Thermoplastic elastomers (TPEs) are rubbery materials with properties and functional performance similar to those of conventional vulcanized rubber. Interest in natural rubber (NR) and thermoplastic blends (TPNRs) has also been increased recently. By blending with polar thermoplastics such as polyamide-12 (PA-12), epoxidized natural rubber (ENR) is one of the modified NR forms used to prepare TPNRs which improves compatibility of the polymer pairs. Blend compatibility was promoted because of interaction between oxirane rings in ENR and polar functional groups in polyamide molecules (i.e. –NH2, -COOH, -NH-CO-) and hence the blend properties. Temperature scanning stress relaxation (TSSR) measurement revealed an improvement in stress relaxation behaviour and thermal resistance of the blends with ENR. Moreover, it is possible to apply the TSSR to determine the compatibility of the blends based on the temperature coefficient (?.max) value in combination with ATR-FTIR technique.