Polystyrene blend with poly vinyl methyl

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... 

The best characterized system has been polystyrene blended with poly(vinyl methyl ether). Several studies showed that this system is miscible... 

The application of this technique as a morphological tool requites that there be a close coupling between polymer photophysics and polymer physics. In the photophysical studies described in this paper emphasis will be placed on the development of analytical models for electronic excitation transport (EET). The areas of polymer physics that we will consider involve the configurational statistics of Isolated chains and phase separation in multicomponent polymer systems. The polymer system of primary interest is the blend of polystyrene (PS) with poly(vinyl methyl ether) (PVME). 

Higher amounts of AN raise this curve to above the decomposition temperature however, at 13% or more AN the SAN copolymers are not miscible with MPC. Polystyrene forms miscible blends with poly-(vinyl methyl ether), PVME, that phase separate at quite low temperatures. Copolymerization of very small amounts of acrylic acid with styrene dramatically elevates the phase separation... 

ABSTRACT. Excimer fluorescence is developed as a quantitative probe of isolated chain statistics and intermolecular segment density for miscible and immiscible blends of polystyrene (PS) with poly(vinyl methyl ether) (PVME). Rotational isomeric state calculations combined with a one-dimensional random walk model are used to explain the dependence of the excimer to monomer intensity ratio on PS molecular weight for 5% PS/PVME blends. A model for a three-dimensional random walk on a spatially periodic lattice is presented to explain the fluorescence of miscible PS/PVME blends at high concentrations. Finally, a simple two-phase morphological model is employed to analyze the early stages of phase separation kinetics. 

Examples of known phosphazene polymer blends are those in which phosphazenes with methylamino, trifluoroethoxy, phenoxy, or oligo-ethyleneoxy side groups form blends with poly(vinyl chloride), polystyrene, poly(methyl methacrylate), or polyethylene oxide).97 100 IPNs have been produced from [NP(OCH2CH2OCH2CH2OCH3)2] (MEEP) and poly(methyl methacrylate).101-103 In addition, a special type of IPN has been reported in which a water-soluble polyphosphazene such as MEEP forms an IPN with a silicate or titanate network generated by hydrolysis of tetraethoxysilane or tetraalkoxytitanane.104 These materials are polyphosphazene/ceramic composites, which have been described as suitable materials for the preparation of antistatic layers in the manufacture of photographic film. 

The materials analyzed were blends of polystyrene (PS) and poly(vinyl methyl ether) (PVME) in various ratios. The two components are miscible in all proportions at ambient temperature. The photooxidation mechanisms of the homo-polymers PS and PVME have been studied previously [4,7,8]. PVME has been shown to be much more sensitive to oxidation than PS and the rate of photooxidation of PVME was found to be approximately 10 times higher than that of PS. The photoproducts formed were identified by spectroscopy combined with chemical and physical treatments. The rate of oxidation of each component in the blend has been compared with the oxidation rate of the homopolymers studied separately. Because photooxidative aging induces modifications of the surface aspect of the material, the spectroscopic analysis of the photochemical behavior of the blend has been completed by an analysis of the surface of the samples by atomic force microscopy (AFM). A tentative correlation between the evolution of the roughness measured by AFM and the chemical changes occurring in the PVME-PS samples throughout irradiation is presented. 

Blends of polystyrene with poly(vinyl methyl ether) have been examined by Gelles and Frank (1 9) and the results analysed using sophisticated statistical methods involving e.e.m. A number of important assumptions are made ... 

Figure 6.2 Plot of /(0)-1 against 1 IT, where the extrapolated zero-angle intensity 7(0) was obtained by neutron scattering with blends of poly(vinyl methyl ether) and deuterated polystyrene. The molecular weight of poly(vinyl methyl ether) is 64.3 x 103, and the molecular weight and volume fraction of the deuterated polystyrene are, respectively, 783 x 103 and 0.13 for sample I, 379 x 103 and 0.13 for sample II, and 232 x 103 and 0.20 for sample III. (From Schwahn et al.6)...

The theory was found to predict complex behavior near the phase separation conditions. As the rate of shear increases, first, the system undergoes homogenization, then demixing, followed by another homogenization and demixing. At high rates of shear, the system should behave similarly as in a quiescent state. These predictions were found to be in qualitative agreement with experimental data, e.g., for blends of ethylene-vinylacetate copolymer with chlorinated polyethylene, EVAc/CPE, or polystyrene with poly(vinyl methyl ether), PS/PVME [Hindawi et al., 1992 Eernandez ef fl/., 1993, 1995]. 

