Scanning electron microscopy (SEM), supported
by electron probe microanalysis (EPMA; Jeol 6310
equipped with an X-ray analyser), and infrared
spectroscopy (Perkin Elmer 1710) were employed
to investigate the properties of natural rubber and
chlorinated natural rubber. Solutions (2% w=v in
xylene) of (i) natural rubber (standard Malaysian
rubber, grade SMRL), (ii) chlorinated natural rubber
(Pergut S20, Bayer, Mn 3:9 3 104 g molÿ1, polydisperisty,
1.8) and (iii) a 1:1 wt% mixture were cast
onto glass and KBr pellets. The solvent was allowed
to evaporate in a fume hood. The samples were dried
in vacuo prior to treatment. In order to simulate the
vulcanization process, some of the films were heated
at 170 8C for 30 min.