Parameter effect on photocatalytic degradation of phenol using TiO2-P25/activated carbon (AC)

P25 powder embedded and TiO₂ immobilized on activated carbon (TiO₂-P25/AC) was prepared by P25 powder modified sol-gel and dip-coated method. The photocatalysts were characterized by XRD, BET, SEM and their photocatalytic activities were evaluated through phenol degradation in a fluidized bed photoreactor. The addition of P25 in the photocatalysts could significantly enhance the photocatalytic activity, and the optimum loading of P25 was 3 g L^?1. The operating parameter results indicated that the optimum pH for phenol degradation was 5.2; the effect of air flow rate gave an optimal value of 2 L min^?1; the increasing of UV light intensity led to an increase of degradation efficiency due to more photons absorbed on the surface of the photocatalyst. The kinetics of the phenol degradation fitted well with the Langmuir-Hinshelwood kinetics model. Finally, the photocatalytic ability of TiO₂-P25/AC was reduced only 10% after five cycles for phenol degradation.     

Performance of a photo‐impinging streams reactor for the phenol degradation process

BACKGROUND: Photocatalysis is one of the advanced oxidation processes that has gained in importance over recent years owing to its ability to decompose a wide range of organic and inorganic pollutants at ambient temperature and pressure. However, there are two essential issues regarding photocatalytic processes, i.e. limitations on photon transfer and on mass transfer. In the present study, a novel photo‐impinging streams reactor, which can minimize such limitations, has been utilized in the photocatalytic degradation of phenol. The design and operating parameters such as type of nozzle, flow rate, catalyst loading, pH, initial phenol concentration and light intensity were found to have the expected impact on the efficiency of the process. The effects of two different co‐oxidants, H₂O₂ and Na₂S₂O₈ on the photocatalysis were also examined. RESULTS: Results indicated that 100 mg L^?1 of phenol in a 750 cm³ solution was completely degraded within 2.5 h reaction time in the presence of TiO₂ without a co‐oxidant present; and within 1 h in the presence of a co‐oxidant. CONCLUSION: A comparison between the current data and those available in the literature revealed higher efficiency and increased performance of the present reactor relative to conventional apparatus. Copyright © 2010 Society of Chemical Industry     

Effect of the status of Sm on the properties of Sm contained N doped TiO2 photocatalysts

Nitrogen-doped TiO₂ (TiO_2?xN_y) nanoparticles with and without adding Sm³⁺ were synthesized by thermohydrolysis of TiCl₃. The samples were characterized by X-ray diffraction, specific surface area determination, UV–Vis diffuse reflectance spectroscopy. The photocatalytic activity of the sample was investigated by employing the oxidative destruction of nitric oxide as a probe reaction using a flow reactor. Although the doping of Sm³⁺ in the lattice of titania was not useful to improve the photocatalytic activity, loading of samarium oxides on the surface of titania resulted in an improvement of the photocatalytic activity of the nitrogen-doped TiO₂. The beneficial effect was explained by an increased separation efficiency of the photogenerated electron–hole pairs.     

Optimizing photocatalytic degradation of phenol by TiO2/GAC using response surface methodology

TiO₂ deposited on granular activated carbon (TiO₂/GAC) was used for photocatalytic degradation of phenol. The effects of photocatalyst loading, initial substrate concentration and addition of an oxidizing agent as H₂O₂ were investigated using a one-factor-at-a-time experiment. Central composite design, an experimental design for response surface methodology (RSM), was used for the modelling and optimization of the phenol degradation. Analysis of variance (ANOVA) indicated that the proposed quadratic model was in agreement with the experimental case with R² and R _adj ² correlation coefficients of 0.9760 and 0.9544, respectively. Accordingly, the optimum conditions for phenol degradation were a photocatalyst loading of two layers, initial phenol concentration of 34.44 mg L^?1 and H₂O₂ concentration of 326.90 mg L^?1. The TiO₂/GAC was used for five cycles with phenol degradation efficiency still higher than 90%. Finally, the phenol that remained adsorbed on GAC was able to migrate to TiO₂ and then photocatalytically be degraded.     

