Kinetics of Aggregation and Dimensions of Supramolecular Structure in Noncrystalline Block Copolymers

Hoffmann, M.; Kämpf, G.; Krömer, H.; Pampus, Gottfried

doi:10.1021/ba-1971-0099.ch023

Cited by 41 publications

(18 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The blends showed macrophase‐separated composite structures containing microphase‐separated domains inside. Learning from the earlier studies4, 5, 11, 12 and based on our own results,4, 5, 11–14 we can conclude that the phase behavior of binary mixtures of two‐component block copolymers seems to be strongly influenced by the chain architecture of the components as well.…”

Section: Introductionsupporting

confidence: 61%

“…Compared with an intensive investigation on the thermodynamics and phase behavior of block copolymers, only limited information is available on their blends. In an earlier study on binary blends of polystyrene‐ block ‐polybutadiene (SB) diblocks, Hoffman et al4 reported a microscopic demixing of blend partners, with two maxima in the domain size distribution. Jiang et al,5 Hadziioannou and Skoulios,6 and Hashimoto et al7–9 investigated binary blends consisting of diblocks and triblocks.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Morphology and micromechanical deformation behavior of styrene–butadiene block copolymers. IV. Structure–property correlation in binary block copolymer blends

Adhikari

Michler

Henning

et al. 2004

J of Applied Polymer Sci

View full text Add to dashboard Cite

ABSTRACT:The structure-property correlation in blends consisting of styrene/butadiene block copolymers forming alternating polystyrene (PS) and polybutadiene (PB) lamellae, and PS domains in rubbery matrix was investigated by different microscopic techniques (transmission electron microscopy, scanning force microscopy, and scanning electron microscopy), uniaxial tensile testing, and dynamic mechanical analysis. Unlike the pure lamellar block copolymer, the blends showed predominantly disordered wormlike morphology formed by the intermolecular mixing. These structures allowed a precise control of stiffness/toughness ratio of the blends over a wide range. The blends showed a gradual transition from predominantly viscoplastic to elastomeric behavior with increasing triblock copolymer content. The results demonstrated that the binary block copolymer blends provide the unique possibility of tailoring mechanical properties on the basis of nanostructured polymeric materials.

show abstract

Section: Introductionsupporting

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Morphology and micromechanical deformation behavior of styrene–butadiene block copolymers. IV. Structure–property correlation in binary block copolymer blends

Adhikari

Michler

Henning

et al. 2004

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…Note that the annealing temperature is happened to be above the T g of the hard segments (≤68°C). The drying temperatures of solvent‐cast films of A–B block copolymers were set coincidentally at slightly above the T g of the hard segment too 20, 21…”

Section: Resultsmentioning

confidence: 99%

Damping of vinyl acetate–n‐butyl acrylate copolymers

Chu

Lee

Huang

2003

J of Applied Polymer Sci

View full text Add to dashboard Cite

ABSTRACT:A photopolymerization process at room temperature was devised to copolymerize vinyl acetate (VAc) and n-butyl acrylate (BA) mainly to prepare rubber-like damping sheet bearing pressure-sensitive adhesive property in this study. The investigations using both the differential scanning calorimeter and rheometric dynamic analysis show the existence of two glass transition temperatures for each copolymer. The scanning electron microscopic pictures reveal that the degree of microphase separation increases with increasing annealing time at 70°C. It was suggested that the rubbery domain (formed by the PBA blocks) disperses in the glassy domain (constituted by the PVAc blocks), making an effective damping entity. Excellent damping was observed for the copolymer samples, with the tan␦ peak values as high as 1.76 -1.80 at a certain temperature range and with tan␦Ͼ 0.3 at quite wide temperature ranges. In addition, the copolymers containing more VAc tend to have the higher damping.

show abstract

“…Contrary to the opinion and observations of certain early investigators (Beecher, et al, 1969, McIntyre andCampos-Lopez, 1970), the shape of the discrete polystyrene domains in SBS copolymers, containing about 27% by weight polystyrene, is not spherical. The domain shape appears to be nearly parallel, slightly curved, cylindrical rods of polystyrene in the polybutadiene matrix (Figure V-l) for solvent cast films (using a good solvent for both components) (Douy and Gallot, 1971, Hendus, et al, 1967, Inoue, et al, 1971, Krigbaum, et al, 1973, Lewis and Price, 1971, Turecek, 1972, Uchida, et al, 1972 for solvent cast films annealed at 100 0 C (Hoffman, et al, 1971) and for compression -51-1 molded samples (Lewis and Price, 1971) The spherical domains only appear in films of block copolymers containing 27% polystyrene cast from a poor solvent for the polystyrene block (e.g. cyclohexane) (Beecher, 1969, Inoue, et al, 1969 and in films of SBS copolymers containing less than 20% polystyrene .…”

Section: Surface Morphologymentioning

confidence: 98%

“…The mercury and the beakers of benzene were all placed inside a partly closed container inside of a fumehood with a very low draft. This care was taken to obtain uniform films and to minimize the kinetic (polystyrene mobility) limitation to obtaining films with the fully developed thermodynamic morphology (discrete polystyrene domains in polybutadiene continuum) (Hoffman, et al, 1971, Lewis and Price, 1971. Films varying in thickness were prepared by varying the concentration and volume of benzene solution used.…”

Section: (A) Film Preparationmentioning

confidence: 99%

Surface hydroxylation of styrene–butadiene–styrene block copolymers for biomaterials

Sefton

Merrill

1976

J. Biomed. Mater. Res.

View full text Add to dashboard Cite

This work pertains to the development of high strength elastomers potentially useful as nonthrombogenic cardiovascular prostheses. Triblock copolymers of the styrene-butadiene-styrene type have been subjected to surface hydroxylation via intermediate epoxides providing reactive sites at the surface for the subsequent coupling of heparin while retaining the unique mechanical properties of the SBS copolymers.Curves of hydroxyl content versus the copolymer film thickness demonstrated the effect of swelling in the surface region on the product distribution and on the time dependence of the hydroxylation process. The results indicatedthat swelling in the surface region is modified by stress transfer to the unreacted, nonswelling core, giving rise to a lower hydroxyl content in thicker films than in thinner films due to separate effects on both the epoxidation agent and on the cleavage agents and an exponential time dependence with the appearance of a significant induction time.Detailed quantitative analysis of the infrared spectra of surface reacted samples indicated the presence of a thickness dependent diffusion lag between the cleavage agents and the peracid, confirming the observation of a decreased hydroxyl content in thicker films. Delamination of surface reacted samples occurred on swelling in chloroform. Through analysis of the weights of the resulting fractions, the depth of penetration and the shape of the reaction front was estimated as a function of time, temperature and the composition of the reaction bath.The general applicability of this surface modification scheme to biomaterial development and the use of SBS triblock copolymers as potential biomaterials was also evaluated.

show abstract

Kinetics of Aggregation and Dimensions of Supramolecular Structure in Noncrystalline Block Copolymers

Cited by 41 publications

References 0 publications

Morphology and micromechanical deformation behavior of styrene–butadiene block copolymers. IV. Structure–property correlation in binary block copolymer blends

Morphology and micromechanical deformation behavior of styrene–butadiene block copolymers. IV. Structure–property correlation in binary block copolymer blends

Damping of vinyl acetate–n‐butyl acrylate copolymers

Surface hydroxylation of styrene–butadiene–styrene block copolymers for biomaterials

Contact Info

Product

Resources

About