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- W2111083362 endingPage "3570" @default.
- W2111083362 startingPage "3553" @default.
- W2111083362 abstract "Abstract Combined in situ rheo‐SAXS (small‐angle X‐ray scattering) and ‐WAXD (wide‐angle X‐ray diffraction) studies using couette flow geometry were carried out to probe thermal stabilty of shear‐induced oriented precursor structure in isotactic polypropylene (iPP) at around its normal melting point (162 °C). Although SAXS results corroborated the emerging consensus about the formation of “long‐living” metastable mesomorphic precursor structures in sheared iPP melts, these are the first quantitative measures of the limiting temperature at which no oriented structures survive. At the applied shear, rate = 60 s −1 and duration t s = 5 s, the oriented iPP structures survived a temperature of 185 °C for 1 h after shear, while no stable structures were detected at and above 195 °C. Following Keller's concepts of chain orientation in flow, it is proposed that the chains with highly oriented high molecular weight fraction are primarily responsible for their stability at high temperatures. Furthermore, the effects of flow condition, specifically the shear temperature, on the distributions of oriented and unoriented crystals were determined from rheo‐WAXD results. As expected, at a constant flow intensity (i.e., rate = 30 s −1 and duration, t s = 5 s), the oriented crystal fraction decreased with the increase in temperature above 155 °C, below which the oriented fraction decreased with the decrease in temperature. As a result, a crystallinty “phase” diagram, i.e., temperature versus crystal fraction ratio, exhibited a peculiar “hourglass” shape, similar to that found in many two‐phase polymer–polymer blends. This can be explained by the competition between the oriented and unoriented crystals in the available crystallizable species. Below the shear temperature (155 °C), the unoriented crystals crystallized so rapidly that they overwhelmed the crystallization of the oriented crystals, thus depleting a major portion of the crystallizable species and increasing their contribution in the final total crystalline phase. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3553–3570, 2006" @default.
- W2111083362 created "2016-06-24" @default.
- W2111083362 creator A5031207407 @default.
- W2111083362 creator A5036450882 @default.
- W2111083362 creator A5070714504 @default.
- W2111083362 date "2006-11-02" @default.
- W2111083362 modified "2023-10-14" @default.
- W2111083362 title "Thermal stability of shear-induced precursor structures in isotactic polypropylene by rheo-X-ray techniques with couette flow geometry" @default.
- W2111083362 cites W1965034296 @default.
- W2111083362 cites W1965465899 @default.
- W2111083362 cites W1965743975 @default.
- W2111083362 cites W1970227030 @default.
- W2111083362 cites W1974108128 @default.
- W2111083362 cites W1975204793 @default.
- W2111083362 cites W1975586401 @default.
- W2111083362 cites W1975641004 @default.
- W2111083362 cites W1976031861 @default.
- W2111083362 cites W1976187169 @default.
- W2111083362 cites W1979699468 @default.
- W2111083362 cites W1980586199 @default.
- W2111083362 cites W1981690915 @default.
- W2111083362 cites W1982410143 @default.
- W2111083362 cites W1983798838 @default.
- W2111083362 cites W1985087777 @default.
- W2111083362 cites W1987865010 @default.
- W2111083362 cites W1988314040 @default.
- W2111083362 cites W1991457724 @default.
- W2111083362 cites W1991687668 @default.
- W2111083362 cites W1992908228 @default.
- W2111083362 cites W1994629676 @default.
- W2111083362 cites W2001312080 @default.
- W2111083362 cites W2002441472 @default.
- W2111083362 cites W2006083802 @default.
- W2111083362 cites W2006238243 @default.
- W2111083362 cites W2014521747 @default.
- W2111083362 cites W2016286640 @default.
- W2111083362 cites W2019927397 @default.
- W2111083362 cites W2022104002 @default.
- W2111083362 cites W2022311375 @default.
- W2111083362 cites W2023477236 @default.
- W2111083362 cites W2023519828 @default.
- W2111083362 cites W2025497176 @default.
- W2111083362 cites W2026193281 @default.
- W2111083362 cites W2029688102 @default.
- W2111083362 cites W2031144384 @default.
- W2111083362 cites W2032714116 @default.
- W2111083362 cites W2033002712 @default.
- W2111083362 cites W2034270987 @default.
- W2111083362 cites W2036459269 @default.
- W2111083362 cites W2039585663 @default.
- W2111083362 cites W2042645776 @default.
- W2111083362 cites W2043644248 @default.
- W2111083362 cites W2046506173 @default.
- W2111083362 cites W2046879677 @default.
- W2111083362 cites W2047829028 @default.
- W2111083362 cites W2050456533 @default.
- W2111083362 cites W2051195783 @default.
- W2111083362 cites W2052761836 @default.
- W2111083362 cites W2052937150 @default.
- W2111083362 cites W2054533592 @default.
- W2111083362 cites W2060431116 @default.
- W2111083362 cites W2060553945 @default.
- W2111083362 cites W2060558368 @default.
- W2111083362 cites W2062046886 @default.
- W2111083362 cites W2062514123 @default.
- W2111083362 cites W2064384154 @default.
- W2111083362 cites W2065719248 @default.
- W2111083362 cites W2066852945 @default.
- W2111083362 cites W2069233283 @default.
- W2111083362 cites W2070506914 @default.
- W2111083362 cites W2073774194 @default.
- W2111083362 cites W2075764950 @default.
- W2111083362 cites W2076191989 @default.
- W2111083362 cites W2079861346 @default.
- W2111083362 cites W2080555366 @default.
- W2111083362 cites W2080760364 @default.
- W2111083362 cites W2084628175 @default.
- W2111083362 cites W2090349344 @default.
- W2111083362 cites W2090654376 @default.
- W2111083362 cites W2096379884 @default.
- W2111083362 cites W2114592600 @default.
- W2111083362 cites W2117137213 @default.
- W2111083362 cites W2121776576 @default.
- W2111083362 cites W2123461234 @default.
- W2111083362 cites W2132412664 @default.
- W2111083362 cites W2146055048 @default.
- W2111083362 cites W2146996718 @default.
- W2111083362 cites W2149620588 @default.
- W2111083362 cites W2152704957 @default.
- W2111083362 cites W2154521540 @default.
- W2111083362 cites W2158929817 @default.
- W2111083362 cites W2160597960 @default.
- W2111083362 cites W2163379366 @default.
- W2111083362 cites W2165142266 @default.
- W2111083362 cites W2168088796 @default.
- W2111083362 cites W2171581132 @default.
- W2111083362 cites W2319298953 @default.
- W2111083362 cites W2330588336 @default.