Thermal Oxidation Reaction Research Articles

Deep Exploration of Lipid Oxidation into Flavor Compounds: A Density Functional Theory Study on (E) -2-Decenal Thermal Oxidative Reaction

Deep Exploration of Lipid Oxidation into Flavor Compounds: A Density Functional Theory Study on (E) -2-Decenal Thermal Oxidative Reaction

Graphitic carbon nitride-based nanostructures as emergent catalysts for carbon monoxide (CO) oxidation

This is the first review that emphasizes the engineering of carbon nitride-based catalysts for thermal, electrochemical, and photoelectrochemical CO oxidation reactions experimentally and theoretically.

To Luminesce or to Change Valence? Insight into the Wavelength Dependency of the Reversible Valence Switching of Europium in Sr3SiO5

A good control over the valence state of dopants in luminescent materials or phosphors is important for the development of highly efficient phosphors for white light-emitting diodes (LEDs). Detailed spectroscopic studies allow us to reveal optically induced charge transfer processes and elucidate the underlying mechanisms in phosphors with additional functionalities such as photochromism or persistent luminescence. However, the spectroscopic study of the valence switching of europium has scarcely been reported. Here, we report on the Sr3SiO5:Eu phosphor, in which photo-reduction (Eu3+ → Eu2+) and photo- or thermal-oxidation (Eu2+ → Eu3+) reactions are demonstrated. The variation of the illumination wavelength influences the efficiency of both the photo-reduction/oxidation and the accompanying dynamic process, especially when the two opposite reactions occur simultaneously. Temperature-dependent annealing indicates a large trap depth for the electron trapped by Eu3+. The good stability of Eu2+ obtained by photo-reduction and the repeatability of the Eu2+/Eu3+ valence switching are confirmed as well. Furthermore, the application of optical information storage is demonstrated based on this phosphor. The results of this work may not only improve the understanding of Eu2+/Eu3+ valence change during illumination but also allow the development of new functional luminescent materials.

Study on yellowing mechanism and inhibiting technology based on amide salts modified polyester

Terephthalic acid and ethylene glycol were used to prepare poly(ethylene terephthalate)-co-amide salts with adipate pentamethylenediamine (AP salts) as the modified monomer, improving the hygroscopicity and softness of poly(ethylene terephthalate) fibers. One of the facets of concern is that the yellowing index of poly(ethylene terephthalate)-co-amide salts increases from 3.8 to 13.8 than poly(ethylene terephthalate) and increases from 2.9 to 11.7 for fibers, limiting its acceptance in textile applications. The convention underpinning the yellowing originated from thermal oxidation and Schiff base reaction in the blend of polyester/polyamide, generating yellowing substances with conjugated imine structure. However, in this paper, an unconventional yellowing mechanism was discovered, attributed to the reaction of AP salts and acetaldehyde (a by-product of poly(ethylene terephthalate)). The structure of yellowing substances was characterized and confirmed the role of conjugated diketoamine (O=C–CH2–CONH–) and conjugated enamines (O=C–C=C–NH–). It is difficult for fiber applications to overcome the yellowing issue. Nevertheless, an inhibiting method for the yellowing phenomenon was provided, end-capping technology, by a clearer understanding of the yellowing processes. Thus, poly(ethylene terephthalate)/APA was prepared with the end-capping product carboxyl-terminated diamide (APA) as the modified monomer, which was synthesized by the reaction of AP salts and adipic acid. The yellowing index decreased from 13.8 to 8.5 than poly(ethylene terephthalate)-co-amide salts and decreased from 11.7 to 6.9 for fibers. This significantly improves the yellowing problem and provides technical support for colorless copolymer fibers.

Thermal Reactions between H2S and O3: Implications for Europa Surface Chemistry

Here we present a laboratory study demonstrating a low-temperature thermal oxidation reaction within H2O + H2S + O3 solid ice mixtures that produces observable sulfur anion products at temperatures as low as 90 K. This reaction primarily produces SO2, sulfur anions (including HSO, HSO, and SO), and O2 at lower temperatures (90–140 K) and hydrated states of sulfuric acid (H2SO4: nH2O, where n = 0, 1, 4) at higher temperatures (150–250 K). We estimate that the overall activation energy to initiate these reactions is 20 ± 3 kJ mol−1, which is significantly lower than the activation energy required to oxidize SO2 to the sulfate ion. Given the detection of sulfur species on the surfaces of the Galilean satellites and the prevalence of radiolytically produced oxidants, we expect that these thermal reactions will play an important role in explaining the results obtained from future observations and missions that can measure the spatial distribution of these species.