Photocatalytic conversion of benzene to phenol using modified TiO2 and polyoxometalates

The application of photocatalytic reactions to organic synthesis has attracted interests in view of the development of environmentally benign synthetic processes. This study investigated the effects of various parameters (electron acceptor, surface modification, and the combination of photocatalysts) on the direct synthesis of phenol from benzene using photocatalytic oxidation processes. The OH radicals generated on UV-illuminated TiO₂ photocatalyst directly hydroxylate benzene to produce phenol, hydroquinone, and catechol. The addition of Fe³⁺, H₂O₂, or Fe³⁺ + H₂O₂ highly enhanced the phenol production yield and selectivity in TiO₂ suspension. Surface modifications of TiO₂ had significant influence on the phenol synthetic reaction. Depositing Pt nanoparticles on TiO₂ (Pt/TiO₂) markedly enhanced the yield and selectivity. Surface fluorination of TiO₂ (F-TiO₂) increased the phenol yield two-fold because of the enhanced production of mobile (free) OH radicals on F-TiO₂. Polyoxometalate (POM) in phenol synthesis played the dual role both as a homogeneous photocatalyst and as a reversible electron acceptor in TiO₂ suspension. POM alone was as efficient as TiO₂ alone in the phenol production. In particular, the addition of POM to the TiO₂ suspension increased the phenol yield from 2.6% to 11% (the highest yield obtained in this study). Reaction mechanisms for each photocatalytic system were discussed in relation to the phenol synthesis.     

Palygorskite and SnO2–TiO2 for the photodegradation of phenol

The photocatalytic removal of phenol was studied using palygorskite-SnO₂–TiO₂ composites (abbreviated as Paly-SnO₂–TiO₂) under ultraviolet radiation. The photocatalysts were prepared by attachment of SnO₂–TiO₂ oxides onto the surface of the palygorskite by in situ sol–gel technique. The products were characterized by XRD, TEM and BET measurements. SnO₂–TiO₂ nanoparticles, with an average diameter of about 10 nm, covered the surface of the palygorskite fibers without obvious aggregation. Compared with palygorskite-titania (Paly-TiO₂), palygorskite-tin dioxide (Paly-SnO₂), and Degussa P25, Paly-SnO₂–TiO₂ and SnO₂–TiO₂ exhibited much higher photocatalytic activity. The photodecomposition of phenol was as high as 99.8% within 1.5 h. The apparent rate constants (k_app) for Paly-SnO₂–TiO_2, TiO₂, and P25 were measured. Paly-SnO₂–TiO₂ showed the highest rate constant (0.03435 min^?1). The chemical oxygen demand (COD) of the phenol solution was reduced from 220.2 mg/L to 0.21 mg/L, indicating the almost complete decomposition of phenol. Reusability of the photocatalyst was proved.     

Solar‐assisted photochemical and photocatalytic degradation of phenol

Photocatalytic (TiO₂, air and solar radiation) and photochemical (H₂O₂ and solar radiation) mineralizations of phenol solutions (up to 500 mg dm^?3) in a batch reactor using concentric solar radiation were studied. A compound parabolic reflector as a concentrating reflector was used to obtain concentrated solar radiation in both cases. Considerable enhancement (Five‐fold) in the rate of degradation was obtained when concentrated solar radiation was used instead of plain solar radiation in photocatalytic degradation. The effect of initial phenol concentration, intensity and presence of anions has been studied in both the cases. Low concentrations of intermediates were observed, during the reaction, over the entire range of phenol concentrations studied in the case of photocatalytic degradation using Degussa‐P25 TiO₂ as photocatalyst and in the absence of anions; whereas significant quantities of intermediates were observed in the case of the photochemical degradation. The presence of anions generally had a detrimental effect on the mineralization process in both cases. Different anions showed different effects. Total organic carbon (TOC) variations with time were also studied. A rational explanation has been given for the decrease in the rate in the presence of anions. © 2001 Society of Chemical Industry     

Hydrothermal preparation of Sn3O4/TiO2 nanotube arrays as effective photocatalysts for boosting photocatalytic dye degradation and hydrogen production

