Waste Plastics: Pyrolysis of Powdered and Powder-free Laboratory Examination Waste Gloves

Aims: The aim of this investigation was to develop a methodology that provides insights to clean up environmental pollution caused by the ever increasing amount of waste plastic materials. The procedure, however, would be practical whenever it is economically advantageous. Thermal cracking of laboratory safety glove (LSG), without catalyst, to useful chemicals is an important part of this research which is reported here.
Study Design: To design the experimental procedure, we primarily concentrated on the thermal stability of the LSG by bearing in mind the results of thermo gravimetric analysis (TGA). Based on such results the appropriate set-up for the decomposition of the LSG was designed.
Place and Duration of Study: The study was done in the Department of Biological and Physical Sciences at South Carolina State University (SCSU), Orangeburg, SC, USA, during the summer of 2013.
Methodology: The thermal cracking process without catalyst was used to convert LSGs into useful liquid and solid chemicals. The LSGs were pushed into the reactor one by one without cutting. Prior to pyrolysis, the thermal stability of materials were determined by thermo gravimetric analysis (from 50ºC to 800ºC) with a heating rate of 10ºC/min while the samples were purged with 10 mL/min argon. The condensed liquids were analyzed by a Shimadzu GC-MS model GCMS-QP 2010s using helium as the mobile phase.
Results: The thermal stability of the LSG both powdered and powder-free was very similar as was expected since it depended on the nature of constituent polymers. The highest decomposition rates were observed at temperatures around 410ºC. The 15% leftover of the powder-free LSG were less than leftover of powered LSG (30%) at 500ºC, in the same way the 18% leftover ashes of powdered LSG was higher than 7% ashes of powdered free LSG at 800ºC. The GC-MS chromatogram of pyrolysis liquids indicated over 350 chemicals. The most abundant compound of pyrolysis was HCl, as was expected from the chemical constituents of chlorinated plastics, followed with eight member carbon isomers. Also, a variety of phthalic acid derivatives with high concentration were recognized in all samples.
Conclusion: The liquids obtained from pyrolysis of LSGs were a complex mixture of hydrocarbons and cyclic compounds. Also, the liquids were saturated with inorganic and organic acids, esters and anhydrides. Therefore, the refinement of liquids resulting from pyrolysis is of necessity to obtain a quality fuel. Also, the condensed liquids contained highly reactive chemicals such as acids, alcohols and alkene, which made them unsuitable fuel for internal combustion engines prior to refinement.