dynamic curing process of epoxy composite was studied using differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and other techniques. The variation of degree of curing with time and temperature was analyzed. The degree of curing was limited at any particular temperature because of the diffusion control in isothermal curing process. Half-life and maximum cure time were discussed in the analysis of the isothermal curing process. The modeling result from isothermal curing process indicated that degree of curing calculated with diffusion control agreed well with experimental data. The degree of curing calculated by two methods for dynamic curing process had a deviation with experimental data in either earlier or later cure stages. The relationship between T g and the degree of curing was described by two models. Both models agreed well with the experimental T g . The isothermal curing diagrams of time–temperature–transformation (TTT) and conversion–temperat...

Blends were prepared of poly(vinyl chloride) (PVC) with four different plasticizers; esters of aconitic, citric, and phthalic acids; and other ingredients used in commercial flexible PVC products. The thermal and mechanical properties of the fresh products and of the products after 6 months of aging were measured. Young's modulus of the PVC blends was reduced about 10-fold by an increase in the plasticizer level from 15 to 30 phr from the semirigid to the flexible range according to the ASTM classification, but a 40-phr level was required for PVC to retain its flexibility beyond 6 months. At the 40-phr level, tributyl aconitate performed better than diisononyl phthalate (DINP) or tributyl citrate, in terms of lowering Young's modulus, both in the fresh materials and those aged for 6 months. The effects of the four plasticizers on the glass-transition temperature (Tg) were similar, with Tg close to ambient temperature at the 30- and 40-phr levels in freshly prepared samples and at 40–60°C in those aged for 6 months. The thermal stability of the PVC plasticized with DINP was superior among the group. Overall, tributyl aconitate appeared to be a good candidate for use in consumer products where the alleged toxicity of DINP may be an issue. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1366–1373, 2006

The fiber characteristics (i.e., the fiber type, morphology, and dimension) and polymer melt flow index (MFI) significantly affected mechanical properties of sugar- cane fiber/HDPE composites. The length and diameter of sug- arcane fibers followed a lognormal distribution before and after compounding. The long fibers had a significant reduction in the dimension and aspect ratio during compounding. How- ever, the short fibers had close values in these two properties before and after compounding. For the resultant sugarcane fiber/polymer composites, the HDPE resins with a low MFI value presented high tensile and impact strengths. Because of high sugar content, the pure rind fiber had a poor performance as filler in the HDPE resins with respect to the raw bagasse fiber and alkali-extracted bagasse fiber. On the other hand, the aspect ratio was proportional to the mechanical performance of the fibers in the HDPE resins. As a result, the fibers with a large aspect ratio and low sucrose content improved the strength properties of the resultant composites. 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5607-5619, 2006

Functional, nutritional, thermal, and rheological properties of Alaska white fish meals were evaluated. Emulsification capacity and stability, and fat and water adsorption of the fish meal samples were evaluated. Five fish meal samples were made from pollock:cod (95:5) processing byproducts collected on five separate days. Results showed that functional and nutritional properties of the fish meals were relatively consistent among the five different runs. All fish meals contained 66.1–69% protein and 6.2–8.1% fat, and had similar amino acid and mineral contents. The denaturation peak, Tmax, values ranged from 46.8 to 48.6°C and the enthalpy values ranged from 1.3 to 1.6 j/g. Doughs made from the white fish meals had viscoelasticity properties with G' greater than G″ and the delta values below 20.