Poly polystyrene system phase diagram

Mutually compatible polymers are relatively rare [84,85], A typical phase diagram of two incompatible polymers and a common solvent is that determined by Kern for the polystyrene - poly(p - chlorostyrene) - benzene system shown in the Fig. 1.11 [86],... 

The phase relationships of two-phase polymer systems also have been of considerable interest in recent years. In an important series of papers, Molau and co-workers (19-24) studied systems, which were denoted POO emulsions (polymeric oil-in-oil), prepared by dissolving a given polymer in monomer and then polymerizing the monomer. During polymerizations of this type the composition of the respective phases reverses, and a phase inversion process was proposed to explain this. A similar process has been suggested as the mechanism by which poly-butadiene forms the dispersed phase in the manufacture of high-impact polystyrenes (22,25). Recently, Kruse has pointed out that this phase-inversion point may correspond to that point on a ternary phase diagram at which the reaction line bisects a tie line (26), and we have advanced a similar point of view in our earlier reports (17,18, 27). 

In the previous section we have described the three types of phase behavior observed in the low-molecular-weight PMMA/PS system and reviewed the four types observed in the low-molecular-weight PS/PMMA system. These various phase relationships have been studied in terms of their dependence on the molecular weight (Mn) and weight percent (W) of the initial polymer present. Further, we have presented quantitative data concerning the sizes of the dispersed particles, again correlated to variations in Mn and W. In this section we will discuss the results in terms of the poly (methyl methacrylate )/polystyrene/styrene and poly-styrene/poly( methyl methacrylate)/methyl methacrylate ternary phase diagrams, whichever is appropriate. 

Figure 20. Assumed ternary phase diagram for the poly(methyl methacrylate)/polystyrene/styrene system for two molecular weights of poly(methyl methacrylate)...

Gervais M, Gallot B (1973) Phase diagram and structural study of polystyrene - poly(ethylene oxide) block copolymers. 1. Systems polystyrene/poly(ethylene oxide)/diethyl phthalate. Makromol Chem 171 157-178... 

In the case of polystyrene blends with poly(vinyl methyl ether) two phase behaviour was found for blends from various chlorinated solvents whereas single phase behaviour was found for blends from toluene The phase separation of mixtures of these polymers in various solvents has been studied and the interaction parameters of the two polymers with the solvents measured by inverse gas chromatography It was found that those solvents which induced phase separation were those for which a large difference existed between the two separate polymer-solvent interaction parameters. This has been called the A% effect (where A% = X 2 Xi 3)-A two phase region exists within the polymer/polymer/solvent three component phase diagram as shown in Fig. 2. When a dilute solution at composition A is evaporated, phase separation takes place at B and when the system leaves the two phase region, at overall... 

Miscible blends of poly(vinyl methyl ether) and polystyrene exhibit phase separation at temperatures above 100 C as a result of a lower critical solution temperature and have a well defined phase diagram ( ). This system has become a model blend for studying thermodynamics of mixing, and phase separation kinetics and resultant morphologies obtained by nucleation and growth and spinodal decomposition mechanisms. As a result of its accessible lower critical solution temperature, the PVME/PS system was selected to examine the effects of phase separation and morphology on the damping behavior of the blends and IPNs. 

Three component triangular diagrams. Both Cowell et al. (1978) and Vincent et al. (1980) presented what they termed three component phase diagrams for aqueous systems composed of water (or electrolyte solution), free poly(oxyethylene) and polystyrene latex particles sterically stabilized by poly(oxyethylene). Such a diagram is reproduced in Fig. 16.7. 

Four types of phase behavior characteristic of the PS/P(MMA-S) system have been described and illustrated in some detail in the previous section and further, the average particle sizes have been tabulated as a function of molecular weight and weight percent of PS initially present in the PS/MMA-S mixture and of the composition of the final P(MMA-S) copolymer resulting after polymerization. In the section we will discuss these results in terms of the ternary polystyrene/poly(methyl methacrylate-styrene)/methyl methacrylate-styrene phase diagram, dealing with (1) the four types of phase relationships, (2) particle size, and lastly (3) multiple emulsions or subinclusions within the dispersed phase. 

