Phenoxy blends

The transport and sorption of water in miscible PES/Phenoxy blends has been studied at 40 °C as a function of blend composition [17]. The isotherms are essentially linear over much of the activity range. The highest values of sorption, diffusion and permeation have been observed for PES with a volume percent of 100, and the lowest values for pure phenoxy. The intermediate compositions show decreasing values with decreases in PES content. In an earlier study of this system [18], the isotherms for the pure components and blends were reported to be practically coincident, except for activities 0.7 where the sorption at a given activity was increased significantly with the phenoxy content of the blend. The differences in sample preparation or incomplete removal of solvent may be responsible for these discrepancies. 

The incorporation of impermeable clay particles into PET (which is a semicrystalline polymer) can improve the barrier properties of PET nanocomposites towards gases and water vapor. This, in turn, results in outstanding property improvements in terms of a decreasing water permeability for food packaging and an increasing flame resistance. When a new system of saturated polyesters 

The sorption isotherms showed that the PHS-5 copolymer absorbed less water vapor than did PMMA, whilst the PHS-15 copolymer (with more polar hydroxyl groups) absorbed more water vapor than did PHS-5, but still less than did PMMA. In both blends the vapor solubility was decreased with increasing amounts of the copolymer. It is well known that, in relatively nonpolar polymers, there is a tendency for the sorbed water molecules to associate or form clusters. Composed predominantly of styrene units, the PHS-5 polymer is relatively nonpolar and the tendency for the sorbed water molecules to form clusters is greatest. 

The cluster function is much smaller for PMMA, when the clustering values in the blend are decreased with decreasing amounts of PHS-5. The clustering of sorbed water molecules is reduced in PHS-15, which contains a larger proportion of polar groups than PHS-5, to a point that it is almost indistinguishable from the clustering in PMMA. 

In fact, for several blends the diffusion coefficients were higher than the average values for the component polymers. 

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Kim HC, Nam KH, Jo WH. The effect of a styrene-methyl methacrylate block copolymer on the morphological, rheological and mechanical properties of poly(2-6-dimethyl-l,4-phenylene ether) (PPE) and poly(hydroxyether of bis-phenol A) (phenoxy) blends. Polymer 1993 34 4043-4051. 

Figure 3.5. Spherulite growth of PCL/Phenoxy blends at T = 45°C [Defieuw et al., 1989d].

Fig. 52. Glass-transition temperature variations in PCL/phenoxy blends (O) data from [137] and (A) from [59], lines calculated from theoretical equations taken from [137]...

Espi and Iruin made estimates of phenoxy miscibility with several polyesters using a group contribution method [135]. Their data were compared with heats of mixing of model compounds and, on that basis, they concluded that PCL/phenoxy blends have negative enthalpies of mixing, which contradicts the conclusions of Coleman and Moskala [85]. 

Fig.53a,b. P-Relaxations in PCL/phenoxy blends for a PCL relaxations b phenoxy relaxations for different compositions of the blends taken from [138]... 

Fig. 54. Variations in P-relaxation maxima for PCL ( ) and phenoxy (A) in PCL/phenoxy blends adapted from [138]...

Fig. 78. Ternary phase diagram for PCL/PC/phenoxy blends (O) single Tg and clear melt, ( ) single Tg and cloudy melt, (x) two TgS and cloudy melts, cmve is calculated boundary between single and multiple phases as described in text taken from [166]...

Qipeng demonstrated that PCL/PVME blends were also characterised by single, composition-dependent TgS (Sect. 18.2). Similarly, all ternary blends of the three polymers exhibited single glass transition temperatures which agreed with values calculated from l/T=I(w/Tgj), an extension of Eq. (23) to multiple components. The author concluded that the polymers were miscible in all proportions but made no reference to the occurrence of PCL crystallisation in the samples. Cloud points were also determined in PCL/PVME and phenoxy/PVME blends PCL/phenoxy blends remained clear to 200 °C. All ternary systems exhibited cloud points and the minimum of the connecting surface was 108 °C at a PCL/phenoxy/PVME composition of 25/25/50. 

Figure 5.2 Tg data for poly(ethyleneoxide)/phenoxy blends (Reprinted (replotted) with permission from Robeson, L.M., Hale, W.F.and IVlerriam,C.N.,/Mocromo/ecu/es(1984) 14,p.l644,copyright(1984) American Chemical Society)...

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