scholarly journals Development of a block copolymer for impact modification of polyhydroxybutyrate (PHB)

2019 ◽  
Author(s):  
Linda Goebel ◽  
Christian Bonten
e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Olivier Talon ◽  
Jean-Pierre Couvercelle ◽  
Claude Bunel

Abstract The compatibilizing effect of pyromellitic anhydride (APy) in blends of PA12 and liquid polybutadiene (HTPB) was investigated. Blends were prepared, with or without APy, and the efficiency of this route of compatibilization was evidenced by observation of their morphologies. The addition of APy led to a finer dispersion of HTPB in the PA12 matrix. The formation of a compatibilizing block copolymer was proven by the evolution of the torque, the amine functionality and the size of the particles during blending, and by extraction of the dispersed phase followed by FTIR analysis. The effect of the mixing procedure was also investigated, and it was shown that the best dispersions were obtained when APy was added to a pre-blend of PA12 and HTPB.


1971 ◽  
Vol 32 (C5) ◽  
pp. C5a-295-C5a-300
Author(s):  
A. KELLER ◽  
J. DLUGOSZ ◽  
M. J. FOLKES ◽  
E. PEDEMONTE ◽  
F. P. SCALISI ◽  
...  

2015 ◽  
Vol 30 (2) ◽  
pp. 171 ◽  
Author(s):  
CHEN Tao-Tao ◽  
LI Dan ◽  
JING Wen-Heng ◽  
FAN Yi-Qun ◽  
XING Wei-Hong

2005 ◽  
Vol 42 (3) ◽  
pp. 180-183 ◽  
Author(s):  
S. G. Schulz ◽  
U. Frieske ◽  
H. Kuhn ◽  
G. Schmid ◽  
F. Müller ◽  
...  

2010 ◽  
Vol 6 (3) ◽  
pp. 277-284 ◽  
Author(s):  
Konstantinos Gardikis ◽  
Konstantinos Dimas ◽  
Aristidis Georgopoulos ◽  
Eleni Kaditi ◽  
Stergios Pispas ◽  
...  

1997 ◽  
Vol 62 (11) ◽  
pp. 1730-1736 ◽  
Author(s):  
Petr Munk ◽  
Zdeněk Tuzar ◽  
Karel Procházka

When two electrolyte solutions are separated and only some of the ions can cross the boundary, the concentrations of these ions are different on both sides of the boundary. This is the well-known Donnan effect. When weak electrolytes are involved, the imbalance includes also hydrogen ions: there is a difference of pH across the boundary and the dissociation of nondiffusible weak electrolytes is suppressed. The effect is very pronounced when the concentration of the weak electrolyte is high and ionic strength is low. The significance of this phenomenon is discussed for polyelectrolyte solutions, and particularly for block copolymer micelles with weak polyelectrolyte shells. The effect is quite dramatic in the latter case.


1993 ◽  
Vol 58 (10) ◽  
pp. 2290-2304 ◽  
Author(s):  
Zuzana Limpouchová ◽  
Karel Procházka

Monte Carlo simulations of chain conformations in a restricted spherical volume at relatively high densities of segments were performed for various numbers of chains, N, and chain lengths (number of segments), L, on a tetrahedral lattice. All chains are randomly end-tethered to the surface of the sphere. A relatively uniform surface density of the tethered ends is guaranteed in our simulations. A simultaneous self-avoiding walk of all chains creates starting conformations for a subsequent equilibration. A modified algorithm similar to that of Siepmann and Frenkel is used for the equilibration of the chain conformations. In this paper, only a geometrical excluded volume effect of segments is considered. Various structural and conformational characteristics, e.g. segment densities gS(r), free end densities gF(r) as functions of the position in the sphere (a distance from the center), distributions of the tethered-to-free end distances, ρTF(rTF), etc. are calculated and their physical meaning is discussed. The model is suitable for studies of chain conformations is swollen cores of multimolecular block copolymer micelles and for interpretation of non-radiative excitation energy migration in polymeric micellar systems.


1993 ◽  
Vol 58 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Minmin Tian ◽  
C. Ramireddy ◽  
Stephen E. Webber ◽  
Petr Munk

No anomalies were observed during the measurement of sedimentation coefficients of block copolymer micelles formed by copolymers of styrene and methacrylic acid in a mixed solvent; 80 vol.% of dioxane and 20 vol.% of water. The shapes of the sedimenting boundaries suggest that the size heterogeneity of the micelles is small. Linear relations between 1/s and c were obtained. The value of the hydrodynamic coefficient κ was between 2 and 4 in a good agreement with the value 2.75 or 2.86 that was obtained by combining Burgers' or Fixman's values of the coefficient of the concentration dependence kvs for hard spheres with Einstein's value of [η] for spheres.


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