Chemical Modification of Natural Rubber in the Latex Stage by Grafting Cardanol, a Waste from the Cashew Industry and a Renewable Resource

Cardanol, an agricultural byproduct of the cashew industry, is a cheap and abundantly available renewable resource. The multifunctional activity of cardanol in the rubber and polymer industries has been well established in recent years. The present study highlights the chemical grafting of cardanol onto natural rubber in the latex stage. The cardanol grafted natural rubber is characterized by FTIR and NMR spectroscopies. The grafting parameters have been optimized for maximum yield in terms of percent grafting and grafting efficiency by the Taguchi method. Four control factors, i.e., initiator concentration, cardanol concentration, reaction temperature, and reaction time, are chosen at three different levels. The optimum parameter combination is found to be the initiator concentration 2 phr, cardanol concentration. 10 phr, reaction temperature 65 degrees C, and reaction time 6 h. The analysis of variance method is used to evaluate the percentage contributions of the different control factors on the percent grafting and grafting efficiency.