Polystyrene -grafted CNTs

The grafting-from approach is based on the mitial immobilization of initiators onto the nanotube surface, followed by in situ polymerization with the formation of the polymer molecules bound to the nanotube. The benefit of this technique is that polymer-functionalized nanotubes with high grafting density can be prepared. However, this method requires a strict control of the amoimts of initiator and substrate [53, 54]. The grafting- from technique is also used for the preparation of styryl-grafted nanotubes [55]. In this work, the carboxylic acid groups on the surface of oxidized MWNTs have been reacted with 4-vinyl-benzyl chlorides via an esterification reaction followed by the polymerization to produce polystyrene (PS)-grafted CNTs [34,36-38]. 

More recently, the Diels Alder cycloaddition was used as a single-step strategy for attaching diene-capped polymers onto CNTs sidewalls through grafting to methods (see Section 3.3.1.6 for more details). Examples include attachment of furfuryl-functionalized polystyrene [35] and cyclopentadienyl-functionalized polymethyl methacrylate [36]. 

Another kind of amphiphilic block copolymer-grafted MWCNTs was prepared by sequential ATRP of styrene and fBA using CNT-Br-1 as the initiator, followed by hydrolysis of the poly(tert-butyl acrylate) (P BA) block into PAA," as shown in Figure 5.12. The polymer amount of the second block can also be adjusted by the feed ratio of fBA to polystyrene (PS)-grafted MWCNTs, demonstrating the living characteristics of the block copolymerization. The core-shell amphiphilic nano-object can self-organize into a film at the interface of chloroform and water. 

Kong et al functionalized CNTs with HPs by SCVP of vinyl benzyl chloride (VBC) in toluene at 110-130 °C for 24-48 h via ATRP using CuBr/ PMDETA or CuCl/bpy as the catalyst, and the grafted content of hyperbranched polystyrene reached 50 wt%. 

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