Effect of particle sizes on film formation behavior of Hevea brasiliensis natural rubber latex

Abstract

© (2015) Trans Tech Publications, Switzerland. Natural Rubber (NR) latex obtained from Hevea brasiliensis contains a wide particle size distribution. The aim of this study is to investigate the effect of small rubber particles (SRP) and large rubber particles (LRP) on the characteristics of film formation. The rubber particle with different mean diameters can be separated by centrifugation at various speeds to prepare SRP and LRP latex. The average size of SRP and LRP were characterized by light scattering technique to show that the size of SRP was in the range of 0.20 μm, while that of LRP was larger with the wide distribution. SRP and LRP latex were dried at room temperature to study the film formation behaviors. The results showed that the film compaction time increased with increasing the particle size of NR. Furthermore, the rubber film were aged at room temperature for 3 weeks in order to observe the surface morphology using atomic forced microscopy (AFM) by tapping mode. The AFM images showed that SRP readily formed a coalescence film, while LRP showed individual particles on the surface of film at 24 h of storage time. The surface of both SRP and LRP films was smoother after storage. However, LRP film still showed individual particles on the surface after 3 weeks of storage time.