Order and Dielectric Relaxation During Polymer Crystallization
In the recent years Broadband Dielectric Spectroscopy (BDS) has been shown to be a powerful technique to investigate crystallization in complex fluids including liquids and polymers. Particularly attractive is when scattering and diffraction experiments a
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Abstract In the recent years Broadband Dielectric Spectroscopy (BDS) has been shown to be a powerful technique to investigate crystallization in complex fluids including liquids and polymers. Particularly attractive is when scattering and diffraction experiments are combined with dielectric spectroscopy during crystallization in real-time. In this chapter we will review the application of BDS to the study of polymer crystallization emphasizing those aspects related to the combination of X-ray scattering techniques, rendering information about the crystalline phase, with BDS providing information about the amorphous phase dynamics. In addition, we will show as well that both the α-relaxation and the β-relaxation can be used for probing polymer crystallization especially when they appear simultaneously and well resolved in the experimental frequency window. Although most of the applications of BDS to polymer crystallization involve thermal treatments we will show that BDS can be also used when other magnitudes like pressure, shear or strain are involved in the crystallization process. Keywords Real time crystallization · Broadband dielectric spectroscopy (BDS) · Natural rubber · Strain induced crystallization
A. Nogales (B) · T. A. Ezquerra Instituto de Estructura de la Materia, IEM-CSIC, Serrano 121, Madrid 28006, Spain e-mail: [email protected] T. A. Ezquerra e-mail: [email protected] M. Soccio Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, Universitá di Bologna, Via Terracini 28, Bologna 40131, Italy e-mail: [email protected] M. Hernández Instituto de Ciencia y Tecnología de Polímeros, ICTP-CSIC, Juan de la Cierva 3, Madrid 28006, Spain e-mail: [email protected] © Springer Nature Switzerland AG 2020 T. A. Ezquerra and A. Nogales (eds.), Crystallization as Studied by Broadband Dielectric Spectroscopy, Advances in Dielectrics, https://doi.org/10.1007/978-3-030-56186-4_8
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Abbreviations BDS FK HN NR PET PPS PPT PTT RAP SAXS WAXS
Broadband dielectric Spectroscopy Frölich-Kirkwood Havriliak Negami equation Natural rubber Poly(ethylene terephthalate) (PET) Poly(propylene succinate) Poly(pentamethylene terephthalate) Poly(trimethylene terephthalate) Rigid amorphous phase (RAP) Small Angle X-ray Scattering Wide Angle X-ray Scattering
1 Introduction Nowadays polymers are ubiquitous in our everyday life. The world polymer materials production reached around 350 million tons in 2017 being about two-thirds of it related to semicrystalline polymers [1]. Similarly to other glass former materials by cooling a polymer from its viscoelastic liquid phase its specific volume, Fig. 1 a, linearly decreases with temperature until the glass transition temperature, T g , is reached [2]. Below T g a change in the specific volume decrease rate with temperature is observed. Before reaching T g the polymer has to transit through the supercooled liquid state (SCL) temperature range defined by T g > T > T 0m being T 0m the equilibrium melting temperature. In the SCL state t
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