10 - Self-extinguishing polymer–clay nanocomposites

Summary

Introduction

Thermodynamically, the introduction of a solid particle into a polymer matrix either decreases or increases the interfacial energy, depending on the degree of interaction between polymer chains and solid surfaces. If strong absorption of the polymer chains on the surfaces takes place, the system can be approached through minimization of the interfacial energy, reducing the energy factors. Furthermore, the minimization of interfacial energy can be optimized by increasing the interfacial area of solid particles. Therefore, in order to maximize reduction of the interfacial energy, the solid particles need a large aspect ratio, making both layered silicates and carbon nanotubes (CNTs) good candidates. In particular, layered silicates cation-exchanged with organophilic surfactants can be delaminated into a single silicate sheet in a polymer matrix and remain as nanosheets with aspect ratio 100–1000. Because of this unique delamination of organophilic silicates, polymer–organoclay nanocomposites are of great interest in industry and academia. Numerous research groups have characterized and predicted the microstructures of polymer/organoclay nanocomposites using advanced techniques.