Статья

Thermal Stability of Quaternary Phosphonium Modified Montmorillonites

Wei XieThermal Analysis Laboratory, Material Characterization Center, Department of Chemistry, Western Kentucky University, Bowling Green, Kentucky 42101; Southern Clay Products, Inc., 1212 Church Street, Gonzales, Texas 78629; Triton Systems, Inc., 200 Turnpike Road, Chelmsford, Massachusetts 01824; Air Force Research Laboratory/MLBP, Building 654, 2941 P Street, Wright-Patterson Air Force Base, Ohio 45433Rongcai XieThermal Analysis Laboratory, Material Characterization Center, Department of Chemistry, Western Kentucky University, Bowling Green, Kentucky 42101; Southern Clay Products, Inc., 1212 Church Street, Gonzales, Texas 78629; Triton Systems, Inc., 200 Turnpike Road, Chelmsford, Massachusetts 01824; Air Force Research Laboratory/MLBP, Building 654, 2941 P Street, Wright-Patterson Air Force Base, Ohio 45433Wei‐Ping PanThermal Analysis Laboratory, Material Characterization Center, Department of Chemistry, Western Kentucky University, Bowling Green, Kentucky 42101; Southern Clay Products, Inc., 1212 Church Street, Gonzales, Texas 78629; Triton Systems, Inc., 200 Turnpike Road, Chelmsford, Massachusetts 01824; Air Force Research Laboratory/MLBP, Building 654, 2941 P Street, Wright-Patterson Air Force Base, Ohio 45433Doug HunterThermal Analysis Laboratory, Material Characterization Center, Department of Chemistry, Western Kentucky University, Bowling Green, Kentucky 42101; Southern Clay Products, Inc., 1212 Church Street, Gonzales, Texas 78629; Triton Systems, Inc., 200 Turnpike Road, Chelmsford, Massachusetts 01824; Air Force Research Laboratory/MLBP, Building 654, 2941 P Street, Wright-Patterson Air Force Base, Ohio 45433Bryan E. KoeneThermal Analysis Laboratory, Material Characterization Center, Department of Chemistry, Western Kentucky University, Bowling Green, Kentucky 42101; Southern Clay Products, Inc., 1212 Church Street, Gonzales, Texas 78629; Triton Systems, Inc., 200 Turnpike Road, Chelmsford, Massachusetts 01824; Air Force Research Laboratory/MLBP, Building 654, 2941 P Street, Wright-Patterson Air Force Base, Ohio 45433Loon‐Seng TanThermal Analysis Laboratory, Material Characterization Center, Department of Chemistry, Western Kentucky University, Bowling Green, Kentucky 42101; Southern Clay Products, Inc., 1212 Church Street, Gonzales, Texas 78629; Triton Systems, Inc., 200 Turnpike Road, Chelmsford, Massachusetts 01824; Air Force Research Laboratory/MLBP, Building 654, 2941 P Street, Wright-Patterson Air Force Base, Ohio 45433Richard A. VaiaThermal Analysis Laboratory, Material Characterization Center, Department of Chemistry, Western Kentucky University, Bowling Green, Kentucky 42101; Southern Clay Products, Inc., 1212 Church Street, Gonzales, Texas 78629; Triton Systems, Inc., 200 Turnpike Road, Chelmsford, Massachusetts 01824; Air Force Research Laboratory/MLBP, Building 654, 2941 P Street, Wright-Patterson Air Force Base, Ohio 45433

2002en

ABI

Аннотация

Organically modified layered silicates (OLS) with high thermal stability are critical for synthesis and processing of polymer layered silicate nanocomposites (PLSN). In the current study, the non-oxidative thermal degradation chemistry of alkyl and aryl quaternary phosphonium-modified montmorillonites (P-MMT) was examined using TGA combined with pyrolysis/GC-MS. The morphology evolution at elevated temperature was investigated using in-situ high-temperature X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The onset decomposition temperature via TGA of these P-MMTs ranged from 190 to 230 °C. The initial degradation of the alkyl P-MMTs follows potentially two reaction pathways − β-elimination [Eβ] and nucleophilic displacement at phosphorus [SN(P)] − reflecting the multiple environments of the surfactant in the silicate. Aryl P-MMT decomposition proceeds via either a reductive elimination through a five-coordinate intermediate or radical generation through homologous cleavage of the P−phenyl bond. Overall, the interlayer environment of the montmorillonite has a more severe effect on stability of the phosphonium surfactant than previously reported for ammonium-modified montmorillonite (N-MMT). Nonetheless, the overall thermal stability of P-MMT is higher than that of N-MMT. These observations indicate that, in addition to their conventional purpose as stabilizers, phosphonium salts offer unique opportunities for melting processing polymer layered silicate nanocomposites.

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Идентификаторы

DOI: 10.1021/cm020705v

Цитирования и источники

Цитирований: 2Использованных источников: 0

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