3937

3715

كارشناسي ارشد

شيمي نساجي و علوم الياف

اصفهان: دانشگاه صنعتي اصفهان، دانشكده نساجي

1386

ده، 109، [II]ص: مصور، جدول، نمودار

ص. ع. به فارسي و انگليسي

محمد مرشد، حسين توانايي

07/03/87

شادپور ملك پور، عليرضا مرادي

1396/03/02

كتابنامه

نساجي

مهندسي نساجي

ID3715

به فارسي و انگليسي: قابل رؤيت در نسخه ديجيتال

AbstractIn this study the process of Thermal stabilization of electrospun special acrylicnanofibers SAF has been investigated Smooth SAF nanofibers with the averagediameter of 236 340 and 467nm were electrospun at 25kV using solutions of 11 13and 15 wt SAF DMF concentration respectively Scanning electronMicroscopy SEM was used to observe and measure the diameters of electrospunnanofibers In order to prevent nanofibers from relaxing and fix nanofibers lengthduring thermal stabilization uniaxially aligned nanofibers were collected and fixed by aframe By comparing FTIR spectrums of thermal stabilized nanofibers and precursorsnanofibers it was observed that stretching peaks of C N and C H functional groups at2243cm 1 and 2940cm 1 decreased significantly and then stretching peak of C Nfunctional group at 1600cm 1 and bending peak of C C H functional group at 810 cm 1appeared These changes in functional groups of nanofibers proved accruing of thermalstabilization reactions Color of the nanofibers changed gradually from white to goldyellow orange brown and finally dark brown during thermal stabilization process Byanalyzing isothermal DSC spectrums and drawing Avrami curves at 210 220 230 240and 250oC their activation energy were calculated to be 23 15 23 20 5 19 8 and 17 6 respectively By analyzing the kinetic of the reaction and drawing its Arrhenius splot it was found that the reaction is first order Extension of reaction EOR wascalculated by comparing the length of C N functional group peak with C N functionalgroup peak at FTIR spectrums By increasing the stabilization temperature from 170 oCto 230oC EOR increased from about 0 to 83 By thermal stabilization of nanofibersat 230oC for 1 hour and 250oC for 45 min EOR increased more than 80 The EOR ofthermally stabilized SAF nanofibers containing Itaconic acid and PANnanofibers without Itaconic acid at 230oC for 1 hour were 83 and 42 respectively Pre treatment of nanofibers by mineral catalyst KMnO4 at solution s concentration of680mg lit enhanced extension of thermal stabilization reactions Diameters ofnanofibers decreased from 236nm 322nm and 467nm to 185nm 264 and 390nm afterthermal stabilization at 230oC for 1 hour respectively The weight of thermallystabilized nanofibers decreased 6 8 and 8 after thermal stabilization at 230oC and250oC for 1 hour respectively The enthalpy of thermal stabilization reactions decreasedfrom 507J g for precursors nanofibers to 135J g 73 of the primary enthalpy forthermally stabilized nanofibers Crystalline index CI and coherent length LC ofthermally stabilized nanofibers in different temperatures were measured by WAXD CI and LC of heated nanofibers at 170oC and thermally stabilized nanofibers attemperatures above 190 oC were 60 303A and 35 260A respectively

محمد مرشد، حسين توانايي

شادپور ملك پور، عليرضا مرادي