استخراج و مشخصه يابي نانو الياف كيتين از قارچ موكور اينديكوس و بررسي اثر اين نانوالياف بر روي خواص بيو كامپوزيت بر پايه نشاسته

چكيده انگليسي :

87 Extraction and characterization of chitin nanofibers from Mucor indicus and study the effect of this nanofibers on starch based biocomposites Fateme Salehi Nik F gorooii@ce iut ac ir June 22 2015 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree MSc Language FarsiSupervisor T Behzad tbehzad@cc iut ac irAbstractIn the recent years due to environmental challenges and non renewability of fossil sources syntheticpolymers in many applications have been replaced by biopolymers Whitin the wide family of biopolymers the starch has the high usage in various domains such as food packaging industry applications because of itsavailability biodegradability and biocompatibility Chitin is one of the most common biopolymers used asfiller and reinforcement agentes in the preparation of nanocomposites The aim of this study is extraction andcharacterization of chitin nanofibers from Mucor indicus and investigation of their effect on starch basedbiocomposites First M indicus was grown in a liquid medium The purpose of this part of the study was toevaluate the effect of liquid medium composition and to produce maximum chitin content The results oftests showed that the maximum chitin was obtained in the presence of 2 5 g l phosphoric acid as phosphatesource 2 5 g l of potassium hydroxide as potassium source and 1 g l of yeast extract After separation ofchitin fibers a mechanical process were used for producing chitin nanofibers During the chemicalextraction process in the first step lipids proteins and carbohydrates soluble in alkali solution wereremoved with alkali washing of the biomass and the alkali insoluble materials was produced In the next step removal of phosphate was carried out After sulfuric acid hydrolysis cell wall analysis showed thatphosphate was less than 1 in the cell wall Finally chitosan was eliminated by lactic acid and thendecolorization was done At the end of this two step cell wall analysis showed that the extracted materialcontained 85 chitin small amounts of chitosan and is free of phosphate The FT IR results showed thatdifferent materials in various stages of extraction were removed successfully The average width of 28 nmwas obtained for nanofibers from SEM images X ray diffraction results showed that crystallinity index ofnanofibers was 82 In order to produce nanocomposites starch 5 g dissolved in water 100 ml and thenthe solution was well mixed with of 5 7 10 of chitin nanofibers and then nanocomposites were prepared The results obtained from the mechanical tests demonstrated that a significant increase in tensile strength andmodulus of the nanocomposite films were found in 5 chitin nanofibers When chitin nanofibers werechanged from 0 to 10 elongation at break was decreased from 107 to 48 Moisture absorption testrevealed that the final moisture absorption of nanocomposite was reduced from 51 to 38 when chitinnanofibers were increased from 0 to 5 The results of transparency test showed that the addition ofnanofibers reduces the transparency of nanocomposite films The transparency index for nanocompositefilms with 3 5 7 and 10 of nanofibers was 2 15 3 14 3 5 and 3 82 respectively Keywords Mucor indicus Optimization Chitin nanofiber Starch Bionanocomposites

صالحي نيك، فاطمه

استخراج و مشخصه يابي نانو الياف كيتين از قارچ موكور اينديكوس و بررسي اثر اين نانوالياف بر روي خواص بيو كامپوزيت بر پايه نشاسته

بهينه سازي , بيونانو كامپوزيت , پليمر زيست تخريب پذير