The Effect of Acid-Treatment of Carbon Nanotubes on the Thermal Kinetics of Isotactic Polypropylene

Integrating stabilizer efficiency of secondary antioxidants to thermal, rheological, optical characterization and filterability study of polypropylene

The framework of the present study is based on investigation of different types of phosphorus based secondary antioxidants and their role in stabilization of polypropylene. Three different chemical entities i.e., Tris (2,4-di-tert-butylphenyl) phosphite, Tetrakis (2,4-di-tert-butylphenyl)-4,4-biphenyldiphosphonite and Bis (2,6-di-tert-butyl-4-methylphenyl pentaerythritol-diphosphite) have been studied for its efficiency as a secondary antioxidants or processing stabilizer. Thermal stability of polymer is predicted using degradation kinetics study and correlated with it’s optical, thermal and rheological response. To further evaluate performance of secondary antioxidants, thermogravimetry analysis was performed for polypropylene at three different heating rates and processed for iso-conversional analysis to get the kinetic parameters. Oxidation induction data and kinetic parameters have been related with efficiency of the stabilizers. Filtration study was also carried out to understand the efficacy of stabilizers during secondary process. Die pressure build up in filtration study is quantified and related with performance of secondary antioxidants.

Polypropylene pyrolysis kinetics under isothermal and non-isothermal conditions: a comparative analysis

The kinetics of polypropylene pyrolysis has been studied under isothermal and non-isothermal conditions using Arrhenius and Kissinger–Akahira–Sunose (KAS) equations. Under isothermal conditions, applying first order kinetic model, activation energy (Ea) and pre-exponential factor (A) were investigated and observed as 119.7 kJ mol−1 and 1.2 × 1010 min−1, while in case of non-isothermal kinetics using Kissinger–Akahira–Sunose method, the average Ea and A were found to be 91.23 kJ mol−1 and 2.3 × 107 min−1, respectively. A comparison among the isothermal and non-isothermal reactions was made on the basis of kinetics parameters. The results from both the methods showed trivial variation in kinetic parameters of the pyrolysis reaction which may be due to two major reasons. Firstly, the selection of the kinetic model applied and secondly the inconsistency due to various experimental conditions used which can be reduced at optimized conditions. As the disposal of plastic materials need reliable kinetics information to model their decomposition reactions, therefore, the kinetics data thus obtained from pyrolysis reaction of model polypropylene will help in the utilization of polypropylene waste as energy source on industrial scale.

Pyrolysis of polypropylene over zeolite mordenite ammonium: kinetics and products distribution

The present work reveals pyrolysis kinetics of polypropylene (PP) over zeolite modernite using thermogravimetry. The activation energy (Ea) and frequency factor (A) were calculated applying Ozawa Flynn Wall, Coats-Redfern, and Tang Wanjun methods. The Ea calculated by all the methods were found in accord with each other. The pyrolysis was also performed in a salt bath in the temperature range 350°C–390°C. It was observed that a temperature of 370°C is the optimum temperature for maximum liquid fuel production. Moreover, the amount of solid residue decreases with the rise in temperature. Similarly, gas fraction also shows linear relationship with temperature. The condensable and noncondensable fractions were collected and analyzed by gas chromatography-mass spectrometry. The fuel properties of the oil produced were assessed and compared with commercial fuel. These properties agree well with fossil fuel and therefore have potential applications as fuel.