Microstructure and rheological properties of triblock copolymers under extrusion conditions

Geiger, K.; Knoll, Konrad; Langela, Marc

doi:10.1007/s00397-002-0230-6

Cited by 26 publications

(21 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Details on the characterization of the copolymer have been reported elsewhere. 18,19 The polystyrene homopolymer (PS010; courtesy of Dr. Marc Langela, Max Planck Institute for Polymer Research, Mainz), prepared by anionic polymerization, has a number average molecular weight (M n ) of 9800 g/mol and a polydispersity index (M w /M n ) of 1.06. The polybutadiene homopolymer (PS004) used has a number average molecular weight (M n ) of about 4000 g/mol.…”

Section: Materials and Sample Preparationmentioning

confidence: 99%

Relationship between nanostructure and deformation behavior of microphase‐separated styrene/butadiene systems

Adhikari

Lebek

Godehardt

et al. 2006

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

ABSTRACT:The relationship between the morphology and the mechanical properties of nanostructured blends, comprising an asymmetric styrene/butadiene star block copolymer, exhibiting cocontinuous-like morphology and low molar mass homopolymers, was studied by electron microscopy, microindentation hardness, and tensile testing methods. Results show that the deformation behavior of these systems is significantly modified by the presence of unentangled homopolymer chains, leading partly to a decrease in mechanical properties. In contrast to common polymer blends, in which usually, the hardness values do not markedly deviate from the additivity law, the H-values in the system investigated show large deviations from the linear additivity behavior. The observed anomalous behavior is discussed in terms of the enhanced local flow processes induced by the phase-separated morphology at a nanometer scale.

show abstract

Section: Materials and Sample Preparationmentioning

confidence: 99%

Relationship between nanostructure and deformation behavior of microphase‐separated styrene/butadiene systems

Adhikari

Lebek

Godehardt

et al. 2006

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

show abstract

“…The synthesis of ST3 is described by Knoll and Nießner. [4] Langela and coworkers [5,6] give further information about the morphology and rheology. Because of orientation effects during extrusion, the morphology of the blends (ST3/PS) perpendicular to the processing direction can nearly be approximated as a cocontinuous domain (20-30% homo-PS) or layer-like structure (40-60% homo-PS) of PS-rich and PB-rich domains exhibiting a mean thickness of d PS and d PB , respectively (Figure 1 and 3).…”

Section: Morphology Of Sb Star Block Copolymer/ps Blendsmentioning

confidence: 99%

“…The details on the synthesis, structure, and rheological properties of asymmetric star block copolymer has been discussed in recent papers. [4][5][6] The overall volume fraction of polystyrene in ST3 is approximately 72% where a hexagonal morphology in the linear block copolymer has been observed. However, the atomic force microscopy (AFM) image in Figure 1b illustrating the typical bulk morphology of the star block copolymer samples shows a more bicontinuous morphology.…”

Section: Introductionmentioning

confidence: 99%

Influence of Domain Size on Toughness of Poly(styrene‐block‐butadiene) Star Block Copolymer/Polystyrene Blends

Lach

Weidisch

Janke

et al. 2004

Macromol. Rapid Commun.

Self Cite

View full text Add to dashboard Cite

Summary: The toughness of poly(styrene‐block‐butadiene) star block copolymer/polystyrene (PS) blends have been investigated using the essential‐work‐of‐fracture approach. The blends show a co‐continuous or layer‐like structure of polystyrene‐rich and polybutadiene‐rich domains arising from the used extrusion process. A tough‐to‐brittle transition at a critical domain size of polystyrene‐rich domains of about 50 nm and a maximum in the non‐essential work of fracture at 20–30% PS (co‐continuous morphology) have been found.

show abstract

“…Chain alignment can be induced by flow (shear) field's methods, such as extrusion [8] and injection molding [9]. Both of these techniques produce morphologies that comprise an oriented shell of the polymer with a relatively disoriented inner core.…”

Section: Introductionmentioning

confidence: 99%

Effect of Moderate Magnetic Annealing on the Microstructure, Quasi-Static, and Viscoelastic Mechanical Behavior of a Structural Epoxy

Tehrani

Al-Haik

Garmestani

et al. 2011

Journal of Engineering Materials and Technology

View full text Add to dashboard Cite

In this study, the effect of moderate magnetic fields on the microstructure of a structural epoxy system was investigated. The changes in the microstructure have been quantitatively investigated using wide angle X-ray diffraction (WAXD) and pole figure analysis. The mechanical properties (modulus, hardness, and strain rate sensitivity parameter) of the epoxy system annealed in the magnetic field were probed with the aid of instrumented nanoindentation, and the results are compared to the reference epoxy sample. To further examine the creep response of the magnetically annealed and reference samples, short 45 min duration creep tests were carried out. An equivalent to the niacroscale creep compliance was calculated using the aforementioned nanocreep data. Using the continuous contact compliance (CCC) analysis, the phase lag angle, tan (ô), between the displacement and applied force in an oscillatory nanoindentation test was measured for both neat and magnetically annealed systems through which the effect of low magnetic fields on the viscoeiastic properties of the epo.xy was invoked. The comparison of the creep .strain rate sensitivity parameter, Ald(0),from short term(80 s), creep tests and the creep compliance J(t} from the long term (2700 s) creep tests with the tan (ô) suggests that former parameter is a more useful comparative creep parameter than the creep compliance. The results of this investigation reveal that for the epoxy system cured under low magnetic fields both the quasi-static and viscoeiastic mechanical properties have been improved.

show abstract

Microstructure and rheological properties of triblock copolymers under extrusion conditions

Cited by 26 publications

References 19 publications

Relationship between nanostructure and deformation behavior of microphase‐separated styrene/butadiene systems

Relationship between nanostructure and deformation behavior of microphase‐separated styrene/butadiene systems

Influence of Domain Size on Toughness of Poly(styrene‐block‐butadiene) Star Block Copolymer/Polystyrene Blends

Effect of Moderate Magnetic Annealing on the Microstructure, Quasi-Static, and Viscoelastic Mechanical Behavior of a Structural Epoxy

Contact Info

Product

Resources

About