Phase Diagram Of Poly Research Articles

Miscibility and phase diagrams of poly(phenyl acrylate) and poly(styrene- co-acrylonitrile) blends

The miscibility of blends of poly(phenyl acrylate) (PPA) and poly(styrene- co-acrylonitrile) (SAN) of different copolymer compositions has been studied by a film clarity test, T g and cloud-point ( T p) studies. It was revealed that the miscibility of solvent-cast blends varies greatly from solvent to solvent. Careful annealing of solvent-cast blends below the cloud temperature and above the T g removed the solvent effect on the lower AN content side of the miscibility window. On the higher AN content side of the miscibility window the solvent effect could not be removed by annealing at the highest permissible temperature ( < T p ⋍ 220° C ). The phase diagrams of the blends were determined. The miscibility window at various temperatures has been constructed. It ranges between 11.5 and 32 wt% AN at 200°C. The various binary polymer segment interaction parameters have been evaluated using the composition of the miscibility window and the mean-field model.

Miscibility and phase diagrams for poly(vinyl methyl ether) and polyacrylate blend systems

The miscibility of binary polymer blend systems consisting of poly(vinyl methyl ether) (PVME) and polyacrylates has been studied. Based on film clarity, glass transition temperature and cloud-point studies, PVME is found to be miscible with poly(ethyl acrylate), poly(n-propyl acrylate) and poly(n-butyl acrylate) but not with poly(methyl acrylate). The phase diagrams of some of these blends are reported.

Poly(p-phenyleneterephthalamide) and poly(m-phenyleneisophthalamide): positional isomers with partial miscibility

The phase diagram of poly(p-phenyleneterephthalamide) (Pp-PT) and poly(m-phenyleneisophthalamide) (Pm-PI) was investigated by means of solid-state 13 C-NMR T 1ρ H decay, WAXD, and DSC scans. It indicates only a limited range of polymer miscibility and wide compositional intervals in which several phases, amorphous and crystalline, coexist. The densities of the amorphous Pm-PT were measured and are sufficiently different to produce χ 12 values and differences in solubility parameters large enough to explain the marginal solubility of the maorphous phases of Pp-PT and Pm-PI in each other

Equilibria of extended‐chain polymers exhibiting crystalline and liquid‐crystalline phases

AbstractThe phase diagram of poly(p‐benzamide) (PBA) in N,N‐dimethylacetamide/LiCl solutions was determined for two PBA samples having weight‐average molecular weights of about 10,000. The various equilibria were studied using analytical, viscometric, and optical microscope measurements. The phase diagram at 25°C, taking as variables the concentration of polymer (Cp) and LiCl (Cs), involves several equilibria which can be summarized as follows: solid ↔ isotropic solution when 0.75 ≤ Cs ≤ 2 g/dl, solid ↔ anisotropic solution when 2 ≤ Cs ≤ 4 g/dl, isotropic solution ↔ anisotropic solution when 2 ≤ Cs ≤ 4 g/dl, and Cp &gt; 6 g/dl, and dilute isotropic solution ↔ gel when Cs &gt; 4 g/dl. In the Cp range in which the isotropic and anisotropic phases coexist, enrichment of the high‐molecular‐weight component of the polymer in the anisotropic phase becomes more marked as the volume fraction of the latter phase is decreased. The two PBA samples exhibit noticeable differences in solubility, absolute viscosity, and in their viscosity‐concentration behavior. The location of the maximum in the latter dependence does not necessarily coincide with the first appearance of the anisotropic phase. In the absence of a flow field, anisotropic solutions exhibit an irreversible increase in viscosity. Inclusion of the equilibria involving the crystalline state furnishes insight into some of the common observations for extended‐chain polymers. A diagram illustrates the superposition of the solubility curves for a crystalline polymer and the liquid‐crystal regions. This indicates that, for the high melting crystalline polymers, the crystalline phase should be stable relative to the concentrated anisotropic phase of the wide biphasic region.

Phase diagram of poly(vinyl chloride) and solution chlorinated polyethylene

The behaviour of mixtures of poly(vinyl chloride) (PVC) and solution chlorinated polyethylene (SCPE) has been investigated as a function of temperature. These polymers have been found to be compatible over some ranges of composition and exhibit the phenomenon of a lower critical solution temperature ( LCST). The thermally-induced phase separation has been investigated by optical, dynamic mechanical, and electron microscope techniques. The single phase mixture has been investigated by scanning analytical electron microscopy. Some investigation of the thermodynamics of the mixture has been made and the heat of mixing term has been found to be negative and small, i.e. favouring mixing. It has been shown that the technique of in situ polymerization overcomes many of the problems of preparing these polymer mixtures in the solid state.