The Synthesis Of The New Block Copolymer Based On 4-hydroxyl-2,2,6,6-tetramethylpiperydine-1-oxyl

The control of macromolecular structure has become an import facet of polymer science from both an academic and industrial viewpoint.Combining the advantages of free-radical polymerization and living polymerization,a range of new polymerization techniques based on living free radical procedures have been developed of the living free techniques developed,the procedures mediated by stable nitroxide free radicals, such as 2,2,6,6-tetramethylpiperydine-l-oxyl(TEMPO),have attracted considerable interest.One of the major drawbacks of NMRP is the long reaction time,narrow reacted monomer and elevated temperatures that are required for these reactions to reachcompletion. Thanks to the development of living polymerization,new nitroxide mediated radical polymerization were developed in the last decade,which could be used controlled polymerization by taking aminO,carboxyl,glycidyl ester and other functional groups as monomer.They have overcame many different places with the previous 2,2,6,6-tetramethylpiperydine-l-oxyl in the presece of nitroxide mediated radical polymerization(NMRP) of limitation.Based on the new nitrogen oxygen stable HTEMPO freedom for the initiator, anionic polymerization, by combining with ring-opening polymerization(ROP), nitroxide mediated radical polymerization (NMRP) of preparation of ABC three).The main results and progresses of this dissertation are underlined as following:1. The ABC amphiphilic triblock copolymers mPAA-b-PCL-b-PS was designed and synthesized. Firstly, the s-caprolactone was polymerized by living anionic polymerization using 4-hydroxyl-2,2,6,6-tetramethylpiperidinyl-1-oxy as initiator and stannous octoate (Sn(Oct)2) as catalyst, and the TEMPO-PCL with 2,2,6,6-tetramethylpiperidinyl-1-oxy(TEMPO) and hydroxyl end group was obtained. The TEMPO radical in TEMPO-PCL acted as a radical trapper to mediate the polymerization of styrene (St) by nitroxide-mediated radical polymerization (NMP) using benzoyl peroxide (BPO) as initiator, and the diblock copolymers were obtained. Then the macroinitiator PCL-b-PCL-Br for atom-transfer radical polymerization was obtained by 2-Bromoisobutyryl bromide reacting with the hydroxyl at the end of resultant diblock PS-b-PCL. Finally, the PS-b-PCL-Br was served to initiate the polymerization of t-butylacrylate (tBA) by atom-transfer radical polymerization (ATRP) in the present of copper bromide and N,N,N',N",N"-Pentamethyldiethylenetriamine(PMDETA), and the desired triblock copolymers PtBA-b-PCL-b-PS were obtained. After hydrolysis of PtBA blocks, new amphipathic triblock copolymer PAA-b-PCL-b-PS was prepared by acid hydrolysis.The investigation of kinetics of the polymerization of styrene confirmed that the polymerization was under control. The desired triblock copolymer and its intermediates were characterized. The final product and intermediate were characterized by FT-IR,1H-NMR and GPC in details.2. The ABC amphiphilic triblock copolymers PS-b-PEO-b-PLA was designed and synthesized. Firstly, the LA was polymerized by living anionic polymerization using 4-hydroxyl-2,2,6,6-tetramethylpiperidinyl-1-oxy and diphenylmethyl-potassium (DPMK) as initiator, and the TEMPO-PEO with 2,2,6,6-tetramethylpiperidinyl-1-oxy(TEMPO) and hydroxyl end group was obtained. The TEMPO-PEO was served as macroinitiator to initiate the polymerization of L-lactide by coordination-insertion ring-opening polymer-ization using stannous octoate (Sn(Oct)2) as catalyst, and the diblock copolymers were obtained.The TEMPO radical in TEMPO-PEO-bb-PLA acted as a radical trapper to mediate the polymerization of styrene (St) by nitroxide-mediated radical polymerization (NMP) using benzoyl peroxide (BPO) as initiator, Finally, The PS-b-PEO-b-PLA were obtained. The desired triblock copolymer and its intermediates were characterized.