The efficient TiO₂ NTs/Sn₃O₄ photocatalysts were synthesized by the hydrothermal deposition of Sn₃O₄ on TiO₂ nanotube arrays (TiO₂ NTs), and the morphology, microstructure and photocatalytic property were adjusted by changing the alkali kind. The TiO₂ NTs/Sn₃O₄ prepared with NaOH exhibited the outstanding photoelectric conversion and photocatalytic environment remediation/H₂ evolution. The methylene blue (MB) dye and Cr(VI) could be removed by the as-prepared photocatalysts under visible light irradiation, and ?O₂^?/?OH radicals were the main active species for MB photodegradation. Furthermore, the high photocatalytic H₂ evolution rate was as high as 6.49 μmol cm^?2 h^?1. The outstanding photocatalytic activity and stability of TiO₂ NTs/Sn₃O₄ photocatalysts would exhibit attractive prospect in the wastewater remediation and electric energy/hydrogen generation.     

Preparation of aerochitin‐TiO2 composite for efficient photocatalytic degradation of methylene blue

An aerochitin–titania (TiO₂) composite was successfully synthesized and characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, field emission scanning electron microscopy, and N₂ adsorption isotherms. The photocatalytic activity of the composite was investigated on the degradation of the model organic pollutant, methylene blue (MB) dye, under UV irradiation. The aerochitin–TiO₂ composite showed excellent adsorptive and photocatalytic activity with a degradation degree of 98% for MB. The first‐order rate constants for the photodegradation MB by TiO₂ nanoparticles and aerochitin–TiO₂ composite were found to be (3.49 ± 0.04) × 10^?3 and (1.82 ± 0.02) × 10^?2 min^?1. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45908.     

Immobilized titanium dioxide/powdered activated carbon system for the photocatalytic adsorptive removal of phenol

Titanium dioxide (TiO₂) and powdered activated carbon (PAC) were fabricated via a layer by layer arrangement on a glass plate using a dip-coating technique for the photocatalytic-adsorptive removal of phenol. Thinner TiO₂ layer coated on PAC sub-layer has larger surface area and better phenol removal than the thicker TiO₂ layer. The system obeyed the Langmuir isotherm model, which exhibited a homogeneous and monolayer adsorption with a maximum capacity of 27.8 mg g^-1. The intra-particle diffusion was the rate-limiting step as the linear plot crossed the origin, while the adsorption was unfavorable at elevated temperature. Under light irradiation, the TiO₂/PAC system removed phenol two-times more effectively than the TiO₂ monolayer due to the synergistic effect of photocatalysis by TiO₂ top layer and adsorption by PAC sub-layer. The COD removal of phenol was rapid for 10mg L^-1 of concentration and under solar light irradiation. It was shown that the PAC sub-layer plays a significant role in the total removal of phenol by providing the adsorption sites and slowing down the recombination rate of charge carriers to improve the TiO₂ photocatalytic oxidation performance.     

Photodegradation of four fluoroquinolone compounds by titanium dioxide under simulated solar light irradiation

BACKGROUND; In this study, simultaneous photocatalytic degradation of four fluoroquinolone (FQ) compounds (i.e. ofloxacin, norfloxacin, ciprofloxacin and enrofloxacin) was investigated in TiO₂ suspensions under simulated solar light irradiation. Effects of experimental variables including pH, TiO₂ dosage, initial substrate concentration and hydrogen peroxide (H₂O₂) on the degradation processes were also investigated. RESULTS: The antibiotics degradation was pH‐influenced. The photocatalytic reaction followed the pseudo‐first‐order model, with reaction rate constants (k) 0.026, 0.027, 0.022 and 0.026 min^?1 for ofloxacin, norfloxacin, ciprofloxacin and enrofloxacin, respectively. Complete elimination of four FQs was achieved in a reaction system composed of 0.5 g L^?1 of TiO₂ and 82.5 mg L^?1 of H₂O₂ at pH 6 after 90 min irradiation. Mineralization of FQs during TiO₂ photocatalysis was slower than the FQs conversion, and the antibacterial activity of the four FQs was completely removed by TiO₂ under simulated solar light irradiation. CONCLUSION: The four FQs can be simultaneously degraded and mineralized with commercially available TiO₂ under simulated solar light irradiation. Microbiological analysis showed that the antibacterial activity of the four FQs was completely removed. These results are helpful for antibiotics removal in the environment, and for exploring new technology for wastewater treatment. Copyright © 2012 Society of Chemical Industry     

