Characterisation of Rapeseed Oil Based Resins Using Infrared and Thermogravimetry Techniques

Rapeseed oil which is a triglyceride had undergone chemical modification on its structure to obtain hydroxyl groups. The hydroxylated chemical structure was crosslinked using methylene-pphenyl diisocyanate to produce a thermoset rapeseed oil resin. The cross linking process was monitored in situ using the Attenuated Total Internal Reflectance Fourier Transform-Infrared spectroscopy and the thermogravimetric analysis techniques. The infrared technique was also used to monitor chemical groups of the unmodified rapeseed oil. A reduction of the absorption band around 3300 cm-1 which is due to the presence of hydroxyl groups was observed indicating the occurrence of the reaction between the hydroxylated rapeseed oil and methylene-p-phenyl diisocyanate. The thermogravimetric analysis technique recorded the reduction of the hydroxyl groups as the loss in mass of the reactants as a function of temperature. The two analytical techniques provided about the same cure time. Both, the infrared and thermogravimetric techniques elucidated useful cure characteristics of the rapeseed oil resin. The applications of more than one analytical method offer a complement of the results.Keywords: Triglycerides, hydroxylation, cure, polyurethane, characterisationTanz. J. Sci. Vol. 37 2011, 17-2

The Influence of the Type of Lime on the Hygric Behaviour and Bio-Receptivity of Hemp Lime Composites Used for Rendering Applications in Sustainable New Construction and Repair Works

The benefits of using sustainable building materials are linked not only to the adoption of manufacturing processes that entail reduced pollution, CO2 emissions and energy consumption, but also to the onset of improved performance in the building. In particular, hemp-lime composite shows low shrinkage and high thermal and acoustic insulating properties. However, this material also shows a great ability to absorb water, an aspect that can turn out to be negative for the long-term durability of the building. For this reason, the hygric properties of hemp-based composites need to be studied to ensure the correct use of this material in construction and repair works. The water absorption, drying and transpirability of hemp composites made with aerial (in the form of dry powder and putty) and hydraulic limes were investigated here and related to the microbial growth induced by the water movements within the material. Results show that hemp-natural hydraulic lime mixes exhibit the highest transpirability and drying rate, the lowest water absorption by immersion and capillary uptake and the least intense microbial attack and chromatic change. A microscopical study of the hemp shives also related their great ability to absorb water to the near-irreversible swelling of their structure under dry-wet conditions.The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 326983 (NaturALiMe), and the Spanish project MAT-2012-34473 of the Ministerio de Ciencia y Competitividad. Author MB, owner of the CANNABRIC company, had some role in the design and preparation of mortar samples and in the preparation of this manuscript, but did not have any additional role in data collection and analysis

Thermal and mechanical properties of chitosan nanocomposites with cellulose modified in ionic liquids

In this paper, ionic liquid treatment was applied to produce nanometric cellulose particles of two polymorphic forms. A complex characterization of nanofillers including wide-angle X-ray scattering, Fourier transform infrared spectroscopy, and particle size determination was performed. The evaluated ionic liquid treatment was effective in terms of nanocrystalline cellulose production, leaving chemical and supermolecular structure of the materials intact. However, nanocrystalline cellulose II was found to be more prone to ionic liquid hydrolysis leading to formation larger amount of small particles. Each nanocrystalline cellulose was subsequently mixed with a solution of chitosan, so that composite films containing 1, 3, and 5% mass/mass of nanometric filler were obtained. Reference samples of chitosan and chitosan with micrometric celluloses were also solvent casted. Thermal, mechanical, and morphological properties of films were tested and correlated with properties of filler used. The results of both, tensile tests and thermogravimetric analysis showed a significant discrepancy between composites filled with nanocrystalline cellulose I and nanocrystalline cellulose II

Potential of Kapok Fibre as a Substitute of Cotton in Textiles

Kapok fibre, commonly known in Kiswahili as ‘sufi\' is obtained from kapok plant, Ceiba pentandra. The conventional end uses of kapok include mattress/pillow stuffing, upholstery and thermal insulation. The market for kapok in these traditional uses has declined considerably over the past 30 years, due to the developments in synthetic materials, such as foamed plastics, which have almost replaced kapok in most of its traditional end uses. Attempts to use kapok fibre for producing textile yarn were not successful due to the slippery nature of the fibres and its brittleness. However, a blend of kapok and cotton fibres was successfully spun into a yarn after blending the two in a kapok/cotton ratio 3:2. The yarn produced exhibited mechanical properties similar to most of the short staple fibres. The fabric produced was lustrous, slippery and with a smooth, soft handle. The fibre yarn resulting from blending kapok with cotton is potentially suitable for producing woven textile fabrics. In addition to its potential use as clothing material, the fabric is being considered for suitability as reinforcement to thermosetting polymeric materials such as polyester and phenolic resins. Journal of Agriculture, Science and Technology Vol. 1 (1) 1997: 66-7

Swelling and dissolution of cellulose, Part III: plant fibres in aqueous systems

International audienceRaw and refined flax, hemp, abaca, sisal, jute and ramie fibres are dipped into N-methylmorpholine N-oxide (NMMO)-water with various contents of water and into hydroxide sodium (NaOH)-water. The swelling and dissolution mechanisms of these plant fibres are similar to those observed for cotton and wood fibres. Disintegration into rod-like fragments, ballooning followed or not by dissolution and homogeneous swelling are all observed as for wood and cotton fibres, depending on the quality of the solvent. Balloons are not typical of wood and cotton and they seem to be present in all plant fibres. Another interesting result is that the helical feature seen on the balloon membrane is not related to the microfibrillar angle. Plant fibres are easier to dissolve than wood and cotton. This is not related to the molar mass of the cellulose chain. Raw plant fibres keeping most its non-cellulosic components do not show the formation of balloons