Method for predicting resistance to heat deterioration of isoprene rubber

摘要

A method for predicting the resistance to heat deterioration of a sulfur-vulcanized isoprene rubber is disclosed. The nuclear magnetic resonance spectrum of the isoprene rubber is obtained by the use of a solid state nuclear magnetic resonance method employing magic angle spinning. The spectrum of a cross-linked structure α and the spectrum of a cross-linked structure β in the nuclear magnetic resonance spectrum are identified. The percentage of the cross-linked structure α and the percentage of the cross-linked structure β in the overall cross-linked structures of the sulfur are computed from the spectrum. From the computed percentages, the resistance to heat deterioration of the isoprene rubber is predicted.

主权项

1. A method for predicting resistance to heat deterioration of a sulfur-vulcanized isoprene rubber, comprising:
measuring a nuclear magnetic resonance spectrum of the isoprene rubber by the use of a solid state nuclear magnetic resonance method employing magic angle spinning, identifying, in the nuclear magnetic resonance spectrum, a cross-linked structure α in which no double link exist near the reaction point of sulfur and a cross-linked structure β in which a double link exists near the reaction point of sulfur, obtaining, from the nuclear magnetic resonance spectrum, a spectrum area Sa of the cross-linked structure α and a spectrum area Sb of the cross-linked structure β, predicting the resistance to heat deterioration of the isoprene rubber, based on the ratio Sa/Sb of the spectrum area Sa to the spectrum area Sb such that
if the ratio Sa/Sb is less than a first reference value, the resistance is predicted as being not good,if the ratio Sa/Sb is not less than the first reference value and less than a second reference value, the resistance is predicted as being good, andif the ratio Sa/Sb is not less than the second reference value, the resistance is predicted as being excellent; and outputting the obtained ratio Sa/Sb and the predicted resistance in order to improve the isoprene rubber in the resistance to heat deterioration.