Mussel-inspired polydopamine/polystyrene composites with 3D continuous structure and improved thermal, mechanical, and flame retarding properties

Polymer materials are widely used in daily life, but the flammability of most polymers has greatly restricted their applications. The addition of flame retardants into polymer matrix to form composites is the most effective method to improve the flame retarding properties. Here, a novel flame retarding composite is reported from polydopamine (PDA) and polystyrene (PS) through a latex technique. To maximize the potential of PDA in improving the properties of composites, PDA layers are first coated on PS microspheres and then the PDA coated PS microspheres are hot pressed to afford PDA/PS composites. Morphological characterizations of the cross sections of composites and the char after burning demonstrate the formation of three-dimensional continuous network of PDA layers inside PS matrix, while differential scanning calorimetry, thermogravimetric analysis, tensile test, and cone calorimeter test confirm the visibly enhanced thermal, mechanical, and flame retarding properties of composites as compared to neat PS. These improvements are attributed to the strong interfacial interactions between PDA and PS, physical barrier effect of continuous PDA layers, and good free-radical scavenging ability of PDA. This work demonstrates the great potential of PDA as additive for green and facile construction of flame retarding composites. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47740.