International Journal of Applied Agricultural Research

Ultrasonic method, as a non-destructive means could be considered for the evaluation of coagulum quality. The objective of this research were to assess the relationship of coagulum quality with the rubber elasticity and the properties of ultrasonic wave, and to develop a mathematical model to relate the coagulum quality with the acoustic characteristics. Test samples were based on model, made by coagulating fresh latex with formic acid and the addition of foreign materials, that were limited to sand, rubber wood shavings, and their mixtures.

The result showed that increasing moisture content caused the increasing of Young modulus, as well as decreasing attenuation and wave velocity. The increase of sand content caused an increase of Young modulus, attenuation, and decrease of wave velocity. The increase of wood shavings caused the increasing of wave velocity and attenuation. The developed mathematical equation to determine the moisture content, dirt content and Young's modulus were expresed as function of density, attenuation, and wave velocity. This preliminary research result is expected to give useful information to develop further investigation for using ultrasonic method in rubber quality evaluation. Experiments are still to be carried out to investigate the effect of other contaminants to ultrasonic wave properties, to serve as base for engineering design of practical scale ultrasonic equipment.