Enhanced visible light response of heterostructured Cr2O3 incorporated two-dimensional mesoporous TiO2 framework for H2 evolution

Mesoporous TiO₂ frameworks incorporated with diverse percentages of Cr₂O₃ nanoparticles (NPs) were achieved through the one-step sol-gel approach for photocatalytic H₂ evolution under visible-light exposure. The obtained isotherms could be classified as type IV, indicating mesopore 2D-hexagonal symmetry. The H₂ evolution rate over mesoporous Cr₂O₃/TiO₂ photocatalyst was observably promoted employing glycerol as a sacrificial agent, providing a comparatively high H₂ yield of 14300 μmolg^?1. The highest photocatalytic efficiency was achieved with an optimal 4% Cr₂O₃/TiO₂ photocatalyst, and the evolution rate was enhanced 1430-fold compared to pristine TiO₂. The eminent photocatalytic performance of mesoporous Cr₂O₃/TiO₂ was ascribable to different key factors such as the narrow bandgap, wide visible light photoresponse, Cr₂O₃ as photosensitizer, synergistic effect and high surface area. The recycle tests for five times over synthesized photocatalyst revealed excellent durability and stability without loss in H₂ evolution. The photocatalytic mechanisms for H₂ evolution over Cr₂O₃/TiO₂ photocatalyst were proposed according to the photocurrent transient and photoluminescence measurements and photocatalytic H₂ evolution results.     

Photocatalysis,microstructure, and surface characterization of TiO2‐loaded wooden‐activated carbon fibers

In this study, TiO₂‐loaded wooden‐activated carbon fibers (TiO₂/WACFs) were prepared by sol–gel method. TiO₂/WACFs were detected by scanning electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy. The results showed that TiO₂ was deposited on almost each WCAF with a coating thickness. All the TiO₂ films on the surface of WACFs were composed of anatase with high photocatalytic property. The characteristic adsorption peaks of nano‐TiO₂ emerged at 1,402 and 471 cm⁻¹ on the infrared spectrum of TiO₂/WACFs. It was also found that Ti was in the binding state of Ti⁴⁺ (TiO₂) in the TiO₂/WACFs. As the calcination temperature increased, the content of elements Ti and Ti O bond of lattice oxygen on the surface of TiO₂/WACFs increased and then decreased, but the loaded nano‐TiO₂ did not affect the formation of graphite structure of WACFs. It is suggested that TiO₂/WACFs obtained at 450°C have the best photocatalytic property. POLYM. COMPOS., 36:62–68, 2015. © 2014 Society of Plastics Engineers     

The construction of TiO2 NTs/Ag3PO4–AgBr by SILAR deposition as promising photocatalysts for hydrogen production and pollutant treatment

The construction of ternary TiO₂ NTs/Ag₃PO₄–AgBr photocatalysts was carried out by the SILAR deposition of Ag₃PO₄ and AgBr on TiO₂ nanotube arrays (TiO₂ NTs) for enhancing the photocatalytic application in H₂ evolution and dyeing wastewater remediation. The adjustment of Ag₃PO₄/AgBr deposition cycles was used to optimize the optical absorption and photocatalytic property. The TiO₂ NTs/Ag₃PO₄–AgBr (5) prepared with 5 cycle deposition of Ag₃PO₄ and AgBr exhibited the optimal photoelectric activity and photocatalytic performances. The photocatalytic rate constants for the degradation of MO, RhB and MB dyes achieved 1.35 × 10⁻², 3.30 × 10⁻² and 4.47 × 10⁻² min⁻¹, respectively, and the visible light-driven photocatalytic H₂ evolution rate achieves 46.87 μmol cm⁻² h⁻¹. •O₂⁻ radicals exhibited the key influence on the organic dye degradation, and the as-prepared photocatalysts showed exceedingly high photocatalytic activity and stability. Furthermore, the photocatalytic mechanism was proposed based on the ESR result.     

