Polystyrene-polyisoprene

Figure C2.1.11. Morjrhologies of a microphase-separated di-block copolymer as function of tire volume fraction of one component. The values here refer to a polystyrene-polyisoprene di-block copolymer and ( )pg is tire volume fraction of the polystyrene blocks. OBDD denotes tire ordered bicontinuous double diamond stmcture. (Figure from [78], reprinted by pemrission of Annual Reviews.)...

Fig. 8. Effect of varying composition on the ordered-phase symmetry in polystyrene-polyisoprene (PS-PI) diblock copolymers [92]...

Measurements of diffusion of tracer polymers in ordered block copolymer fluids is another potentially informative activity, since molecular diffusion is one of the most basic dynamic characteristics of a molecule. Balsara, et al. have measured the retardation of diffusion due to ordering in the diffusion of polystyrene tracer homopolymers in polystyrene-polyisoprene matrices of various domain sizes [167]. Measurement of the tracer diffusion of block copolymer molecules will also be important. Several interesting issues are directly addressable via measurements... 

Several studies have been published which utilize size exclusion chromatography (SEC) for characterization of the molecular weight distribution of multi-arm structures of polystyrene, polyisoprene, and block copolymers of styrene/ butadiene and styrene/isoprene (1, 2, 8, 17, 25-26). An... 

S-I-S Polystyrene Polyisoprene Polystyrene Poly(ethylene-co- propylene) ... 

Materials that are constructed from organic polymers such as polyethylene, polystyrene, polyisoprene (natural rubber and a synthetic elastomer) and poly(vinyl chloride) are common features of our daily lives. Most of these and related organic polymers are generated from acyclic precursors by free radical, anionic, cationic or organometallic polymerisation processes or by condensation reactions. Cyclic precursors are rarely used for the production of organic polymers. 

Balsara NP, Hammouda B (1994) Shear effects on solvated block-copolymer lamellae -polystyrene-polyisoprene in dioctyl phthalate. Phys Rev Lett 72(3) 360-363... 

Fig. 6. Examples of electron micrographs of the inverse centered cubic structure38). Copolymer polystyrene-polyisoprene-polystyrene SIS. 1107 containing 10% polystyrene. White circles are polystyrene spheres.

In an investigation of the effect of chain geometry on the two phase morphology of polystyrene-polyisoprene block copolymers, Price et al. have studied films of AB linear, AB stars with 2,3 or 4 branches196,197), graft copolymers 198 200>, and ABC block terpolymers201. ... 

ABC copolymers polystyrene-polyisoprene-poly(vinyl-2-pyridine)(S.I.V2P) with number-molecular average weight of 23000,102000, and 23000 were prepared by stepwise anionic polymerization. Films obtained by solvent casting from methylcyclohexane and benzene were observed by electron microscopy after staining the polyisoprene block with osmium tetroxide or the poly(vinyl-2-pyridine)... 

The substantial work on polystyrene/polybutadiene and polystyrene/ polyisoprene blends and diblock and triblock copolymer systems has lead to a general understanding of the nature of phase separation in regular block copolymer systems (5,6). The additional complexities of multiblocks with variable block length as well as possible hard- and/or soft-phase crystallinity makes the morphological characterization of polyurethane systems a challenge. 

The ability of Th-FFF to separate polymers by chemical composition [2] was demonstrated in the separation of polystyrene, polyisoprene and polybutadiene polymers of similar molecular weight [349] and extended to polytetrahydrofuran [350]. An impressive example of the ability to separate according to chemical composition was reported for two polymers indistinguishable by SEC (See Fig. 10). 

Tong, Z. Einaga, Y. Fujita, H., "Phase Equilibrium in Polymer + Polymer + Solvent Ternary Systems. III. Polystyrene + Polyisoprene + Cyclohexane System Revisited," Polym. J., 19, 965 (1987). 

Tseng, H.-S. Lloyd, D. R. Ward, T. C., "Interaction Parameters of Polystyrene-Polyisoprene-Toluene Systems at 45 C from Gel Permeation Chromatography," J. Polym. Sci., Polym. Phys. Ed., 25, 325 (1987). 

Figure 7. A split-screen image, with a TEM micrograph of a cubic structure in a polystyrene / polyisoprene star diblock copolynaer on the left half, and a computer simulation using the structure indicate in Figure 1 on the right half. The lattice parameter is approximately 300A, the dark regions correspond to polyisoprene and the light regions to polystyrene.

We have conducted experiments on different polymers [21, 22] (polystyrene, polyisoprene, polymethylmethacrylate) and used data in the literatiure on polystsTene [20] and polyWtadiene [23] in order to check the scaling laws predicted by relation (5-3). 

Polystyiene-polybutadiene Polybutadiene-poly(a-methyl styrene) Polybutadiene-poly(vinyl naphthalene) Polystyrene-polybutadlene-polystyrene Polybutadiene-polystyrene-polybutadiene Polystyrene-polyisoprene Pblystyrene-polyisoprene-polystyrene Polyia>prene-poly(vinyl-2-p dine) PofyiK>prene-poly(vinyl-4-pyridine) Polyisoprene-poly(methyl methacrylate) Polystyrene-poly(butadiene or ia>prene)-polystyrene Star polystyrene-polybutadiene with 4 branches Star polybutadiene-polystyrene with n branches Star polystyrene-polybutadiene with n branches Star polystyrene-polyisoprene with n brandies Polystyrene-polyisoprene-poly(vinyl-2-pyridine) Polystyrene-poly vinyl-2-pyridine) Polystyrene-poly(vinyl-4-pyridine) Poly(vinyl-2-pyridine)-poly(vinyl-4-pyridine)... 

Figure 13.15 Reduced storage modulus versus reduced frequency arco for a lamellae-forming polystyrene-polyisoprene diblock copolymer (M = 22,000) at temperatures above the order-disorder transition temperature Todt = 152°C, and quenched to temperatures below it. The disordered samples show terminal behavior, and the ordered (but unoriented) ones show nonterminal behavior. (Reprinted with permission from Patel et al.. Macromolecules 28 4313. Copyright 1995, American Chemical...

Figure 13.22 Damping functions hf y) and hs y) for the fast and slow relaxation processes of a 15 wt% solution of a micelle-forming polystyrene-polyisoprene diblock copolymer (molecular weights, respectively, of 14,000 and 29,000) in a low-molecular-weight (A/ = 4,000) polyisoprene. Damping functions for linear and star polymers and for silica dispersion are shown for comparison. (From Watanabe et al. 1997, with permission from Macromolecules 30 5905. Copyright 1997, American Chemical Society.)...

Figure 4.25. High magnification image.s obtained by transmission electron microscopy of stained thin sections of a hyperbolic mesopha.se of a linear diblock copolymer, polystyrene-polyisoprene, whose morphology follows the D-surface (single node circled in middle picture) and possibly the gyroid. Staining produces high contrast between the two block domains. Note the very different magnifications.

Levy and Schlick (9) applied this technique to the system polystyrene-polyisoprene and produced polymers containing 3, 5, 7, and 9 blocks respectively. 

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