NMR Study of β Relaxation in Modified and Blended Isotactic Polypropylene

Relaxation of Shear-Induced Precursors in Isotactic Polypropylene and Random Propylene-Ethylene copolymers

Extensional-flow-induced crystallization of isotactic polypropylene

A filament stretching extensional rheometer with a custom-built oven was used to investigate the effect of uniaxial flow on the crystallization of polypropylene. Prior to stretching, samples were heated to a temperature well above the melt temperature to erase their thermal and mechanical histories and the Janeschitz-Kriegl protocol was applied. The samples were stretched at extension rates in ...

High-pressure crystallization of isotactic polypropylene droplets

Dispersions of isotactic polypropylene (PP) particles in polystyrene (PS) were produced by interfacially driven breakup of nanolayers in multilayered systems that were fabricated by means of layer-multiplying coextrusion. The droplet size was controlled by the individual PP layer thickness ranging from 12 to 200 nm. In addition, PP was melt blended with PS to produce PP droplets larger than tho...

A first principles investigation of isotactic polypropylene

Bulk isotactic polypropylene in the a form was studied using density functional theory-based computations. The computed physical structure of this system is in excellent agreement with available experimental data. The electronic band structure, ionization potential, and electron affinity were also determined. The impact of various types of chemical imperfections (including double bond, hydroxyl...

Probing self-assembled 1,3,5-benzenetrisamides in isotactic polypropylene by 13C DQ solid-state NMR spectroscopy.

Using (13)C double quantum solid-state NMR spectroscopy, we were able to observe nuclei of a supramolecular BTA based additive on the nanoscale in a matrix of i-PP at a concentration of only 0.09 wt%. These nuclei exhibit the analogous structural features as the crystalline phase of the neat additive.