Factors influencing the selection of clay modifiers

The development of a complete formulation and processing system for the production of nanocomposites or thermally stable clays and nanocomposites must resolve a number of important issues, beyond the thermal stability of the clay modifier. We will describe some aspects of the approach followed by our group to achieve this goal. The main objective of the case study to be described was to evaluate a number of phosphonium compounds for the production of thermally stable organoclays that would be suitable for preparing satisfactory PS nanocomposites by melt-compounding. 

In the first step, commercially available phosphonium salts, listed in Table 3.7, were used to modify montmorillonite. Standard techniques were used with water-soluble surfactants, whereas a two-phase reaction was used with surfactants exhibiting low water solubility. The thermal stability of the organoclays and the quality of the PS nanocomposites incorporating these organoclays were compared to the behavior exhibited by a conventional ammonium organoclay. 

Notes Cloisite refers to Cloisite lOA. PS1510 and PS1220 are low- and high-molecular weight resins, respectively. Reproduced from [84]. 

---