Detection Target
Determination of microstructure of Butadiene rubber
Overview
This solution conforms to the ISO 12965 Butadiene rubber — Determination of microstructure by infra-red spectrometry. This International Standard specifies a method for the determination of the microstructure of butadiene rubber (BR) by infra-red spectrometry using a cast film.
Apparatus
HKL-12965 FTIR for microstructure of Butadiene rubber
Principle
A small quantity of extracted rubber is dissolved in methylene chloride and cast on a salt plate. A spectrum is obtained over the range 2000 cm-1 to 600 cm-1. From the absorbances at fixed wavelengths, the cis, trans and vinyl contents are calculated.
Procedure
Mill the test sample to as thin a sheet as possible. Extract the rubber in accordance with ISO 1407 using ethanol/toluene azeotrope (ETA). Dry the extracted rubber under vacuum in the oven at 50 °C to 60 °C.
Take approximately 100 mg of extracted sample and dissolve it in around 20 ml of methylene chloride. If gel is present, filter the solution.
Ensure that the salt plate is levelled horizontally before the film is cast. Place 3 or 4 drops of the solution on the plate and spread evenly over the beam area. Allow the solvent to evaporate, preferably at room temperature.
Check that the transmittance over the measurement range lies between 50 % and 30 %. If grossly outside these limits, clean the salt plate and repeat step 3 with more or less solution.
When step 4 is satisfied, scan over the range 2000 cm−1 to 600 cm-1.
Draw a baseline from 2000 cm−1 to 600 cm−1, taking care that no peaks are cut .
Spectrum Example
