Polystyrene storage modulus

Poly(styrene-fc-butadiene) copolymer-clay nanocomposites were prepared from dioctadecyldimethyl ammonium-exchanged MMT via direct melt intercalation [91]. While the identical mixing of copolymer with pristine montmorillonite showed no intercalation, the organoclay expanded from 41 to 46 A, indicating a monolayer intercalation. The nanocomposites showed an increase in storage modulus with increasing loading. In addition, the Tg for the polystyrene block domain increased with clay content, whereas the polybutadiene block Tg remained nearly constant. 

Fig. 5.8. Storage modulus vs frequency for narrow distribution polystyrene melts, reduced to 160° C by temperature-frequency superposition. Molecular weight range from Mw = 8900 (L9) to Mw= 581000 (L18) (124). [Reproduced from Macromolecules 3, 111 (1970).]...

The dynamic viscoelasticity and the thermal behaviour of films of Thermoelastic 125 cast from solutions in four solvents - toluene (T), carbon tetrachloride (C), ethyl acetate (E), and methyl ethyl ketone (M) — have been studied by Miyamato133 The mechanical loss tangent (tan 8) and the storage modulus E dependences exhibit two transitions at —70 °C and 100 °C which have been attributed to onset of motion of polybutadiene and polystyrene segments, respectively. The heights of the polybutadiene peaks on tan 6 curves decrease in the order C > T > E > M, while for polystyrene the order is reversed C < T < E < M. These phenomena have been related to the magnitude of phase separation of the polystyrene and polybutadiene blocks. 

The effect of entanglements on the relaxation of polymer chains is illustrated in Fig. 3-22, which shows the storage modulus G for a series of polystyrene melts of differing... 

Figure 3.22 Storage modulus, G, as a function of frequency reduced to 160°C for nearly monodis-perse polystyrenes of molecular weight ranging from 580,000 to 47,000, from left to right. (Reprinted with permission from Onogi et al., Macromolecules 3 109. Copyright 1970, American Chemical Society.)...

Figure 13.13 Reduced storage modulus G and dynamic viscosity rj = G /w as functions of reduced frequency uto) for a cylinder-forming polystyrene-polybutadiene-polystyrene triblock copolymer with block molecular weights of 7000-43,000-7000. The curves are time-temperature-shifted to a reference temperature of 138°C the open symbols were obtained in the low-temperature ordered state the closed symbols were obtained in the high-temperature disordered state. (From Gouinlock and Porter 1977, reprinted with permission from the Society of Plastics Engineers.)...

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...

Oscillatory shear data on dilute solutions of polystyrene with M= 860000 gmol in two -solvents (circles are in decalin at 16°C and squares are in di-2-ethylhexyl phthalate at 22 °C). Open symbols are the dimensionless storage modulus and filled symbols are the dimensionless loss-... 

The measured G and G" (or equivalently rj and 77") values, as a function of the frequency w, can be displayed as a spectrum — the viscoelastic spectrum. Figures 4.9 and 4.10 show the storage modulus spectra G lo) and the loss modulus spectra G" oj), respectively, of a series of nearly monodisperse polystyrene samples. 

Fig. 4.9 Storage modulus vs. frequency for nearly monodisperse polystyrene melts. Molecular weight ranges from Mw = 8.9 X 10 (L9) to Mw = 5.8 X 10 (L18). Reproduced, with...

Storage modulus curves for polystyrene (PS)/poly(dlmethyl siloxane) (PDMS) films (a) without and (b) with 1.0 wt% cyclodextrin (CD) core. The solid lines represented samples with no PDMS. The initial and retained amounts of PDMS are shown in the insets for the other samples. (Reproduced from Busche, B. Tonelli, A. E., and Balik, C. M. 2010. Properties of polystyrene/poly(dimethyl siloxane) blends partially compatibiUzed with star polymers containing a y-cyclodextrin core and polystyrene arms. Polymer 51 6013-6020 with permission from Elsevier.)... 

Hwang et al. [113] synthesized via in situ polymerization high-impact polystyrene (HlPS)/organically modifled montmorillonite (organoclay) nanocomposites. X-ray diffraction and TEM experiments revealed that intercalation of polymer chains into silicate layers was achieved, and the addition of nanoclay led to an increase in the size of the robber domain in the composites. In comparison with neat HIPS, they found that the HIPS/organoclay nanocomposites exhibited improved thermal stabiHly as well as an increase in both the complex viscosity and storage modulus, and they may have been influenced by a competition between the incorporation of clay and the decrease in the molecular weight of the polymer matrix. 

FIG. 3. Storage modulus of TR 41-1649, with 0.482 polystyrene ( ), cast from THF/MEK. Pure polystyrene of low molecular weight (O) and polybutadiene (-jt) are also shown these were incorporated in the SBS model. The three lines running near the SBS data represent three types of interphase character sharp interface (-----), linear interphase... 

FIG. 5 (top). Storage modulus of TR 41-1648, with 0.293 polystyrene. Results are shown for samples cast from MEK (A), a 9 1 blend of THF/MEK ( ), and cyclohexane (O). Except for the partially obscured dashed line through the THF/MEK data, representing the no-interphase assumption, all lines display optimal curve-fits using nonlinear interphase composition profiles. Above 100 C, the solid-like plateau again appears for the liquid state. 

FIG. 7 (top). Storage modulus of TR 41-1647, with 0.268 polystyrene, cast from THF/MEK. Data symbols and lines correspond to those in Fig. 3, although the polystyrene-rich phase properties ( ) were altered by a priori calculation to account for the presence of 11% polybutadiene. The plateau anomaly again appears above 100 C. 

The storage modulus in the plateau between the two transitions depends both on the overall composition and on which phase is continuous. Electron microscopy shows that the polystyrene phase is continuous in the present case. As the elastomer component increases (small spheres, then cylinders, then alternating lamellae), the material gradually softens. When the rubbery phase becomes the only continuous-phase, the storage modulus will decrease to about 1 X 10 dynes/cml... 

Figure 9.21 Shear storage modulus versus frequency for narrow molecular-weight polystyrenes at 160°C. Molecular weights range from Mw= 8900g/mol (L9) to /Wiv=581,000g/mol (LI 8) (88).

Fig. 44 Master curves of storage modulus G plotted against frequency to at a reference temperature of200°C for CaC03-filled polystyrenes. The contents of CaC03 particles are 0, 20, 40 and 60wt.%. (From Ref. 48.)...

Fig. 46 Storage modulus G o)) (open points) and dynamic viscosity (solid points) as a function of frequency, co, for carbon-black-filled polystyrene melts at 170°C. (From Ref. 49.)...

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