Elastomers
Polymer - Structure - Property
Rubbers in both dry and latex form shall be coded from the chemical composition of the polymer chain using the following classes: M, N, O, R, Q, T, U, and Z.
O - Rubbers having Oxygen in the polymer chain
CO, ECO, GECO, and GPO.
R - Rubbers having Oxygen in the polymer chain
ABR, BIIR, BR, CIIR, CR,ENR, ENRG, HNBR, IIR, IR, NBR, NIR, NR, NRG, PBR, PSBR, SBR, SIR, XBR, XSBR, and XNBR, where the parenthetical letter S or E shall be used to indicate whether the rubber or latex was prepared by solution or emulsion polymerization and the prefix X shall be used if the rubber have substitute carboxylic acid groups.
Q - Rubbers having Silicone and Oxygen in the polymer chain
FMQ, FVMQ, PMQ, PVMQ, MQ, and VMQ.
T - Rubbers having Sulfur in the polymer chain
OT and EOT
U - Rubbers having Carbon, Oxygen, and Nitrogen in the polymer chain
AFMU, AU, and EU
Z - Rubber having Phosphorus and Nitrogen in the polymer chain
FZ and PZ
Heat and oil resistance of elastomers
In ASTM Oil No. 3, in accordance with ASTM D 2000.
Predicted service life
Based on extrapolation of measured values of the tensile stress relation (material: NBR wetted with peroxide) measured in air and nitrogen at various temperatures. E = elongation, EA = activation energy of the ageing process.
Vulcanization properties
Influence of cross-linking density on the elastomer properties.
Cross-linking characteristics of elastomers by measurement of the torque
1) The flow period covers the time interval from the
start of measurement to the start of cross-linking, i.e. to
the increase of torque. It identifies the range of viscous
flow, which is used to fill the mold. During this period
the torque initially decreases.
2) The cross-linking period shows information on the
required times for the material to transition to the stable
shape status.
3) Complete cross-linking is achieved when all possible
cross-linking points have formed.