Effect of acid treatment on crosslink density
Fig. 2 demonstrates the effect of acid treatment on the crosslink density of NRL films. Generally, it is observed that crosslink density of NRL films treated with acid is lower than that of the control. The reason for the slight reduction in crosslink density is not understood but is probably due to the denatured proteins. During the drying process, evaporation occurs, protein domains are formed around the rubber particles [13] and act as a filler in the NRL [14]. Since the proteins are denatured, the proteins that occupy the space between the latex particles would not be able to behave like cement which binds the particles together. Hence, the measured crosslink density of the films will be slightly lower.