Polymer blends and composites from renewable resources

Progress in the production and modification of PVDF membranes

A mean-field phase diagram for conformationally symmetric diblock melts using the standard Gaussian polymer model is presented. Our calculation, which traverses the weak- to strong-segregation regimes, is free of traditional approximations. Regions of stability are determined for disordered (DIS) melts and for ordered structures including lamellae (L), hexagonally packed cylinders (H), body-centered cubic spheres (QIm3m), close-packed spheres (CPS), and the bicontinuous cubic network with Ia3d symmetry (QIa3d). The CPS phase exists in narrow regions along the order−disorder transition for χN ≥ 17.67. Results suggest that the QIa3d phase is not stable above χN ∼ 60. Along the L/QIa3d phase boundaries, a hexagonally perforated lamellar (HPL) phase is found to be nearly stable. Our results for the bicontinuous Pn3m cubic (QPn3m) phase, known as the OBDD, indicate that it is an unstable structure in diblock melts. Earlier approximation schemes used to examine mean-field behavior are reviewed, and compa...

Unifying Weak- and Strong-Segregation Block Copolymer Theories

Rheological behavior of multiwalled carbon nanotube/polycarbonate composites

Nylon 6 nanocomposites: the effect of matrix molecular weight

Two types of multiphase flow may be distinguished on the basis of their degree of phase separation. One type is dispersed multiphase flow, in which one or more components exist as discrete phase, dispersed in another component forming the continuous phase. The other type is stratified multiphase flow, in which two or more components form continuous phases separated from each other by continuous boundaries.

Multiphase flow in polymer processing

Rheology in polymer processing

Determination of the order-disorder transition temperature of block copolymers

The effects of temperature, molecular weight and its distribution, side chain branching, and the structure of polymers on the elastic behavior of bulk homopolymers were investigated, by using logarithmic plots of first normal stress difference (N1) against shear stress (σ12) and logarithmic plots of storage modulus (G′) against loss modulus (G″) For the investigation, we have used data from the literature as well as our recent experimental results, covering a very wide range of temperature and shear stress or loss modulus It has been found that such plots are very weakly sensitive to (or virtually independent of) temperature and to the molecular weight of high molecular weight polymers, but strongly dependent upon the molecular weight distribution and the degree of side chain branching A theoretical interpretation of the observed correlations is presented, using molecular theories

Chang Dae Han

Papers

Multiphase flow in polymer processing

Rheology in polymer processing

Determination of the order-disorder transition temperature of block copolymers

Correlations of the first normal stress difference with shear stress and of the storage modulus with loss modulus for homopolymers

Rheology and processing of polymeric materials