Carbon nanotube–polymer composites: Chemistry, processing, mechanical and electrical properties

Thermal conductivity of carbon nanotubes and their polymer nanocomposites: A review

5. In Situ Polymerization 3907 5.1. General Polymerization 3907 5.2. Photopolymerization 3910 5.3. Surface-Initiated Polymerization 3912 5.4. Other Methods 3913 6. Colloidal Nanocomposites 3913 6.1. Sol-Gel Process 3914 6.2. In Situ Polymerization 3916 6.2.1. Emulsion Polymerization 3917 6.2.2. Emulsifier-Free Emulsion Polymerization 3919 6.2.3. Miniemulsion Polymerization 3920 6.2.4. Dispersion Polymerization 3921 6.2.5. Other Polymerization Methods 3923 6.2.6. Conducting Nanocomposites 3924 6.3. Self Assembly 3926 7. Other Preparative Methods 3926 8. Characterization and Properties 3928 8.1. Chemical Structure 3928 8.2. Microstructure and Morphology 3929 8.3. Mechanical Properties 3933 8.3.1. Tensile, Impact, and Flexural Properties 3933 8.3.2. Hardness 3936 8.3.3. Fracture Toughness 3937 8.3.4. Friction and Wear Properties 3937 8.4. Thermal Properties 3938 8.5. Flame-Retardant Properties 3941 8.6. Optical Properties 3942 8.7. Gas Transport Properties 3943 8.8. Rheological Properties 3945 8.9. Electrical Properties 3945 8.10. Other Characterization Techniques 3946 9. Applications 3947 9.1. Coatings 3947 9.2. Proton Exchange Membranes 3948 9.3. Pervaporation Membranes 3948 9.4. Encapsulation of Organic Light-Emitting Devices 3948

Polymer/Silica Nanocomposites: Preparation, Characterization, Properties, and Applications

Miniaturizing a simple photomechanical system could expand its range of applications. Polymer solutions and solids that contain light-sensitive molecules can undergo photo-contraction, whereby light energy is converted into mechanical energy1,2,3,4,5,6,7,8. Here we show that a single film of a liquid-crystal network containing an azobenzene chromophore can be repeatedly and precisely bent along any chosen direction by using linearly polarized light. This striking photomechanical effect results from a photoselective volume contraction and may be useful in the development of high-speed actuators for microscale or nanoscale applications, for example in microrobots in medicine or optical microtweezers.

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Photomechanics: directed bending of a polymer film by light.

Switches, and Actuators Masahiro Irie,*,† Tuyoshi Fukaminato,‡ Kenji Matsuda, and Seiya Kobatake †Research Center for Smart Molecules, Rikkyo University, Nishi-Ikebukuro 3-34-1, Toshima-ku, Tokyo 171-8501, Japan ‡Research Institute for Electronic Science, Hokkaido University, N20, W10, Kita-ku, Sapporo 001-0020, Japan Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan Department of Applied Chemistry, Graduate School of Engineering, Osaka City University, Sugimoto 3-3-138, Sumiyoshi-ku, Osaka 558-8585, Japan

Photochromism of Diarylethene Molecules and Crystals: Memories, Switches, and Actuators

Epoxy−amine networks were modified with well-defined inorganic building blockspolyhedral oligomeric silsesquioxanes (POSS). POSS molecules were incorporated in the organic−inorganic networks as dangling units of a network chain or as network junctions. Mono- or polyepoxide POSS monomers were used to prepare the two types of networks. The structure of the POSS-containing networks, including the structure evolution during network formation, was determined by SAXS, WAXS, and TEM. The POSS pendant on a network chain shows a strong tendency toward aggregation and crystallization, depending on the POSS organic ligands. During network formation, ordering of the crystal domains takes place. The POSS−POSS interaction is the main factor controlling the network structure. Also, the polyepoxy POSSs monomers aggregate in the organic matrix; however, during network formation the system becomes more homogeneous and POSSs as network cross-links become better dispersed. Still, in the cured organic−inorganic networks the P...

Epoxy Networks Reinforced with Polyhedral Oligomeric Silsesquioxanes (POSS). Structure and Morphology

The rubbery epoxy network, based on diglycidyl ether of Bisphenol A (DGEBA) and poly(oxypropylene)diamine (Jeffamine D2000), was reinforced with a nanometer-sized inorganic building blockspolyhedral oligomeric silsesquioxanes (POSS). The organic−inorganic networks contained POSS as pendant units of a network chain or as network cross-links of various functionality. Thermomechanical properties and thermal stability of the POSS-containing networks were determined by DMA and TGA. The strongest reinforcement was achieved in the networks with pendant POSS forming ordered crystalline domains, which act as physical cross-links. The POSS skeleton with “soft“ flexible substituents, such as octyl, shows formation of weak aggregates only, which do not contribute to reinforcement. The rubbery modulus of the networks with POSS in a junction grows with increasing POSS functionality due to enhanced network cross-link density. These networks are more homogeneous, and the modulus of the network with the octafunctional POS...

Epoxy Networks Reinforced with Polyhedral Oligomeric Silsesquioxanes (POSS). Thermomechanical Properties

Formation and structure of the epoxy-silica hybrids

The mechanism of acid curing of epoxy resins catalyzed with tertiary amines was investigated by using model systems composed of phenylglycidyl ether and benzoic acid or acetic acid anhydrides in the presence of benzyldimethylamine. The reaction was studied by NMR spectrometry, liquid chromatography, and ozone absorption. The main findings are that (1) the tert-amine is bound chemically and irreversibly during the reaction under the formation of a quaternary ammonium salt 

and (2) 1-phenyloxypropanediol-2,3-dibenzoate or diacetate is the main reaction product. The suggested reaction mechanism involves initiation in which the tertiary amine reacts with the epoxy group, giving rise to a zwitterion that contains a quaternary nitrogen atom and an alkoxide anion; the latter immediately reacts with the anhydride and quaternary salt is formed. In a later stage the carboxy anion of the quaternary salt reacts first with the epoxy group, then with the anhydride. By this reaction diester is formed and the carboxy anion is regenerated.

Libor Matějka

Papers

Epoxy Networks Reinforced with Polyhedral Oligomeric Silsesquioxanes (POSS). Structure and Morphology

Epoxy Networks Reinforced with Polyhedral Oligomeric Silsesquioxanes (POSS). Thermomechanical Properties

Formation and structure of the epoxy-silica hybrids

Curing epoxy resins with anhydrides. Model reactions and reaction mechanism

Formation of nanostructured epoxy networks containing polyhedral oligomeric silsesquioxane (POSS) blocks