Poly blends calculations

Figure 6.2 displays the results of % versus the weight fraction of poly(vinyl alcohol) (PVA) in PVA/chitosan (CS) blends calculated from Equations (6.5) and (6.7) [25]. Xcruiaii exhibits a linearity (around 0.18) over their studied composition range of the blends. For the blends from 10% to 40% weight fraction... 

Fig. 7a,b. Miscibility maps calculated at 25 °C for poly(alkyl methacrylate ) blended with a STVPh and b STHFS [83]... 

Diblock copolymers, especially those containing a block chemically identical to one of the blend components, are more effective than triblocks or graft copolymers. Thermodynamic calculations indicate that efficient compat-ibilisation can be achieved with multiblock copolymers [47], potentially for heterogeneous mixed blends. Miscibility of particular segments of the copolymer in one of the phases of the bend is required. Compatibilisers for blends consisting of mixtures of polyolefins are of major interest for recyclates. Random poly(ethylene-co-propylene) is an effective compatibiliser for LDPE-PP, HDPE-PP or LLDPE-PP blends. The impact performance of PE-PP was improved by the addition of very low density PE or elastomeric poly(styrene-block-(ethylene-co-butylene-l)-block styrene) triblock copolymers (SEBS) [52]. 

II 50/50 blends of poly(VC-rrw-VAc) and poly(ethylene-ran-VAc) at 160 °C symbols as in I. The solid and dashed curves were calculated as in I, the latter for infinite molecular masses [57]. 

The utility of the DSC for studying polymer-polymer miscibility has been demonstrated for poly(vinyl chloride)/nitrile rubber polyfvinyl methyl ether)/poly-styrene and poly(2,6-dimethyl 1,4-diphenylene oxide)/poly(styrene-co-chloro-styrene)It has also been particularly useful for measuring the melting point depressions of crystalline polymers in blends Mn order to calculate the interaction parameter as will be discussed later. 

IGC was used to determine the thermodynamic miscibility behavior of several polymer blends polystyrene-poly(n-butyl methacrylate), poly(vinylidene fluoride)-poly(methyl methacrylate), and polystyrene-poly(2,6-dimethyl-1,4-phenylene oxide) blends. Specific retention volumes were measured for a variety of probes in pure and mixed stationary phases of the molten polymers, and Flory-Huggins interaction parameters were calculated. A generally consistent and realistic measure of the polymer-polymer interaction can be obtained with this technique. 

As was already stated (see Figure 6), the temperature dependence of the shift factor aT is a function of the elastomer phase content. The strong effect of the rubber content on the temperature dependence of the shift factor aT could be explained by an increase in free volume of the SAN resin induced by the elastomer phase, as was suggested by Prest and Porter (13) for polystyrene-poly (phenylene oxide) blends. In order to verify this hypothesis, log aT experimental data for SAN and relative blends were used to calculate the WLF parameters and, in turn, the free volumes (f0) at the reference temperature (T0) and the thermal expansion coefficients (a) by the equation ... 

IPN crosslinked PBA, crosslinked uncrosslinked SAN Poly(p-hydroxy styrene), PVPh and EVAl Acrylic core-shell copolymer and either PBT or PET Poly(allyl methacrylate-co-butyl acrylate-co-butanediol dimethacrylate-co-styrene-co-methyl methacrylate) or poly (aery lonitrile-co-butyl aery late-co-tricy clodeceny 1 aery late-co- styrene) Poly(acrylate-V-cyclohexyl maleimide), PMI, and a copolymer PMMA — core, crosslinked butyl acrylate-styrene copolymer — middle layer, and PMMA shell d = 200-300 nm PEG/atactic PMMA blends were characterized by PVT at T = 20-200°C and P = 0-200 MPa. Free volume fraction was calculated from an equation of state... 

For less demanding thermodynamic calculations, Eq 2.41 can be simplified. Thus, to express conditions of miscibility in PS blends with poly(styrene-co-4-bromostyrene) the binary interaction parameter per one mer of styrene (within the T = 440-500 K region) was expressed as [Strobl et al, 1986] ... 

In systems 1-solvent, 2-polymer, and 3-poly-mer, any method that determines either AG or its derivatives should make it possible to calculate Thus, for example, osmotic pressure measurements were used to characterize PS/PVME blends... 

The permeability coefficients of (alkylsulfonyl)methyl-substituted poly(oxy-alkylene)s and their blends were calculated by measuring the permeability coefficients of the composite films and using the following equation (77) ... 

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