Decomposition of polyamide via slow pyrolysis: Effect of heating rate and operating temperature on product yield and composition

Kinetic Analysis of Pyrolysis and Thermo-Oxidative Decomposition of Tennis String Nylon Wastes

“…However, with an acid catalyst of H 3 PO 4 , the E a was also reduced to E a = 164 kJ/mol, together with log A = 14.0 min −1 and a reaction order of n = 1.9. A rather similar E a value of 205 kJ/mol has also been reported in the work of Pannase et al [11], where nylon-6 pyrolysis was performed via model-free Coats-on redmine Redfern (CR), Flynn-Wall-Ozawa (FWO), and Starink (SK). However, quite distinctly, they reported that the degradation reaction is controlled by a contracting sphere R3 model other than the chemical order model identified by using the master-plot method [11].…”

“…It is well-known that pyrolysis and combustion are two effective methods to chemically converse plastic wastes into valuable substances for sustainable energy development [1,2]. To date, a number of attempts have been made to study pyrolysis and oxidative thermal degradations of nylon-6 and its wastes [3][4][5][6][7][8][9][10][11][12]. Principally, nylon-6 has been reported to thermally degrade into ε-caprolactam monomer through a chain end backbiting process or a ring transition state formed within polymer chains [3][4][5] and a yield as high as 83-85 wt.% of ε-caprolactam could be obtained [6,7].…”

“…Likewise, Kim et al [9] performed a pyrolysis study of teabag waste at 400 and 700 • C and reported that the highest caprolactam yield has turned to be 59.2 wt.%. In contrast, the pyrolysis product composition may become diverse when changing pyrolysis conditions [10,11]. Bozi and Blazsó [10] studied the effect of acidic Y zeolite catalyst on nylon-6 pyrolysis and reported that the pyrolysis product may become mainly dihydro-azepine isomers instead of ε-caprolactam via cis-elimination or intramolecular rearrangement of amide groups and more aromatics and light unsaturated hydrocarbons will be yielded when using greater amounts of zeolite.…”

“…Bozi and Blazsó [10] studied the effect of acidic Y zeolite catalyst on nylon-6 pyrolysis and reported that the pyrolysis product may become mainly dihydro-azepine isomers instead of ε-caprolactam via cis-elimination or intramolecular rearrangement of amide groups and more aromatics and light unsaturated hydrocarbons will be yielded when using greater amounts of zeolite. Interestingly, Pannase et al [11] reported that the condensed pyrolytic oil of fresh nylon-6 ropes, obtained at 823 K under 5 K/min and 873 K under 10 K/min and analyzed via Fourier transform infrared spectroscopy (FTIR), shows a high resemblance with conventional fuel such as diesel.…”

“…Apart from the study of degradation product compositions, kinetic analysis of thermal degradation of nylon-6 has also been attempted in terms of kinetic triplet parameters of as apparent activation energy E a , pre-exponential factor A and reaction mechanism model function f (α) using isothermal thermogravimetric (TG) data or dynamic non-isothermal TG data [4,5,7,11,12]. Holland and Hay [4] studied the pyrolysis of nylon-6 and reported an E a calculated at 190 kJ/mol along with the first-order reaction for pyrolysis of fresh nylon.…”