Performance and Economic Assessment of the Treatment of Phenol with TiO2 Photocatalysis,Photo‐Fenton,Biological Aerated Filter,and Wetland Reactors

The performance and economic cost of the removal of phenol with TiO₂ photocatalysis, photo‐Fenton reactions, biological aerated filter (BAF), and constructed wetland (CW) reactors has been studied. The BAF achieved complete removal with a maximum phenol concentration of 200 mg·L^?1. The BAF‐CW combination provided a phenol‐free effluent with a maximum phenol concentration of 650 mg·L^?1. In both cases, a complete detoxification of the treated water was achieved at the concentrations studied. The efficiency of TiO₂ photocatalysis was limited to concentrations below 50 mg L^?1 to minimize removal reduction and toxicity of the intermediates. Photo‐Fenton was more efficient, but also more expensive because of the high cost of H₂O₂. The photo‐Fenton‐BAF combination is proposed to be the most suitable one.     

Microwave photocatalysis III. Transition metal ion‐doped TiO2 thin films on mercury electrodeless discharge lamps: preparation,characterization and their effect on the photocatalytic degradation of mono‐chloroacetic acid and Rhodamine B

BACKGROUND: Mercury electrodeless discharge lamps (Hg‐EDLs) were used to generate UV radiation when exposed to a microwave field. EDLs were coated with doped TiO₂ in the form of thin films containing transition metal ions Mⁿ⁺ (M = Fe, Co, Ni, V, Cr, Mn, Zr, Ag). Photocatalytic degradation of mono‐chloroacetic acid (MCAA) to HCl, CO₂, and H₂O, and decomposition of Rhodamine B on the thin films were investigated in detail. RESULTS: Polycrystalline thin doped TiO₂ films were prepared by dip‐coating of EDL via a sol–gel method using titanium n‐butoxide, acetylacetone, and a transition metal acetylacetonate. The films were characterized by Raman spectroscopy, UV/Vis absorption spectroscopy, X‐ray photoelectron spectroscopy (XPS), electron microprobe analysis and by atomic force microscopy (AFM). The photocatalytic activity of doped TiO₂ films was monitored in the decomposition of Rhodamine B in water. Compared with the pure TiO₂ film, the UV/Vis spectra of V, Zr and Ag‐doped TiO₂ showed significant absorption in the visible region, and hence the photocatalytic degradation of MCAA had increased. The best apparent degradation rate constant (0.0125 min^?1), which was higher than that on the pure TiO₂ film by a factor of 1.7, was obtained with the Ag(3%)/TiO₂ photocatalyst. The effect of doping level of vanadium acetylacetonate on the photocatalytic efficiency of the V‐doped TiO₂ was determined. CONCLUSIONS: Transition metal ion‐doped TiO₂ thin films showed significant absorption in the visible region. The metal doped TiO₂ photocatalyst (with an appropriate amount of V, Zr and Ag) on the Hg‐EDLs increased the degradation efficiency of MCAA in a microwave field. Copyright © 2009 Society of Chemical Industry     

Preparation and characterization of cerium‐doped titanium dioxide/ultrahigh‐molecular‐weight polyethylene porous composites with excellent photocatalytic activity

Porous ultrahigh‐molecular‐weight polyethylene (UHMWPE)‐based composites filled with surface‐modified Ce‐doped TiO₂ nanoparticles (Ce–TiO₂/UHMWPE) were prepared by template dissolution. The composites were characterized by Fourier transform infrared spectroscopy, ultraviolet (UV)–visible spectroscopy, diffuse reflectance spectra, and scanning electron microscopy); the photocatalytic activity was also evaluated by the decomposition of methyl orange under UV exposure. The results demonstrate that the severe aggregation of Ce–TiO₂ nanoparticles could be reduced by surface modification via a silane coupling agent (KH570). The Ce–TiO₂/UHMWPE porous composites exhibited a uniform pore size. Doping with Ce⁴⁺ effectively extended the spectral response from the UV to the visible region and enhanced the surface hydroxyl groups of the TiO₂ attached to the matrix. With a degradation rate of 85.3%, the 1.5 vol % Ce–TiO₂/UHMWPE sample showed the best photocatalytic activity. The excellent permeability of the porous composites is encouraging for their possible use in wastewater treatment. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Degradation of 1‐amino‐4‐bromoanthraquinone‐2‐sulfonic acid using combined airlift bioreactor and TiO2‐photocatalytic ozonation

