Swelling of lamellar diblock copolymer by homopolymer: influences of homopolymer concentration and molecular weight

1991 ◽  
Vol 24 (23) ◽  
pp. 6182-6188 ◽  
Author(s):  
Karen I. Winey ◽  
Edwin L. Thomas ◽  
Lewis J. Fetters
Keyword(s):  
Molecular Weight ◽  
Diblock Copolymer

Synthesis of poly(methyl methacrylate)-b-poly(acrylic acid) by DPE method

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Dong Chen ◽  
Ruixue Liu ◽  
Zhifeng Fu ◽  
Yan Shi
Keyword(s):  
Molecular Weight ◽  
Acrylic Acid ◽  
Methyl Methacrylate ◽  
Diblock Copolymer ◽  
Self Assembly ◽  
Gel Permeation Chromatography ◽  
Amphiphilic Diblock Copolymer ◽  
Poly Methyl Methacrylate ◽  
Copolymer Poly ◽  
Poly Acrylic Acid

AbstractAmphiphilic diblock copolymer poly(methyl methacrylate)-b-poly(acrylic acid) (PMMA-b-PAA) was prepared by 1,1-diphenylethene (DPE) method. Firstly, free radical polymerization of methyl methacrylate was carried out with AIBN as initiator in the presence of DPE, giving a DPE-containing PMMA precursor with controlled molecular weight. tert-Butyl acrylate (tBA) was then polymerized in the presence of the PMMA precursor, and PMMA-b-PtBA diblock copolymer with controlled molecular weight was prepared. Finally, amphiphilic diblock copolymer PMMA-b-PAA was obtained by hydrolysis of PMMA-b-PtBA. The formation of PMMA-b-PAA was confirmed by 1H NMR spectrum and gel permeation chromatography. Transmission electron microscopy and dynamic light scattering were used to detect the self-assembly behavior of the amphiphilic diblock polymers in methanol.

Mechanical Properties of Blends of Crystallizable Polybutadienes Containing Amorphous Polybutadiene Diblock Copolymers

1994 ◽  
Vol 67 (2) ◽  
pp. 342-347
Author(s):  
Moira Marx Nir ◽  
Robert E. Cohen
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Surface Area ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Tensile Failure ◽  
Interfacial Surface ◽  
Failure Properties ◽  
Enhanced Properties

Abstract Tensile failure properties of syndiotactic 1,2 polybutadiene/trans 1,4 polybutadiene crystalline blends are improved by addition of 5–10% amorphous 1,2 polybutadiene/1,4 polybutadiene diblock copolymer. The effect of block molecular weight and microphase behavior of the diblock copolymer was investigated. Heterogeneous diblocks enhance blend properties to a greater extent than homogeneous diblocks. In blends with enhanced properties, percent coverage of interfacial surface area by diblock is on the order of 10%.

The Ordered Bicontinuous Double Diamond Structure in Binary Blends of Diblock Copolymer and Homopolymer.

1989 ◽  
Vol 171 ◽  
Author(s):  
Karen I. Winey ◽  
Edwin L. Thomas
Keyword(s):  
Molecular Weight ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Composition Range ◽  
Volume Fraction ◽  
Diamond Structure ◽  
Binary Blends ◽  
Resultant Effect ◽  
Strong Segregation ◽  
Double Diamond

ABSTRACTWe report the observation of the ordered bicontinuous double diamond (OBDD) structure in binary blends of poly(styrene-isoprene) diblock copolymer and homopolystyrene. The overall polystyrene volume fraction range is 64 - 67 PSvol% for the OBDD structure in binary blends of a lamellar diblock (SI 27/22) and a homopolymer (14.0 hPS). This composition range is approximately within the polystyrene volume fraction range established for pure diblock copolymers in the strong segregation regime having the OBDD structure. Ordered lamellae are observed at approximately 65 PSvol% when the homopolystyrene molecular weight is greater than the molecular weight of the polystyrene block of the copolymer. This observation is discussed in terms of the decreased degree of mixing between the homopolymer and the corresponding block and the resultant effect on the interfacial curvature.

Morphologies in Blends of Diblock Copolymer and Homopolymer: Morphology Diagrams and the Intermaterial Dividing Surface

1991 ◽  
Vol 248 ◽  
Author(s):  
Karen I. Winey
Keyword(s):  
Molecular Weight ◽  
Diblock Copolymer ◽  
Mean Curvature ◽  
Morphological Data ◽  
Copolymer Composition ◽  
Binary Blends ◽  
Morphological Transitions ◽  
The Mean ◽  
Dividing Surface ◽  
Double Diamond

AbstractBinary blends of diblock copolymer (AB) and homopolymer (hA) self assemble upon solvent evaporation into a great variety of microphase separated morphologies. The ordered lamellar, bicontinuous double diamond, cylindrical and spherical morphologies were observed by TEM and SAXS in our studies, as well as a range of micellar morphologies.The mean curvature (H) and the area per copolymer junction (σj), which characterize the intermaterial dividing surface, increased with increasing homopolymer concentration in the blend and/or with decreasing homopolymer molecular weight. These trends were generally obeyed both between and within ordered morphology types. The increase in H and σj was related to an increased degree of mixing between the homopolymer and the block of the copolymer.Two types of isothermal morphology diagrams were constructed to consolidate the extensive morphological data and to illustrate the general morphological transitions in AB/hA blends. The constant molecular weight morphology diagrams illustrated the interdependence of the copolymer composition and the homopolymer concentration. The constant copolymer composition diagrams emphasized the importance of the relative homopolymer molecular weight and the overall blend composition.

Property of diblock copolymer having extremely narrow molecular weight distribution

Polymer ◽  
2008 ◽  
Vol 49 (8) ◽  
pp. 2170-2175 ◽  
Author(s):  
Soojin Park ◽  
Du Yeol Ryu ◽  
Jin Kon Kim ◽  
Moonhor Ree ◽  
Taihyun Chang
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Diblock Copolymer ◽  
Weight Distribution ◽  
Narrow Molecular Weight Distribution

Modification of Interfacial Properties of Polymer Blends with Diblock Copolymer

1996 ◽  
Vol 461 ◽  
Author(s):  
S. Kim ◽  
C. C. Han
Keyword(s):  
Molecular Weight ◽  
Phase Separation ◽  
Polymer Blends ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Phase Region ◽  
Domain Growth ◽  
Two Phase ◽  
Phase Separation Kinetics ◽  
Styrene Butadiene

ABSTRACTThe effect of diblock copolymer on the phase-separation process of polymer blends has been investigated by using light scattering and optical microscopic observations. To quench the system into the two phase region, a shear-jump technique is employed instead of the conventional temperature-jump technique. The samples studied are blends of low-molecular-weight polystyrene and polybutadiene with and without added styrene-butadiene block copolymer as a compatibilizer. It was observed that the addition of diblock copolymers could accelerate the phase separation kinetics depending on the shear history. As the concentration of diblock copolymer increases, the distribution of domain sizes becomes narrower and the growth rate slows down. The extent of slowing-down depends on the molecular weight and concentration of the copolymer. The time dependence of domain growth is clearly observed with optical microscopy.

Dependence of the OBDD morphology on diblock copolymer molecular weight in copolymer/homopolymer blends

1993 ◽  
Vol 26 (5) ◽  
pp. 956-962 ◽  
Author(s):  
Richard J. Spontak ◽  
Steven D. Smith ◽  
Arman Ashraf
Keyword(s):  
Molecular Weight ◽  
Diblock Copolymer ◽  
Homopolymer Blends
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