ساخت و مشخصه يابي بيونانو كامپوزيت تهيه شده از پلي لاكتيك اسيد بازيافتي و نانو الياف سلولزي باگاس

چكيده انگليسي :

86 Development and Characterization of Bio nanocomposites from Recycled Polylactic Acid and Bagasse Nanofibers Pezhman Heidarian p heidarian@ce iut ac ir January 14 2014 Departemant of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSuperviser Tayebeh Behzad tbehzad@cc iut ac ir and Keikhosro Karimi karimi@cc iut ac irAbstractToday nano sized reinforcement had a great attention in nanocomposite technology NFC can be generatedby using high mechanical fibrillation include of high pressure Homogenizer and super grinder Theobtained cellulose nanofiber had a longer length over diameter fibers with a web like structure As a result the both obtained cellulose nanofiber is interest reinforcement in green nanocomposite technology Nanofibrillal cellulose NFC and cellulose nanocrystal based composites can be prepared by variousprocessing methods e g melt processing solvent casting and in situ polymerization In this worknanofibrillal cellulose NFC was to isolate characterize and optimize from depithed sugarcane bagasse bya sulphur free and bio refinery based approach Chemical pretreatments were applied to isolate individualmicro sized cellulose fibers First Extractives and non structural materials were extracted based onnational renewable energy laboratory NREL standard Afterward hemicellulose and lignin were isolatedby auto hydrolysed in deionized hot water and alkalization pulped by soda anthraquinone AQ respectively Finally the pulps were bleached by elemental chlorine free ECF sequences to removinginsoluble lignin and other impurities To avoid overdosing of chlorine required content in bleaching stage kappa number was be applied as a critical parameter In order to reach high degree of NFC cellulosemicro fibers was disintegrated in high mechanical fibrillation process using by PFI mill refiner and ultra fine friction grinder Morphological change and molecular structure of depithed bagasse during chemicalpretreatments studied by scanning electron microscopic SEM and optical microscopic OM Themicroscopic image characterization showed that the applied chemical pre treatments were effective toremoving extractives hemicellulose and lignin and isolated cellulose fibers had a smooth surface Theparticle size and morphology NFC were characterized by dynamic light scattering DLS and transitionelectron microscopy TEM According to DLS result the hydrodynamic diameter of NFC were rangedwithin 860 nm Image analysis of TEM result shown the considerable percentage of isolated NFC haddiameter less 100 nm and length about micro meter The chemical composition was studied using NRELprocedure and chemo physical properties and functional groups followed by fourier transform infraredspectroscopy FTIR According to chemical composition and FTIR results during the pulping process hemicelluloses and lignin were significantly removed and insoluble lignin was almost totally eliminatedduring the bleaching process The obtained NFC will be used as reinforcement in nanocompositeproduction On the other hand processing of recycled polylactic acid rPLA nanocomposite was involved a preparation of NFC rPLA master batch b preparation of NFC rPLA compound c preparation of NFC rPLA composite The composites were prepared with different NFC contents up to 5 wt Morphology mechanical and dynamic mechanical properties DMA was studied to see how different NFCconcentrations affected the composites properties The tensile modulus and strength increased from 527 5MPa to 716 5 MPa and from 23 9 MPa to 32 6 MPa respectively for nanocomposites with 3 wt NFC The DMA results proved the tensile test results storage modulus increased from 8214 MPa to 1024 MPafor nanocomposites with 3 wt NFC The addition of nanofibers shifted the tan delta peak towards highertemperatures The tan delta peak of the rPLA shifted from 66 C to 67 6 C for composites with 3 wt NFC Biodegradation studies in compost soil at 58 C showed that for nano composites b

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ساخت و مشخصه يابي بيونانو كامپوزيت تهيه شده از پلي لاكتيك اسيد بازيافتي و نانو الياف سلولزي باگاس

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