Modification of Polyamide Resins by Addition of Polyvinylpyrrolidone

The effect of the addition of polyvinylpyrrolidone (PVP) to polyamide resins was studied using polyamide 6 (PA6) and an amide copolymer with a low melting point (PA-L). For the PA6/PVP blends, the crosslinking reaction occurred during rheology measurements in the molten state. The blends did not show a phase-separated structure. Furthermore, the crystallization of PA6 was greatly inhibited by PVP addition. These results suggest that the PVP chains were dissolved in PA6 in the molten state, although the effect of the crosslinking reaction on the structure development is unknown. In the case of the PA-L/PVP blends, melt-mixing and the rheology measurements were performed at low temperature to avoid the crosslinking reaction. It was found that PVP was miscible with PA-L in the molten state when the PVP content was 10 and 15 wt%. The intermolecular interaction between the polyamide resins and PVP was detected from the peak shift of the infrared absorbance. PVP addition enhanced the moisture content in both polyamide resins and decreased the contact angle with water droplets. These results suggested that the surface properties and mechanical properties of polyamide resins, which are affected by the moisture content, are modified by PVP addition.