Polymer monomer state diagram

For a long time we searched without success for a homogeneous reaction in the cholesteric state until we began to study the cholesterylvinylfumarate monomer. In the following we present the polymer/monomer state diagram of this substance. 

Figure 3. Polymer/monomer state diagram of p-methyl, p -acryloyloxyazoxybenzene obtained by polarizing microscopy Mp composition (weight fraction of polymer). Characteristic points ( ), decreasing birefringence CY), mesomorphic transition mesomorphic melting (%), solidus (O), liquidus. The meaning of the areas (A), isotropic liquid (B), isotropic liquid -j- mesomorphic plasticized polymer (C), liquid (D), glassy states of plasticized polymer in mesomorphic phase (E), crystalline monomer -f mesomorphic plasticized polymer in the glassy state (F), crystalline monomer -j-mesomorphic plasticized polymer in the liquid state (G), mesomorphic monomer -f mesomorphic plasticized polymer in the liquid state.

Figure 4. Polymer/monomer state diagram of cholesterylvinylsucci-nate. composition (weight...

Figure 7. Polymer/monomer state diagram of cholesterylvinylfumarate obtained by DSC. (V), AHi initial stage of transition, (If), second peak (J, C, X and peaks or shoulders on the main transition of AH. ( ), AH initial stage of transition, (O), second peak on aHa transition.

Figure 10 shows the polymer/monomer state diagram of a copolymer prepared from -methyl, -acryloyloxyazoxybenzene and cholesterylvinylsuccinate and its original monomer mixture. The... 

In our present work the mesomorphic state polymerization was investigated from the point of view of solid-state polymerization. The thermodynamic interactions of monomers and polymers can he represented hy state diagrams. Effects reported hy Sadron et al. may only he expected in the homogeneous areas of the state diagrams. The thermodynamic conditions leading to such areas are fulfilled frequently in smectic states hut rarely in cholesteric or nematic ones. 

Figure 13. A schematic 3-dimensional state diagram for a hypothetical 3-component aqueous system. The two solutes (e.g. polymer + monomer) are toth non-ciystallizing, interacting, and plasticized by water, which is the crystallizing solvent. The diagram illustrates the postulated origin of a sigmoidal curve of Tg vs. w% solute composition. (Reproduced with permission from reference 3. Copyright 1988 Oxbridge University Press.)...

Conjugated polymers are generally poor conductors unless they have been doped (oxidized or reduced) to generate mobile charge carriers. This can be explained by the schematic band diagrams shown in Fig. I.23 Polymerization causes the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the monomer to split into n and n bands. In solid-state terminology these are the valence and conduction bands, respectively. In the neutral forms shown in Structures 1-4, the valence band is filled, the conduction band is empty, and the band gap (Eg) is typically 2-3 eV.24 There is therefore little intrinsic conductivity. 

PVDF is mainly obtained by radical polymerisation of 1,1-difluoroethylene head to tail is the preferred mode of linking between the monomer units, but according to the polymerisation conditions, head to head or tail to tail links may appear. The inversion percentage, which depends upon the polymerisation temperature (3.5% at 20°C, around 6% at 140°C), can be quantified by F or C NMR spectroscopy [30] or FTIR spectroscopy [31], and affects the crystallinity of the polymer and its physical properties. The latter have been extensively summarised by Lovinger [30]. Upon recrystallisation from the melted state, PVDF features a spherulitic structure with a crystalline phase representing 50% of the whole material [32]. Four different crystalline phases (a, jS, y, S) may be identified, but the a phase is the most common as it is the most stable from a thermodynamic point of view. Its helical structure is composed of two antiparallel chains. The other phases may be obtained, as shown by the conversion diagram (Fig. 7), by applying a mechanical or thermal stress or an electrical polarisation. The / phase owns ferroelectric, piezoelectric and pyroelectric properties. 

The state in which the system reached equilibrium is presented in part B of the diagram. The mixture of solvent, S, polymer, P, and monomer, M, has total volume V° before mixing and V after mixing. According to Aminabhavi and Munk the value q can be calculated. This value expresses extra weight of monomer per gram of polymer in comparison with the amount in the surrounding solution. The equation below can be used for calculation ... 

Let s take the PtH42 polymer as an example. The monomer units are clearly intact in the polymer. At intermediate monomer-monomer separations (e.g., 3 A) the major inter-unit-cell overlap is between z2 and z orbitals. Next is the xz, yz 7r-type overlap all other interactions are likely to be small. Diagram 27 is a sketch of what we would expect. In 27 I haven t been careful to draw the integrated areas commensurate to the actual total number of states, nor have I put in the two-peaked nature of the DOS each level generates all I want to do is to convey the rough spread of each band. Compare 27 to Fig. 8. 

Fig. 12. Equation of state (a) and phase diagram (b) of a bead-spring polymer model. Monomers interact via a truncated and shifted Lennard-Jones potential as in Fig. 6 and neighboring monomers along a molecule are bonded together via a finitely extensible non-linear elastic potential of the form iJpENE(r) = — 15e(iJo/

Figure 2 Temperature-concentration diagram of states of solution of fiexibie (pa1) (a) and semifiexibie (p>1) (b) polymer chains (the monomer unit iength a is set to unity).

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