Lattice fluid theory in the analysis of interaction parameters and phase behaviour of blends involving copolymers of cyclohexyl methacrylate, methyl methacrylate and various styrene derivatives

Comparison of Lattice-Fluid Binary Parameters For Mixtures and Block Copolymers

“…The scaling parameters reported for PCL are 641 K, 540.1 MPa, and 1182 kg m −3 , for T * , P * , and ρ * respectively. [54] Note that the P * and ρ * parameters obtained in this study are similar to those previously reported for the same homopolymers, whereas the T * parameters are lower but of the same order. It is pertinent to mention that Orbey et al found that different sets of the three input parameters in the SL equation of state gave equally acceptable pure component property estimates.…”

Compositional Variation of Glass-Transition Temperature in Miscible Polymer Blends Involving Weak and Strong Specific Interactions

“…PS and PPMS are shown to be miscible over the entire range of compositions with PCHMA. [25] These blends showed a single T g , which was composition dependent and was situated between those of the pure components. The T g -composition diagrams for the miscible PCHMA/PS and PCHMA/PPMS blends showed a negative miscibility deviation, and are shown in Figure 1 and 2, respectively.…”

“…between the vinyl phenol units. For example, as a consequence of the reduction of OH1OH interactions in the copolymer (poly[styrene 75 -co-(vinyl phenol 25 )]), the flex energy of the copolymer (Table 3) has a much lower value than does pure PVPh. Recently, Boudouris et al [34] have developed a group contribution approach to predict theoretically the flex energies of pure polymers which could be very useful when no PVT data exists for a given polymer.…”

“…The T g -composition diagrams for the miscible PCHMA/PS and PCHMA/PPMS blends showed a negative miscibility deviation, and are shown in Figure 1 and 2, respectively. This behaviour corresponds to blends with weak interactions in which, although favourable interactions P* exist [25] (DP * CHMA/S = -0.15 cal N cm -3 and DP * CHMA/PPMS = -0.08 cal N cm -3 ), the weak interactions and lack of symmetry effects decreases the packing of the blend (the free volume increases) and in consequence, T g appears below additivity. [35,36] The T g of these mixtures can be predicted by solving numerically Equation (21) for composition dependent T 2 , putting S = 0 at T 2 .…”

“…As a result, the framework of this last blend becomes stiffer (k 12 is negative) and given that the packing of the mixture increases, the observed positive T g deviation is therefore expected. Finally, we studied a compatible blend system, PCHMA/P(S 75 -co-VPh 25 ), for which the T g -composition curve is S-shaped. In this system, there is a blend packing increase by the hydrogen interaction between PCHMA and VPh unit and also, a packing decrease related to the entropy increase by the interaction between PCHMA and S. These two behaviours compete with each other, and if in the PCHMA rich region, where almost no hydrogen bonds exists, the entropy increase dominates, at the rest of the compositions the hydrogen bonding contribution to the T g should be taken into account.…”