Monomer Pyrrole Essay

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2. Experimental Technique 2.1 Materials The monomer pyrrole was procured from Spectrochem Pvt. Ltd. Mumbai (India). Pyrrole was double distilled at 1310C and stored at 40C prior to use for synthesis. Polyvinyl alcohol (PVA) was obtained from S. D. Fine Chem. Ltd., Mumbai. Degree of hydrolysis of this powder is 86-89 % and M.W. was 85000 – 124000. It was used as host polymer during the preparation of composites of polypyrrole. Ferric Chloride anhydrous (Iron (III) chloride) was also obtained from S. D. Fine Chem. Ltd., Mumbai. It was used as oxidizing agent during polymerization. The purity of all chemicals was of analytical grade and used as-received, without further purification. All solutions were prepared using distilled water. Ammonia…show more content…
at 70°C and then cool  Step 2 Add 1.65 ml pyrrole to 40 ml of 4% PVA solution Cool to 0-5°C  Step 3 Dissolve Oxidant Ferric Chloride (2 gm) in 10ml distilled water Precool and add dropwise to the solution prepared in Step 2  Step 4 Stir composite solution prepared in STEP 3 for 5 hours at 0°C  Step 5 Pour 5 ml of polymerized composite solution into optically flat petri dishes Solvent evaporates on its own, when left to dry at room temperature  Step 6 Rip off the free standing PPy/PVA composite films from the Petri dishes Fig. 1: Synthesis scheme of PPy-PVA composite…show more content…
Fabricated sensor was fixed inside the gas chamber. The schematic diagram of a typical gas sensing unit is shown in Fig. 3. Measured quantity of NH3 gas (from a canister of 1000 ppm concentration) was injected through syringe so as to yield desired gas concentration in the chamber. The resistance was measured by using Scientific Programmable 4½ digit Digital Multimeter (SM5015). Once steady state was achieved, recovery of sensor was recorded by exposing the sensor to air. This was done by opening both the valves V1 and V2 of the chamber simultaneously. At the same time, the vacuum pump was switched on. Valve V1 allowed fresh air to enter into the chamber while valve V2 allowed the gas to exit the chamber. The vacuum pump accelerated the process of degassing. All the gas sensitivity measurements were carried out at room temperature
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