تهيه و مشخصه يابي كامپوزيت اپوكس تقويت شده با نانوالياف سلولزي الكتروريسي شده

چكيده انگليسي :

81 Preparation and characterization of epoxy composite reinforced by electrospun cellulose nanofibers Abdol Rasool jahanbani Ar jahanbani@ce iut ac ir Department chemical engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi tbehzad@cc iut ac ir Dr T Behzad Dr S Borhani sborhani@cc iut ac irAbstractIn Recent years the applications of organic and biodegradable resources have received moreattention due to environmental impacts and lack of fossil fuels and increasing global energy demand Cellulose is the most abundant biopolymer in the world and therefore extensive studies have beenmade on cellulose and nano cellulose extraction from different resources In this study a newapproach to extract nano cellulose has been proposed which include chemical methods followed byelectro spinning Also wheat straws used as a raw material because it is so cheap and has no economicvalue In chemical method to remove non cellulosic materials and for fibrils to swell was firstly wheat straws were pretreated for 2 hours in a 17 5wt NaOH solution Then acid hydrolysisperformed for 135 min at 75 C in presence of hydrochloric acid 2 molar In the next step alkalihydrolysis by a dilute solution of sodium hydroxide 2 by weight in water bath at 80 C for 2 hours Acid hydrolysis and alkali hydrolysis remove of hemicellulose and soluble lignin To remove theinsoluble lignin bleaching process in two stages by the hydrogen peroxide and sodium hypochloritewas performed The chemical composition of the fiber and kappa number test was determined thatshowed more non cellulosic fibers have been removed and the structure of fibers has a 86 5 cellulose These results which remove lignin and cellulose materials from the fiber structure in FTIRtest were repeated SEM images showed that the fibers are well removal of non cellulosic and fiberdiameter is reduced Cellulose nano fibers by electrospinning was produced at the next stage Thecellulose in various concentrations of sodium hydroxide urea thiourea solution was electrospun Optical microscopy showed that all concentrations below 5wt of fibers were electrospraed and notwell formed at this concentrations Measuring the viscosity of the solution showed that the lowviscosity of solutions causes of not spinning Then the solvent TFA was used for electrospinningprocess Because of the high vapor pressure of solvent electrospinning process was conducted in ahigh relative humidity Cellulose was dissolved in the solvent in different concentrations and7 5wt was best In this concentration fibers were long but still uniform fiber diameter were achieved Theaverage fiber diameter was obtained to be 150 nm To improve the fiber quality 5 by weight ofmethylene chloride was added to the solution to improve the electrical conductivity of the solution SEM images showed that a fiber diameter and fiber length is suitable The average diameter of thenanofibers was measured to be 120 nm Cellulose fibers were also characterized by FTIR analysis wasfound that nanofibers were still contained some of the solvents TFA Then an epoxy basedcomposited reinforced by a mat of electrospun cellulose nanofibers was prepared by hand lay upmethod Tensile test results showed that the tensile strength elongation and modulus of thenanocomposites were increased Impact test showed that by adding a mat of nano fibers in epoxycomposite materials was also increased impact resistance significantly Key Words cellulose electrospinning nanofibers epoxy resin nanocomposites

جهانباني، عبدالرسول

تهيه و مشخصه يابي كامپوزيت اپوكس تقويت شده با نانوالياف سلولزي الكتروريسي شده

رزين اپوكسي , نانو كامپوزيت