Terpolymers, structural calculations

Under the copolymerization of more than two monomers Eqs. (5.3) cannot be integrated explicitly, and in order to determine the system trajectories one should need the numerical calculations. Examples of such calculations of the conversional change of composition and structure characteristics of the terpolymers have been reported in Refs. [195-200]. One should pay special attention to Ref. [200] where the programs for the computer realization of such calculations are presented. Under the copolymerization of four or more monomers, the composition drift with the conversion was calculated [7,8] only within the framework of the simplified terminal model described above in Sect. 4.6. 

We have previously reviewed ( 1, 2) the methods used to calculate structural features of copolymers and terpolymers from monomer reactivity ratios, monomer feed compositions and conversions, and have written a program for calculating structural features of copolymers from either terminal model or penultimate model reactivity ratios (3). This program has been distributed widely and is in general use. A listing of an instructive program for calculating structural features of instantaneous terpolymers from monomer feed compositions and terminal model reactivity ratios was appended to one of our earlier reviews (.1). 

This program was written to calculate structural features of terpolymers prepared via the following propagation reactions from radicals AA, BA, CA, B and C and from monomers A, B and C. Reactivity ratios utilized by this program are also defined in the following scheme ... 

Fig. 24 SAXS pattern of PI-/7-PS-/ -P2VP- -PI tetrablock terpolymer. Sample geometry is edge view with incident X-rays parallel to film surface. Vertical thick bars at lower section denote calculated diffracted intensities based on non-centrosymmetric periodic structure shown in Fig. 23b solid curve domain scattering calculated using profile of two-step stairs. Vertical dotted bars calculated intensities based on centrosymmetric structure shown in (d) dashed curve domain scattering for symmetric profile in same figure. From [89]. Copyright 2003 American Chemical Society...

Theoretical approximations and morphology predictions were recently carried out for miktoarm star terpolymers of the ABC type. The literature concerning theoretical predictions for this complex architeaure is rather limited, as the synthesis of such materials leading to morphologically three-phase stmaures has been developed rather recently. The behavior of miktoarm star terpolymers was simulated using the Monte Carlo calculation method. This approach was already used for the microdomain structural behavior of diblock copolymers of the AB type, and the consideration that needed to be taken into account for the calculations was the addition of the C chain at the common junction point of the A... 

Fig. 7.37. (a) The temperature dependence of the domain spacing D calculated from the first-order scattering maxima for SAXS ( ) and SANS ( ) from a Pl-b-DPS-b-PVME triblock terpolymer, and schematic models for the domain structure at (b) T < 140 °C and (c) T > 140 °C. The spheres shown as open (o) and filled ( ) circles represent domains composed of PI and PVME blocks, respectively. (Reproduced with permission from [255]. Copyright 2002, Wiley-VCH, Weinheim.)... 

The morphology in linear ABC was reported independently by two research groups in 1999. Shefelbine et al reported a mesostructure in PI-PS-PDMS frustrated system. With only SAXS and TEM investigations they could not confirm the structure. But by supplementing their experimental analysis with SCFT calculations they could conclude that the PI-PS-PDMS triblock terpolymer had formed a pentacontinuous morphology with two discrete domains... 

---