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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.

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.

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.

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.

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.

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 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 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 tribological behavior of polytetrafluroethylene (PTFE) and PTFE composites with filler materials such as carbon, graphite, E glass fibers, MoS 2 and poly-p-phenyleneterephthalamide (PPDT) fibers, was studied. The present filler additions found to increase hardness and wear resistance in all composites studied. The highest wear resistance was found for composites containing (i) 18% carbon + 7% graphite, (ii) 20% glass fibers + 5% MoS2 and (iii) 10% PPDT fibers. Scanning electron microscopy (SEM) was utilized to examine composite microstructures and study modes of failure. Wear testing and SEM analysis showed that three-body abrasion was probably the dominant mode of failure for PTFE + 18% carbon + 7% graphite composite, while fiber pull out and fragmentation caused failure of PTFE + 20% glass fiber + 5% MoS2 composite. The composite with 10% PPDT fibers caused wear reduction due to the ability of the fibers to remain embedded in the matrix and preferentially support the load. Differential scanning calorimetry (DSC) analysis was also performed to study the relative heat absorbing capacity and thermal stability of the various composites in an effort to correlate these properties to the tribological performance. The results indicated that composites with higher heat absorption capacity exhibited improved wear resistance. The dominant interactive wear mechanisms during sliding of PTFE and its composites are discussed in view of the present findings. © 2002 Published by Elsevier Science B.V.

This paper presents a new synthetic polycarboxylic compound, i.e. a benzocaine-modified maleic anhydride-cyclohexyl-1,3-dioxepin copolymer. p-Aminobenzoic acid is linked via an anaesthesine (p-aminoethylbenzoate, benzocaine) to the carboxylic groups of the copolymer, both as a spacer and to increase the hydrophobicity of the polymer through the phenyl group. The structure of the modified copolymer is characterized by thin-layer chromatography and by i.r. and n.m.r. spectroscopy.

It is shown that the isomerization of cis polyacetylene at 195°C for long periods is accompanied by structural modifications. Infra-red and pyrolysis gas-chromatography data suggest that the aromatization process occurs even at this temperature.