Synthesis Of Novel Hyperbranched Polymers Via Michael Addition Reaction

Hyperbranched polymers, which are characteristic of three-dimensional globular architecture, have attracted considerable and increasing attention from polymer scientists in recent years mainly due to their unique chemical and physical properties, such as good solubility, low solution and bulk viscosity, and the abundance of terminal functional groups. In last decade, the field of hyperbranched polymers has been well established with a large variety of synthetic approaches, means of characterization, potential application research.However, currently, some key problems are still existed. First, the synthesis method of hyperbranched polymers is limited and not facile, intermediates and synthesized polymers are limited, the cost is too high, so hyperbranched polymers is difficult to be synthesized in a large scale. Second, difficulty of controlling structure limits their large scale applications. Third, the hyperbranched polymers are not well-characterized, especially the molecular weight and the degree of branching. In this masteral dissertation, synthesis and functional application of hyperbranched polymers are chosen as the major topic. This work aims at exploring the answers of the problems aforementioned.A new straightforward"AD+CB₂"strategy for synthesis of novel hyperbranched poly(amino-ester)s and hyperbranched poly(ester sulfide)s from readily available monomers has been developed. Michael addition reaction of 2-amino-2-ethylpropane-1, 3-diol/3-Mercapto-1, 2-propanediol (CB₂) to methyl acrylate/Methyl methacrylate (AD) dominantly generated AB₂ intermediates during the initial reaction stage by optimizing the reaction conditions. They generally contained one ester and two hydroxyl groups. Further self-polycondensation of the AB₂ intermediates at higher temperature and in the presence of catalyst yielded hyperbranched polymers. The experimental results indicated that Ti(OBu)4 possessed promising catalytic performance, as evidenced by producing higher molecular weight in a shorter reaction duration. The structures and properties of these polymers have been explored in detail by FTIR spectra, NMR spectra, Gel Permeation Chromatography(GPC), differential scanning calorimetric (DSC) measurements, and thermogravimertric analyses (TGA). All these polymers possessed low viscosity, good solubility, excellent thermal properties and higher degrees of branching (DBs), DB typically remained in the range of 0.5-0.7.