Ordering and structure formation in triblock copolymer solutions. Part I. Rheological observations

Modification of a thermoplastic elastomer gel through the addition of an endblock-selective homopolymer

“…To discern if a microstructural (lattice) disordering transition similar to that reported by Soenen et al, 29,39 Kleppinger et al, 37 and Laurer et al 33 occurs in the TPEGs examined here, temperature sweeps have been performed on the unmodified and two PPO-modified TPEGs at ␥ o ϭ 1% and ϭ 1 rad/s. Results from these tests are displayed in Figures 7-9.…”

“…In all three cases, GЈ is observed to remain nearly constant up to a composition-dependent temperature in the vicinity of 100°C. (Note that the T g of the PS in the copolymer is lower than this due to the short length of the copolymer endblocks-25000 g/mol each-and interfacial mixing, 33 as well as oil-induced plasticization 29 ). At this disordering temperature (denoted T d ), GЈ abruptly decreases, whereas GЉ (and, hence, tan ␦ ϭ GЉ/GЈ) exhibits a and GЉ (filled symbols) as functions of oscillatory frequency () for the TPEG with 3.0 wt % PPO at three different temperatures (in°C): 28 (circles), 112 (triangles), and 132 (diamonds).…”

“…At 28°C, GЈ is clearly independent of over the frequency range measured. Prior studies 29,32,33 of unmodified TPEGs have demonstrated that such invariance can extend over a range of up to four orders of magnitude or more, indicating that these materials can be considered physical gels. Frequency spectra collected at 28°C for the remaining two blends in the series appear similar to the spectra provided in Figure 5 and are not included here for that reason.…”

Silica reinforced triblock copolymer gels

“…Rheological studies [30][31][32][33][34] of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock copolymer gels showed that the gels are in a rubber-like viscoelastic state at ambient temperature, which means that the polystyrene domains act as permanent physical crosslinks. Above the glass transition temperature (T g ) of the PS nanodomains, there is a change from a rubbery gel to a plastic fluid.…”

Dielectric and thermal properties of thermoplastic elastomer gels in the presence of nanographite

“…It has good mechanical, electrical and thermal properties but difficult to disperse. Alternatively, numerous studies reported over the past decade have sought to establish fundamental relationships between morphology and property development in thermoplastic elastomer gels (TPEGs) as explicit functions of copolymer molecular weight, copolymer concentration, solution concentration, solvent quality, and process (temperature and shear) history [4][5][6][7][8][9][10][11]. Recently, the colloidal properties of nanocomposite polymer clay gels and solutions have also received considerable attention in the literature.…”