Poly[3]rotaxane : Synthesis and Property of The Novel Polymer

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The present research has been carried out to study the synthesis and property of novel polymer "poly[3]rotaxane" by using protocol of reversible covalent bond cleavage. A dumbbell molecule was designed as an axle component which contained two secondary ammonium moieties on it and two bulky groups at the termini, by using thiol-disulfide interchange reaction. A mixture of the dumbbell molecule and a isophthaloyl diamide possessing two dibenzo-24-crown-8-ether moieties was treated with a catalytic amount of benzenethiol to give 65% yield of poly[3]rotaxane with Mn 25000. The effects of the structures of the components, solvent, catalyst, and concentration on the polymerization were studied in detail. When the axle component having longer alkyl chain was employed, the polymerization was sluggish to require much longer reaction time (more than 1 week) to reach the equilibrium. However, the molecular weight of the resulting polymers were higher than that from shorter alkyl chain derivative, … More probably because of the suppression of the formation of 1:1 adduct of the two componets, i.e. the axle and wheel monomers.Thermal analyses and decomposition of poly[3]rotaxane were examined. Glass transition temperature and 5% weight loss temperature were 140℃ and 330℃, respectively, as determined by TGA and DSC analyses. Poly[3]rotaxane was treated with triohenylphosphine-water system as a typical reducing system for disulfide, and the corresponding reduced form of the dumbbell (a thiol) and the homofitopic crown ether (the wheel molecule) as the starting materials were recovered, suggesting the recycling property of poly[3]rotaxane.The synthetic method of poly[3]rotaxane was extended to the corresponding network polymer, polyrotaxane network. Poly(crown ether) was used instead of the homoditopic crown ether resulted in the formation of solvent-insoluble gel material which was well swelled in DMF by the reaction with the dumbbell molecule. The gelled polymer as polyrotaxane network was translucent when dried but transparent when swelled in DMF. The property of the elastic swelled gel was controllable by changing the conditions, monomer feed ratio, concentration, solvent and so on Less