PHYSICS OF AMORPHOUS POLYMERS

The physics of amorphous polymers is an extraordinarily wide field of research. In this review some of the central questions are addressed. 

Brief physics of amorphous polymer matrices 6.2.1. Equilibrium structure of amorphous chains... 

Perez J (1998) Physics and Mechanics of Amorphous Polymers. AA Balkema Publishers, Rotterdam, p 280-285... 

A.O. Pozdnyakov, B.L. Baskin, O.F. Pozdnyakov, Fullerene C60 diffusion in thin layers of amorphous polymers polystyrene and poly(amethylstyrene), Techical Physics Letters, vol. 

The prediction of the chemical thermostability is based on the rules on the thermal stability and the reactivity of chemical bonds known for low-molecular-weight compounds. Instead, the physical thermostability depends on the transition points of the macromolecules, i.e., the glass transition temperature Tg in case of amorphous polymers, and additionally the crystalline melting point in case of crystalline polymers. 

Many physical and mechanical properties of amorphous polymers improve rapidly as the molecular weight increases up to the threshold molecular weight (Sec. 2.2). However, the change levels off after a moderately high molecular weight is reached (Figure 5.1). 

In fact, most polymers have a distinct temperature above which the chains become much more flexible. This temperature can be measured by a variety. of techniques and is called the glass transition temperature, or Tg. For PDMS it is -127°C, while for PS it is approximately 100°C. It is this tremendous difference in glass transition temperatures that makes PDMS and PS behave so differently (at room temperature). The physical properties of amorphous polymers are determined in large part by the freedom of the chains to move, and this determines the glass transition temperature. Although commercial... 

Struik L, "Physical Aging of Amorphous Polymers and other Materials", Elsevier, Amsterdam, 1978. 

Large specimens of amorphous polymers that can be subjected to large loads and can produce large displacements in creep generally have been the subject in creep studies of physical aging. Electronic sensing of displacements with sensitive oscillators and amplifiers have been employed in measuring displacements when loads of 1-50 kg were applied. 

Haward, R. N. The Post-Yield Behaviour of Amorphous Plastics, in The Physics of Glassy Polymers, (ed. Haward, R. N.), London, Applied Science Publ., 1973, p. 340... 

DJ Plazek, RA Andrekanik. The physical aging of amorphous polymers. In E Riande, ed. Keynote Lectures in Selected Topics of Polymer Science. Madrid CSIC, 1995 page 117. 

Lamarre, L., and Sung, G. S. P. (1983). Studies of physical aging and molecular motion by azochromophoric labels attached to the main chains of amorphous polymers. Macromolecules 16,1729-1736. 

J. R. Flick and S. E. B. Petrie, Studies in Physical and Theoretical Chemistry, 10, 145-163 (1978). (Volume title Structure and Properties of Amorphous Polymers. Edited by A. G. Walton. Contains the Proceedings of the Second Symposium on Macromolecules, held in Cleveland, Ohio, October 31-November 2, 1978). 

As another (and perhaps more important for making reasonable practical predictions in a very simple manner) improvement in the ability to predict the thermal conductivities of polymers, a direct correlation was developed between the i(298K) of amorphous polymers and some of their most important structural features. This correlation will be presented in Section 14.B. While the indirect relationship (Equation 14.6) describes the physics of thermal... 

The Arrhenius equation has been employed as a first approximation in an attempt to define the temperature dependence of physical degradation processes. However, the use of the WLF equation (Eq. 3.6), developed by Williams, Landel, and Ferry to describe the temperature dependence of the relaxation mechanisms of amorphous polymers, appears to have merit for physical degradation processes that are governed by viscosity. 

Krtswski, R.J. Labovitz, H. Sieglaff, C.L., pp.67-76 in "Structure and Properties of Amorphous Polymers", A.G. Walton (Ed.), Studies in Physical and Theoretical Chemistry, Volume 10, Elsevier Scientific Publishing Company, Amsterdam, 1980. Flick, J.R. Petrie, S.E.B., pp.145-171, ibid. 

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