Preparation And Application Of Controlled Polymers Via Ring-Opening Metathesis Polymerization

Macromolecular materials now have become the necessities of aviation, industry, agriculture and ordinary life. We can not image the civilization without macromolecular materials. Look back the evolution history of polymer science over the past century; we can see that the synthesis methods and its application of macromolecular chemistry played an important role in the development of the polymer science. Also, it accelerated the extensive application of macromolecular materials, and leaded the modern society into the period of synthesized materials.Along with the development of polymer science, material science and molecular biological science etc. in the past decade, we can clearly see that , the potential application in information memory, drug encapsulation and release, light catalysis have gained more attention ,and many research departments have already devoted plenty of money and manpower. Development and application of living polymerization, allow preparation of controlled polymers and nanostructure materials. Exploitation and application of new living polymerization will become future trend in macromolecular field, which have far-reaching potential for the study of molecular-level behavior at interfaces, in thin films, and in solution, while also enabling the development of encapsulation, drug-delivery, and nanoscale imprint-patterning technologies.In the past decades, ring-opening metathesis polymerization (ROMP) has evolved into a valuable tool for the polymer synthesis. Although a relatively new player on the field of polymer chemistry, ROMP has emerged as a powerful and broadly applicable method for synthesizing macromolecular materials. The origins of ROMP can be traced to the mid-1950s. However, the rapid rise in popularity and utility of this polymerization technique is the result of extensive work on the identification and isolation of key intermediates involved in the general olefin metathesis reaction. This led to the development of well-defined ROMP catalysts and ultimately enabled the synthesis of a wide range of polymers with complex architectures and useful functions. In particular, along with the synthesis of well-defined, stable and highly-efficient catalysts, the reaction in temperate condition was carried out. This will give this method new vigor.In this paper, ROMP of norbornene catalyzed by Grubbs 1st catalyst was carried out. The molecular weight and molecular weight distribution of this reaction can be controlled by changing the stirring time of catalyst, choosing different solvents and the adding of PPh3. Because of the particular mechanism of ROMP, the big ring tensility of norbornene and its tendency to unclose the carbon-carbon double bonds in order to reduce the energy of system, here we designed followed experiments: stirring time of the catalyst, polarity of the solvents used in the reaction and adding of PPh3 effects to the molecular weight and PDI of norbornene, also effectively decreased the molecular chain-transfer (so called"backbiting") reactions. This is the first time to research the effects of all the conditions used in ROMP reaction of norbornene catalyzed by Grubbs'1st catalyst, so as to obtain the optimal conditions of this reaction.In this paper, the hydrophobic poly(N-propyl-norbornene-exo-2,3- dicarboximide) with controlled molecular weight were prepared by living ring-opening metathesis polymerization. The lipase from Pseudomonas sp. was successfully immobilized on this hydrophobic polymer support through physical adsorption. The immobilized lipase exhibited a higher activity and enantioselectivity for transesterification of 2-octanol than that of free lipase. Furthermore, the effect of polymers molecules weight on properties of immobilized lipase was studied. It was found that along with molecular weight of polymer increased, catalytic activity and E value of the immobilized lipase increased. As the polymeric molecular weight is about 40kDa, the highest E value (58 at 54.2% of conversion, enantiomeric excess = 99%) was obtained. When the molecular weight of polymer was above 40kDa, catalytic activity and E value of the immobilized lipase decreased. When the polymeric molecular weight is about 40kDa, optimal condition of the immobilized lipase for transesterification reaction of 2-octanol was studied.In this paper, we synthesized a macromolecular monomer which took PEG (Mn=2000Da) as its side chain. Then, we obtained comb-like polymer via ROMP. We worked over molecular weight and PDI of these polymers, and its water-solubility etc. We obtained amphiphilic block copolymer via ROMP with this macromolecular monomer and norbornene. We researched the effects of adding order of two monomers to the molecular weight and PDI, and illustrated that it was caused by the steric hindrance and the ability to give electrons of this macromolecular monomer. We used these copolymers to research their self-assembly action, in this process, we researched the different appearances and sizes of the nanoparticle. Then, we researched the behaviors of this amphiphilic copolymer in drug encapsulation and release. Finally, we got the curve of drug release in vitro.