پديد آورنده :
يوسفي، مصطفي
عنوان :
بررسي ساختار رشته هاي پلي﴿ اتيلن ترفتالات﴾ كشيده شده در دماي نزديك به انتقال شيشه اي
گرايش تحصيلي :
شيمي نساجي
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده نساجي
صفحه شمار :
يازده، 142،[II] ص: مصور، جدول، نمودار
يادداشت :
ص.ع. به: فارسي و انگليسي
استاد راهنما :
محمد مرشد، محمد حقيقت كيش
استاد مشاور :
حسين توانايي، محمد قانع
توصيفگر ها :
الياف پلي استر
تاريخ نمايه سازي :
13/7/87
استاد داور :
روح الله باقري، عبدالكريم حسيني، ناصر محمدي، شادپور ملك پور
كد ايرانداك :
ID204 دكتري
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتال
چكيده انگليسي :
AbstractIn spite of many researches which have been conducted on the microstructure ofpoly ethylene terephthalate PET fibers there is not a comprehensive model to describethese structures It is well known that there is a close relationship between the fiberstructure and its properties as well as fiber production process parameters In this regardthere is a great interest in the study of the intermediate mesophase structure which arisesfrom the drawing of as spun or partially oriented yarns at near glass transition temperaturerange In this research PET filaments were drawn with different draw ratios at 80 C toobtain filaments with different structures Formation of mesophase structure wasinvestigated by different techniques such as Wide Angle X ray Scattering WAXS Fourier Transform Infrared Spectroscopy FTIR Differential Scanning Calorimetry DSC Dynamic Thermal Mechanical Analysis DMTA density measurements thermalshrinkage mechanical properties and birefringence WAXS results of the drawn samplesdid not show any noticeable peaks whereas FTIR results showed the increase of transconformation and chain folding The formation of regular chain folding in the drawnsamples was attributed to the formation of crystallites with folded chain structure Thebirefringence of the filaments was increased due to the drawing which indicated theincrease of overall molecular orientation of the filaments Density of the drawn filamentswas also increased due to the drawing which indicated the increase of molecularcompactness and crystallinity There was a correlation between crystalline fraction of thesamples and trans conformation of the molecular chains This correlation was morepronounced in the crystalline fraction which was obtained by density measurementstechnique DSC results showed broadening of the crystallization peak which may be due tothe increasing fraction of extended chains in the amorphous regions The curves of lossmodulus versus temperature from DMTA results were resolved into two or three peaks atabove 0 C temperature range which indicated the existence of different structures in thenon crystalline regions These double or triple resolutions appear to indicate that the non crystalline regions of the filaments consist of different structures These structures appearto comprise from complete disorder to oriented amorphous mesophase The area underthe first peak in the resolution of the curve into two peaks or the areas under the first twopeaks in the resolution of the curve into three peaks were increased due to increase in thedraw ratio which was attributed to the increase in the fraction of the oriented non crystalline mesophase regions The loss modulus temperature curves below 0 C werealso resolved into two peaks The area under these peaks did not show any remarkablevariations with changing the draw ratio Our results showed that the drawing processincreased the ratio of oriented amorphous regions As a result it seems that drawing ofpoly ethylene terephthalate filaments at near glass transition temperature causedformation of an intermediate structure in the filaments with the characteristic of extendedchains in the non crystalline regions and formation of small folded chains crystallites Onthe basis of these observations some schematic models were proposed for the structure ofthe poly ethylene terephthalate filaments drawn at near glass transition temperature range
استاد راهنما :
محمد مرشد، محمد حقيقت كيش
استاد مشاور :
حسين توانايي، محمد قانع
استاد داور :
روح الله باقري، عبدالكريم حسيني، ناصر محمدي، شادپور ملك پور
