Tunnel Polymerization of Butadiene by Twice Functionalized Organoclay Intercalated by Cobalt and Chromium Catalysyts

A few weight percent loading of organoclay in polymer matrices leads to hybrid inorganic/organic materials, which exhibit remarkable improvements in thermal, barrier, and mechanical properties with respect to conventional composites. Among various approaches for the synthesis of polymer nanocomposites, new in situ techniques involve the direct addition of a clay intercalated by a catalyst to a monomer solution. Clay surface modification plays a very important role in polymer/clay nanocomposite direct preparation since the dispersion degree is dependent on the concentration of active sites nanoconfined within the filler lamellae. Herein we report a revision of the in situ polymerization, "tunnel polymerization", of 1,3-butadiene by using a twice functionalized organoclay (TFC). A sodium clay was first made organophilic by means of ion exchange with short carbon-chain cationic surfactant (ar-vinylbenzyl)trimethylammonium chloride (VBTA) and then treated with trimethylchlorosilane (TMSCl). The TFC was then reacted with methylaluminoxane (MAO) activator which replaces most of the VBTA within the clay galleries, without interacting with the edge hydroxyl groups previously grafted by silane molecules. Thus, MAO anchored to the silicate was able to alkylate the metal compound and allows for the growth of polymer chains directly in between the clay lamellae.