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

Recently, polymer nanocomposites reinforced with lower volume fraction of nanoceramics and carbon nanotubes have attracted steadily growing interest due to their peculiar and fascinating properties as well as their unique applications in commercial sectors. The incorporation of nanoceramics such as layered silicate clays, calcium carbonate or silica nanoparticles arranged on the nanometer scale with a high aspect ratio and/or an extremely large surface area into polymers improves their mechanical performances significantly. The properties of nanocomposites depend greatly on the chemistry of polymer matrices, nature of nanofillers, and the way in which they are prepared. The uniform dispersion of nanofillers in the polymer matrices is a general prerequisite for achieving desired mechanical and physical characteristics. In this review article, current development on the processing, structure, and mechanical properties of polymer nanocomposites reinforced with respective layered silicates, ceramic nanoparticles and carbon nanotubes will be addressed. Particular attention is paid on the structure–property relationship of such novel high-performance polymer nanocomposites.

Structural and mechanical properties of polymer nanocomposites

Poly(e-caprolactone) (PCL)/layered double hydroxide (LDH) nanocomposites were prepared success- fully via simple solution intercalation. The nonisothermal melt crystallization kinetics of neat PCL and its LDH nano- composites was investigated with the Ozawa, Avrami, and combined Avrami-Ozawa methods. The Ozawa method failed to describe the crystallization kinetics of the studied systems. The Avrami method was found to be useful for describing the nonisothermal crystallization behavior, but the parameters in this method do not have explicit meaning for nonisothermal crystallization. The combined Avrami- Ozawa method explained the nonisothermal crystallization behavior of PCL and its LDH nanocomposites effectively. The kinetic results and polarized optical microscopy obser- vations indicated that the addition of LDH could affect the mechanism of nucleation and growth of the PCL matrix. The Takhor model was used to analyze the activation ener- gies of nonisothermal crystallization. V C 2010 Wiley Periodicals,

Crystallization behavior of poly(ε-caprolactone)/layered double hydroxide nanocomposites

For the last decades, nanocomposites materials have been widely studied in the scientific literature as they provide substantial properties enhancements, even at low nanoparticles content. Their performance depends on a number of parameters but the nanoparticles dispersion and distribution state remains the key challenge in order to obtain the full nanocomposites’ potential in terms of, e.g., flame retardance, mechanical, barrier and thermal properties, etc., that would allow extending their use in the industry. While the amount of existing research and indeed review papers regarding the formulation of nanocomposites is already significant, after listing the most common applications, this review focuses more in-depth on the properties and materials of relevance in three target sectors: packaging, solar energy and automotive. In terms of advances in the processing of nanocomposites, this review discusses various enhancement technologies such as the use of ultrasounds for in-process nanoparticles dispersion. In the case of nanocoatings, it describes the different conventionally used processes as well as nanoparticles deposition by electro-hydrodynamic processing. All in all, this review gives the basics both in terms of composition and of processing aspects to reach optimal properties for using nanocomposites in the selected applications. As an outlook, up-to-date nanosafety issues are discussed.

/pdf/review-on-the-processing-and-properties-of-polymer-5e2mpcjjxh.pdf

Review on the Processing and Properties of Polymer Nanocomposites and Nanocoatings and Their Applications in the Packaging, Automotive and Solar Energy Fields.

Dynamic mechanical and morphological studies of isotactic polypropylene/fumed silica nanocomposites with enhanced gas barrier properties

Effect of in situ prepared silica nano-particles on non-isothermal crystallization of polypropylene

The melt viscosity of poly(propylene) is found to reduce dramatically through the addition of a minute amount of silica nanoparticles. We attribute this unique effect to “selective adsorption of high molar mass polymer chains” on the surface of the nanofillers. This represents a paradigm shift regarding commonly accepted relations between the molar mass and viscosity of molten polymers. This strong viscosity decrease provides major advantages for polymer processing, and materials with improved properties are obtained.

http://www.mate.tue.nl/~peters/Papers/2008/JainEA_ViscDecr_2008.pdf

Strong decrease in viscosity of nanoparticle-filled polymer melts through selective adsorption

https://pure.rug.nl/ws/files/14673650/2005PolymerJain.pdf

Synthetic aspects and characterization of polypropylene-silica nanocomposites prepared via solid-state modification and sol-gel reactions

A new route has been developed to produce PP/silica nanocomposites starting from porous PP reactor powder and making use of sol-gel chemistry. Silica-like, nano-sized particles were prepared in the pores of the PP reactor powder with a controlled degree of adhesion between PP and silica. Magic-angle spinning (MAS) 29 Si NMR spectra showed that the chemical building blocks of the silica-like clusters are of Q 3 and Q 4 -type. For (vinyl triethoxy silane (VTES)-grafted PP)/silica nanocomposites, VTES was grafted via solid-state modification (SSM) in porous PP particles. Subsequently, silica particles were prepared by sol-gel technology in the VTES-grafted PP. MAS 29 Si NMR and FT-IR spectroscopy showed that the grafted VTES becomes part of the in-situ formed silica particles. The study on the mechanical properties of (VTES-grafted PP)/silica nanocomposites showed that the silica particles improved the impact toughness of PP by a factor of 2, when there is no chemical interaction between the particles and the matrix, while for (VTES-grafted PP)/silica nanocomposites the impact toughness decreased. This indicates that chemical bonding between the filler particles and the PP-matrix results in brittle failure and supports the hypothesis that debonding is necessary for improving the impact toughness of PP with inorganic fillers.

Synthesis, characterization and properties of (vinyl triethoxy silane-grafted PP)/silica nanocomposites

Morphology development from a semi-interpenetrating polymer network structure (semi-IPN structure), induced by first-stage photocuring and aided by annealing, is investigated in a binary blend of a photocurable polymer (2,2-bis(4-(acryloxydiethoxy)phenyl)propane; BPE4), and a linear polymer (polysulfone; PSU). A blend with a miscible semi-IPN structure is produced by photocuring below the glass transition temperature (T g ) of the homogenous mixture of BPE4 and PSU, and is then annealed and post-cured at a higher temperature. The investigation reveals that the phase structures, which can be controlled by appropriately tuning the annealing temperature, range from BPE4-rich domain structures, through interconnected structures. to PSU-rich domain structures. The BPE4-rich domains are connected linearly to form an interconnected structure. The BPE4-rich and PSU-rich domains are restricted to the nanometre scale, with sizes of less than 100 nm over almost the entire operating range of annealing temperatures and composition. By adjusting the degree of the crosslinking in the semi-IPN structures, the characteristic length scale of the phase-separated structures can be varied. The meechanical properties (tensile strength and modulus) are at a maximum in the blend with the interconnected structute, due to the high conversion of BPE4 and the strong interfacial adhesion between the two phases, supported by the stability of the morphology resulting from the annealing.

S. Jain

Papers

Effect of in situ prepared silica nano-particles on non-isothermal crystallization of polypropylene

Strong decrease in viscosity of nanoparticle-filled polymer melts through selective adsorption

Synthetic aspects and characterization of polypropylene-silica nanocomposites prepared via solid-state modification and sol-gel reactions

Synthesis, characterization and properties of (vinyl triethoxy silane-grafted PP)/silica nanocomposites

Nanostructures Developed from Semi-Interpenetrating Polymer Network Structures