Pyrolysis and thermo‐oxidative degradation of polycyclopentadiene

Thermal degradation of polycyclopentadiene polymer (PCPD) was investigated by pyrolysis gas chromatography (PGC) in the temperature range of 500–950°C. The nature and composition of the pyrolyzates at various temperatures are presented, and the mechanism of degradation is explained. The activation energy of decomposition (E_a) was obtained from an Arrhenius‐type plot using the concentration of the product ethylene (C₂) at different pyrolysis temperatures and the value was found to be 138 kJ mol⁻¹. Thermo‐oxidative degradation of PCPD in the presence of ammonium perchlorate (AP), the most commonly used oxidizer for polymeric fuel binders, was studied at a pyrolysis temperature of 700°C. The compositions of the products with varying amounts of AP are given, and the exothermicity of oxidative decomposition reactions is evaluated. The energetics of the degradation processes are compared with those of polybutadiene type polymers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 635–641, 2000     

Enhancement of mechanical and optical performance of commercial polystyrenes by blending with siloxane‐based copolymers

Well‐defined poly(styrene‐block ‐dimethylsiloxane) copolymers (PS‐b ‐PDMS) with low polydispersity index (M_w /M_n ) and different compositions were synthesized by sequential anionic polymerization of styrene (S) and hexamethyl(ciclotrisiloxane) (D₃) monomers. Synthesized PS‐b ‐PDMS copolymers were characterized by ¹H‐nuclear magnetic resonance, size exclusion chromatography, Fourier transform infrared spectroscopy, and transmission electron microscopy. The physicochemical characterization determined that block copolymers have molar mass values close to ～135,000 g mol^?1, narrow M_w /M_n < 1.3, and chemical composition ranging from low to intermediate PDMS content. Blends of these copolymers with a commercial polystyrene (PS) were obtained by melt mixing and subsequently injection. Films obtained were flexible, and showed lower transparency than the original PS matrix. On the other hand, a 10 wt % incorporation of PS‐b ‐PDMS copolymers leads to better mechanical performance by enhancing elongation at break (～8.8 times higher) and opacity values (～18 times higher). In addition, UV–Vis barrier capacity of the resulting blends is also increased (up to 400% higher). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45122.     

Thermal degradation behavior and gas phase flame‐retardant mechanism of polylactide/PCPP blends

The thermal degradation behavior of the blend based on polylactide (PLA) and poly(1,2‐propanediol 2‐carboxyethyl phenyl phosphinate) (PCPP) was investigated by the thermogravimetric analysis (TGA). Thermal degradation activation energies (E_a) of neat PLA and PLA/15% PCPP blend were calculated via the Flynn–Wall–Ozawa method. The E_a of the blends increased with the addition of PCPP increasing when the conversion was higher than 10%. In addition, the appropriate conversion models for the thermal degradation process of PLA and PLA/15% PCPP were studied via the Criado method. At the same time, the main gaseous decomposition products of PLA and its blend were identified by TGA/infrared spectrometry (TGA–FTIR) analysis. And it revealed that the PCPP improved the flame‐retardant property of PLA via altering the release of the flammable gas and nonflammable gas. Moreover, the PCPP improved the flame‐retardant property of PLA by inhibiting exothermic oxidation reactions in the combustion, which was further proved by pyrolysis–gas chromatography–mass spectrometry analysis. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40480.     

Kinetics of thermal degradation of nanometer calcium carbonate/linear low‐density polyethylene nanocomposites

To improve the thermal properties of linear low‐density polyethylene (LLDPE), the CaCO₃/LLDPE nanocomposites were prepared from nanometer calcium carbonate (nano‐CaCO₃) and LLDPE by melt‐blending method. A series of testing methods such as thermogravimetry analysis (TGA), differential thermogravimetry analysis, Kim‐Park method, and Flynn‐Wall‐Ozawa method were used to characterize the thermal property of CaCO₃/LLDPE nanocomposites. The results showed that the CaCO₃/LLDPE nanocomposites have only one‐stage thermal degradation process. The initial thermal degradation temperature T₀ increasing with nano‐CaDO₃ content, and stability of LLDPE change better. The thermal degradation activation energy (E_a) is different for different nano‐CaCO₃ content. When the mass fraction of nano‐CaCO₃ in nanocomposites is up to 10 wt %, the nanocomposite has the highest thermal degradation E_a, which is higher (28 kJ/mol) than pure LLDPE. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermal degradation and combustion of polymeric blends

