Structural studies of agar–gelatin complex coacervates by small angle neutron scattering, rheology and differential scanning calorimetry

2007 ◽  
Vol 41 (3) ◽  
pp. 301-307 ◽  
Author(s):  
S. Santinath Singh ◽  
V.K. Aswal ◽  
H.B. Bohidar
2003 ◽  
Vol 36 (4) ◽  
pp. 970-975 ◽  
Author(s):  
J. Pleštil ◽  
H. Pospíšil ◽  
A. Sikora ◽  
I. Krakovský ◽  
A. I. Kuklin

Tetronic RED 9040, a reverse-type [poly(propylene oxide) as terminal blocks] octablock star copolymer with four poly(ethylene oxide)/poly(propylene oxide) arms attached to the ethylenediamine core was studied in D2O at concentrations between 1 and 60 g dL−1in the temperature range from 283 to 353 K. Depending on concentration and temperature, various structures (unimers, random network, micelles, micellar aggregates, micellar networks) were indicated by small-angle neutron scattering (SANS). Some structure characteristics of unimers, micelles and micellar networks have been determined by fitting model scattering functions to the SANS data. A competition between the increasing association number and dehydration of the micelles is suggested as a possible explanation of the observed non-monotonic temperature dependence of the structure parameters of concentrated systems. A partial phase diagram was suggested on the basis of SANS and differential scanning calorimetry (DSC) data and visual inspection of the solutions.


1986 ◽  
Vol 79 ◽  
Author(s):  
J. M. Lefebvre ◽  
R. S. Porter ◽  
G. D. Wignall

AbstractAmorphous Polymethylmethacrylate/Polyethyleneoxide blends deformed by solid-state coextrusion exhibit anomalous anisotropic Small Angle Neutron scattering patterns in the low q range. It is shown that upon drawing the samples have undergone phase separation to some extent. The resulting structure of the system is characterized by combining scattering techniques with Differential Scanning Calorimetry.


1993 ◽  
Vol 321 ◽  
Author(s):  
A. Xenopoulos ◽  
J. D. Londono ◽  
G. D. Wígnall ◽  
B. Wunderlich

ABSTRACTDifferential scanning calorimetry (DSC) was used to study blends of polystyrene (PS) and poly (p-Methylstyrene) (PpmS). The presence of two glass transitions on heating after quenching was interpreted as evidence of phase separation at the temperature of the liquid before quenching. The small difference between the glass transitions of the homopolymers in the PS/PpmS system of “13 K limits the reliable detection of double glass transitions for blends to concentrations between 30 and 70%. The results of the DSC technique are supported by comparison with small angle neutron scattering (SANS) data.


2015 ◽  
Vol 48 (6) ◽  
pp. 1860-1869 ◽  
Author(s):  
Aurel Radulescu ◽  
Günter Goerigk ◽  
Lewis Fetters ◽  
Dieter Richter

The single-chain properties and self-assembly behavior in dilute solution of olefin block copolymers obtained by chain-shuttling technology and consisting of alternating crystallizable and amorphous ethylene/1-octene blocks were investigated by pinhole and focusing small-angle neutron scattering techniques, optical microscopy in bright-field and crossed-polarizer modes, and differential scanning calorimetry. The complex hydrocarbon soluble (precipitant free) macro-aggregates formed with decreasing temperature are characterized by spherulitic textures. The spherulites yield, on one hand, a morphology that depends on the chain structure properties and, on the other hand, multiple structural levels with a hierarchical organization that ranges from 10 Å up to tens of micrometres. This morphology displays peculiarities dictated by the polydisperse character of these materials.


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