The affinity of amphiphilic compounds for water is important in various processes, e.g., in conformational transitions of biopolymers, protein folding/unfolding, partitioning of drugs in the living systems, and many others. Herein, we study the conformational transition of two isomer forms of poly(methacrylic acid) (PMA), isotactic (iPMA) and atactic (aPMA), in water. These isomers are chemical...

Propene polymerization with isotactic (iso)-specific C₂-symmetric rac-Me₂Si(2-Me-Benz(e)-Ind)₂ZrCl₂ (1) and rac-Me₂Si(2-Me-4-Ph-1-Ind)₂ZrCl₂ (2) were conducted under various conditions for achieving iso-specific living polymerization of propene. When Complex 1 was activated with trialkylaluminum-free modified methylaluminoxane (dMMAO) at -40 °C, the number-average molecular weight (Mn) linearly...

A two part study utilizing isotactic poly(4 -methyl-1-pentene) (PMP) was undertaken to investigate a three stage process (melt-extrusion/annealing/uniaxial-stretching) (MEAUS) to produce microporous films. In this report, the thermal annealing (second stage) and subsequent uniaxial-stretching (third stage) results of selected PMP films from three resins, labeled A, B & C, are discussed. From se...

Nucleation of the γ-form in isotactic polypropylene (PP) under high pressure was investigated. Three nucleating agents were used to nucleate crystallization of PP under atmospheric pressure: commercial Hyperform HPN-20E from Milliken Chemical, poly(tetrafluoroethylene) particles nucleating the α-form, and calcium pimelate nucleating the β-form. Crystallization of neat PP and PP with addition of...

In order to clarify the structure formation processes in the induction period of polymer crystallization the annealing time dependence of depolarized light-scattering (DPLS) intensities has been investigated as a function of crystallization temperature for poly(ethylene terephthalate), poly(ethylene naphthalate), syndiotactic polystyrene, and isotactic polystyrene. It is found that the inductio...

A family of chiral zinc amido-oxazolinate complexes are shown to be highly active and isoselective initiators for the ring-opening polymerization (ROP) of rac-lactide, yielding isotactic stereoblock polylactides (PLA) with Pm up to 0.91. This represents the highest isoselectivity observed with zinc-based catalysts for ROP of rac-lactide.