The thermal stability of polymer blends was investigated by means of gas chromatography–mass spectroscopy (GC/MS) and thermal analysis. Evaluated changes in thermal stability can be attributed to blending. On the other hand, we were interested in whether blending may provide a method to control thermal stability and combustibility of polymeric materials. A new scheme of thermal degradation for polystyrene‐polydimethylsiloxane (PDMS) blend was suggested. In the case of polystyrene (PS) as a part of the blend, the products of degradation of PS diffuse through the phase boundary, which cause interaction with PDMS polymers. Apparently, PDMS acts as an inert component, slowing down the termination reaction by dilution of macroradicals formed in random scission degradation process of the PS component. On the other hand, it stabilizes the PS by means of interpolymer recombination, which leads to cross products of thermal degradation. Two of the degradation products: 2‐phenyl‐4(1′,3′,3′,5′,5′‐pentamethylcyclotrisiloxane)‐butane and 2‐phenyl‐4(1′,3′,3′,5′,5′,7′,7′‐heptamethylcyclotrisiloxane)‐butane were assigned to the products of cross‐interpolymer recombination which can accelerate the process of PDMS depolymerization by means of radical initiation of PS* fragments. The connection between a polymer thermal oxidative degradation and its combustion under diffusion flames condition was shown by using composition of polypropylene‐polypropylene‐co‐polyethylene (PP/PP‐co‐PE). In general, the solid‐phase polymer reaction can play a very important role in the reduction of polymer combustibility. It was shown that the composition of PP/PP‐co‐PE (62 : 38) has the highest induction period of autooxidation, which correlates with its combustibility. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3300–3311, 2002     

Durable flame‐retardant finished cotton fabrics characterized by thermal degradation behaviors

After a series of investigations on the durable flame‐retardant finishes, it was thought to be important to study these durable flame‐retardant finished materials from the thermal analytical standpoint. Accordingly, cotton fabric was finished with N‐methylol dialkyl phosphonopropionamide (Pyrovatex C) by thermofixation and tetrakis (hydroxymethyl) phosphonium sulfate (THPS) precondensate by ammonia cure (Proban), as well as with THPS monomer by heat cure under various conditions, and subjected to the thermogravimetry (TG) to observe thermal degradation behaviors and obtain apparent activation energy (E_a). TG curves of Proban‐finished samples showed the largest shift to lower temperatures with a steep slope; thermofixed THPS‐finished sample gave a smaller shift with similar steep slope, whereas Pyrovatex‐finished samples exhibited a similar shift but with a gradual slope. E_a versus residual ratio curves led us to conclude that C N bond‐rich Proban polymer requires the highest E_a and decomposes with considerable rapidity, whereas ethylene‐bond‐rich Pyrovatex‐finished samples with melamine crosslinking decompose gradually with the lowest E_a. As for the relationship between flame retardance and E_a distribution in the process of thermal degradation, typical differences among the above three kinds of finished samples were found, which are compared and discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 975–987, 1999     

Thermal degradation of poly(dimethylsilylene) and poly(tetramethyldisilylene‐co‐styrene)

Thermal degradation of poly(dimethylsilylene) homopolymer (PDMS) and poly(tetramethyldisilylene‐co‐styrene) copolymer (PTMDSS) was investigated by pyrolysis‐gas chromatography and thermogravimetry (TG). PDMS decomposes by depolymerization, producing linear and cyclic oligomeric products, whereas PTMDSS decomposes by random degradation along the chain resulting in each monomeric product and various other combination products. The homopolymer was found to be much less stable than the copolymer. The decomposition mechanisms leading to the formation of various products are shown. The kinetic parameters of thermal degradation were evaluated by different integral methods using TG data. The activation energies of decomposition (E) for the homopolymer and the copolymer are found to be 122 and 181 kJ/mol, respectively, and the corresponding values of order of reaction are 1 and 1.5. The observed difference in the thermal stability and the values of the kinetic parameters for decomposition of these polymers are explained in relation with the mechanism of decomposition. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Determination of oxygen diffusion coefficient of poly(methacrylonitrile) II and the calculation of diffusion activation energy

