Gel Permeation Chromatography for Molecular Weight Determination.pptx

Polymer Science Presentation

1. Topic: Gel Permeation Chromatography (GPC) for Molecular Weight Determination

2. PRESENTED BY Md. Tanvir Hasan Molla 201903015 Md. Hasibul Islam Akash 201903017 Ikbal Hossain 201903014 Sourov Das 201903016 Istiak Ahmed Hasib 201903013 01

3. PRESENTED TO DR. JAGANNATH BISWAS Associate Professor Department of Textile Engineering Green University of Bangladesh 02

4. Contents 05 What is Molecular weight of polymers? 04 GPC Introduction 06 Solvent 07 Detector 03 Injector Column Pump GPC Limits Conclusion 07 08 09 11 11 How GPC Works to determine the molecular weight 05 Exactly what can GPC tell about molecular weight 10

5. GPC Introduction Gel permeation chromatography (GPC) is one of the most powerful and versatile analytical techniques available for understanding and predicting polymer performance. It is the most convenient technique for characterizing the complete molecular weight distribution of a polymer. 04

6. What is Molecular weight of polymers? Molecular weight of a polymer is defined as sum of the atomic weight of each of the atoms in the molecules, which is present in the polymer. 05 How GPC Works to determine the molecular weight

7. Solvent There are a wide range of solvents used in GPC, from non-polar to aqueous. The critical part is to select a solvent that fully dissolves your studied material. The solvent must also be compatible with the column being used. A common non-polar solvent is tetrahydrofuran (THF), while even water can be used as an aqueous solvent. 06

8. Injector Most GPCs have an autosampler with an injector. Using an autosampler, you can set up a very large run and let it run overnight, while you are working on other tests, or (and I would never do this!) while you check Facebook. Obviously the important part of using an autosampler is to keep track of the order of your samples. Column In GPC, higher molecular weight material passes through the column first. A GPC column is made up of the mobile phase and a stationary phase of porous particles. 07

9. Pump Pump pressure and flow rate are two very important variables in GPC. Too much pressure can damage sample and the column, but too little pressure may never elute out of the column. Flow rate is also critical. A flow rate that is too slow makes the test unnecessarily slow, while a flow rate that is too fast can provide inaccurate measurements. 08

10. Detector Numerous types of detectors also exist for GPC, including ultraviolet, refractive index, infrared, density, etc. Normally two detectors are used in conjunction with each other, so that molecular weight can be directly calculated. The actual chromatogram from GPC shows the amount of material that exited the column at a certain time. 09

11. 10 GPC can provide number average molecular weight (Mn), weight average molecular weight (Mw), z average molecular weight (Mz), molecular weight distribution (MWD), and the polydispersity index (PDI) Exactly what can GPC tell about molecular weight

12. GPC Limits While GPC can provide much needed insight into sample molecular weight, samples often have overlapping molecular weights. Also, samples are more finicky with GPC than others. 11 Conclusion GPC can determine several important parameters. These values are important, since they affect many of the characteristic physical properties of a polymer. Subtle batch-to-batch differences in these measurable values can cause significant differences in the end-use properties of a polymer.