Phenolic resin/poly(dimethylsiloxane adipamide) (PDMSA) blends, which have been prepared, show miscibility due to intermolecular H-bonding existing between phenolic resin and the PDMSA. The specific H-bonding of novolac type phenolic/PDMSA blends was characterized by means of glass transition temperature behavior and Fourier Transform Infrared Spectroscopy (FTIR). The strength of intermolecular H-bonding within the phenolic blend is a function of the H-bonded group of the PDMSA modifier and corresponds to the deviation glass transition temperature (DeltaT(g)). Phenolic/PDMSA blends were completely miscible, as confirmed by the T 1 study. The FTIR result is in good agreement with the inference from T,, behavior. The char yield of phenolic/PDMSA corresponds to the phenolic resin content. The molecular mobility of phenolic/PDMSA blends increases with PDMSA content in the phenolic-rich region.