Large eddy simulations of heat transfer and thermal oxidative coking of aviation kerosene in vertical U-tube at a supercritical pressure

The onboard fuel in an advanced aero engine can be used to cool the highly compressed hot air in a heat exchanger to restore the air's cooling capacity. In the process, the high fuel temperature leads to thermal oxidative reactions and surface coking. Large eddy simulations have been conducted in this paper to study the combined effects of buoyant and centrifugal forces on heat transfer and thermal oxidative coking of the aviation kerosene, RP-3, in vertical U-bend tubes at a supercritical pressure of 4 MPa. Numerical results indicate that buoyancy exerts its impact on fluid flows and heat transfer mainly in vertical straight sections of the tube, promoting turbulence generation in the downward flow and suppressing turbulence in the upward flow. This causes differences of the heat transfer and surface coking rate in the up-down and down-up cases. Centrifugal force plays an important role in fluid flows and heat transfer in the U-bend section. Strong secondary flows driven by the centrifugal effect significantly enhance heat transfer in the outer region but weaken heat transfer in the inner region of the U-bend section, resulting in up to 300 K circumferential wall temperature difference in the present cases. The large wall temperature gradient and high wall temperature lead to significant thermal oxidative coking inside the tube near the entrance and in the inner region near the exit of the U-bend section. Results herein provide fundamental understanding and have practical implication for the design and safe operation of an air-fuel heat exchanger in aerospace applications.

Hierarchical Porous Carbon Nitride-Crumpled Nanosheet-Embedded Copper Single Atoms: An Efficient Catalyst for Carbon Monoxide Oxidation.

Rational design of metal single-site embedded porous graphitic carbon nitride (P-g-C3N4) nanostructures exploiting maximum atom utilization is warranted to enhance the thermal CO oxidation (COOx) reaction. Herein, a facile, green, one-pot, and template-free approach is developed to fabricate the hierarchical porous P-g-C3N4-crumpled ultrathin nanosheets atomically doped with copper single atoms (Cu-P-g-C3N4). Mechanistically, the quick protonation of melamine and pyridine under acidic conditions induces deamination to form melem, which is polycondensed under heating. The interconnected pores, high surface area (240 m2g-1), and maximized exposed isolated Cu atomic active sites (1.8 wt %) coordinated with nitrogen atom P-g-C3N4 are the salient features of Cu- P-g-C3N4 that endowed complete conversion to CO2 at 184 °C. In contrast, P-g-C3N4 only converted 3.8% of CO even at 350 °C, implying the electronic effect of Cu single atoms. The abundant Cu-nitrogen moieties can drastically weaken the binding affinity of the CO-oxidation (COOx) intermediates and products, thus accelerating the reaction kinetics at a low temperature. This study may promote the fabrication of P-g-C3N4 doped with various single atoms for the oxidation of CO.

Wear characteristics of flat die in flat die pellet mills based on Glycyrrhiza uralensis

During granulation, a serious wear problem may be found in flat die as a key component of a flat die pellet mill. Specific to this problem, Glycyrrhiza uralensis was selected as the wear-causing material to investigate the wear mechanism of the flat die. Additionally, carburizing steel (20Cr and 20CrMnTi) and stainless steel (4Cr13) commonly used in flat die were adopted to conduct wear tests. To explore the influence of Glycyrrhiza uralensis powder and rods on friction and wear properties of the above three types of steel materials, a CFT-I general-purpose tester for surfaces was applied under dry friction conditions. Moreover, x-ray diffractometer (XRD), three-dimensional profilometry, scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS) were used to analyze the phase compositions, surface morphologies, and elementary compositions of the samples. As demonstrated by relevant results, the influence of Glycyrrhiza uralensis on the flat die is primarily embodied in abrasive, adhesive, and fatigue wear, and a thermal oxidation reaction occurs on the surface of the flat die. By comparing the wear conditions of the three steel materials between the powder and rods of Glycyrrhiza uralensis, it is found that flat die damages caused by glycyrrhiza rods are more severe than those of its powder. Additionally, the lowest friction coefficients are generated by 20CrMnTi, which are 0.40 and 0.88, respectively. In terms of the mean wear depth, its values are 1.2 and 2 μm, which are below those of 20Cr and 4Cr13. The results herein reveal that flat die made of 20CrMnTi have excellent wear and ductile fracture resistance characteristics. Hence, this study may provide a theoretical guide for selecting flat die materials.

