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Synthesis And Characterization Of Specially Polyurethane Elastomers

Fazal-ur-, Rehman (2010) Synthesis And Characterization Of Specially Polyurethane Elastomers. PhD thesis, University of Agriculture, Faisalabad.

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Abstract

Dyed and un-dyed polyurethane elastomers have been synthesized via the prepolymer method and analyzed by using different analytical techniques such as Fourier transform infrared (FTIR) spectroscopy, Proton nuclear magnetic resonance (1H-NMR) and Carbon-13 nuclear magnetic resonance (13C-NMR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning colorimetery (DSC) and thermogravimetric and differential thermal analysis (TG/DTA), tensile testing, contact angle measurement, water absorption percentage (%), density and hardness. FTIR and NMR techniques were used to confirm the chemical structure of the synthesized PUEs. While XRD was executed to determine the extent of crystallanity as a function of chain extenders, diisocyanates and for the dye (Disperse Red 5/1,4- butanediol) as chain extender. Which also have shown that the dye molecule becomes the part of the polymeric chain of the PUEs. Scanning electron microscopy was employed to analyze the surface morphology of PUEs with variation of chain extenders, diisocyantes and dye content. SEM images of PUEs have shown that hard segments are completely dispersed in the soft segment matrix. Other methods like contact angle measurement and water absorption percentage (%) were also used to determine the surface properties.The results have shown that the samples of PUEs based on HTPB were hydrophobic and this nature was increased as the chain extender length was increased.The same trend was observed in the variation of aromatic to aliphatic diisocyanates as well as the content of DR5 dye was increased. Thermal analysis was performed to analyze the thermal behavior of the PUEs by using TG/DTA and DSC which show that all the PUEs were stable up to 215 oC and all the samples were degraded to constant mass at 470oC. Mechanical properties of the PUEs were studied by tensile testing, it is revealed that chain extender length and diisocyantes affect the mechanical properties while dyed polyurethane had represented the inverse mechanical behaviour with respect to un- dyed PUEs. The present study gave us reliable results for dyed and un-dyed PUEs and it was found that the dye had been incorporated in the polymeric chains and the effect was significant on surface morphology, thermal and mechanical properties such as tensile strength, modulus and elongation at break.

Item Type:Thesis (PhD)
Uncontrolled Keywords:Strength, Characterization, Thermal, Synthesis, Polymeric, Diisocyanates, Elastomers, Thermal, Elongation, Degraded, Specially, Polyurethane
Subjects:Physical Sciences (f) > Chemistry(f2)
ID Code:7476
Deposited By:Mr. Javed Memon
Deposited On:16 Oct 2012 09:01
Last Modified:16 Oct 2012 09:01

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