Sazal K. Kundu

Nonequilibrium Plasma Polymerization of HFC-134a in a Dielectric Barrier Discharge Reactor: Polymer Characterization and a Proposed Mechanism for Polymer Formation

Nonequilibrium plasma polymerization of hydrofluorocarbon HFC-134a (CF3CH2F) in argon bath gas has been studied in a dielectric barrier discharge reactor at atmospheric pressure and in the absence of oxygen and nitrogen. The reaction resulted in the formation of a polymeric solid fraction and the noncrosslinked properties of this material assisted in its characterization by solution state 13C and 19F nuclear magnetic resonance spectroscopy. Gel permeation chromatography revealed that the polymers include low (number average molecular weight, Mn values between 900 and 3000 g mol-1) and high (Mn approximately 60000 g mol-1) molecular weight fractions. A detailed polymerization mechanism is proposed, based on the published literature and the findings of the current investigation.

Reaction of carbon tetrachloride with methane in a non-equilibrium plasma at atmospheric pressure, and characterisation of the polymer thus formed

In this paper we focus on the development of a methodology for treatment of carbon tetrachloride utilising a non-equilibrium plasma operating at atmospheric pressure, which is not singularly aimed at destroying carbon tetrachloride but rather at converting it to a non-hazardous, potentially valuable commodity. This method encompasses the reaction of carbon tetrachloride and methane, with argon as a carrier gas, in a quartz dielectric barrier discharge reactor. The reaction is performed under non-oxidative conditions. Possible pathways for formation of major products based on experimental results and supported by quantum chemical calculations are outlined in the paper. We elucidate important parameters such as carbon tetrachloride conversion, product distribution, mass balance and characterise the chlorinated polymer formed in the process.

Reaction of chloroform in a non-oxidative atmosphere using dielectric barrier discharge

This paper investigates the reaction of chloroform under non oxidative conditions in a quartz dielectric barrier discharge reactor. A non thermal plasma is generated in the dielectric barrier discharge reactor at atmospheric pressure where argon functions as a carrier gas and is mixed with chloroform and fed into the plasma zone. Parameters such as chloroform conversion, product distribution, reactor temperature and polymer characterisation are studied in this paper. A reaction mechanism outlining the reaction steps leading to the formation of major products is presented.

Non-thermal plasma polymerization of HFC-134A in a dielectric barrier discharge reactor; Polymer characterization and a proposed mechanism for polymer formation

Non-thermal plasma polymerization of HFC-134a in argon bath gas has been studied in a dielectric barrier discharge reactor at atmospheric pressure and in the absence of oxygen and nitrogen. The reaction resulted in the formation of a polymeric solid fraction and the non-crosslinked properties of this material assisted in its characterization by solution state 13C and 19F NMR spectroscopy. Gel permeation chromatography (GPC) revealed that the polymers include low (number average molecular weight, Mn values between 900 g mol-1 and 3000 g mol-1) and high (Mn approximately 60 000 g mol-1) molecular weight fractions. A detailed polymerization mechanism is proposed, based on published literature and the findings of the current investigation.

Reaction of CCl 3 F (CFC-11) with CH 4 in a dielectric barrier discharge reactor

The reaction of CCl 3 F (CFC-11) with CH 4 in a non-equilibrium plasma has been examined. CFC-11 has the highest ozone depleting potential (ODP) among all refrigerants used commercially (ODP value of 1) and also has very high global warming potential (GWP) of 4680 and an atmospheric lifetime of 45 years.1 The manufacture of CFC-11 was banned by the Montreal Protocol in 1996 due to its deleterious effects on Earths ozone layer. It is widely recognized that significant quantities of CFC-11 remain in polyurethane foams in discarded refrigerators or refrigerators awaiting disposal. While there are several methods developed to recover CFC-11 from polyurethane foams, a suitable process is required for its disposal. In this study, a dielectric barrier discharge reactor, employing alumina dielectrics (the detail description can be founds in2, 3), has been applied for the conversion of CFC-11 with the aim of synthesizing value-added materials. It has been found that polymers of non-crosslinked architecture can be synthesized from the reaction of CFC-11 and CH 4 . This work is focused on structural analyses of the polymers as well as discussions on conversion of CFC-11 under various conditions and characterization of the electrical discharge.

Non-thermal plasma polymerization of HFC-134a in a dielectric barrier discharge reactor; Polymer characterization and understanding the mechanism of polymer formation

Summary form only given. The plasma polymerization of HFC-134a (CF3CH2F) has been investigated in a non-thermal plasma dielectric barrier discharge reactor. HFC-134a is a green house gas and it has a global warming potential of 1410 with respect to CO2 and 100-year time horizon. Its release is regulated in many countries and its manufacture is likely to be controlled in the near future. A dielectric barrier discharge reactor, constructed from concentric alumina tubes was used for the investigation. The polymer generated from reaction was soluble in tetrahydrofuran solvent which suggests that it is non-crosslinked. The polymer was characterized using various NMR spectroscopic techniques (e.g., 13C, 19F) which reveal that the functional groups in the polymer include CHF, CF2 and CF3 groups. Based on these data, a detailed reaction mechanism has been developed which is similar but not identical to those available in the open literature. We previously reported the conversion of HFC-143a, the characterization of plasma discharge and the molecular weight of the polymers. This work is focused on a detailed structural analysis of the polymers and a proposed mechanism for their formation.