Effect of High-Voltage Electrostatic Field Heating on the Oxidative Stability of Duck Oils Containing Diacylglycerol.

High-voltage electrostatic field (HVEF) as an emerging green technology is just at the beginning of its use in meat products and by-products processing. In this study, we employed duck oil to produce duck-oil-based diacylglycerol (DAG), termed DDAG. Three different DDAG volume concentrations (0, 20%, and 100%) of hybrid duck oils, named 0%DDAG, 20%DDAG, and 100%DDAG, respectively, were used to investigate their thermal oxidation stability in high-voltage electrostatic field heating and ordinary heating at 180 ± 1 ℃. The results show that the content of saturated fatty acids and trans fatty acids of the three kinds of duck oils increased (p < 0.05), while that of polyunsaturated fatty acids decreased (p < 0.05) from 0 h to 8 h. After heating for 8 h, the low-field nuclear magnetic resonance showed that the transverse relaxation time (T21) of the three oils decreased (p < 0.05), while the peak area ratio (S21) was increased significantly (p < 0.05). The above results indicate that more oxidation products were generated with heating time. The peroxide value, the content of saturated fatty acids, and the S21 increased with more DAG in the duck oil, which suggested that the oxidation stability was likely negatively correlated with the DAG content. Moreover, the peroxide value, the content of saturated fatty acids and trans fatty acids, and the S21 of the three concentrations of duck oils were higher (p < 0.05) under ordinary heating than HVEF heating. It was concluded that HVEF could restrain the speed of the thermal oxidation reaction occurring in the duck oil heating and be applied in heating conditions.

Thermal-aging constitutive model for a silicone rubber foam under compression

Silicone rubber foam is a key function component in engineered systems. The long-term effect of temperature and compressive strain can degrade the mechanical properties of the foam. In this work, the temperature and aging time dependence of the mechanical behavior of the silicone rubber foam under long-term compressive strain was investigated by accelerated aging tests and uniaxial compression tests. The Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and crosslinking density were used to evaluate the chemical changes of the foam samples under different conditions. The ATR-FTIR and crosslinking density results indicate that crosslinking reaction and chain scission reaction occurred simultaneously. The crosslinking reaction dominated during the aging process resulting in the increase of the crosslinking density. The mechanical properties results show that the increase in the temperature and/or aging time can lead to the hardening of mechanical behaviors due to thermal aging-induced oxidative reactions. A thermal-aging constitutive model for the compressed foam was established by incorporating the dependence of the model parameters on temperature and aging time into the Hyperfoam model. Two types of exponential models were proposed to describe the dependence of model parameters on temperature and aging time. The performance of the thermal-aging constitutive model was verified by comparing the model predictions with independent testing data. Results show that the model can accurately describe the compressive stress-strain responses of the unaged and the aged foams under long-term compressive strain.

Ultra-selective molecular-sieving gas separation membranes enabled by multi-covalent-crosslinking of microporous polymer blends

High-performance membranes exceeding the conventional permeability-selectivity upper bound are attractive for advanced gas separations. In the context microporous polymers have gained increasing attention owing to their exceptional permeability, which, however, demonstrate a moderate selectivity unfavorable for separating similarly sized gas mixtures. Here we report an approach to designing polymeric molecular sieve membranes via multi-covalent-crosslinking of blended bromomethyl polymer of intrinsic microporosity and Tröger’s base, enabling simultaneously high permeability and selectivity. Ultra-selective gas separation is achieved via adjusting reaction temperature, reaction time and the oxygen concentration with occurrences of polymer chain scission, rearrangement and thermal oxidative crosslinking reaction. Upon a thermal treatment at 300 °C for 5 h, membranes exhibit an O2/N2, CO2/CH4 and H2/CH4 selectivity as high as 11.1, 154.5 and 813.6, respectively, transcending the state-of-art upper bounds. The design strategy represents a generalizable approach to creating molecular-sieving polymer membranes with enormous potentials for high-performance separation processes.

