Synthesis of Mainchain-type Polyesters by Atom Transfer Radical Polyadditions and Novel Nitroxide Agent

• Main Authors: Yu-Min Han, 韓裕民
• Other Authors: 黃智峯
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/53713114528549576322

碩士 === 國立中興大學 === 化學工程學系所 === 103 === Since 1995 development of living/control radical polymerization technology, extends many polymerization techniques for the polymer conformation that have great contribution, while the polymerization of ATRP face many challenges for some of functional groups. normal atom transfer radical polymerization(ATRP) can not be directly polymerization of the mainchain-type polyester structure. In this study, the first part of the paper we use atom transfer radical polyaddition(ATRPA) technology to direct the preparation of a polymer main chain structure having an ester group, and ester group structure with easily degradable properties. Polyester backbone in the special conditions decomposes to form oligomers; both in the biomedical or of environmentally friendly materials are great for development. We studied the mainchain-type polyester PVBBiB, by VBBiB/Cu(0)/CuBr2/dNbpy system at 10 °C under polymerization reaction. This type of polymer, as a result of the relationship between halogen leaving group effects, easily induce ring-closing, so that the polymer chains self-decomposition into oligomers. We use halogen exchange to polymerize VBBiB/Cu(0)/CuCl2/dNbpy system to achieve polymer with Br and Cl substitution in order to control of self-decomposition. The other hand increase the steric hindrance of the approach used by VBBPA/Cu(0)/CuBr2/dNbpy system can effectively control the self-decomposition. ATRPA also derived from the atom transfer radical addition reactions (ATRA), a polymerization reaction from inimer, polyaddition mainly using two different active sites differences. Under appropriate control, the polymerization will produce active halogen in the chain ends, and there is no active halogen in the side chain. This feature allows the use of only the end of the halogen with activity, repeated addition reaction. That is ATRPA represented selective polymerization techniques. Nitroxide radical polymerization between the active controlled radical polymerization is relatively easy. Only requires nitroxide or alkoxyamine, no additional catalyst or ligand, does not need the sulfide. Recent developed nitroxide agents such as TIPNO, SG1 remained high polymerization temperatures (125-145 °C), long reaction time of problems. For monomer selection or lowering the polymerization temperature has been a significant improvement. In this type of nitroxide divided into R1, R2, R3, R4 four substituents portion, each could have a polar group or a steric hindrance. The study found an increase of increasing polarity or steric hindrance help undermine C-ON bonding to reduce the polymerization temperature. And R4 represents a radical group activity. The second part of this paper we study the concept of using hydrogen bonds and polar groups of thiophene to weaken C-ON bond breaking energy to design a novel nitroxide initiator. To detailed polymerizations of MA and BA with this novel initiator were studied to overcome the difficulty of achieving controlled/living polymerization fashions of acrylic monomers using typical nitroxide reagent.