Determination of molecular weight distribution of polyethylene terephthalate by gelpermeation chromatography

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...

Simulated Distillation and Molecular Weight Determination by Supercritical Fluid Chromatography

Supercritical fluid chromatography (SFC) has recently become a popular technique for the analysis of crude oils. It has been demonstrated for simulated distillation (1) and for hydrocarbon type separation (2-3). The advantages of SFC over gas chromatography (GC) in simulated distillation are the wider boiling range and lower temperature thus preventing cracking of heavy molecules during analysi...

Preparation of Ultra High Molecular Weight Polyethylene Using Ziegler-Natta Catalyst System: Optimization of Parameters by Response Surface Methodology

Determination of molecular weight of heparin by size exclusion chromatography with universal calibration.

The molecular weight (MW) of heparin can be accurately determined by size exclusion chromatography using "universal calibration." A universal calibration curve was constructed for Superose 12 with standard pullulan samples and verified using characterized ficoll fractions. This calibration yielded the correct MW of heparin as determined by light scattering, when the ionic strength of the mobile...

Wear of Ultra High Molecular Weight Polyethylene