Oxidation characteristics and explosion risk of 2, 5-dimethylfuran at low temperature

The thermal oxidation reaction of 2,5-dimethylfuran (DMF) was investigated using a custom-designed mini closed pressure vessel test (MCPVT) and traced by 1H nuclear magnetic resonance(1H NMR). The oxidation behavior was monitored by-via temperature–time (T-t) and pressure–time (p-t) plots of MCPVT recording. Oxidation products were determined via gas chromatography-mass spectrometry (GC–MS), and the generated peroxide was examined by iodimetry and thin-layer chromatography (TLC), with the thermal decomposition hazard evaluation by differential scanning calorimeter (DSC) and MCPVT. Results show that the DMF oxidation reaction proceeded through initial oxygen absorption at 39.3 °C, followed by an exothermic self-accelerating oxidation at 84.5 °C. DMF could form high level peroxide in auto-oxidation; the decomposition of peroxides would lead to the radical oxidation that the generated ·OH radical mainly attacks on the position 2/5 of DMF with subsequent addition of O2 initiating ring-opening reaction, in which DMF was firstly converted to cis-3-hexene-2,5-dione, and then produced the trans-3-hexene-2,5-dione with strong photoisomerism. DMF oxidation showed a high level of residue formation, and those solid products contained considerable amount of peroxides with a high thermal hazard; its exothermic onset temperature (T0) and decomposition heat (QDSC) of 58.8 °C and 1982.3 J∙g−1, and the decomposition maximum temperature rising rate (dT/dt)max and maximum of pressure rising rate (dp/dt)max was 9.98 °C∙s−1 and 291 kPa∙s−1, respectively. Thermal decomposition of those peroxide products could give rise to thermal runaway of DMF oxidation, and further transformed into a detonation possibly.

SOLVENT EFFECT ON ZERO-VALENT IRON NANOPARTICLES (nZVI) PREPARATION AND ITS THERMAL OXIDATION CHARACTERISTIC

Zero-valent iron (ZVI) nanoparticle exists a nanoscale (1-100 nm) of the iron particle with zero oxidation number. It has acquired considerable attention for its potential to capture the free-electron moieties. The production and storage of ZVI material, however, is challenging because it is relatively unstable. In this research, we aim to study of solvent effects on ZVI preparation and its characterization. The nano-scaled ZVI was synthesized by a chemical reduction method. Iron (III) chloride hexahydrate (FeCl3·6H2O) was as a chemical precursor and sodium borohydride solution (NaBH4) as a reducing agent. Two parameters used in this study were: i) solvent types (ethanol, diethyl ether, and acetone) ii) proportion of solvent and deionized water (4:0, 4:1, and 4:2 by volume). We characterized the physical and chemical properties of the synthesized samples (e.g. particle size and distribution, morphology, and the chemical composition) using various techniques, for example, TEM, UV-Vis spectrophotometer, and XRD. Moreover, we performed a thermal oxidation reaction of synthesized powder samples using DSC and TGA tools. The results show that the nZVI particle formed a spherical shape with the smallest particle size of 39 nm. The solvent type was the key parameter protecting the oxidation reaction during the synthesis process. According to the spherical shape of the synthesized nZVI samples, an estimated specific surface area was also reported. The cubic structure of nZVI particles was estimated at 79-81 wt.%, and almost 20 wt.% was attributed to iron oxide (Fe2O3) cubic phase. The oxidation reaction occurred above 400oC. The minimum enthalpy of thermal oxidation was approximately 1600 J/g. Furthermore, the relation between thermal oxidation enthalpy and nZVI particle sizes were revealed and predicted by the Boltzmann equation.

Effects of oxygen impurity and desorption temperature on heel build-up in activated carbon

Oxygen’s presence during thermal desorption of volatile organic compounds from activated carbon can promote heel build-up and loss of adsorption capacity. This study investigated the simultaneous effect of desorption temperature (200 °C and 288 °C) and oxygen concentration (≤5, 10,000, and 21,000 ppmv) on heel build-up. For this purpose, 5-cycle adsorption/desorption tests of 1,2,4-trimethylbenzene on a microporous activated carbon were completed. At low oxygen concentration (≤5 ppmv), desorption at 288 °C resulted in lower cumulative heel compared to at 200 °C; however, at high oxygen concentration (10,000 and 21,000 ppmv), desorption at 288 °C resulted in higher cumulative heel compared to 200 °C. Thermal gravimetric analysis (TGA) was used to assess the thermal stability of the heels formed on the samples. At high oxygen concentrations, the heel associated with desorption at 288 °C was more thermally stable than the heel formed at 200 °C, which can be attributed to thermal oxidation reactions of the adsorbate in the activated carbon pores.

