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Small‐angle x‐ray scattering study of thermoreversible poly(vinyl chloride) gels
Authors:Motohiro Seki  Satoru Yamamoto  Yuji Aoki  Katsuhiro Takagi  Yoshinobu Izumi  Shuichi Nojima
Abstract:Poly(vinyl chloride) (PVC)/bis(2‐ethylhexyl)phthalate (DOP) gels were prepared at room temperature from tetrahydrofuran solutions of PVC and DOP. PVC/DOP gels of different molecular weights at various PVC concentrations (c) were investigated with small‐angle X‐ray scattering (SAXS). The mean distance between two neighboring inhomogeneities (D) and two characteristic lengths, the intrainhomogeneity distance (d1) and interinhomogeneity distance (d2), were evaluated from Bragg's law and the distance distribution function, respectively. Both D and d2 can be expressed by a power‐law relation (e.g., D and d2c?0.5). After a period of rapid cooling to 25 °C from the sol state, the structural evolution was examined with time‐resolved SAXS measurements. An Avrami analysis with the SAXS invariant data revealed that the growth kinetics of PVC/DOP gels was one‐dimensional growth from predetermined nuclei, regardless of c. These results suggest that the PVC/DOP gels are constructed from a fibrillar structure that forms gel structures at high concentrations or low temperatures. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2340–2350, 2001
Keywords:poly(vinyl chloride) (PVC) gels  SAXS  distance distribution function  gel structure  structure evolution
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