The paper describes the use of micro thermal analyzer (mu TA) for assessment of compatibilization in blends of nitrile rubber (NBR) with neat high-density polyethylene (HDPE), phenolic resin modified together with dynamically vulcanized HDPE and polyvinyl chloride (PVC). Micro thermal analyzer (mu TA) was employed to identify different locations by the study of thermal conductivity of the surface and topographic features. Local thermal analysis (LTA), e.g., micro thermomechanical analysis (mu TMA) and micro differential thermal analysis (mu DTA), were conducted at these locations. Blending of NBR with unmodified HDPE shows incompatibility. Modification of HDPE by phenolic resin and dynamic cross-linking by peroxide resulted in technological compatibilization of the blend, while NBR and PVC generated characteristics of a miscible blend. (c) 2007 Elsevier B.V. All rights reserved.