BACKGROUND: Traditional treatment systems failed to achieve efficient degradation of anthraquinone dye intermediates at high loading. Thus, an airlift internal loop reactor (AILR) in combination with the TiO₂‐photocatalytic ozonation (TiO₂/UV/O₃) process was investigated for the degradaton of 1‐amino‐ 4‐bromoanthraquinone‐2‐ sulfonic acid (ABAS). RESULTS: The AILR using Sphingomonas xenophaga as inoculum and granular activated carbon (GAC) as biocarrier, could run steadily for 4 months at 1000 mg L^?1 of the influent ABAS. The efficiencies of ABAS decolorization and chemical oxygen demand (COD) removal in AILR reached about 90% and 50% in 12 h, respectively. However, when the influent ABAS concentration was further increased, a yellow intermediate with maximum absorbance at 447 nm appeared in AILR, resulting in the decrease of the decolorization and COD removal efficiencies. Advanced treatment of AILR effluent indicated that TiO₂/UV/O₃ process more significantly improved the mineralization rate of ABAS bio‐decolorization products with over 90% TOC removal efficiency, compared with O₃, TiO₂/UV and UV/O₃ processes. Furthermore, the release efficiencies of Br^? and SO₄^2? could reach 84.5% and 80.2% during TiO₂/UV/O₃ treatment, respectively, when 91.5% TOC removal was achieved in 2 h. CONCLUSION: The combination of AILR and TiO₂/UV/O₃ was an economic and efficient system for the treatment of ABAS wastewater. © 2012 Society of Chemical Industry     

Degradation of Polyvinylpyrrolidone by Photocatalytic Ozonation and Evaluation of the Influence of Some Operational Parameters

Photocatalytic degradation of polyvinylpyrrolidone (PVP) by titanium dioxide and ozone in an annular reactor was investigated using a 125-W mercury vapor lamp as the light source. It was observed that the TiO₂/O₃/UV process presented a greater efficiency than the TiO₂/UV process. In fact, around 90% of the mineralization was obtained in 1 h of reaction, reflecting the synergistic effect of the combination of O₃ and TiO₂ under UV light, because the sum of the rate constants of the individual processes is less than the rate constant of the combined process. The effects of the initial PVP concentration, photocatalyst dosage, ozone input flow rate and pH on the PVP degradation rate were studied. In general, the results suggest that PVP can undergo a cross-linking process when the TiO₂/O₃/UV treatment is applied. The reaction rate was increased when the photocatalyst dosage was increased up to 2.0 g L^?1; however, increasing the initial PVP concentration led to a drop in the reaction rate. The efficiency also decreased at basic pH, because ozone is decomposed under alkaline conditions. In addition, it was noted that most of the nitrogen atoms of the macromolecules of PVP can be transformed into nitrate and ammonia during photocatalytic ozonation.     

Synthesis,characterization, and thermal degradation of oligo‐2‐(morpholinoiminomethyl)phenol and its Pb(II) complex compound

The oxidative polycondensation reaction conditions of 2‐(morpholinoiminomethyl)phenol were studied with H₂O₂, air O₂, and sodium hypochloride (NaOCl) oxidants in an aqueous alkaline medium between 40 and 90°C. The structure of oligo‐2‐(morpholinoiminomethyl)phenol was characterized with ¹H‐ and ¹³C‐NMR, Fourier transform infrared, ultraviolet–visible, size exclusion chromatography, and elemental analysis techniques. Under the optimum reaction conditions, the yield of oligo‐2‐(morpholinoiminomethyl)phenol was 28% for the H₂O₂ oxidant, 12% for the air O₂ oxidant, and 58% for the NaOCl oxidant. According to the size exclusion chromatography analysis, the number‐average molecular weight, weight‐average molecular weight, and polydispersity index of oligo‐2‐(morpholinoiminomethyl)phenol were 2420 g/mol, 2740 g/mol, and 1.187 with H₂O₂, 1425 g/mol, 2060 g/mol, and 1.446 with air O₂, and 1309 g/mol, 1401 g/mol, and 1.070 with NaOCl, respectively. Thermogravimetry/dynamic thermal analysis showed that the oligo‐2‐(morpholinoiminomethyl)phenol–lead complex compound was more stable than 2‐(morpholinoiminomethyl)phenol and oligo‐2‐(morpholinoiminomethyl)phenol against thermal degradation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3795–3804, 2006