Low‐Frequency Molecular Motions in Polyethylene

Structure and Molecular Motions in Rubidium Tetraphenylborate

By X-ray diffraction it was found that at 293 K the crystals of rubidium tetraphenylborate are tetragonal, space group I4̄2m, a = b = 11.212(2) Å, c = 8.098(2) Å, with 2 molecules of Rb[C24H20B] # in the unit cell. The molecular reorientations as functions of temperature were studied by H NMR. Two types of motions were detected: an anisotropic reorientation of the tetraphenylborate anions about ...

Molecular Motions in Functional Self-Assembled Nanostructures

The construction of "smart" materials able to perform specific functions at the molecular scale through the application of various stimuli is highly attractive but still challenging. The most recent applications indicate that the outstanding flexibility of self-assembled architectures can be employed as a powerful tool for the development of innovative molecular devices, functional surfaces an...

Synthesis of high molecular weight polyethylene using FI catalyst

A FI Zr-based catalyst of bis[N-(3,5-dicumylsalicylidene)-2′,6′­diisopropylanilinato]zirconium(IV) dichloride was prepared and used for polymerization of ethylene. The effects of reaction conditions on the polymerization were examined in detail. The increase in ethylene pressure and rise in polymerization temperature up to 35 oC were favorable for catalyst/MAO to raise the catalytic activity as...

Wear of Ultra High Molecular Weight Polyethylene

Investigations of Random Molecular Motions by NMR

The aim of this contribution is to demonstrate that NMR spin relaxation is an efficient method for the investigation of random molecular motions. Information on random motion is important for the characterization of liquids, polymers, and biological samples. Random motions are time-dependent phenomena and have to be treated with timedependent statistical mechanics. On the other hand, spin relax...