The effect of melt flow index, melt flow rate, and particle size on the thermal degradation of commercial high density polyethylene powder

• Published in: Journal of thermal analysis and calorimetry Vol. 114; no. 3; pp. 1333 - 1339
• Main Authors: Seifali Abbas-Abadi, Mehrdad, Nekoomanesh Haghighi, Mehdi, Yeganeh, Hamid, Bozorgi, Babak
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.12.2013; Springer
• Subjects: Activation energy; Analytical Chemistry; Applied sciences; Chemical reactions and properties; Chemistry; Chemistry and Materials Science; Degradation; Exact sciences and technology; Flow rate; High density; Inorganic Chemistry; Measurement Science and Instrumentation; Melts; MFI; Organic polymers; Particle size; Physical Chemistry; Physicochemistry of polymers; Polyethylene; Polymer Sciences; Powders; Specific gravity; Thermal degradation; HDPE; MFI; Particle size; TG; DTG; MFR; Molecular mass; Thermal degradation; High density ethylene polymer; Thermogravimetry; Melt index; Powder; Particle size distribution; Commercial form; Thermal analysis; Kinetics
• ISSN: 1388-6150; 1588-2926; 1572-8943
• DOI: 10.1007/s10973-013-3133-0

The powder of EX5 grade of high density polyethylene—without any additives—manufactured by Amirkabir petrochemical company was separated by shaker equipment. The separated powder of average diameter ~25, ~62.5, ~87.5, ~112.5, ~137.5, ~175 and the particles >200 μm was tested by a thermogravimetric (TG) analysis instrument in nitrogen atmosphere and heating rates of 10, 20, and 30 °C min −1 . In addition, the separated powders were analyzed by a melt flow index (MFI) instrument, and the viscosity average molecular mass ( M v ) of the powders was tested by a viscometer. Kinetic evaluations were performed by Friedman and Kissinger analysis methods and apparent activation energy for the overall degradation of the powders was determined. The effects of molecular mass, MFI, MFR, and particle size on the degradation TG curve, derivative thermogravimetry curve breadth, and activation energy of thermal degradation were considered. The results showed that the M v of EX5 pipe grade produced by two serial reactors is increased by increasing of the particle size and, MFI is decreased with a little deviation by particle size increasing. The particle size has no obvious effect on the melt flow rate (MFR), and MFR as function of molecular mass distribution does not change very much. The results showed that the powder with bigger particles and higher molecular mass moderately increases the activation energy and shifts the degradation curve to the higher temperatures.