2. P R E S E N T E D B Y
Md. Tanvir Hasan Molla
201903015
Md. Hasibul Islam Akash
201903017
Ikbal Hossain
201903014
Sourov Das
201903016
Istiak Ahmed Hasib
201903013
01
3. P R E S E N T E D T O
DR. JAGANNATH BISWAS
Associate Professor
Department of Textile Engineering
Green University of
Bangladesh
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Contents
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What is Molecular
weight of polymers?
04
GPC Introduction
06
Solvent
07
Detector
03
Injector
Column
Pump
GPC Limits
Conclusion
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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.
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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.
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How GPC Works to determine the molecular weight
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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.
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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.
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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.
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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.
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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
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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.
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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.
