Sodium hydride/trialkylaluminum complexes for the controlled anionic polymerization of styrene at high temperature

A new generation of anionic initiators (butyl-lithium free), based on trialkylaluminum and a readily available alkali metal hydride, has been developed for the control of styrene polymerization at high temperature. Triisobutylaluminum and sodium hydride form heterocomplexes that are efficient for the initiation of styrene polymerization at 100 degrees C in toluene or in bulk. To be active under such conditions, these systems require the presence of an excess of metal hydride with respect to AlR3 ([Al]/[Na] < 1). PS chains are specifically initiated by the hydrides coming from NaH, and molar masses are controlled in the range 0.8 < [Al]/[Na] < 1. Fast exchange between dormant 1:1 and active 1:2 complexes (Al:Na), and ligand rearrangements within the 1:2 complex, can explain the observed results

A sulfonated polyphenylenesulfone (sPPSU) as the supporting substrate in thin film composite (TFC) membranes with enhanced performance for forward osmosis (FO)

10.1016/j.cej.2013.01.007Chemical Engineering Journal22015-23CMEJ

Retarded anionic polymerization (RAP) of styrene and dienes

The possibilities to achieve a quantitative living-like anionic polymerization of styrene and dienes in the absence of solvent and at elevated temperature and using inexpensive initiating systems were explored to make the anionic polymerization competitive with industrial radical processes and allow the industrial production of anionic polystyrene (PS). It implied at first to control the reactivity and stability of initiating and propagating active species in such unusual operating conditions. To achieve these goals the so-called styrene and butadiene ''Retarded Anionic Polymerization'' (RAP) have been developed. This review focuses on the description of different bimetallic anionic polymerization systems which are able to approach or fulfill the industrial conditions for styrene and dienes anionic polymerizations