Structural Characterization of Diene Block Copolymers by GPC and Ozonolysis—GPC Measurements

1987 ◽  
Vol 60 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Yasuyuki Tanaka ◽  
Hisaya Sato ◽  
Junichi Adachi
Keyword(s):  
Molecular Weight ◽  
Chemical Composition ◽  
Block Copolymers ◽  
Block Structure ◽  
Triblock Copolymers ◽  
Thermoplastic Elastomer ◽  
Chemical Composition Distribution ◽  
Block Structures ◽  
Styrene Butadiene

Abstract The sequence distribution and block structure of styrene units in commercial styrene—butadiene and styrene-isoprene copolymers were analyzed by GPC measurements on the original copolymers and on ozonolysis products. Tapered-block structures are clearly differentiated by ozonolysis—GPC measurements. The content of large block styrene sequences in S-B-S type block copolymers was found to be 77 to 99% or more. S-B and S sequences in addition to the S-B-S sequence were observed for most of the triblock copolymers. A star-shaped S-B-S copolymer was distinguished from a linear copolymer by comparison of the molecular weight and chemical composition of the main and shoulder peaks by GPC and also by reference to the molecular weight of the block styrene sequence determined by ozonolysis—GPC measurements. A mixture of block copolymers was estimated for a high-styrene thermoplastic elastomer by GPC and ozonolysis—GPC measurements together with the measurement of chemical composition distribution. In a similar way the block structure was analyzed for S-I-S triblock copolymers.

Characterization of hetero-block copolymers by the log-normal distribution model

2016 ◽  
Vol 7 (17) ◽  
pp. 2992-3002 ◽  
Author(s):  
Michael J. Monteiro ◽  
Mikhail Gavrilov
Keyword(s):  
Molecular Weight ◽  
Chemical Composition ◽  
Block Copolymers ◽  
Normal Distribution ◽  
Distribution Model ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Log Normal ◽  
Log Normal Distribution

Fitting multiple and of different chemical composition molecular weight distributions using the log-normal distribution (LND) model.

scholarly journals Stratigraphy of amethyst geode-bearing lavas and fault-block structures of the Entre Rios mining district, Paraná volcanic province, southern Brazil

2013 ◽  
Vol 86 (1) ◽  
pp. 187-198 ◽  
Author(s):  
LÉO A. HARTMANN ◽  
LUCAS M. ANTUNES ◽  
LEONARDO M. ROSENSTENGEL
Keyword(s):  
Block Structure ◽  
Underground Mines ◽  
Mining District ◽  
Volcanic Province ◽  
Fault Block ◽  
River Bed ◽  
World Class ◽  
Entre Rios ◽  
Block Structures

The Entre Rios mining district produces a large volume of amethyst geodes in underground mines and is part of the world class deposits in the Paraná volcanic province of South America. Two producing basalt flows are numbered 4 and 5 in the lava stratigraphy. A total of seven basalt flows and one rhyodacite flow are present in the district. At the base of the stratigraphy, beginning at the Chapecó river bed, two basalt flows are Esmeralda, low-Ti type. The third flow in the sequence is a rhyodacite, Chapecó type, Guarapuava subtype. Above the rhyodacite flow, four basalt flows are Pitanga, high-Ti type including the two mineralized flows; only the topmost basalt in the stratigraphy is a Paranapanema, intermediate-Ti type. Each individual flow is uniquely identified from its geochemical and gamma-spectrometric properties. The study of several sections in the district allowed for the identification of a fault-block structure. Blocks are elongated NW and the block on the west side of the fault was downthrown. This important structural characterization of the mining district will have significant consequences in the search for new amethyst geode deposits and in the understanding of the evolution of the Paraná volcanic province.

Synthesis and thermal properties of triblock copolymers of methyl methacrylate using combination of anionic and controlled radical polymerization: Poly(methyl methacrylate) center block bearing different microstructures

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhengji Song ◽  
Carole Pelletier ◽  
Yinghua Qi ◽  
Jasim Ahmed ◽  
Sunil K. Varshney ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Block Copolymers ◽  
Methyl Methacrylate ◽  
Radical Polymerization ◽  
Triblock Copolymers ◽  
Controlled Radical Polymerization ◽  
Alkyl Methacrylate ◽  
Poly Methyl Methacrylate ◽  
H Nmr

AbstractABA and/or ABC type triblock copolymers were synthesized by living anionic and controlled radical polymerization in which poly(methyl methacrylate) was used as central block. The structural composition of these block copolymers were determined by 1H NMR. The block length/molecular weight and microstructure of these polymers were measured by SEC. The microstructure of resultant central alkyl methacrylate block can be tailored from highly syndiotactic to highly isotactic structure by varying the solvent and/or initiator. The thermal and rheological properties of center poly(methyl methacrylate) block and poly(styreneb- methyl methacrylate-b- styrene) tri block copolymers were studied in detail.

Viscoelastic Behavior of Styrene-Butadiene-Styrene Block Copolymers in Temperature Range of Glass-Rubber Transition of Styrene Block

1996 ◽  
Vol 69 (1) ◽  
pp. 73-80 ◽  
Author(s):  
N. Nakajima
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Viscoelastic Behavior ◽  
Shear Mode ◽  
Molecular Weight Polymer ◽  
Styrene Butadiene Styrene ◽  
The Difference ◽  
Tan Δ ◽  
Styrene Butadiene ◽  
Butadiene Styrene

Abstract Dynamic mechanical measurements were performed with styrene-butadiene-styrene (SBS) block copolymers, Kraton D-1101 and D-l 102. Isochronal data were obtained from −130 to 85°C in the tensile mode at 1 Hz and from 60 to 160°C in the shear mode at 1 rad/s. The isothermal measurements were also performed at 60, 90, 120, 140, and 160°C in the frequency range of 0.0316 to 100 rad/s. The results suggest that the two polymers have different morphologies although the styrene content and the diblock content are about the same for both polymers. Kraton D-1101, which has 1.5 times higher molecular weight, has 3–5 times higher rubbery modulus, compared to D-1102. The lower molecular weight polymer, D-1102, appears to have a larger amount of the mixed phase at the boundary. This is suggest by the lower temperature of the “domain disruption”, Tdd and the higher magnitude of tan δ at Tdd. This explains the difference in the rubbery moduli of the two polymers.

Characterization of the Chemical Composition Distribution of Ethylene/1-Alkene Copolymers with HPLC and CRYSTAF-Comparison of Results

2015 ◽  
Vol 216 (7) ◽  
pp. 721-732 ◽  
Author(s):  
Rajesh Chitta ◽  
Tibor Macko ◽  
Robert Brüll ◽  
Christophe Boisson ◽  
Emilie Cossoul ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Composition Distribution ◽  
Comparison Of Results ◽  
Chemical Composition Distribution
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