Poly(methacrylonitrile) (PMAN) samples in the shape of a cylinder used in this study were obtained from methacrylonitrile by bulk polymerization. The electron spin resonance (ESR) method has been used to calculate oxygen diffusion coefficient (D) into PMAN samples exposed to high‐energy radiation at different doses in vacuum by observing the ESR radical signal change. In order to calculate the dose‐independent diffusion coefficient (D₀), ln D values were plotted against dose values. The low dose region of this curve was extrapolated to a zero‐dose value, and D₀ was calculated as D₀ = 3.1 × 10⁻⁹ cm²/s. Although D₀ values were in very good agreement with the one obtained for the thin‐film sample of PMAN, the dose dependence of the oxygen diffusion into the cylindrical PMAN samples was observed as being converse of the thin‐film of PMAN,¹ as expected, because of the big difference of the surface/mass values between relatively big cylindrical PMAN samples and thin‐film of PMAN samples. The activation energy (E_a) values of the oxygen diffusion into PMAN were calculated as E_a1 = 27.9 kJ/mol for the 20–60°C temperature range E_a2 = 74.2 kJ/mol for the temperatures above 60°C of the 36 kGy gamma‐irradiated samples. The temperature value of the break point of activation energy was near to the T_g of PMAN.² © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1108–1118, 1999     

Reaction kinetics of graft copolymerization and thermochemical studies of the degradation of poly(vinyl alcohol) graft copolymer

Poly(vinyl alcohol) (PVA) is a water‐soluble and biomedical polymer. 2‐Acrylamido‐2‐methyl‐1‐propanesulfonic acid was grafted onto PVA using ammonium persulfate as radical initiator. The influences of synthesis conditions such as temperature, concentrations of initiator, PVA and monomer were investigated. Both the initial rate of grafting and the final percentage of grafting were increased by an increase in reaction temperature. The reaction kinetics were studied to determine the rate constants of the first‐order reactions. An activation energy of 16.3 kJ mol^?1 was found for the grafting reaction. The graft copolymers were characterized by IR and intrinsic viscosity measurements. A proposed mechanism of the grafting reaction is discussed. Kinetics of the thermal degradation were studied using a thermogravimetric method and the order of thermal stabilities are given. The apparent activation thermodynamic parameters, E_a, ΔH*, ΔS* and ΔG* were determined and correlated to the thermal stabilities of the homo‐ and grafted polymers. © 2001 Society of Chemical Industry     

Functionalized N‐(4‐hydroxy phenyl) maleimide monomers: Kinetics of thermal polymerization and degradation using model‐free approach

N‐(4‐Hydroxy phenyl) maleimide (HPMI) is prepared and is functionalized with acryloyl, methacryloyl, allyl, propargyl, and cyanate groups. The structural and thermal characterizations of the materials are done using FTIR, NMR, DSC, and TGA. Curing and degradation kinetics are performed using Flynn–Wall–Ozawa, Vyazovkin, and Friedman methods. Activation energies (E_a) for the polymerization of the synthesized monomers varied and are dependent on the nature of the functional group present in HPMI. The propargyl functionalized monomer shows the highest E_a values whereas the methacryloyl functionalized monomer shows the lowest E_a values. In the case of thermal degradation of the polymerized materials, the apparent E_a values for acryloyl, methacryloyl and cyanate functionalized materials are slightly higher than that of poly‐HPMI (PHPMI). The thermally cured allyl and propargyl functionalized materials show a different trend and may be attributed to the complications arising due to Claisen rearrangement reaction during the thermal curing. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39935.     

