高分子材料研究方法-凝胶色谱法

6.1.4 Measurement of MWD
6.2 Principles of Gel Chromatography

High Performance Liquid Chromatography (HPLC) Gel Chromatography


Separation Mechanisms
6.1 Background
GPC


1860~1930: porous materials have adsorptionseparation function (especially for dye) 1940~1970: appearance of Liquid Chromatography 1964: The first GPC produced by Waters company
Relation between molecular weight and properties of polymer
6.1.2 Statistic Average Molecular Weight

Number-average Molecular Weight

Weight-average Molecular Weight
6.1.2 Statistic Average Molecular Weight

Z-average Molecular Weight

Viscosity-average Molecular Weight
6.1.3 Expressions of MWD


Parameters
Breadth parameter of molecular weight distribution: variance and standard deviation between different molecular weights and the average molecular weight Polydispersity index of molecular weight:
GPC
Mobile phase in GPC
Mobile phase pump auto-injector column(s) detector(s) data acquisition

6.1.3 Expressions of MWD


Graphic Methods
Discrete distribution curves Continual distribution curves
6.1.4 Measurement of MWD


Theories
Reactions: terminal analysis Thermodynamics of dilute solutions: colligative properties (boiling point elevation, freezing point depression, osmotic pressure) Kinetics: ultracentrifugal sedimentation, viscosity, volume exclusion Optical properties: scattering
6.2.1 HPLC


Classification
Distribution chromatography
①
Liquid-liquid chromatography ② Normal phase LLC / Reverse phase LLC: polarity ③ Bonded stationary phase
6.2.1 HPLC


Classification
Adsorption chromatography
①
Stationary phase: absorbents ② Adsorption of mobile phase ③ Gradient elution ④ Applications: additives in polymers


1970: HPLC （rapid test 、good separation effects、 less sample、more sensitive）; New technology of HPLC applied in GPC area
6.1 Background



Significance of Molecular Weight Distribution (MWD) Statistic Average Molecular Weight Expressions of MWD Measurement of MWD
6.2.Hale Waihona Puke Baidu HPLC


Classification
Ion-exchange chromatography
①
Stationary phase: ion-exchange resin ② Applications: amino acids, proteins
6.2.1 HPLC


Classification
6.2.1 HPLC



Definition
High Performance Liquid Chromatography Also called high pressure liquid chromatography
①
Small particles of stationary phase: <10 μm ② High pressure injection pumps ③ Automatic detectors
Gel chromatography
①
Stationary phase: porous gel-like packings ② Large molecules → ↓ retention value / small molecules → ↑ retention value ③ Also called “gel exclusion chromatography (GEC)” Gel permeation chromatography (GPC): organic solvent