Influence of multi-dimensional nanomaterials composite form on thermal and ultraviolet oxidation aging resistances of SBS modified asphalt

In this study, for enhancing the resistance of asphalt against thermal oxidative and ultraviolet oxidative reaction simultaneously, the concept of multi-dimensional nanomaterials (MDNs) is proposed, referring to combinations of zero dimensional nanomaterials (like nano silica (nano-SiO2), nano zinc oxide (nano-ZnO), or nano titanium dioxide (nano-TiO2)) and two dimensional nanomaterials (like organic expanded vermiculite (OEVMT) or organic montmorillonite (OMMT)). Different combinations of nanoparticles and layered silicates were introduced into styrene–butadiene–styrene copolymer modified asphalt (SBSMA) to obtain the composite of MDNs and SBSMA. The SBSMA binders modified by MDNs were aged by laboratory simulated accelerated aging methods, and the influences of different MDNs composites on the physical and rheological properties of the SBSMA before and after aging were studied. The results show that the low-temperature ductility and the high-temperature performance of SBSMA are enhanced by adding MDNs. Especially, OEVMT + TiO2 and OMMT + TiO2 not only bring about 11.2% increase in ductility but also make SBSMA display the best rutting resistance, and OEVMT + ZnO brings about 23.7% increase in high-temperature viscosity. Furthermore, MDNs can change the trend of viscoelastic behavior of SBSMA with temperature and enhance the elastic response of SBSMA by hindering viscous movements of asphalt molecules. MDNs can effectively alleviate the aging negative effects on physical and rheological properties of SBSMA by hindering the growth of oxidation products and protecting SBS modifier from degradation. Meanwhile, this study indicates that among various MDNs composite forms, OEVMT + TiO2 or OMMT + TiO2 have the most obvious improving effects on both the thermal oxidative and ultraviolet oxidative aging resistances of SBSMA.

Laser-induced digital oxidation for copper-based flexible photodetectors

Copper oxide compounds (CuxO) with bandgaps of 1.3–2.1 eV (CuO) and 2.1–2.6 eV (Cu2O) have been investigated as promising p-type semiconducting materials. CuxO is generally obtained by deposition or thermal oxidation, but those methods are not optimal for flexible substrates. Furthermore, additional patterning steps are required to fabricate devices.We present an easy, controllable method to fabricate a metal-semiconductor-metal (MSM) photodetector using laser-induced oxidation of a thin Cu film. After laser irradiation, the Cu film is heated under ambient conditions, and this leads to a thermal oxidation reaction, in which Cu oxide is monolithically formed in the Cu film and a Cu-CuxO-Cu MSM structure is produced. Since the laser offers localized heating, an arbitrary CuxO pattern can be written in the Cu film by spatially controlled heating. In addition, by optimizing the heating time, the laser-induced oxidation can be successfully performed even on a flexible substrate. To study the laser-induced oxidation, we examined the correlation between laser parameters and the oxidation pattern and analyzed the composition using scanning electron microscopy, Raman spectroscopy, and X-ray photoemission spectroscopy. Furthermore, we measured the transient photoresponse and employed scanning photocurrent microscopy to investigate the mechanism of carrier transport behavior.

Obtaining and Investigation of the β-Cyclodextrin Inclusion Complex with Vitamin D 3 Oil Solution.

Background. The research results of fat-soluble vitamin D3 (cholecalciferol) encapsulation with β-cyclodextrin have been presented in this work. The vitamin D3 inclusion complex with β-cyclodextrin was obtained under microwave radiation. The surface morphology of obtained clathrate inclusion complexes was described with the help of a scanning electron microscope. The thermographic measurement results on a differential scanning calorimeter have been presented. The activation energy of the β-cyclodextrin : vitamin D3 clathrate complex thermal oxidative destruction reaction was calculated. The clathrate thermal destruction kinetic parameters were determined. The inclusion complex spectral properties were characterized by IR-Fourier and 1H and 13C NMR spectroscopy. The existence of β-cyclodextrin inclusion complex with vitamin D3 in a 2 : 1 ratio was confirmed by the experimental results. The activation energy of thermal destruction of the inclusion complex of β-cyclodextrin with vitamin D3 was calculated using four different methods.

