Biodegradation
pardis yousefi; Sepideh Hamedi; Esmaeil Rasooly Garmaroody; mojtaba koosha
Abstract
Bio-refinery includes technologies which can convert biomass resources to valuable products. In this study, carboxymethylation of the xylan-rich hemicelluloses extracted from sugarcane bagasse pith was performed. DS of the carboxymethyl xylan (CMX) was determined 0.68 using ICP-OES analysis. The presence ...
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Bio-refinery includes technologies which can convert biomass resources to valuable products. In this study, carboxymethylation of the xylan-rich hemicelluloses extracted from sugarcane bagasse pith was performed. DS of the carboxymethyl xylan (CMX) was determined 0.68 using ICP-OES analysis. The presence of absorption bands at 1580 and 1311 cm-1 in the FTIR spectrum of the modified xylan are associated to the stretching vibration of C-O bonds of carboxymethyl groups. The carboxymethyl xylan/chitosan (CMX/CS) films were then prepared by casting method. XRD pattern showed that the intensity of the characteristic peaks of the chitosan reduced after film preparation which may be due to decreasing the crystalline nature of the film. SEM images showed that the surface of the film is uniform. The observed exothermic peak in DSC thermograms showed that the films degraded at higher than 200oC. Water vapor permeability (WVP) of the carboxymethyl xylan/chitosan film was measured 0.84± 0.1 g mm/m2 h kPa. Colorimetric analysis proved that the white index (WI) of the CMX/CS film increased as compared with xylan/chitosan film. In contrary, the yellow index (YI) of the CMX/CS film decreased. Swelling ratios of the CMX/CS and xylan/CS films were measured as 130.42 and 95.71 respectively. The prepared CMX/CS films exhibited higher tensile strength in compared to xylan/chitosan film. This may be resulted from the interactions between amine groups of chitosan and carboxyl groups of CMX. CMX/CS film exhibited the higher antibacterial activity against E. coli that S. aureus.
Composite wood products
Ashkaan Keshaavarz; Hossein Jalali Torshizi; Faranak Mohamadkazemi; Mojtaba Koosha
Abstract
Nowadays, research studies about optimal application of natural resources in products manufacturing instead of fossil and non-renewable resources are of utmost and ever growing importance. Cellulosic resources as the future reliance of Green products and also mineral mines as plenty, cheap and available ...
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Nowadays, research studies about optimal application of natural resources in products manufacturing instead of fossil and non-renewable resources are of utmost and ever growing importance. Cellulosic resources as the future reliance of Green products and also mineral mines as plenty, cheap and available materials, especially in Iran, are appropriate options for various products developing. Then, effects of cellulosic fibers and Rockwool fibers (0.25% and 0.5%) in the absence and presence (0.1% and 0.2%) of nano bentonite on conventional and specific properties of Epoxy composite were evaluated. Tensile strength (47.9 MPa), modulus of rupture (86.3 MPa) and modulus of elasticity (2100 MPa) for the mineral fiber/epoxy composite and bentonite/epoxy nanocomposite were higher than the cellulosic fiber/epoxy composite. However, cellulosic fiber/epoxy composite showed higher energy absorption of the ballistic impact with lesser damage area caused by the impact than rockwool/epoxy composite which provide better protection against the ballistic impact. In the presence of nano bentonite particles into the epoxy resin context, rupture and elasticity moduli and tensile strength were dependent on the type and amounts of the additives with superiority of the mineral fibres/epoxy nanocomposite than the cellulosic fibers ones. In contrast, the composites energy absorption caused by the ballistic impact and its damaged area were more successful and favorable in cellulosic fibers than the mineral ones. Somehow that the highest absorbed energy of ballistic impact (60.7 J) and the least damaged area (10.7 cm2) were achieved by the highest application of cellulosic fibers (0.5%) and nano-bentonite (0.2%).
