Dried and defatted jute fibers were acetylated for different time and temperature in the absence of catalyst and solvent. Extent of acetylation were measured by weight percent gain (WPG). These values were compared with the standard method of acetylation using a cosolvent (pyridine) system. The characterization of acetylated fibers was performed by FTIR, DSC, TGA, and SEM studies. The maximum WPG was 18.0 for an acetic anhydride-pyridine system at 120ЊC for 4 h whereas using only acetic anhydride WPG was 12.3 at the same reaction condition. Thermal stability of acetylated jute was found to be higher than the untreated jute. SEM studies were carried out to investigate the fiber surface morphology. FTIR studies also produced evidence for acetylation.
Rubber wood (Hevea brasiliensis) was impregnated with styrene and glycidyl methacrylate (GMA) as the crosslinking monomer. After impregnation, the polymerization was accomplished by catalyst heat treatment. Water uptake (%) and water vapor exclusion (%) of the rubber wood were found to be improved on treatment. Dimensional stability expressed in terms of volumetric swelling in water vapor (90% relative humidity) as well as in liquid water and water repellent effectiveness (WRE) of the treated samples were determined and also found to be improved. The wood-polymer interaction was confirmed by FTIR spectroscopy. Thermal properties of untreated and treated wood samples were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetery (DSC) and an improvement in thermal stability was observed for the wood-polymer composites. The improvement in properties observed as more with styrene-GMA (1:1) combination.
In the present work, a set of experimental polypropylene (PP) clay composites containing pristine bentonite clay of Indian origin has been prepared and then characterized. The polymer clay composites are processed by solution mixing of polypropylene with bentonite clay using a solvent xylene and high speed electric stirrer at a temperature around 130°C and then by compression molding at 170°C. The mechanical properties of PP-clay composites like tensile strength, hardness and impact resistance have been investigated. Microstructural studies were carried out using scanning electron microscope and transmission electron microscope and the thermal properties were studied using differential scanning calorimeter. Mechanical properties of the prepared composites showed highest reinforcing and toughening effects of the clay filler at a loading of only 5 mass % in PP matrix. Tensile strength was observed to be highest in case of 5 mass % of clay loading and it was more than 14% of that of the neat PP, while toughness increased by more than 80%. Bentonite clay-PP composite (5 mass %) also showed 60% increase in impact energy value. However, no significant change was observed in case of hardness and tensile modulus. Higher percentages of bentonite clay did not further improve the properties with respect to pristine polypropylene. The study of the microstructure of the prepared polymer layered silicate clay composites showed a mixed morphology with multiple stacks of clay layers and tactoids of different thicknesses.
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