Relaxation response of polymers containing highly flexible side groups monitored by broadband dielectric spectroscopy.

The relaxation behavior of poly(5-acryloxymethyl-5-methyl-1,3-dioxacyclohexane), a polymer containing highly flexible side groups, is studied by broadband dielectric spectroscopy in the frequency and temperature ranges 10(-1)-10(9) Hz and 123-473 K, respectively. Above the glass transition temperature T(g) the dielectric loss in the frequency domain exhibits a prominent alpha absorption, followed in increasing order of frequencies by two secondary absorptions called beta and gamma. At temperatures slightly higher than T(g), the a relaxation is well separated from the beta, but as temperature increases overlapping between both relaxations augments forming an alphabeta absorption in the vicinity of 420 K. This latter absorption displays a shoulder on its high-frequency side corresponding to the y relaxation. The strength of the a relaxation decreases with increasing temperature, eventually vanishing at the temperature at which the alphabeta absorption is formed. The time retardation spectra of the isotherms are calculated and further used to facilitate the deconvolution of the overlapping relaxations. The fact that the temperature dependence of the beta relaxation also describes that of the alphabeta absorption suggests that both relaxations have the same nature. It seems that as temperature increases, the a relaxation feeds on the beta absorption until its complete disappearance. The gamma relaxation, in turn, seems to increase at the expense of the alphabeta process at high temperature.

[1]  Evaristo Riande,et al.  Electrical Properties of Polymers , 2004 .

[2]  P. Calle,et al.  Radical Polymerization of Isomeric Methacrylic Monomers: cis- and trans-(2-Phenyl-1,3-dioxan-5-yl) Methacrylate , 2002 .

[3]  V. Compañ,et al.  Response of acrylate polymers containing substituted 1,3-dioxacyclohexane groups in the ester residue to mechanical and electric perturbation fields , 2001 .

[4]  Á. Alegría,et al.  Merging of the Dielectric α and β Relaxations in Glass-Forming Polymers , 2001 .

[5]  R. Diaz-calleja.  Comment on the Maximum in the Loss Permittivity for the Havriliak−Negami Equation , 2000 .

[6]  E. Riande,et al.  Influence of oxycycloaliphatic groups in the relaxation behavior of acrylic polymers , 1999 .

[7]  M. Beiner,et al.  Crossover region of dynamic glass transition in poly(n-hexyl methacrylate) by heat capacity spectroscopy , 1998 .

[8]  M. Beiner,et al.  Dielectric Spectroscopy in the αβ Splitting Region of Glass Transition in Poly(ethyl methacrylate) and Poly(n-butyl methacrylate): Different Evaluation Methods and Experimental Conditions , 1998 .

[9]  Á. Alegría,et al.  The merging of the dielectric α- and β-relaxations in poly-(methyl methacrylate) , 1998 .

[10]  E. Riande,et al.  Molecular Dynamics Simulations of the Time Dependent Dipolar Correlation Function for Esters Containing Substituted 1,3-Dioxacyclohexane Rings in Their Structure , 1997 .

[11]  E. Riande,et al.  Dynamics and Polarity of Substituted 1,3-Dioxacyclohexanes , 1996 .

[12]  R. Colby,et al.  Concentration fluctuation induced dynamic heterogeneities in polymer blends , 1996 .

[13]  F. Stillinger,et al.  A Topographic View of Supercooled Liquids and Glass Formation , 1995, Science.

[14]  William H. Press,et al.  The Art of Scientific Computing Second Edition , 1998 .

[15]  Dianne P. O'Leary,et al.  The Use of the L-Curve in the Regularization of Discrete Ill-Posed Problems , 1993, SIAM J. Sci. Comput..

[16]  W. Gotze,et al.  Relaxation processes in supercooled liquids , 1992 .

[17]  Alvarez,et al.  Relationship between the time-domain Kohlrausch-Williams-Watts and frequency-domain Havriliak-Negami relaxation functions. , 1991, Physical review. B, Condensed matter.

[18]  Graham Williams,et al.  Anelastic and Dielectric Effects in Polymeric Solids , 1991 .

[19]  William H. Press,et al.  Numerical recipes in C. The art of scientific computing , 1987 .

[20]  V. A. Morozov,et al.  Methods for Solving Incorrectly Posed Problems , 1984 .

[21]  Thomas A. Weber,et al.  Hidden structure in liquids , 1982 .

[22]  J. Ferry.  Viscoelastic properties of polymers , 1961 .

[23]  A. K. Doolittle,et al.  Studies in Newtonian Flow. V. Further Verification of the Free‐Space Viscosity Equation , 1957 .

[24]  Raymond M. Fuoss,et al.  Electrical Properties of Solids. VIII. Dipole Moments in Polyvinyl Chloride-Diphenyl Systems* , 1941 .

[25]  G. Tammann,et al.  Die Abhängigkeit der Viscosität von der Temperatur bie unterkühlten Flüssigkeiten , 1926 .

[26]  W. M. Myers.  CALCINING AS AN AID TO GRINDING1 , 1925 .

[27]  C. Angell.  Entropy, fragility, “landscapes”, and the glass transition , 1997 .

[28]  John J. Fitzgerald,et al.  Dielectric spectroscopy of polymeric materials : fundamentals and applications , 1997 .

[29]  F. Garwe,et al.  Influence of cooperative α dynamics on local β relaxation during the development of the dynamic glass transition in poly(n-alkyl methacrylate)s , 1996 .

[30]  Colmenero,et al.  Interconnection between frequency-domain Havriliak-Negami and time-domain Kohlrausch-Williams-Watts relaxation functions. , 1993, Physical review. B, Condensed matter.

[31]  S. Provencher.  CONTIN: A general purpose constrained regularization program for inverting noisy linear algebraic and integral equations , 1984 .

[32]  Graham Williams.  Molecular aspects of multiple dielectric relaxation processes in solid polymers , 1979 .

[33]  S. Dev,et al.  Further considerations of non symmetrical dielectric relaxation behaviour arising from a simple empirical decay function , 1971 .

[34]  Graham Williams,et al.  Non-symmetrical dielectric relaxation behaviour arising from a simple empirical decay function , 1970 .