The methods of preparation and formation of supermolecular structures in quiescent and sheared melts and the properties of the β-modification of isotactic polypropylene (β-iPP) are reviewed. The introduction of selective β-nucleants is the most reliable method for preparation of samples rich in β-modification or of pure β-iPP. The advantages and drawbacks of the known β-nucleating agents are summarized. It is emphasized that pure β-iPP can be prepared under laboratory and processing conditions in the presence of highly active and selective β-nucleants. Nevertheless, there are no literature data—apart from that of the author's groups—which evidenced unambiguously the formation of pure β-iPP. It hints at the insufficient selectivity of β-nucleants used or at the inappropriate crystallization or melting conditions applied by other scientists. The structure formation during the high-temperature hedritic crystallization is discussed comprehensively and illustrated by polarized light microscopy and scanning ele...

β-MODIFICATION OF ISOTACTIC POLYPROPYLENE: PREPARATION, STRUCTURE, PROCESSING, PROPERTIES, AND APPLICATION

Polymorphism in isotactic polypropylene

A critical assessment of unbalanced surface stresses as the mechanical origin of twisting and scrolling of polymer crystals

Mesophases in polyethylene, polypropylene, and poly(1-butene)

Thermal conductivity, diffusivity, effusivity and specific heat of polypropylene matrix filled with copper particles of two different sizes were investigated. A parallel study of the evolution of the electrical conductivity was also carried out. The highest heat transport ability was observed for the composites filled with the smaller particles. Electrical conductivity investigations showed that the size of fillers also influences the percolation threshold. The Agari's model provides a good estimation of the thermal conductivity of composites for all filler concentrations. It was used in order to give a comparative analysis of both electrical and thermal properties of such two-phase systems. Nevertheless, the physical meaning of the two fitting parameters C1 and C2 of Agari's model has to be completed.

Electrical and thermal behavior of polypropylene filled with copper particles

The dependence of the order in the orientation of the chains in the crystalline structure on the crystallization temperature is described for the α-form of isotactic polypropylene.

B. Pirozzi

Papers

Crystalline order and melting behavior of isotactic polypropylene (α form)

Polymorphism of isotactic poly-α-butene: Conformational analysis of the chain and crystalline structure of form 2

Synthesis and characterization of syndiotactic 3,4-polyisoprene prepared with diethylbis(2,2'-bipyridine)iron-MAO

Conditions for the α1-α2 transition in isotactic polypropylene samples

The role of intermolecular interactions in determining the mode of packing of crystalline polymers. Energy calculations on isotactic polypropylene