However, as its macromolecular backbone incorporates
unsaturated cis-1,4-polyisoprenes, NR likes any other polymer
is susceptible to oxidative or thermal degradation, particularly
when formed into thin films. Once the degradation
begins, NR readily becomes tacky and loses mechanical
integrity. NRL products have, therefore, short shelf lives
and life cycles. Though various anti-ageing agents have
been successfully developed for dry NR products and limited
anti-ageing agents for NRL were reported by using tris
(nonylated phenyl) phosphite [7] and non-water-soluble