Nanomatrix Structure of Natural Rubber

The morphology of natural rubber was observed by transmission electron microscopy and focused ion beam-scanning electron microscopy. Nanomatrix of non-rubber components such as proteins and phospholipids was found to be inherently formed in natural rubber, in which natural rubber particles of about 1 μm in average diameter were dispersed. The nanomatrix of non-rubber components disappeared after removing proteins from natural rubber, whereas it thickened after increasing the amount proteins. Viscoelastic properties of natural rubber were dependent upon the nanomatrix of non-rubber components: that is, the lager the amount of proteins (the thicker the thickness of nanomatrix), the higher the storage modulus. The outstanding mechanical properties of natural rubber were related to the formation of nanomatrix structure.