Polyme Analysis 2010 Part 13 pdf

Double Bonds FTIR Bending Vibrations Single Bonds (not to Hydrogen) Triple Bonds ['naitrail] FTIR -The aromatic ring, (C6H5): + the group of bands (C-H) above 3010 +a distinctive C=C stretch at about 1600cm-1 -The saturated main chain CH groups: the bands below 3010 C C H H H n Transmission FTIR of polystyrene I s , I R : intensities in the sample and reference beams -Sample preparation dependent on the physical form of the sample to be analysed. 1. Solids -Nujolmull -Potassium bromide disks -Preparing a solution in a suitable solvent *NujolMull -The sample is ground to give a very fine powder -A small amount is then mixed with nujol → a paste -Several drops of this paste are then applied between two sodium chloride plates -The plates are then placed in the instrument sample holder readyfor scanning. Sample Preparation FTIR *Potassium Bromide disk -A very small amount of the solid (approximately 1-2 mg) is added to pure potassium bromide powder (KBr, ∼200 mg) and ground up as fine as possible. -This is then placed in a small die and put under pressure mechanically (several minutes) -Removing the die and the KBrdisk formed. The disk is then placed in a sample holder ready for scanning. Sample Preparation FTIR 2. Liquids -The simplest and most common method of sample preparation. -A drop of the sample is placed between two potassium bromide or sodium chloride circular plates to produce a thin film. -The plates are then placed in a holder ready for analysis. 3. Thin Films -Placing a sample in a suitable holder, such as a card with a slot cut for the sample window. Sample Preparation FTIR . chloride circular plates to produce a thin film. -The plates are then placed in a holder ready for analysis. 3. Thin Films -Placing a sample in a suitable holder, such as a card with a slot cut for