9Burfield D R, Gan S N. Nonoxidative crosslinking relations in natural rubber( I ) : Determination of crosslinking groups[ J]. J Polym Sci : Polym Chem Edn, 1975,13 (12) :2725 - 2734.
10David R B, Kooi-Ling Lim, Kia-Sang Law, et al. Analysis of epoxidized natural rubber: A comparative study of d. s. c., n. m. r. , elemental analysis and direct titration methods[J].Polymer, 1984,25 ( 7 ) : 995 - 998.