Synthesis of polydimethylsiloxane‐block‐polystyrene‐block‐polydimethylsiloxane via polysiloxane‐based macroinitiator in supercritical CO2

Polydimethylsiloxane‐block‐polystyrene‐block‐polydimethylsiloxane (PDMS‐b‐PS‐b‐PDMS) was synthesized by the radical polymerization of styrene using a polydimethylsiloxane‐based macroazoinitiator (PDMS MAI) in supercritical CO₂. PDMS MAI was synthesized by reacting hydroxy‐terminated PDMS and 4,4′‐azobis(4‐cyanopentanoyl chloride) (ACPC) having a thermodegradable azo‐linkage at room temperature. The polymerization of styrene initiated by PDMS MAI was investigated in a batch system using supercritical CO₂ as the reaction medium. PDMS MAI was found to behave as a polyazoinitiator for radical block copolymerization of styrene, but not as a surfactant. The response surface methodology was used to design the experiments. The parameters used were pressure, temperature, PDMS MAI concentration and reaction time. These parameters were investigated at three levels (?1, 0 and 1). The dependent variable was taken as the polymerization yield of styrene. PDMS MAI and PDMS‐b‐PS‐b‐PDMS copolymers obtained were characterized by proton nuclear magnetic resonance and infrared spectroscopy. The number‐ and weight‐average molecular weights of block copolymers were determined by gel permeation chromatography. Copyright © 2004 Society of Chemical Industry     

Morphology of poly(styrene‐block‐dimethylsiloxane) copolymer films

The morphologies of poly(styrene‐block‐di‐methylsiloxane) (PS‐b‐PDMS) copolymer thin films were analyzed via atomic force microscopy and transition electron microscopy (TEM). The asymmetric copolymer thin films spin‐cast from toluene onto mica presented meshlike structures, which were different from the spherical structures from TEM measurements. The annealing temperature affected the surface morphology of the PS‐b‐PDMS copolymer thin films; the polydimethylsiloxane (PDMS) phases at the surface were increased when the annealing temperature was higher than the PDMS glass‐transition temperature. The morphologies of the PS‐b‐PDMS copolymer thin films were different from solvent to solvent; for thin films spin‐cast from toluene, the polystyrene (PS) phase appeared as pits in the PDMS matrix, whereas the thin films spin‐cast from cyclohexane solutions exhibited an islandlike structure and small, separated PS phases as protrusions over the macroscopically flat surface. The microphase structure of the PS‐b‐PDMS copolymer thin films was also strongly influenced by the different substrates; for an asymmetric block copolymer thin film, the PDMS and PS phases on a silicon substrate presented a lamellar structure parallel to the surface at intervals. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1010–1018, 2007     

Influence of symmetry/asymmetry of the nanoparticles structure on the thermal stability of polyhedral oligomeric silsesquioxane/polystyrene nanocomposites

The thermal degradation of two polyhedral oligomeric silsesquioxane/polystyrene (POSS/PS) nanocomposites of formula R₈(SiO_1.5)₈ POSS/PS and R′₁R₇(SiO_1.5)₈ POSS/PS (where R′ = Phenyl and R = Cyclopentyl), at 5% of POSS concentration, was studied in both inert (flowing nitrogen) and oxidative (static air) atmospheres. Compounds were prepared by the polymerization of styrene in the presence of POSS. Degradations were carried out into a thermobalance, in the scanning mode, at various heating rates, and the obtained thermogravimetric (TG) curves were discussed and interpreted. The initial decomposition temperature (T_i), the temperature at 5% mass loss (T_5%), the glass transition temperature (T_g), and the activation energy (E_a) of degradation of nanocomposites were determined and compared with each other and with those of unfilled PS. The T_i, T_5%, and degradation E_a values of nanocomposites were higher than those of neat PS, thus indicating a better heat resistance and lower degradation rate, and then a better overall thermal stability. The use of POSS with a symmetric structure, in the synthesis of PS based nanocomposite, showed a decrease of T_g value not only in respect to asymmetric POSS/PS nanocomposite but also in respect to neat polymer, thus suggesting an influence of filler structure in the thermal properties of the materials. POLYM. COMPOS., 33:1903–1910, 2012. © 2012 Society of Plastics Engineers     

Thermal degradation of cellulose and its phosphorylated products in air and nitrogen

The thermal degradation of cellulose and its phosphorylated products (phosphates, diethylphosphate, and diphenylphosphate) were studied in air and nitrogen by differential thermal analysis and dynamic thermogravimetry from ambient temperature to 750°C. From the resulting data various thermodynamic parameters were obtained following the methods of Broido and Freeman and Carroll. The values of E_a for decomposition for phosphorylated cellulose were found to be in the range 55–138 kJ mol^?1 in air and 85–152 kJ mol^?1 in nitrogen and depended upon the percent of phosphorus contents in the samples. The mass spectrum of cellobiose phosphate indicated the absence of the molecular ion, indicating that the compound was thermally unstable. The IR spectra of the pyrolysis residues of cellulose phosphate gave indication of formation of a compound having C?O and P?O groups. A fire retardancy mechanism for the thermal degradation of cellulose phosphate has been proposed.     

