Rheology of Organoclay Nanocomposites Based on End-Functionalized Polymer

3 Rheology of Organoclay Nanocomposites Based on End-Functionalized Polymer 

In this section, we present the dispersion characteristics and rheology of end-functionalized polymers investigated by Zha et al. (2005). In their study, a PS and an SI diblock copolymer were synthesized via anionic polymerization. Then, the chain end of the PS was carboxylated to obtain end-fimctionalized PS-t-COOH, and the chain end of the PI block in the SI diblock copolymer was carboxylated to obtain end-functionalized SI-t-COOH. Subsequently, both PS-t-COOH and SI-t-COOH were neutralized using sodium hydroxide (NaOH) to obtain PS-t-COONa and SI-t-COONa. Each of the end-functionalized polymers was mixed with Cloisite 30B or Cloisite 20A to prepare nanocomposites. Table 12.2 gives sample codes of the eight organoclay nanocomposites prepared. 

It is interesting to observe in Eigure 12.52 that the values of G for the (PS-t-COONa)/Cloisite SOB nanocomposite decrease extremely slowly with increasing 

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