Polystyrene-h-polybutadiene

The above data prove that the polystyrene-h-polybutadiene prepolymer is quantitatively transformed into block copolymers with perfluorinated side chains. The narrow molecular-weight distribution (I) = MW/MN) of the prepolymers is maintained by the described reaction sequence. 

Therefore, at room temperature Fluoro-PSB-II a thermoplastic elastomer with a soft polymer phase (fluorinated block) and a hard phase (PS-block), similar to the parental polystyrene-h-polybutadiene block copolymer. Depending on the relative volume fraction of both components and the continuity of the phases, the resulting bulk material is rubbery or a high-impact solid. 

PDMAEMA-fo-PBMA) [62] in alcohols and polystyrene-h-polybutadiene (PS-h-PB) [49] andpolystyrene-h-poly(propyrene-flZt- ethylene) (PS-h-(PP-aZt-E)) [58], linear PS [47], and PMMA [47] in hydrocarbon are used. 

As an example of blends with attractive interactions. Fig. 65 shows a superstructure in which interactions between methacrylic acid groups and pyridine side groups of a polystyrene-h-polybutadiene-b-poly(t-butyl methacry-late-sfflf-methacryhc acid) (PS-h-PB-h-P(MAA-sfflf-fBMA)) triblock quaterpolymer and a PS-h-P2VP diblock copolymer lead to a wavy lamellar structure with cylinders from mixed P2VP and P(MAA-staf-fBMA) blocks [194]. 

The synthesis of block copolymers with blocks of ultralow cohesion energy densities on the basis of polystyrene-h-polybutadiene via two highly efficient polymer analogous reactions has been presented. 

Several studies have concerned the microstnicture of lamellae in materials such as the block copolymers polystyrene-h/oc/r-poly-l-vinylpyridine [139] and polystyrene-h/oc/r-polybutadiene [140], as well as single crystals of poly-para-xylylene [139], and reveal features (such as intersecting lamellae (figure Bl.19.29)) that had not been previously observed. 

Some work has been done on blends of ABC and AB or AC or AB C block copolymers, such as polystyrene-b-polybutadiene-b-poly(methyl methacrylate) (PS-h-PB-fc-PMMA) triblock terpolymers with PS-h-PB or PB-h-PMMA or other systems. Besides known morphologies for these block copolymers (though at other overall compositions with respect to the different chemical... 

The absolute number of monomer units of the polystyrene (m) and polybutadiene (n) blocks were determined by combined H-NMR and GPC measurements. The triblock copolymer is a commercially available polystyrene-b-polybutadiene-i-polystyrene polymer and was purchased from Aldrich (M = 100,000 28 wt% polystyrene). 

We further assume that the blocks in the aggregates as well as in the continuous phase would have the lowest possible free energy if their coil dimensions would equal those of the corresponding homopolymers in athermic solutions. Conformation restrictions (8, 15, 16, 72), which are caused by a block end being connected with a second block that does not mix with the first one, are thus neglected. (At least one end of each block is situated in the interface.) For blocks of polystyrene and polybutadiene the following equations are valid (19, 24, 33, 56, 65) (with the end-to-end distance h = hi2) ... 

Inukai, S., Niihara, K.-L, Noguchi, T., Ueki, H., Magario, A., Yamada, E., Inagaki, S., Endo, M. Preparation and properties of multi wall carbon nanotubes/ polystyrene-block-polybutadiene-block-polystyrene-composite. Ind. Eng. Chem. Res. 50, 8016-8022 (2011)... 

Suppose that a polystyrene-h/ocA -polybutadiene-h/oc -polystyrene triblock copolymer is synthesized with block molecular weights of 10,000-80,000-... 

Breiner et al. (36) studied the so-called knitting pattern found for the triblock copolymer polystyrene-h/ock-poly(ethylene-5 tot-butylene)-h/c c -poly(methyl methacrylate) see Figure 13.17. [The poly(ethylene-5 tflt-buty-lene)-component was formed by hydrogenating the original polybutadiene block, which contained some 1,2-placements as well as the more usual 1,4-placements.] In this morphology, poly(methyl methacrylate) forms peristaltic lamellae in which opposite maxima and minima are spanned by ellipsoidalshaped cylindrical poly(ethylene-co-butylene). Of course, such complexity arises from the combined need of the chains to be able to wander from domain... 

