Kinetic modelling of phenols consumption during polyethylene thermal oxidation

Abstract

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Thermal aging kinetic and effects on mechanical behavior of fully recycled composite based on polypropylene/polyethylene blend

“…In order to be able to detect antioxidants, follow their disappearance and carbonyls build up, many analytical methods are proposed in literature such as IR and UV spectrophotometry and differential scanning calorimetry (DSC) under oxygen (OIT) . Coupling the chemical consumption and physical loss of stabilizers and proposing valid kinetic models is a complex and interesting field that's why in recent years many researchers have been attracted to study it …”

Comparison of stabilization by Vitamin E and 2,6-di-tert-butylphenols during polyethylene radio-thermal-oxidation

“…According to this work, and other previous papers (Richaud et al, 2008, Richaud et al, 2011, Richaud, 2013, the action of stabilizers is can be described by adding the following equations to the general mechanistic scheme: Richaud et al, 2008, Richaud et al, 2011, Richaud, 2013. The following set of differential equations Figure 9 were [POOH] 0 was considered as an adjustable parameter expressing the level of unstable moiety in several PE from different sources).…”

“…The resulting phenoxyl radical A° isomerizes, and then reacts with another peroxyl or with O 2 , with another phenoxyl by dismutation or coupling, or generate a new form of stabilizer (Allen et al, 1985;Pospı́šil et al, 1991;Pospı́šil, 1993;Pospı́šil et al, 1996;Pospı́šil et al, 2002). These mechanisms can be represented by a "kinetically equivalent" scheme (Richaud et al, 2011;Richaud, 2013) using a limited number of adjustable parameters:…”

“…Those k S1 values of vitamin E were plotted in an Arrhenius diagram ( Figure 8) together with values determined from AO1 for which a lot of values were compiled in the case of thermal oxidation (Richaud, 2013) and those determined from We will not speculate here on the possible activation energy of k S1 (vitamin E) the low temperature data is expected to correspond to irradiation at room temperature whereas it is known that irradiation induces a slight heating of sample (Costa et al, 2008). However, it seems clear that:…”

“…In UHMWPE films thin enough (such those used in Costa et al (2009) to neglect all diffusion phenomena, k S1 … k S4 can be estimated "simply" by an inverse approach from ageing experiments (Richaud et al, 2008;Richaud et al, 2011;Richaud, 2013). For that purpose, Vitamin E stabilization reactions are added to the scheme previously established for additive free PE (Khelidj et al, 2006) …”