Heterogeneous polymer systems

Wessling, B. (1996) Cellular automata simulation of dissipative structure formation in heterogeneous polymer systems, formation of networks of a dispersed phase by flocculation. J. Phys. II, 6, 395-404. 

A review of the application of ESR to the study of free radical polymerisation is given by Yamada and co-workers [146]. A survey of the application ESR spectroscopy spin label/probe methods in heterogeneous polymer systems is provided by Veksli and co-workers [147]. Spin probe methods allow the study of the MD of the polymer, its free volume, phase separation and phase morphology. 

Photovoltaic and photoconductive phenomena for various types of CT complexes between saturated polymers and dopant molecules, heterojunctions between polymers and organic and inorganic photoconductors were also investigated in the last few years [86-92]. The quantum efficiency of the energy conversion of 10-3% was obtained for such systems and output power density of 3 x 102 mV cm-2. The mobilities of the heterogeneous polymer systems with despersed inorganic photoconductors reach the value — 10 3-10-4 m2 V 1s 1. 

The effects associated with the influence of the phase border are especially obvious in heterogeneous polymer systems, where both components are of a polymeric nature. Such systems include polymer blends and polymers filled with polymeric filler. These two types of systems differ in that in blends it is difficult to distinguish between the two polymers as a disperse phase and dispersion media due to uniform distribution of both components in the volume. 

Permeability measurements for polymer blends prepared by mixing different latices have been reported by Peterson (14). Interpreting transport data for such heterogeneous systems as polymer blends is extremely difficult, however (3, 9,15). The main purpose of the present investigation is, therefore, to study the applicability of gas permeation measurements to characterize polymer blends and not to evaluate the different theoretical models for the permeation process in heterogeneous polymer systems. 

The so-called Force Modulation Mode (FMM) was introduced in 1991 as a modification of contact-mode SFM [123] and has since found a wide range of applications in heterogeneous polymer systems [124-129]. The FMM imaging is performed by z-modulating the probe (or sample) at a low frequency of about 5 to 20 kHz and an amplitude greater than 10 nm. The frequency is sig-... 

Stiffness Mapping for the Characterisation of Heterogeneous Polymer Systems... 

Molau G (1965) Heterogeneous polymer systems. III. Phase separation in styrene-acrylonitrile copolymers. J Polym Sci, Polym Lett Ed 3 1007-15. 

Figure 5.1. Density of composite vs. concentration of carbon black around the CVC. [Data from Weeling B, Electrical Conductivity in Heterogeneous Polymer Systems. Conductive Polymers, Conference Proceedings, 1992, Bristol, UK.]...

Weeling B, Electrical Conductivity in Heterogeneous Polymer Systems. Conductive Polymers, Conference Proceedings, 1992, Bristol, UK. 

Molau GE. Heterogeneous polymer systems I. Polymeric oil in oil emulsion. J Polym Sci Part A 1965 3 1267-1278. 

A. Kreituss and H, L. Frisch. Free Volume Estimates in Heterogeneous Polymer Systems, 1. 

FIRST COMPUTER SIMULATION OF DISSIPATIVE STRUCTURE FORMATION IN HETEROGENOUS POLYMER SYSTEMS... 

The process of the formation of flocculated networks of dispersed particles or phases in heterogeneous polymer systems consists of various elements [72e,37,89,90], which need to be understood before looking at the simulations ... 

In contrast to this, based on experimental results, a new theory has recently been developed by us [37], which is applicable to all heterogeneous polymer systems [88,89], Our main principle is to define the non-equilibrium character of colloidal dispersions in polymeric matrices and to interpret the experimental findings (phase separation, dispersion-flocculation phase transition, [84]) as dissipative structures . This term has been first introduced by Prigogine [77a,b] for... 

The new non-equilibrium thermodynamic theory of heterogeneous polymer systems [37] is aimed at giving a basis for an integrated description for the dynamics of dispersion and blending processes, structure formation, phase transition and critical phenomena. Our new concept is derived from these more general non-equilibrium thermodynamics and has been worked out on the basis of experiments mainly with conductive systems, plus some orienting and critical examples with non-con-ductive systems [72d]. The principal ideas of the new general non-equilibrium thermodynamical theory of multiphase polymer systems can be outlined as follows. 

In this Section we will present the new model for impact modification in polymer blends. This new model is derived from the new non-equilibrium thermodynamical description of heterogeneous polymer systems and interprets crazing fracture energy dissipation and the fracture mechanism in a new way on the basis of dissipative structures in polymer blends and their dynamics. 

T uminescence emission from irradiated materials has been known for many years. The phenomenon has been studied primarily on inorganic systems but also with polymers. A review of this work has been published by Partridge (i). A clearer understanding of the processes involved has led in more recent years to the use of this technique as a tool to probe the structure of heterogeneous polymer systems (2,3). This chapter describes the technique and shows its utility for the analysis of polymer blends and block copolymers. 

The properties of all heterogeneous polymer systems are determined by the same four factors component properties, composition, structure and interfacial interactions. 

POSITRON ANNIHILATION LIFETIME STUDIES OF FREE VOLUME IN HETEROGENEOUS POLYMER SYSTEMS... 

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