TGA of Natural Rubber (NR) - METTLER TOLEDO

TGA of Natural Rubber (NR)

Purpose

To measure a typical TGA curve of natural rubber.

 

Sample

Unvulcanized NR

 

Conditions

Measuring cell: TGA/SDTA851e

Pan: Alumina 30 µl

Sample preparation: Piece of rubber of approx. 20 mg

TGA measurement: Heating from 50 °C to 625 °C under nitrogen (50 ml/min) and then from 625 °C to 850 °C under air (50 ml/min), Heating rate 30 K/min 

Atmosphere: Nitrogen then air, automatically switched

The DTG curve shows that the pyrolysis of NR takes place in two steps: a main step, which is the origin of the DTG peak at about 400 °C, and a small secondary step seen as a shoulder at somewhat higher temperature (about 450 °C). On switching from nitrogen to air, the TGA curve shows practically no combustion of carbon, indicating that no carbon black was formed during pyrolysis. Volatile compounds vaporize at lower temperature before pyrolysis begins.

 

Evaluation

The evaluation of the individual steps is summarized in the following table:

 

Conditions

NR pyrolyzes at relatively low temperatures (395 °C). The main pyrolysis step is followed by a small step at about 460 °C whose height is about 7% of the main step. A small amount of carbon black remains after pyrolysis. The ash content can also often be neglected. 

 

TGA of Natural Rubber (NR) | Thermal Analysis Handbook No.HB426 | Application published in METTLER TOLEDO TA Application Handbook Elastomers, Volume 2