Preparation and compatibilization effect of ?-cyclodextrin end-functionalized polystyrene for immiscible PCL/PS blends

Abstract

The compatibilizing effect of ?-cyclodextrin end-functionalized polystyrene (?-CD-PS) on immiscible PCL/PS blends has been studied using 2D NOESY NMR and DSC techniques. The ?-CD-PS was obtained via copper(I)-catalyzed azide-alkyne click reaction (CuAAC) of mono azide functional ?-CD (?-CD-N3) and low molecular weight PS as a compatibilizer. The preparation of inclusion complexes based on ?-CD and PCL (equimolar ratio) was investigated, aiming to reduce the interfaces of PCLand PS and compatibilizer the immiscible PCL/PS mixture. Compatibilization was visually observed when turbid PCL/PS solutions became clear upon heating and extended stirring. Several solutions were prepared with PCL/PS contents ranging from 100/0, 70/30, 50/50, and 30/70 (wt%) with ?-CD-PS contents (equivalent to PCL moles) by solution casting technique. The 30/70 PCL/PS blend containing stoichiometric 1:1 inclusion complex of ?-CD and PCL showed significant changes in DSC analysis. Moreover, 2-fold and 4-fold ?-CD-PS (stoichiometric 2:1 and 4:1 ?-CD:PCL) were tested to 50/50 PCL/PS blends to observe the amount of compatibilizer for obtaining good miscibility.