Phase diagram methacrylate /methyl

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)...

Figure 6.3. The metastable phase diagram for the polyure-thane-poly(methyl methacrylate) SIN at 60°C. The PMMA gels at and above the plane Gj- U -PU. The intersection of the PMMA gelation plane and the surface along the curve A represents the condition of simultaneous phase separation and PMMA gelation.

Figure 4 Ternary phase diagram for the system methyl methacrylate (MMA)-acrylic acid (AA)-20 wt% solution of sodium dodecylsulfate in water (w/SDS)-ethylene glycol dimethacrylate (EGDMA) at 25 0.1°C and 1 atm. Compositions are on weight percent basis EGDMA content is 4% of the combined weight of MMA and AA. Domain A, two-phase region domain B, W/O microemulsion domain C, bicontinuous microemulsion domain D, OAV microemulsion. (From Ref 50.)...

The phase diagrams of the ternary systems allow one to make a direct comparison between emulsion and microemulsion polymerization processes just by varying the surfactant concentration, as shown by Gan and coworkers [84,91,127]. Figure 8 represents the polymerization rate conversion curves for methyl methacrylate polymerization at different surfactant concentrations. 

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. 

The effect of a simple shear flow on the phase behavior and morphology was investigated with the use of a parallel-plate apparatus (Fig. 8.4, Madbouly et al. 1999a) for some polymer mixtures poly(methyl methacrylate) (PMMA)/ poly(styrene-co-acrylonitrile) (SAN-29.5) and polystyrene (PS)/poly(vinyl methyl ether) (PVME), which have an LCST-type phase diagram PS/PMMA, which has a UCST-type phase diagram and polycarbonate (PC)/SAN and nylon4, 6(PA4,6)/ poly(phenylene sulfide) (PPS), which are immiscible in the whole measurable region under the quiescent state. 

Methacrylic acid-c< -methyl methacrylate Methyl metiiacrylate-co-4-vinylpyridine Phase diagram I had 91.48 or 77.7 mol% methyl methacrylate II had 80.2 mol% methyl methacrylate Djadoun (1983)... 

From studies of styrene-aaylonitrile copolymer (SAN) and poly(methyl methacrylate) (PMMA) blends, Higashida et al. [75] used previously determined values of the interaction parameter between styrene (S) and acrylonitrile (AN) units [76] and phase diagrams of PCL/SAN blends obtained by Chiu and Smith [20] to estimate values of Xs/pcl Xan/pcl functions of temperature and AN content On this basis they calculated phase diagrams similar to that determined experimentally by Chiu and Smith [20]. They also predicted that mixtures of PS and PCL oHgomers should be miscible at low temperatures and that such mixtures should exhibit UCST behaviour which was in agreement with experimental observations values of the interaction parameters determined by Higashida are quoted in Table 4. 

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. 

Phase Separation and Gelation Studies. A phase diagram of linear poly(ethylene oxide) (LPEO) and divinyl benzene (DVB) cross-linked poly(methyl methacrylate) as a function of polymerization of the latter was also researched hy duPrez and co-workers (49) (Fig. 11). The temperature of measurement was also a variable, but the curve separating the one-phased system from the two-phased system did not change much in the narrow temperature range covered. 

Fig. 11. A ternary phase diagram of the semi-IPN based on methyl methacrylate, poly(methyl methacrylate), and linear poly(ethylene oxide).

Fig. 13. A tetrahedron metastable phase diagram for the SIN polymerization of poly(methyl methacrylate) and polyurethane.

Fig. 9.3 a, b. Phase diagram in butanone of a copoly(methyl methacrylate-methacrylic acid) and b copoly(styrene-vinylpyridine) according to Morawetz et al. [16]. The contents in methacrylic acid and vinylpyridine (percent of monomer units in the chains) are respectively a. 0% 0% (homopolymers) — —... 

Nwabunma D, Kyu T (2(X)1) Phase behavior, photopolymerization and morphology development in mixtures of eutectic nematic liquid crystal and photocurable monomer. Polymer 42 801-806 Ohta S, hiasawa S, Yamaguchi Y (2012) Size control of phase-separated liquid crystal droplets in a polymer matrix based on the phase diagram. J Polym Sci Part B Polym Phys 50 863-869 Parab SS, Malik MK, Deshmukh RR (2012) Dielectric relaxation and electro-optical switching behavior of nematic liquid crystal dispersed in poly (methyl methacrylate). J NonCryst Solids 358 2713-2722... 

Both, natural and synthetic polymers with associative properties arising from hydrophobic interactions give aqueous solutions with LCST. Among the most known systems having LCST behaviour should be mentioned polyethylene glycol-water and aqueous solutions of methyl cellulose. Also, in poly(methacrylic) acid, LCST phase diagrams were determined from the change in shear modulus and turbidity. For alkali chitin, the main key role played by hydrophobic interactions in LCST is evident from the decrease in the fluorescence ratio observed in Fig. 3b. 

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