Blend studies polystyrene/poly

Chen and Gardella used this surface engineering strategy to create siloxane-rich surfaces [40]. Their approach involved the blending of a homopolymer (A) with a block copolymer composed of a block with the same chemical identity as the homopolymer (A) and a block of PDMS. For all homopolymer types studied (polystyrene, poly(cc methyl.styrene) and Bisphenol A polycarbonate), XPS analysis of Si C ratios revealed a significant enrichment of the PDMS... 

Evidence from spectral studies for interactions other than the above hydrogen bonds is not very plentiful. Polystyrene/poly(2,6 dimethyl-l,4-phenylene oxide) blends have been studied by infra-red and ultraviolet spectroscopy . Interactions involving the aromatic rings of the two polymers were proposed. Studies of low molecular weight ethers with aromatic compounds have shown evidence for specific interactions and this has recently been extended to blends of polystyrene with poly(methyl vinyl ether)... 

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. 

Halogenated styrenes can form a number of copolymers, some used in blends with polystyrenes or other polymers. Examples of such copolymers are poly(o-chloro-styrene-co-p-chlorostyrene), polystyrene-co-poly(2-chlorostyrene) [14], poly(methyl acrylate-co-4-chlorostyrene), etc. A few studies on thermal behavior of these polymers are available [15, 16]. 

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). 

On the basis of a systematic study of the emulsifying effect of block copolymers in PS-PI and in polystyrene-poly (methyl methacrylate) (PS-PMM) polyblends (3), it was possible to represent schematically the appearance of the films for different blend compositions as functions of molecular weight and composition of the block copolymer (Cop), as well as of molecular weight of the homopolymers (see Figure 2). Thus in a polyblend containing PS and PI of practically the same molecular weight — M2), the best... 

Libera [99] has presented an alternative for the study of polymer morphology avoiding the staining procedure as a way to induce amplitude contrast. EEe proposed the use of EELS to study different polymer systems to obtain several levels of resolution (related to the radiation sensitivity of the material) when studying interfaces, such as those in polystyrene-poly(2-vinyl pyridine) homopolymer blends, epoxy-alumina interfaces, and hydrated polymers. Polymers could be distinguished from each other on the basis of the energy-loss spectra in their low loss (valence) and core loss (elemental composition). 

Examples of such compatibilized systems that have been studied include EPDM/PMMA blends compatibilized with EPDM- -MMA, polypropylene/polyethylene blends with EPM or EPDM, polystyrene/nylon-6 blends with polystyrene/nylon-6 block copolymer, and poly(styrene-co-acrylonitrile)/poly(styrene-co-butadiene) blends with butadiene rubber/PMMA block copolymer. 

Naidu, B. V. K., MaUikarjuna, N. N., and Aminabhavi, T. M. 2004. Blend compatibility studies of polystyrene/poly(methyl methacrylate) and polystyrene-acrylonitrile by densitometry, viscometry, refractometry, ultraviolet absorbance, and fluorescence techniques at 30°C. Journal of Applied Polymer Science 94 2548-2550. 

Proton spin-temperature equilibration between the hard- and soft-segment-rich domains of the polyurethane elastomer on the order of 10-100 ms might be considered fast relative to a macroscopically phase-separated blend [26] or copolymer, but slow relative to a strongly interacting mixture [25]. This is reasonable for a microphase-separated material whose solid state morphology has been the subject of considerable theoretical and experimental research. Under fortuitous circumstances, intimate (near-neighbor) contact between dissimilar molecules in a mixture can be studied via direct measurement of proton spin diffusion in a two-dimensional application of the 1H-CRAM PS experiment (Combined Rotation And Multiple Pulse Spectroscopy). Belfiore et al. [17,25,31] have detected intermolecular dipolar communication in a hydrogen-bonded cocrystallized solid solution of poly(ethylene oxide) and resorcinol on the f00-/xs time scale, whereas Ernst and coworkers [26] report the absence of proton spin diffusion on the 100-ms time scale for an immiscible blend of polystyrene and poly(vinyl methyl ether), cast from chloroform. 

Pan, D.H.K., Prest Jr., W.M. Surfaces of polymer blends X-ray photoelectron spectroscopy studies of polystyrene/poly(vinyl methyl ether) blends. J. Appl. Phys. 58(8), 2861-2870 (1985)... 

Cowie, J.M.G., Devlin, B.G., McEwen, I.J. A study of surface enrichment in polystyrene/ poly(vinyl methyl ether) blends using attenuated total reflectance infra-red spectroscopy 1. Polymer 34(3), 501-504 (1993)... 

In this paper, an attempt is made to relate the mechanical (tensile) properties of a family of related polyblends to the state of compatibility of the blend. The prototype compatible blend studied is that of poly (2,6-dimethy1-1, 4-phenylene oxide)(PPO) and polystyrene (PS). Evidence for the compatibility of PPO and PS is substantial and is reviewed elsewhere (5). Films molded from blends of PPO and PS are optically clear and exhibit a single composition dependent glass transition temperature (Tg). 

Lau S-F, Pathak J, Wunderlich B (1982) Study of Phase Separation in Blends of Polystyrene and Poly-a-methylstyrene in the Glass Transition Region. Macromolecules 15 1278-1283. 

The effect of molecular weight on the interfacial excess (z(B) ), tension jabc) and width (vv bc) in polystyrene/poly(d(8)-styrene-co-4-bromostyrene)/poly (styrene-co-4-bromostyrene) (AB C) system was studied by Genzer and Composto (1998). Low-energy forward recoil spectrometry (LE-FRES) was used to measure z(B) as a function of the B volume fraction in the B C blend. The experimental z(B) s were found to be in excellent agreement with those calculated using the... 

Phase behavior of blends of polystyrene with poly(4-methylstyrene) has been studied by Chang and Woo (2001). Their study clearly indicates that an increase of molecular weight leads to a reductimi in the entropic COTitribution to the Gibbs free energy of mixing, which is less favorable for miscibility (Fig. 10.33). 

One promising approach to producing a true molecular composite is to make rod and coil components thermodynamically miscible by introducing attractive interactions, such as hydrogen bonds (16-18), between them. This method has proven useful for enhancing miscibility in flexible-flexible blends. Even more useful (stronger) interactions may be ionic interactions, such as ion-ion and ion-dipole interactions various studies on ionomer blends have demonstrated that ionic interactions can enhance the miscibility of otherwise immiscible polymer pairs (79). Polymers studied include polystyrene, poly(ethyl acrylate), poly(ethyleneimine), nylon, and poly (ethylene oxide) (20-22). 

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