Search

The feasibility of employing chemical methods for enhancement of cellulose-based materials is dependent on the availability, price, and green index of the modifying agent. This study details the use of iodomethane, an inexpensive organo halide, to increase the hydrophobicity of thermo mechanical (TMP) samples, which renders them better structural elements for composite materials. For this system, we studied the influence of various concentration of iodomethane, concentration of caustic, and reaction time. Infrared spectroscopy suggested reaction of the organo halide with the hydroxyl groups of cellulose and lignin components of TMP. Pulp samples treated for 4 h or at low caustic concentration showed the least improvements plausibly due to pulp degradation or poor pulp swelling, respectively. On the other hand, pulp treated at 3 h using high concentrations of caustic were characterized with surfaces that were more hydrophobic. Thus, this study outlines a fast and organic solvent-free (clean up) method that can be used to enhance pulp samples for composite applications. [ABSTRACT FROM AUTHOR]

The aim of this study was to characterize the surface, morphological, and thermal properties of hemp fibers treated with two commercially available, inexpensive, and water soluble sulfonic acid derivatives. Specifically, the cellulosic component of the fibers were targeted, because cellulose is not easily removed during chemical treatment. These acids have the potential to selectively transform the surfaces of natural fibers for composite applications. The proposed method proceeds in the absence of conventional organic solvents and high reaction temperatures. Surface chemical composition and signature were measured using gravimetric analysis, X-ray photoelectron spectroscopy (XPS) and Fourier transform infra-red spectroscopy (FTIR). XPS data from the treated hemp fibers were characterized by measuring the reduction in O/C ratio and an increase in abundance of the C C O signature. FTIR confirmed the reaction with the emergence of peaks characteristic of disubstituted benzene and amino groups. Grafting of the sulfonic derivatives resulted in lower surface polarity. Thermogravimetric analysis revealed that treated fibers were characterized by lower percent degradation between 200 and 300 °C, and a higher initial degradation temperature. [ABSTRACT FROM AUTHOR]

The main aim of this study was to investigate the effect of mercerization prior to enzymatic treatments on the surface, on the thermal and morphological properties of hemp fibres. Hemp fibres were treated with sodium hydroxide (5%, w/v) and five different enzyme systems. The enzymes studied were xylanase, xylanase + 10% cellulase, pectinmethylesterase, polygalacturonase and laccase. A previous report utilizing enzymes alone ( George et al., 2014 ) was used as a baseline to determine the impact of caustic swelling of the hemp fibres coupled to enzymatic treatment. Thermal gravimetric analysis (TGA) was used to study the effect of each system on thermal properties of the hemp fibres. Scanning electron microscopy (SEM) was used to monitor the changes in the morphological features of the hemp fibres, while X-ray photoelectron spectroscopy (XPS) was used to study the influence of each treatment of the surface chemical composition. Force tensiometry was used to investigate the effect of the different systems on the surface polarity of the treated fibres. The additional treatment with NaOH + hemicellulases was found to result in enhanced thermal properties when compared to previous systems. SEM micrographs confirmed greater fibre bundle rupture and increase in surface roughness of the base + enzyme treated samples. This work demonstrates that mercerization prior to enzymes, depending on the mode of action and arrangement of chemical components of the fibre, can be an effective method for improving the thermal and surface properties of fibres for composite applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] Enzymatic treatments produced a homogeneous cellulose surface for subsequent activation. [•] Removal of thermally labile pectic and hemicellulosic content resulted in improved thermal stability. [•] The ultra structure of flax fibres (versus hemp) renders it more susceptible to enzymatic degradation. [ABSTRACT FROM AUTHOR]

Highlights: [•] We characterized hydrolysates of cattle tissues known as specified risk materials. [•] We measured protein cleavage as function of hydrolysis protocol. [•] We identified the reactive functionalities available. [•] We suggested possible industrial applications. [ABSTRACT FROM AUTHOR]