The thermal oxidation mechanism of TMPTO with antioxidants investigated by ReaxFF MD

PurposeThis paper aims to study the thermal oxidation performance of antioxidant additives in ester base oils deeply.Design/methodology/approachReaxFF molecular dynamics was used to simulate the thermal oxidation process of butyl octyl diphenylamine and octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate as two antioxidant additives act on the Trimethylolpropane trioleate (TMPTO) base oil. Meanwhile, combining with the infrared spectroscopy characterization results of the thermal oxidation test, this paper provides theoretical support for the development of high-performance synthetic lubricants and their antioxidant additives.FindingsThe results show that butyl octyldiphenylamine easily removes the hydrogen atom on the secondary amine, which promotes the formation of more long carbon chain diene radicals or polyene hydroperoxides from TMPTO. Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate could easily decompose into octadecyl hydroperoxide and 2,6-di-tert-butyl 4-propionylphenol, which could convert into 2-tert-butyl-4-peroxyethyl-6-hydroperoxy-tert-butylphenol in the middle of the thermal oxidation reaction, prompting TMPTO to form more short-chain alkenyl and olefin hydroperoxide or other oxide.Originality/valueThe main change characteristics of base oil molecules are the first thermal decomposition to form oleic acid groups and ethane cyclopropane methyl oleate. Under the action of butyl octyldiphenylamine and octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate, the deep oxidation and decomposition reaction are slowed down.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0037/

Lumen Maintenance of Ternary Ag-Alloy Wire Bonded LED Package after Reliability Tests

In this investigation, ternary Ag-alloy wires were doped with different Pd and Au concentrations, and each wire was encapsulated in an LED package. The static and dynamic reliability were tested, and the lumen maintenance performance was examined. The static reliability tests included the sulfur test, LTSL, HTSL, and WHTSL. According to the sulfur test data, higher Pd and Au contents led to better lumen maintenance. Furthermore, the bonding wire of the LED with better lumen maintenance in the sulfur test had higher electrical resistance. The brightness decay rate of the white light LEDs was low in low-and high-temperature environments, but it was significantly higher after the WHTSL test. The dynamic reliability test after 1,000 hours of HTOL and WHTOL showed that the lumen maintenance improved with higher Pd and Au contents, indicating that doping Ag-alloy wires with sufficient amounts of Pd and Au can retard degradation due to thermal and humidity aging and oxidation reaction. Therefore, ternary Ag-Pd-Au alloy wires produced with specific drawing and annealing processes are suitable for application to mid-power white light LEDs.

Effects of silicone lens aging on degradation kinetics of light-emitting diode package in various accelerated testing

Silicone is commonly used in light-emitting diode (LED) package as lens and/or encapsulation owing to its high light transmittance, large refractive index, and good thermal stability. However, the effect of silicone lens aging on the lumen decay and color shift of LED package is a considerable concern for package level reliability. This study empirically investigates the effects of silicone lens aging on lumen decay and color shift of LED package under three accelerated tests, namely, the constant stress-accelerated degradation test, step-up stress-accelerated degradation test, and step-down stress-accelerated degradation test (SDSADT). Results reveal that silicone lens aging substantially contributed to lumen decay and color shift of LEDs and considerably influenced the degradation kinetics of LED package. The color coordinates of LED package covered with aged silicone specimen in three testing methods exhibit a steady yellowing shift law at the same 45-degree direction. Silicone lens aging primarily reduces its transmittance to blue light as accumulated thermal oxidation and hydrolysis reaction, and its effect on the blue peak intensity of LED is independent of the stress-loaded order of step stress-accelerated degradation testing (SSADT). In addition, the effect law of silicone lens aging on LED lumen and color shift could be presented with the exponential and power function models, respectively. Lumen decay and color shift are mostly independent of the historical stress and loaded order in SSADT. The SDSADT testing manner more effectively distinguishes the color shift effect of thermal stress level compared with other accelerated tests. These findings are assumed to benefit the design and reliability assessment of LED products.