Styrene isoprene diblock copolymers

Figure 8. Typical GPC traces of SGLC-coil BCPs via polymer analogous reaction [62] (see Scheme 9 for structures) (a) polystyrene precursor (b) styrene -isoprene diblock copolymer (c) hydroxylated styrene-isoprene diblock copolymer (unimolecular micelle in tetrahydrofuran) (d) final FLC-coil diblock copolymer.

Several authors used the continuum mechanics for modeling conventional polymer composites as well as PNC. Ren and Krishnamoorti [2003] used a K-BKZ integral constitutive model to predict the steady-state shear behavior of a series of intercalated nanocomposites containing an organo-MMT and a disordered styrene-isoprene diblock copolymer. The model predicts the low-y shear stress properties calculated from the experimental linear stress relaxation and the relaxation-based damping behavior. However, as it does not take into account the effect of clay platelet orientation, it is unable to predict the shear stress behavior at intermediate y and the normal stress behavior at all y and clay contents. 

Classification Thermoplastic elastomer Definition Produced by coupling styrene-isoprene diblock copolymers into S-l-S triblock with typical styrene content of 14%... 

Morese-Seguela, B., St. Jacques, M., Renaud, J. M., and Prud homme, J., Microphase separation in low molecular weight styrene-isoprene diblock copolymers studied by DSC and - C NMR, Macromolecules, 13, 100-106 (1980). 

Fig. 17. Desmeared small-angle X-ray scattering intensities for a styrene/isoprene diblock copolymer (78% styrene, M 320000) and its mixtures with polystyrene (M 81000) (the weight fraction of the latter in the mixture is indicated on the plot). The dotted curves are best fitting curves calculated for scattering from isolated spheres. (From Hashimoto, Fujimura, Hashimoto, and Kawai >)...

S-DMS refers to styrene-dimethylsiloxane diblock copolymers S-l refers to sty-rene-isoprene diblock copolymers S-l-S and I-S-I refer to styrene-isoprene-styrene and to isoprene-styrene-isoprene triblock copolymers, respectively and S-EO and EO-S-EO refer to styrene-ethylene oxide diblock copolymers and to ethylene oxide-styrene-ethylene oxide triblock copolymers, respectively. 

Bang J, Jain SM et al (2006) Sphere, cylinder, and vesicle nanoaggregates in poly (styrene-b-isoprene) diblock copolymer solutions. Macromolecules 39 1199-1208... 

We will focus in this paper on the rheological properties, at room temperature, of styrene-isoprene block copolymers, particularly Triblock [SISj-Diblock [SI] copolymer blends. We will describe the effect of the molecular parameters of the copolymers on the rheological behavior, and wiU propose, on the basis of molecular dynamics models derived from the reptation concept and the analysis of the dynamic behavior of the blend [SIS-SI], a model which allows calculation of the variation of the complex shear modulus as a function of frequency. Different types of macromolecules have been designed from calculations using this molecular model in order to improve the processing and end-user properties of the full formulations (HMPSAs). 

Satti, A. J. Ciolino, A. E. Villar, M. A. Schmidt, V. Giacomelli, C., Micelles Formed by Highly Asymmetric Polystyrene-i-Polydimethylsiloxane and Poly-styrene-b-poly[5-(N,N-diethylamino)isoprene] Diblock Copolymers. Langmuir 2010, 26,14494-14501. 

Soto-Figueroa C, Rodriguez-Hidalgo MDR, Martinez-Magadan JM, Vicente L. Dissipative particle dynamics study of order-order phase transition of BCC, HPC, OBDD, and LAM structures of the poly(styrene)-poly(isoprene) diblock copolymer. Macromolecules 2008 41 3297. 

Block copolymer chemistry and architecture is well described in polymer textbooks and monographs [40]. The block copolymers of PSA interest consist of anionically polymerized styrene-isoprene or styrene-butadiene diblocks usually terminating with a second styrene block to form an SIS or SBS triblock, or terminating at a central nucleus to form a radial or star polymer (SI) . Representative structures are shown in Fig. 5. For most PSA formulations the softer SIS is preferred over SBS. In many respects, SIS may be treated as a thermoplastic, thermoprocessible natural rubber with a somewhat higher modulus due to filler effect of the polystyrene fraction. Two longer reviews [41,42] of styrenic block copolymer PSAs have been published. 

Figure 4. Electron micrographs of diblock copolymers of styrene and isoprene cast from toluene and microtomed normal to the surface as indicated (31).

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