In practice, the existence of both UCST and LCST has been established for polymer-solvent systems. About 10 years ago, Schmitt discussed UCST, LCST and combined UCST and LCST behavior in blends of poly(methyl methacrylate) with poly(styrene-co-acrylonitrile) (PMMA-PSAN), Ueda and Karasz reported the existence of UCST in chlorinated polyethylene (CPE) blends using DSC, Inoue found that elastomer blends of cis-l,4-polybutadiene and poly(styrene-co-butadiene) exhibit both UCST and LCST behavior and Cong et al. (72) observed that blends of polystyrene and carboxylated poly(2,6-dimethyl-l,4-phenylene oxide) copolymers with a degree of carboxylation between molar fraction 8% and 10% exhibit both UCST and LCST behavior. They used DSC to establish the phase diagram. 

Figure 1 (a) Three-component phase diagram for the system polystyrene-poly(vinyl methyl ether)-chloroform (i) postulated phase diagram for the system PVC-chlorinated polyethylene-vinyl chloride... 

MIY Miyashita, N., Okada, M., and Nose, T., Critical exponents and phase diagram of polymer blend solutions Polystyrene/poly(methyl methaciylate)/d6-benzene system. Polymer, 35, 1038, 1994. 

Other recent studies which involve and illustrate the power of the FTIR technique include surface studies of PVC systems with PMMA [192] and poly(e-caprolactone) (PCL) [193, 194] PVC with styrene/acrylonitrile copolymers [195] polyester/nitrocellulose [196] EVA copolymer with PVC and chlorinated polyethylene (CPE) [197] and interactions in blends involving p-sulphonated polystyrene [198, 199]. FTIR techniques have been used to map the phase diagram of an aromatic polyamide-poly(ethylene oxide) blend [200], while microscopy-FTIR has been used to obtain information on intermolecular interactions and conformational changes in specific domains in functionalised polyolefins with PVC or polystyrene [201]. Segmental motions and microstructure studies from combined DSC and FTIR measurements have been used to interpret solid-state transitions in miscible rubber blends [202]. 

Figure 7.9 Small-angle neutron scattering experiments of polymer blends of polystyrene (PS) and poly(methylstyrene) (PMS) showing the agreement with the RPA-result /" (< ) linear in q. The inset shows schematically the phase diagram, which for the PS/PMS system...

In spite of this, an attempt has been made to construct a phase diagram for the curing semi-IPN based on poly(butyl methacrylate) (PBMA) and styrene-divinylbenzene (DVB) copolymer (Fig. 1) [53]. The system polystyrene (PS)/PBMA shows limited compatibility at low concentrations and low molecular mass of components, and full incompatibility at higher concentrations and molecular weights. With increasing conversion, the quality of the solvent (mixture of styrene and DVB) becomes poorer in relation to PBMA. As a result, after reaching a certain degree of conversion, the system can no... 

Practically, the addition of a nonadsorbing polymer to a dispersion can induce flocculation of dispersed particles due to the depletion attraction. This was first observed by Cowell, Lin-In-On, and Vincent [1434]. When large amounts of poly (ethylene oxide) are added to an aqueous dispersion of hydrophilized polystyrene latex particles, the particles start to flocculate. For an organic dispersion, namely, hydrophobized silica particles in cyclohexane, de Hek and Vrij [1435] observed depletion-induced flocculation when dissolved polystyrene was added. Other combinations of particles and polymers followed [1436]. Phase diagrams for different particle-solvent-polymer systems were successfully drawn using the depletion potential of Asakura as interaction potential between dispersed spheres [1437] and for dissolved polymers using statistical mechanics [1438]. 

CHA Chalykh, A.E., Prokopov, N.I., Gritskova, I.A., and Gerasimov, V.K., Phase equihbriitm diagrams for polystyrene-poly(methyl methacrylate)-styrene systems (Russ.), Vysokomol. Soedin., Ser. A, 38, 1888, 1996. 

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