Synthesis Of Twin-Tail Tadpole-Shaped And8-Shaped Amphiphilic Cyclic Copolymers

The relations between structures and properties of polymers have attracted many researchers’attention. Nowadays with the development of controlled/"living" polymerization and coupling methods with high efficiency, it provides the mature and reliable technical support for synthesis of these well-defined structure copolymers, such as miktoarm star, comb-shaped, linear-dendritic, and cyclic-based copolymers. Compared with linear and branched ones, cyclic polymers with "endless" polymer main chains show distinctively unique properties due to their closed ring topology. Thus it shows the important significance both in the theoretical research or practical application. However, a detailed physical understanding of cyclic polymers has been limited largely by synthetic complications although many ways for the synthesis of cyclic polymer have been designed.In this thesis, Glaser coupling reaction is used as cyclization technique to synthesize cyclic polymers. Combination with living anionic polymerization (LAP), ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP), The twin-tail tadpole-shaped (cyclic polystyrene)-block-[linear poly (tert-butyl acrylate)]2[(c-PS)-b-(l-PtBA)2] and8-shaped (cyclic polystyrene)-block-[poly(ethylene oxide)][(c-PS)-b-(c-PEO)] was synthesized. The main results obtained are showed as follows:1. Twin-tail tadpole-shaped (c-PS)-b-(l-PlBA)2was designed and synthesized; The telechelic polystyrene precursor with a propargyl group and an ethoxyethyl protected hydroxyl group at both ends was sequentially prepared by LAP of St monomers initiated by naphthalene lithium, termination with ethoxyethyl glycidyl ether (EEGE), and then selective propargylation of active hydroxyl groups with propargyl bromide. The intramolecular cyclization was carried out by Glaser coupling reaction. After separation and purification, the macroinitiator with two bromoisobutyryl groups at the junction point was obtained by hydrolysis of cyclic polystyrene with two ethoxyethyl protected hydroxyl groups at the junction point with HCl, then esterification of it with2-bromoisobutyryl bromide, and finally the ATRP procedure of tert-butyl acrylate (tBA) from macroinitiator for target (c-PS)-b-(l-PtBA)2. Using trifluoroacetic acid (TFA), the tadpole-shaped (cyclic polystyrene)-block-[linear poly (acrylic acid)]2was synthesized by hydrolysis of (c-PS)-b-(l-PtBA)2.2. Amphiphilic8-shaped copolymer (cyclic polystyrene)-block-[cyclic poly(ethylene oxide)][(c-PS)-b-(c-PEO)] was designed and synthesized:Firstly, telechelic polystyrene with a propargyl group and an ethoxyethyl protected hydroxyl group at both ends were used as macro-initiator in the presence of DPMK to initiate ROP of ethylene oxide to give the triblock copolymer, poly(ethylene oxide)-block-polystyrene-block-poly(ethylene oxide)(PEO-b-PS-b-PEO). Then, the end hydroxyls were modified to propargyls. The intramolecular cyclization was carried out by Glaser coupling reaction. The cyclic product with two ethoxyethyl protected hydroxyl groups at each side was hydrolyzed with HCl and propargylated with propargyl bromide. And finally using Glaser coupling reaction again,(c-PS)-b-(c-PEO) was obtained.All the intermediates and target products were characterized by GPC、1H NMR and MALDI-TOF MS in detail.