Thermal degradation studies on rigid polyurethane foams blown with pentane

The effect of sodium dihydrogenphosphate, trisodium pyrophosphate, and sodium aluminocarbonate on the thermal decomposition of rigid polyurethane (PUR) foams, based on diphenylmethane‐4,4‐diisocyanate, diphenyl‐2,2‐propane‐4,4‐dioxyoligo(ethylene oxide), and oxyalkylenated toluene‐2,6‐diamine, blown with pentane, was studied. Thermogravimetric (TG) data have shown that there is a stabilization effect of additives in the initial stage of degradation, both in nitrogen and air atmosphere, and the decomposition proceeded in two steps up to 600°C. Results of the kinetic analysis by the isoconversional methods of Ozawa–Flynn–Wall and Friedman yielded values of (apparent) activation energy (E_a) and preexponential factor (A). For phosphate‐stabilized PUR samples, E_a remained stable over a broad area of the degree of conversion, while for carbonate‐containing sample two regions of E_a were observed. Further advanced kinetic analysis by a nonlinear regression method revealed the form of kinetic function that was the best approximation for experimental data—for a two‐stage consecutive reaction the first step was the Avrami–Erofeev nucleation‐dependent model, and the second step was a chemical reaction (1st or nth order) model. The integrated thermogravimetric (TG)/Fourier transform infrared (FTIR) technique probed the thermal degradation of modified PURs by analyzing the evolved gases. The solid residue remaining at different temperatures was identified by diffuse reflection FTIR (Kubelka–Munk format). The complex thermal behavior was discussed on the basis of the obtained results—it can be shown that the global stabilization effect is a multistage process whose initial conditions are of critical importance in governing the nature of the entire process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2319–2330, 2003     

Kinetics of commercial olive oil oxidation: Dynamic differential scanning calorimetry and Rancimat studies

Four samples of olive oil were oxidized under polythermal (dynamic) conditions in the cell of a normal‐pressure differential scanning calorimeter (DSC) and in the Metrohm Rancimat apparatus. The DSC experiments were carried out in an oxygen flow atmosphere using different linearly programmed heating rates in the range of 4–20 °C/min. Through DSC exotherms, the extrapolated onset temperatures were determined and used for the assessment of the thermal‐oxidative stabilities of the samples. Using the Ozawa‐Flynn‐Wall method and the Arrhenius equation, the activation energies (E_a), pre‐exponential factors (Z) and reaction rate constants (k) for oil oxidation under DSC conditions were calculated. The Rancimat measurements of oxidation induction times were carried out under isothermal conditions in an air atmosphere at temperatures from 100 to 140 °C with intervals of 10 °C. Using the Arrhenius‐type correlation between the inverse of the induction times and the absolute temperature of the measurements, E_a, Z, and k for oil oxidation under Rancimat conditions were calculated. The primary kinetic parameters derived from both methods were qualitatively consistent and they help to evaluate the oxidative stabilities of oils at increased temperatures.     

