SIS triblock copolymer

Styrene-1,3-butadiene-styrene (SBS) or styrene-isoprene-styrene (SIS) triblock copolymers are manufactured by a three-stage sequential polymerization. One possible way of the synthesis is to start with the polymerization of styrene. Since all polystyrene chains have an active anionic chain end, adding butadiene to this reaction mixture resumes polymerization, leading to the formation of a polybutadiene block. The third block is formed after the addition of styrene again. The polymer thus produced contains glassy (or crystalline) polystyrene domains dispersed in a matrix of rubbery polybutadiene.120,481,486... 

Figure 21.13 Storage and loss moduli of an SIS triblock copolymer as a function of temperature. Formulation with tackifying resins brings the peak in loss modulus to near ambient temperatures for adhesives...

The structures of TPNR and their composites with carbon black were investigated by SAXS, and small-angle neutron scattering (SANS). Thomas et al. studied the deformation of cylindrical PS domains of a near single crystal styrene-isoprene-styrene (SIS) triblock copolymer by SAXS. The structural changes in the hexagonal lattice of cylinders on uniaxial tensile deformation were related to the macroscopic mechanical behaviour. 

In the case of the SI-Cl, one notes from Figure 7 that the changes in 2-D SAXS patterns with temperature are very similar to Vector 4111, except that the diffraction peaks are relatively broader compared with Vector 4111. This broadness might be due to less alignment of cylindrical microdomains fca- SI-Cl. On the basis of these results we concluded that the transition mechanism between HEX and BCC microdomains for SI diblock and SIS triblock copolymers would be similar. 

In present study, we employed both SAXS and theological measurements to investigate the order-disorder and order-order transitions in a series of SIS triblock copolymer/low molecular weight PS homopolymer mixtures, which did not show macrophase separation in the whole temperature and composition range covered in this experiment, Phase diagrams obtained from both measurements were compared with the predictions based on the Whitmore-Noolandi theory. The difference between the theory and the experiment was discussed in terms of the change in homopolymer distribution and microdomain morphology by the addition of homopolymer to block copolymer. 

Figure 8.3 TEM images of three commercial SIS triblock copolymers (Dexco Polymers) ...

Figure 8.4 (a) TEM image of a lamella-forming SIS triblock copolymer at T <... 

Figure 8.9 Temperature dependence of G for a highly asymmetric SIS triblock copolymer specimen having a 0.18 weight fraction of PS block (Vector 4111, Dexco Polymers Company), which was annealed at 140 °C for 2 days prior to the isochronal dynamic temperature sweep experiments at an angular frequency of 0.01 rad/s in the heating process. (Reprinted from Sakamoto et al., Macromolecules 30 1621. Copyright 1997, with permission from the American Chemical Society.)...

Figure 8.15 Log G versus log G" plots for a highly asymmetric solvent-cast SIS triblock copolymer (SIS-110) specimen during heating at various temperatures (°C) (O) 140, (A) 151, ( ) 155, (V) 160, (O) 162, (O) 164, ( ) 166, (A) 168, ( ) 170, (T) 172, ( ) 174, m 180, (C) 190, (A) 200, (H) 202, (V) 204, ( ) 206, (O) 208, (A) 210, (11) 212, and (V) 214. Prior to the rheological measurements, the specimen was annealed at 110 °C for 3 days. The inset describes the temperature dependence of G obtained from the isochronal dynamic temperature sweep experiment at < = 0.01 rad/s during heating. (Reprinted from Choi et al.. Macromolecules 36 7707. Copyright 2(X)3, with permission from the American Chemical Society.)...

Neat SIS triblock copolymer Neat SIS triblock copolymer 16 mol% hydroxyl group in the SIOHS 32 moI% hydroxyl group in the SIOHS 16 mol% hydroxyl group in the SIOHS 32 moI% hydroxyl group in the SIOHS... 

Since the earliest successful synthesis of block copolymers in seminal investigation of living anionic polymerization by Szwarc [ 1,2], diene-based block copolymers, such as polystyrene- tocA -polybutadiene (SB diblock), polystyrene-fetocA -polyisoprene (SI diblock), polystyrene-fetocfc-polybutadiene-( tocfc-polystyrene (SBS triblock), and polystyrene- /oc -polyisoprene-I tocA -polystyrene (SIS triblock) copolymers have been widely used in the thermoplastic elastomer industry due to their unique physical properties not attainable with the constituent homopolymers alone. 

The H-W theory can also be used to predict the Fqdt of ABA-type triblock copolymers. The Fortran computer program for predicting the Foot of ABA-type triblock copolymers is also included in the Supplementary Material. For an SIS triblock copolymer having block molecular weights, = 1.3 x lO for one PS endblock and Mw = 1.14 x 10 for the PI midbloek, using the a T) given by (26) the H-W theory predicts a Fqdt of 248°C. 

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