Quantifying Dry Rubber Content in Latex Solution Using an Ultrasonic Pulse

The quality of latex solution harvested from a para rubber tree is determined by the amount of dry rubber content (DRC). In this work, we propose the use of an ultrasonic pulse for quantifying the DRC in latex solution. Fresh latex solutions are acquired locally from different regions in the south of Thailand. The DRC of the solutions is evaluated for calibration purposes by the standard technique as recommended in ISO126:2005. Along with the calibration experiment, the ultrasonic pulse experiment is performed on the same set of the solutions in cylindrical tubes of different lengths. The ultrasonic pulse transverse longitudinally through the tubes which are fully contained with the latex solutions. Ultrasonic speeds and spatial attenuations for different dry rubber contents can then be obtained. Our results reveal that the ultrasonic speed and spatial attenuation are linearly proportional to the amount of dry rubber content in latex solution. Using the empirical relationship between the spatial attenuation and the DRC, we can predict the DRC with the accuracy comparable to that of the microwave-drying technique. Given the size of the tube, our setup is relatively small and can be portable.