Thermooxidative degradation of methyl methacrylate‐graft‐natural rubber

The thermooxidative degradation of methyl methacrylate‐graft‐natural rubber (MG) at different heating rates (B) has been studied with thermogravimetric analysis in an air environment. The results indicate that the thermooxidative degradation of MG in air is a one‐step reaction. The degradation temperatures increase with B. The initial degradation temperature (T_o) is 0.697B + 350.7; the temperature at the maximum degradation rate, that is, the peak temperature on a differential thermogravimetry curve (T_p), is 0.755B + 368.8; and the final degradation temperature (T_f) is 1.016B + 497.4. The degradation rates at T_p and T_f are not affected by B, and their average values are 46.7 and 99.7%, respectively. The maximum thermooxidative degradation reaction rate, that is, the peak height on a differential thermogravimetry curve (R_p), increases with B. The relationship between B and R_p is R_p = 2.12B + 7.28. The thermooxidative degradation kinetic parameters are calculated with the Doyle model. The reaction energy (E) and frequency factor (A) change with an increasing reaction degree, and the variational trends of the two kinetic parameters are similar. The values of E and A increase remarkably during the initial stage of the reaction, then keep relevantly steady, and finally reach a peak during the last stage. The velocity constants of the thermooxidative degradation vary with the reaction degree and increase with the reaction temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1227–1232, 2003     

Thermal study on phenyl,hepta isobutyl‐polyhedral oligomeric silsesquioxane/polystyrene nanocomposites

A comparative study concerning the thermal stability of polystyrene (PS) and three polyhedral oligomeric silsesquioxane/polystyrene (POSS/PS) nanocomposites of formula R₇R′(SiO_1.5)₈/PS (where R = isobutyl and R′ = phenyl), at various (3, 5, and 10%) POSS concentration was carried out in both inert (flowing nitrogen) and oxidative (static air) atmospheres. Nanocomposites were synthesized by in situ polymerization of styrene in the presence of POSS and the experimental filler concentration in the obtained compounds, determined by ¹H NMR spectroscopy, was in all cases slightly higher than that in the reactant mixtures. Inherent viscosity (η_inh) determinations indicated that the average molar mass of polymer in the nanocomposites was practically the same than neat PS and were in agreement with calorimetric glass transition temperature (T_g) measurements. The temperature at 5% mass loss (T_5%) and the activation energy (E_a) of degradation process of synthesized nanocomposites were determined and compared with each other and with those of unfilled PS. On the basis of the results from thermal and IR spectroscopy characterizations, nanocomposite with 5% of molecular filler appears the most thermally stable. The results were also compared with literature data on similar PS‐based nanocomposites. POLYM. COMPOS., 2013 © 2013 Society of Plastics Engineers     

Octa(aminophenyl) polyhedral oligomeric silsesquioxane/boron‐containing phenol–formaldehyde resin nanocomposites: Synthesis,cured, and thermal properties

Octa(aminophenyl) polyhedral oligomeric silsesquioxane (OAP‐POSS) and boron‐containing phenol‐formaldehyde resin (BPFR) were synthesized, respectively. The BPFR nanocomposites with different OAP‐POSS content (wt%) were prepared, and their properties were characterized. The results show that the thermal degradation process of this nanocomposites can be divided into three stages, and they are all following the first order mechanism. The residual ratio and thermal degradation activation energy E_a of 9 wt% OAP‐POSS/BPFR nanocomposites are both better than others and the E_a increase gradually in three stages, which is 93.3, 134.0, and 181.9 kJ mol⁻¹, respectively. Its residual ratio at 900°C is 36.48%. The mechanical loss peak temperature T_p is 228°C for 12 wt% OAP‐POSSS/BPFR nanocomposites, which is higher 48°C than pure BPFR. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Oxidation Rates of Triacylglycerol and Ethyl Ester Fish Oils

Fish oil is available primarily as triacylglycerols (TAG) or ethyl esters (EE). Anecdotal evidence suggests that TAG have superior bioavailability and oxidative stability compared to EE. In this work, peroxide value (PV) and p‐anisidine value (AV) were used to monitor oxidation in commercially available TAG and EE fish oils incubated at temperatures from 5 to 60 °C. Pseudo first‐order kinetics were assumed and rate constants were calculated for each temperature. At all temperatures, the rates of oxidation were higher for EE oils than TAG oils. For PV and AV measured in both oils, non‐linear Arrhenius models were plotted, generating activation energies that ranged from 7 to 103 and 2 to 159 kJ/mol for PV and AV, respectively. Although TAG were more resistant to oxidation than EE, they had lower activation energies (E_a) at ≤15 °C for reactions measured with PV and AV. The E_a for EE was negative at temperatures ≥45 °C, indicating that reaction rate was influenced by factors in addition to temperature.