Interaction Strengths in Styrene−Diene Block Copolymers and Their Hydrogenated Derivatives

Adams, J. La Monte; Quiram, Daniel J.; Graessley, William W.; Register, Richard A.; Marchand, Gary R.

doi:10.1021/ma9710500

Cited by 47 publications

(94 citation statements)

References 27 publications

(58 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All the materials contained a stabilizer package to reduce the rate of oxidative degradation at elevated temperatures, and samples examined by GPC after rheological testing typically showed no indication of degradation. SIS was selectively hydrogenated to SEPS, as described previously, 18 until no olefinic unsaturation was detectable by 1 H NMR; GPC traces of the saturated product indicated an absence of chain scission and branching.…”

Section: Experimental Materialsmentioning

confidence: 99%

See 1 more Smart Citation

Phase behavior and viscoelastic properties of entangled block copolymer gels

Vega

Sebastian

Loo

et al. 2001

J Polym Sci B Polym Phys

Self Cite

131

View full text Add to dashboard Cite

Triblock copolymers in midblock-selective solvents can form physical gels. However, at low triblock contents (near the percolation threshold), the bridging of chains between micelles can lead to macrophase separation. Adding a styrene-isoprene diblock to a styrene-isoprene-styrene triblock copolymer in squalane can eliminate macrophase separation, yielding a wide range of stable, single-phase gels with a disordered arrangement of micelles. The plateau modulus of these triblock gels scales with the 2.2 power of polymer content, indicating the importance of entanglements in dictating the modulus. Comparing gels made from the midblock-saturated derivative of the same polymer [styrene-(ethylene-alt-propylene)-styrene] in squalane reveals that the modulus differences in the gels are a direct consequence of the difference in the entanglement molecular weight of the midblock homopolymer in bulk. Finally, the broad relaxation spectrum of these triblocks is well-described by a recent theory for the dynamics of entangled star polymers, with the breadth of the relaxation spectrum dictated by the number of entanglements per midblock in the gel.

show abstract

Section: Experimental Materialsmentioning

confidence: 99%

“…We also used SAXS to locate the order-disorder-transition temperatures (T ODT ) of the bulk polymers (listed in Table I) and for concentrated solutions capable of ordering (Ͼ13 wt % total polymer concentration), as described previously. 16,18,20,21 …”

Section: Phase-behavior Assessmentmentioning

confidence: 99%

Phase behavior and viscoelastic properties of entangled block copolymer gels

Vega

Sebastian

Loo

et al. 2001

J Polym Sci B Polym Phys

Self Cite

131

View full text Add to dashboard Cite

show abstract

“…Changing the chemical nature of one or both the component blocks can have dramatic effects on the self-assembly of the resultant material. Modification of the polydiene block in polystyrene-polydiene-polystyrene block copolymers has received much attention [35][36][37][38][39][40][41], including the selective hydrogenation of the midblock. Because the transition temperature from a rubbery gel to a plastic fluid (T P ) is too low for many applications, polystyrene has been either replaced by a higher T g block [42][43][44][45] or chemically modified [46][47].…”

Section: Introductionmentioning

confidence: 99%

Silica reinforced triblock copolymer gels

Theunissen

Overbergh

Reynaers

et al. 2004

Polymer

View full text Add to dashboard Cite

The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has been investigated. Different types of chemically modified silica have been compared in order to evaluate the influence of the compatibility between gel and filler.Time-resolved SANS and small-angle X-ray scattering (SAXS) shows that the presence of silica particles affects the ordering of the polystyrene domains during gelsetting. The scattering pattern of silica-reinforced gels reveals strong scattering at very low q, but no structure and formfactor information. However, on heating above the viscoelastic to plastic transition, the 'typical' scattering pattern of the copolymer gel builds-up. All reinforced gels are strengthened by the addition of the reinforcing agent. The transitions from a viscoelastic rubber to a plastic fluid and from a plastic fluid to a viscoelastic liquid are shifted to more elevated temperatures when silica is added to the triblock copolymer gel.

show abstract

“…The diblock was synthesized by sequential anionic polymerization of butadiene, then of a styrene/butadiene mixture [10], followed by catalytic hydrogenation [11]. The E block, which constitutes 14.3 wt% of the diblock, is itself effectively a random copolymer (containing 8 wt% butene) due to the microstructure of the precursor polybutadiene.…”

mentioning

confidence: 99%

Polymer Crystallization in 25-nm Spheres

2000

Self Cite

View full text Add to dashboard Cite

Crystallization within the discrete spheres of a block copolymer mesophase was studied by time-resolved x-ray scattering. The cubic packing of microdomains, established by self-assembly in the melt, is preserved throughout crystallization by strong interblock segregation even though the amorphous matrix block is well above its glass transition temperature. Homogeneous nucleation within each sphere yields isothermal crystallizations which follow first-order kinetics, contrasting with the sigmoidal kinetics normally exhibited in the quiescent crystallization of bulk polymers.

show abstract

Interaction Strengths in Styrene−Diene Block Copolymers and Their Hydrogenated Derivatives

Cited by 47 publications

References 27 publications

Phase behavior and viscoelastic properties of entangled block copolymer gels

Phase behavior and viscoelastic properties of entangled block copolymer gels

Silica reinforced triblock copolymer gels

Polymer Crystallization in 25-nm Spheres

Contact Info

Product

Resources

About