Utilizing an ingenious control over the enhanced segmental mobility of polymer chains, we proposed a novel low-temperature processing strategy for polymeric materials, where the materials were processed substantially below their normal glass transition temperature. This state of art was achieved by the combination of the confinement effects and the stress-induced effects on polymer nanoparticles. This method proved to be universal for various polymer systems, that is, polystyrene, polyvinyl chloride, polycarbonate, and polyphenylene oxide. Compared with the traditional high-temperature processing, the low-temperature processing efficiently avoids thermal degradation, and the processed polymer maintains moderate mechanical properties. In addition, this approach provides a straightforward method for the preparation of heat-labile bioactive polymer composites without biological surface modification. The prepared lysozyme/polystyrene composite exhibits excellent bactericidal activity and striking sustained release characteristics. This facile, universal and energy-saving low-temperature processing strategy is expected to open avenues toward expanding manufacturing methodology and the applications of polymeric materials, especially for bioactive composites, where conventional high-temperature processing is not applicable. (c) 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 2514-2520