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Preparation of the Functional POSS Nano-particles Wearing Perfluoro Aryl Ether Dendron and Study of Their Polymer Blends

Author: SongLiYun
Tutor: PengShunJin
School: Wuhan University of Science and Technology
Course: Materials Physics and Chemistry
Keywords: functional POSS nano-particle solution blending epoxy resin polyurethane modification
CLC: TB383.1
Type: Master's thesis
Year: 2011
Downloads: 51
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Abstract


As one of the effective methods for materials modification, organic/inorganic nanoparticle hybrid technology can better the comprehensive properties of polymer hybrid materials through combining the excellent properties of organic materials, such as good processing and favorable toughness, as well as ones of inorganic materials, like superior mechanical property and thermal stability. Both epoxy resin and polyurethane are two kinds of general polymer materials. Now, it has been becoming mainstream to make those common materials obtain high performance by utilizing the functional nano-particles to modify them in the field of materials research.The structure characteristics, preparation technologies of polyhedral oligomeric silsesquioxane （POSS） and the research development and application of those polymers modified with it were reviewed in this paper; Two kinds of new fluorinated dendrons functional POSS nano-particles were synthesized via the mesylate reaction, whose structures were characterized using IR, 1H-NMR and 29Si-NMR. The product yields which are affected by different temperatures, the proportion of reactants and the dosage of solvent, were discussed. The epoxy resin and polyurethane modified respectively using the synthesized fluorinated dendrons functional POSS nano-particles by solution blending method were filmed by dipping, spinning and cast molding. The results listed as following can be obtained after analyzing the surfaces composition, the cross-sectional SEM images, the surfaces properties, the absorption capacity and the thermal stability of hybrid films:（1） Comparing with the traditional synthetic methods, synthesis of the fluorinated dendrons needed less time, obtained less by-products which were purified more easily using the mesylate reaction .（2） The XPS data showed that the F contents on surfaces of RfNH（CH2）2NH（CH2）3POSS/ epoxy resin and RfNH（CH2）2NH（CH2）3 POSS/polyurethane blend films were higher than their blocks, which revealed that the dendritic perfluoro-aryl ether construction units in POSS nano-particles has the tendency of oriented alignment to the surfaces of hybrid films during the process of curing.（3） The results of the cross-sectional SEM images revealed that the phase separation of POSS nano-particles didn’t emerge when RfNH（CH2）2 NH（CH2）3POSS nano-particles solution blending to modify epoxy resin and polyurethane, respctively.（4） The surface energy and surface wettability of blend films manifested that the surface energy of RfNH（CH2）2NH（CH2）3POSS/epoxy resin and RfNH（CH2）2NH（CH2）3POSS/ polyurethane blend films decreased with increasing content of RfNH（CH2）2NH（CH2）3POSS nano-particles; The higher of the degree of branching of dendritic perfluoro-aryl ether construction units in POSS nano-particles was, the more evident variation of surface energy of the blend films was. （5） Through calculating the weight changes of hybrid films before and after they absorbing water, we can conclude respectively RfNH（CH2）2NH（CH2）3POSS/epoxy resin and RfNH（CH2）2NH（CH2）3 POSS/polyurethane blend films and find that comparing with epoxy resin and polyurethane, the water absorptivity of the two kinds of hybrid films decreased and water resistance increased, respectively. Moreover, the diffusion coefficients of water in these blend films raised.（6） The TGA and DSC results revealed that the thermal decomposition temperature of the RfNH（CH2）2NH（CH2）3POSS/epoxy hybrid blends raised by 8℃and the solid residual percentage was ten times higher than epoxy resin. Moreover, the Tg raised by 37℃; The thermal stability of blend film regarded maleic anhydride as a curing agent was better than triethylenetetramine as a curing agent; The temperature scope of rapid decomposition for the RfNH（CH2）2NH（CH2）3POSS/polyurethane hybrid blends became broader and the solid residual percentage was five times higher than pure polyurethane although the initiating thermal decomposition temperature decreased slightly.（7） The curing kinetics study of RfNH（CH2）2NH（CH2）3POSS/polyurethane indicated that the curing activity of polyurethane modified by RfNH（CH2）2NH（CH2）3POSS nano-particles decreased slightly. The curing activity energies of pure polyurethane RfNH（CH2）2NH （CH2）3POSS/polyurethane were 58.41kJ/mol and 69.46kJ/mol, respectively.

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