3. Natural rubber structure

NR rubber is a high-molecular-weight, linear cis-1,4-polyisoprene polymer (figure 2 ) (virtually 100% cis-bonded). The aqueous dispersion harvested from plantations, latex, contains between 30% and 40% solid matter, depending on the age of the trees and the time of year when the latex is recovered. . The average particle size is 0.15 to 3.0 µm. The non-aqueous part of the latex consists of rubber and about 2.0% protein, 1-2% resin, 1% fatty acid, 1% carbohydrate and about 0.5% inorganic salt.