Noticeably, an absorption peak at 1758 cm1 is visible in the residues of all the dynamically vulcanized blends after thorough
extraction with dichloromethane for 3 days, suggesting that PLA reacted with NR during melt-blending in the presence
of DCP.
The extent of the compatibilization reaction can be approximately described by the amount of grafted PLA per
unit of residual NR, as measured by the ratio of absorption peak area at 1758 cm-1 to that at 1375 cm-1 (C-H symmetric deformation of NR's -CH3), i.e., A1758/A1375.