Controlled Synthesis Of Blend Polymers With Special Chain Structure And Properties

Atom Transfer Radical Polymerization (ATRP), as one of the most popular living polymerization processes, has been developed rapidly in the last ten years. It has been fully recognized and promoted by many scientific research personnel, and has already been put into industrial production. Compared with those relatively regular and already popularized industrial aggregation methods, living polymerization can get accurate molecular weight, molecular weight distribution and end functional groups. With the progress of science and technology, the conventional linear and cross-linking polymer materials can no longer satisfy the needs of the society. Since major changes could be brought about to the physical and chemical properties of polymers by changing their structures, polymers which have more complicated structures have gained more and more favor of the researchers. And the biggest characteristic of Atom Transfer Radical Polymerization process happens to be its design of the molecular structure of polymers.This first chapter of this article took the introduction of living polymerization as its main line. Several common living polymerization methods so far were firstly summarized. Then the topic of Atom Transfer Radical Polymerization (ATRP) was introduced. A series of optimization of ATRP method has been derived with scientists’ scientific study of ATRP. A brief introduction of the mechanism of ATRP and the related research work of ATRP were also presented in this chapter.The second chapter of this article introduced that the cyclic poly(n-butyl acrylate)-block-poly(methyl methacrylate)(cyclic-PBA-b-PMMA) can be synthesized successfully by the combination of Atom Transfer Radical Polymerization and click reactions. The cyclic copolymers were obtained by the intramolecular cyclization reactions between the linear precursors at high dilution. The chemical structures, molecular weights and molecular weight distributions of the cyclic block copolymers obtained were well characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). The thermal properties of these cyclic block copolymers and their linear counterparts were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It is interesting that the cyclic block copolymers have similar glass transition temperatures but higher degradation temperatures compared to their linear counterparts. The morphologies of the prepared samples were investigated via transmission electron microscopy (TEM). Unlike the linear block polymers, the cyclic block copolymers exhibited unique morphologies. Obviously, the cyclic block copolymers displayed a continuous dispersed morphology, and the dispersed phase had a worm-like structure. Meanwhile, nano-scaled phase separation was also observed between PBA and PMMA phase. When annealed above the glass transition temperatures of two blocks, PBA and PMMA, both linear and cyclic copolymers possessed well ordered nano-structures, and the size of these separated domains increased obviously after annealing.The third chapter of the article was an introduction of the study of multi-walled carbon nanotubes and polymer (PMMA and PBA) nano-composites. Through the study of the surface modification of multi-walled carbon nanotubes via the process that has been studied by other researchers, the multi-walled carbon nanotubes atom transfer radical polymerization initiator has been synthesized successfully. After modification of multi-walled carbon nanotubes step by step, modified multi-walled carbon nanotubes have a better disperse than these original multi-walled carbon nanotubes. This could solve the problem that carbon nanotubes are easy to unite in matrix material. The reaction kinetics of methyl methacrylate (MMA) and n-butyl acrylate (BA) polymerization was studied. The results of the study showed that the polymerization of the surface of multi-walled carbon nanotubes had the characteristics of living polymerization. The surface of multi-walled carbon nano tubes can graft PMMA and PBA polymer chain segments through the polymerization process of the Atom Transfer Radical Polymerization. Multi-walled carbon nanotubes modified by polymer chains are fixed at the end of a polymer chain. Then through the particular compatibility between components and the intermolecular forces of the binary polymer matrix poly (methyl methacrylate) and poly (butyl acrylate), they could be used to solve the distribution problem of multi-walled carbon nanotubes in polymer matrix. Experiment by analyzing the Fourier transform infrared spectroscopy, nuclear magnetic resonance analysis, differential scanning calorimetry, thermogravimetric analysis of synthetic product were characterized. The results of transmission electron microscope show that after being modified with PBA and PMMA, multi-walled carbon nanotubes have very good dispersion in polymer matrixes, and tend to be much more evenly distributed. After the solution blending of PBA and PMMA, micro phase separation was observed and double continues phases about PMMA and PBA can be seen. After the solution blending of multi-walled carbon nanotubes grafted with PBA and PMMA, multi-walled carbon nanotubes dispersed in PBA phase only and their non multi-walled carbon nanotubes dispersed in PMMA phase. Tensile test data show that contain the PMMA of multi-walled carbon nanotubes have a higher tensile strength.The fourth chapter of the article introduced the study of the surface modification of cellulose through the method of Atom Transfer Radical Polymerization. In the first phase of the experiment, the cellulose atom transfer radical polymerization initiator was synthesized. By using the method of ATRP polymerization, cellulose was grafted with PMMA and PBA molecular chain to form comb polymers which has the cellulose as their main chain. The surface chemical modification of cellulose was characterized in experiments by Fourier transform infrared spectroscopy, nuclear magnetic resonance and thermogravimetric analysis of synthetic product, and the results show that successful synthesis of cellulose atom transfer radical polymerization initiator was achieved. MMA and BA monomer has been initiated by cellulose atom transfer radical polymerization initiator, and their reaction kinetics has been studied. The results showed that cellulose surface atom transfer radical polymerization has the characteristics of living polymerization. Tensile test data show that contain the PMMA of cellulose have a higher tensile strength.