Application of near infrared spectroscopy for quality evaluation in Para rubber industry

Abstract

Quality of products manufactured from Para rubber was an important aspect for merchandizing. Near infrared spectroscopy in a wavelength range of 900 to 1700 nm, which was a rapid and non-destructive technique, was applied to create quality predicting models for various Para rubber products. Near infrared hyperspectral imaging (NIR-HIS) technique was implemented to predict dry rubber content (DRC) of cup lump. Classification of adulterated Para rubber sheet was investigated using NIR-HSI. And NIR portable system was also developed for moisture content determination of Para rubber timber. The results showed that the DRC of the cup lump could be predicted with high accuracy with the coefficient of determination (R2) of 0.99 and root mean square of error of prediction (RMSEP) of 0.64%. Regarding the Para rubber sheet, the sulphuric acid coagulated sheets was classified from the formic acid coagulated sheet very good accuracy of 98.3%. Finally, The NIR portable system was developed and could be used to determine the moisture content of the timber with R2 and RMSEP of 0.96 and 5.37%, respectively. The application of NIRS was successful and provided feasibility for development into a future commercial use.