Please use this identifier to cite or link to this item:
|Title:||Solvent – induced self – organization approach for polymeric architectures of micropores, hexagons and spheres based on polyurethanes prepared via novel melt transurethane methodology|
|Citation:||Journal of Polymer Science Part A: Polymer Chemistry 45(12):2351-2366;2007|
|Abstract:||Solvent - induced self-organization approach was developed, for the first time, to produce polyurethane micro porous templates and higher ordered morphologies such as micro or nanometer- sized polymeric hexagons and spheres. A novel melt transurethane methodology was designed as developed for synthesizing new class of cycloaliphatic polyurethanes under nonisocyanate and solvent-free conditions. In this new process, a diurethane monomer was polycondensed with equimolar amounts of diol in presence of Ti(OBu)4 as catalyst with the removal of low boiling alcohol from the equilibrium. The hydrogen bonding of the polyurethanes are very unique to their chemical structure and they undergo selective phase-separation process in solution to produce hexagonally packed microporous templates. The increase of water content in the polymer solution enhances the phase- separation process and the micro pores coalesce to isolate the encapsulated polymer matrix into polymeric hexagons or densely packed solid spheres. The concentration - dependent solution FTIR and 1H NMR of the polyurethanes revealed that the polymers processing higher H-bonding association constants (K) have greater tendency to undergo solvent-induced self-organization phenomena. The mechanism of solvent-evaporation process indicated that only microporous polyurethanes have tendency to form higher ordered hexagons and spheres whereas others failed to show any new morphology.|
|Appears in Collections:||2007|
Files in This Item:
|195.76 kB||Adobe PDF||View/Open Request a copy|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.