Wide-line H FID and relaxation measurements of a relatively simple motionally heterogeneous system, the triblock copolymer styrene-butadiene-styrene, have been performed in a temperature range between the polystyrene and polybutadiene glass transition temperatures. The two FID and the two Tip components found at each temperature have been correlated by means of a 2D approach. It is shown that this approach allows dynamic information, not accessible simply by interpreting proton Ti and Tip data, to be revealed. In the case examined, the correlation found could be confirmed by high-resolution H... 

Huckstaedt, H., Abetz, V., and Stadler, R. (1996) Synthesis of a polystyrene-arm-polybutadiene-arm-poly(methyl methacrylate) triarm star copolymer. Macromolecular Rapid Communications, 17,599-606. 

Figure 18.13 TEM images and models of (a) the knitting pattern kp) and (b) barber pattern hoc) in PS-PEB-PMMA. ((a) Reprinted with permission from H. Ott, V. Abetz and V. Altstadt, Morphological studies of poly(styrene)-block-poly(ethylene-co-butylene)-block-poly(methyl methacrylate) in the composition region of the knitting pattern morphology, Macromolecules, 34, 7, 1069-1075, 2001. 2001 American Chemical Society, (b) Reprinted with permission from U. Krappe, R. Stadler and I. Voigt-Martin, Chiral assembly in amorphous ABC triblock copolymers. Formation of a helical morphology in polystyrene-block-polybutadiene-block-poly(methyl methacrylate) block copolymers, Macromolecules, 28, 13, 4558-4561, 1995. 1995 American Chemical Society.)...

Figure 7 shows an electron micrograph of an ultramicrotomed section of a polystyrene-h/ock-polybutadiene-h/oc/c-polystyrene copolymer in which the domain morphology consists of polystyrene cylinders in a polybutadiene matrix. The specimen was sectioned from a compression-moulded sheet. 

Figure 7 Electron micrograph of an ultrathin section of a polystyrene-h/ocfc-polybutadiene-h/oci -polystyrene (10000 71 000 10000 M ) copolymer showing polystyrene cylinders in a polybutadiene matrix. Scale bar indicates 100 nm...

One of the more detailed studies, which was reported by Plestil and Baldrian, deals with solutions of a polystyrene-h/ocfc-polybutadiene (5700 59 000 M ) copolymer in heptane, a selectively bad solvent for polystyrene. Measurements in heptane were made at four temperatures ranging from 18 to 50 °C. The analysis of results was complicated by the knowledge (gained from ultracentrifugation) that a significant proportion of the chains were unassociated. 

S-B(h)-S Polystyrene-b-polybutadiene(hydrogenated)-b-polystyrene triblock copolymer 37-38, 47... 

Figure 1 Sample morphologies of bulk cylinder-forming polystyrene-f)-polybutadiene (PS-fhPBD) diblock copolymers confined within nanopores in AAO membranes, showing the formation of complex morphologies such as single, double, and triple helices. Reproduced from Dobriyal, P. Xiang, H. Kazuyuki, M. et at. Macromolecules 2009, 42,9082, with permission. Copyright 2009, American Chemical Society.

Figure 9.17 Plot of log [i ]M versus retention volume for various polymers, showing how different systems are represented by a single calibration curve when data are represented in this manner. The polymers used include linear and branched polystyrene, poly(methyl methacrylate), poly(vinyl chloride), poly(phenyl siloxane), polybutadiene, and branched, block, and graft copolymers of styrene and methyl methacrylate. [From Z. Grubisec, P. Rempp, and H. Benoit, Polym. Lett. 5 753 (1967), used with permission of Wiley.]...

Grafting reactions onto a polymer backbone with a polymeric initiator have recently been reported by Hazer [56-60]. Active polystyrene [56], active polymethyl methacrylate [57], or macroazoinitiator [58,59] was mixed with a biopolyester polyhydroxynonanaate [60] (PHN) or polybutadiene to be carried out by thermal grafting reactions. The grafting reactions of PHN with polymer radicals may proceed by H-abstraction from the tertier carbon atom in the same manner as free radical modification reactions of polypropylene or polyhy-droxybutyratevalerate [61,62]. 

---