Blends of polystyrene(PS) and poly(vinyl methyl ether) (PVME) have attracted much interest because of their compatibility over a wide range of blend composition . The compatibility of PVME with styrenic copolymers has also been extensively investigated. 

Thin films of blended deuterated polystyrene (dPS) and poly(vinyl methyl ether) (PVME) were imaged as a fimction of the dPS PVME ratio. Near the critical composition of 35% dPS, an imdulating, spinodal-like structure was observed, whereas for compositions away from the critical mixture ratio, regular mounds or holes (< dPS < < crit and < dPS > (pent, respectively) were present. These variations were assigned to surface tension effects (120). Blends of PBD, SBR, isobutylene-brominated p-methylstyrene, PP, PE, natural rubber, and isoprene-styrene-isoprene block rubbers were imaged (Fig. 18). Stiff, styrenic phases and rubbery core-shell phases were evident as the authors utilized force-modulated afm to determine detailed microstructure of blends, including those with fillers such as carbon-black and silica (121). 

The characterization of surface structure for miscible blends is a more formidable task, requiring techniques that are sensitive to the composition of the blend within several nanometers of the surface. X-ray photoelectron spectroscopy (xps) provided the first direct and quantitative evaluation of surface composition and surface composition gradients for miscible polymer blends of poly(vinyl methyl ether) (PVME) and polystyrene (PS) (22,23). Since that time, the situation has changed dramatically with the advance of theory and the application of exciting new experimental techniques to this problem. In addition to xps and pendant drop tensiometry (22,23), forward recoil spectroscopy (28), neutron (29) and x-ray reflectivity (30), secondary ion mass spectroscopy (either dynamic or time-of-flight-static) (31,32), and attenuated total reflectance Fourier transform infrared spectroscopy (33-35), have been applied successfully to study surface segregation. The advent of these new tools has enabled a multitechnique experimental approach toward careful examination of the validity of current surface segregation theories (36-39). 

Figure 1-23. A synchronous 2D IR spectrum of a blend comparing the reorientational motions of transition dipoles associated with the polystyrene phenyl and poly(vinyl methyl ether) methoxyl groups [57).

Miscibility and interactions in polystyrene and sodium sulfonated polystyrene with poly(vinyl methyl ether) PVMF blends. Part II. FTIR. Polymer, 44, 6627-6631. 

The samples used are the polystyrene (PS) and poly(vinyl methyl-ether) (PVME) blends whose mechanical properties can be freely changed by controlling the blend ratio. In this case, in order to make the sample the measurement standard, the molecular weight of the polystyrene used is relatively low to avoid phase separation at room temperature. Ordinarily, the modulus of PS is on the order of GPa and PVME is on the order of MPa the moduli of blends can vary continuously in the range of these values as a function of the blend ratio. This is why this blend system was chosen as the standard of mechanical properties. The cantilever used is a V-shaped lever with thickness of 0.8 pm and length of 100 pm. At the tip, a very small Si3N4 scanning needle is fixed. The modulus of the cantilever is 0.68 N/m, which is stiffer than the one for ordinary contact measurement. Two different measurements were conducted. The first is the... 

All of the fluorescence observations were successfully interpreted in terms of the Flory-Huggins thermodynamics. This indicates that, although the possible existence of kinetic restrictions must be recognized, they may be less significant if the only objective is to explain the occurrence of changes in the photophysical parameters. In a later chapter, we review work on blends of polystyrene with poly(vinyl methyl ether) that permits interpretation of the absolute values of the photophysical parameters. 

Fig. 14 Creation of a single specimen polymer blend phase diagram from orthogonal polymer composition and temperature gradients. The polymers are polystyrene and poly(vinyl methyl ether) (PVME) a composition library placed orthogonal to a temperature gradient b completed gradient library polymer blend phase diagram. White points are data derived from traditional measurement for comparison. See text for details, (b reproduced with permission from [3])...

Consider a binary polymer blend [43] of deuterated polystyrene, PSD, (Mw = 1.95 x 10s g/mole, Mw/Mn = 1.02) and poly(vinyl methyl ether), PVME, (Mw = 1.59 x 10s g/mole, Mw/M = 1.3) with a composition of 48.4% PSD (volume fraction). SANS data were taken at various temperatures ranging from ambient to 160°C. De Gennes s RPA formula ... 

RamachandraRao VS, Watkins JJ. Phase separation in polystyrene-poly(vinyl methyl ether) blends dilated with compressed carbon dioxide. Macromolecules 2000 33 5143-5152. 

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