Surface modification of inorganic nanoparticles for development of organic–inorganic nanocomposites—A review

Polylactide (PLA)-based nanocomposites

The integration of inorganic nanoparticles into polymers has been used for the functionalization of polymer materials with great success. Whereas in traditional polymer composites, micron sized particles or agglomerates typically cause significant light scattering hampering optical applications, in nanocomposites the particle dimensions are small enough for the production of highly transparent composites. A challenge for the generation of such materials is to develop an integrated synthesis strategy adapting particle generation, surface modification and integration inside the polymer. Surface grafting using polymerizable surfactants or capping agents allows for linking the particles to the polymer. Novel techniques such as in situ polymerization and in situ particle processing are beneficial to avoid aggregation of inorganic particles inside the polymer matrix. The functions associated with inorganic fillers are widespread. Layered silicates and related materials are nowadays commercially available for improving mechanical and barrier properties in packaging. With the availability of highly transparent materials, the focus has shifted towards optical functions such as luminescence and UV-protection in transparent polymers. IR-active fillers are used in laser-holography for transparent poly(methyl methacrylate) (PMMA) nanocomposites. Refractive index modulation and ultrahigh refractive index films were developed based on inorganic materials such as PbS. The integration of magnetic nanoparticles has a great potential for applications such as electromagnetic interference shielding and magneto-optical storage.This tutorial review will summarize functions associated with the integration of inorganic nanofillers in polymers with a focus on optical properties.

Functional inorganic nanofillers for transparent polymers

Nanoscale particles for polymer degradation and stabilization—Trends and future perspectives

This article provides an up-to-date review on nanocomposites composed of inorganic nanoparticles and the polymer matrix for optical and magnetic applications. Optical or magnetic characteristics can change upon the decrease of particle sizes to very small dimensions, which are, in general, of major interest in the area of nanocomposite materials. The use of inorganic nanoparticles into the polymer matrix can provide high-performance novel materials that find applications in many industrial fields. With this respect, frequently considered features are optical properties such as light absorption (UV and color), and the extent of light scattering or, in the case of metal particles, photoluminescence, dichroism, and so on, and magnetic properties such as superparamagnetism, electromagnetic wave absorption, and electromagnetic interference shielding. A general introduction, definition, and historical development of polymer-inorganic nanocomposites as well as a comprehensive review of synthetic techniques for polymer-inorganic nanocomposites will be given. Future possibilities for the development of nanocomposites for optical and magnetic applications are also introduced. It is expected that the use of new functional inorganic nano-fillers will lead to new polymer-inorganic nanocomposites with unique combinations of material properties. By careful selection of synthetic techniques and understanding/exploiting the unique physics of the polymeric nanocomposites in such materials, novel functional polymer-inorganic nanocomposites can be designed and fabricated for new interesting applications such as optoelectronic and magneto-optic applications. Keywords: nano-filler; nano-inclusion; hybrid; effective additive; surface modification; superparamagnetism; UV absorption; in-situ polymerization; dichroism (Published: 2 August 2010) Citation: Nano Reviews 2010, 1: 5214 - DOI: 10.3402/nano.v1i0.5214

/pdf/nanocomposites-of-polymer-and-inorganic-nanoparticles-for-1tmjl4fsok.pdf

Nanocomposites of polymer and inorganic nanoparticles for optical and magnetic applications

A study on the photo-degradation of zinc oxide (ZnO) filled polypropylene nanocomposites

Spherical alumina (Al2O3) nanoparticles were incorporated into diglycidyl ether of bisphenol A (DGEBA) epoxy resin. The objective of this study is to investigate the effect of water absorption on the mechanical and dielectric properties of the Al2O3/epoxy nanocomposites. The results from tensile tests indicate that the incorporation of the Al2O3 nanoparticles into the epoxy can improve the stiffness of the matrix. DMA results show that the stiffness improvement is more pronounced at the rubbery state of the matrix. The Al2O3 nanoparticles can increase the dielectric constant of the epoxy resin due to the increase in the total interfacial area. Upon water absorption, the mechanical properties of the Al2O3/epoxy nanocomposites decrease evidently, because of the damage of water on the epoxy resin. However, the ductility can be improved by the water absorption process. In addition, both dielectric constant and dielectric loss of the Al2O3/epoxy nanocomposites increases greatly after water absorption treatment.

Effect of water absorption on the mechanical and dielectric properties of nano-alumina filled epoxy nanocomposites

The objectives of this paper are to study the crystallization behavior and fracture characteristics of spherical alumina (Al 2 O 3 ) nanoparticle-filled polypropylene (PP) composites. Nanocomposites containing 1.5-5.0 wt % of the Al 2 O 3 nanoparticles (pretreated with silane coupling agent) were prepared for this investigation. Wide angle X-ray diffraction (WAXD) results show that a small amount of β-crystal of PP forms after adding the Al 2 O 3 nanoparticles. According to differential scanning calorimetric (DSC) and optical microscopy (OM) measurements, the Al 2 O 3 nanoparticles make PP spherulite size reduced and crystallization temperature of PP enhanced, by acting as effective nucleating agents. However, there are no obvious differences in the crystallinity for the virgin PP and the Al 2 O 3 /PP nanocomposites. Tensile test shows that both the Young's modulus and the yield strength of the Al 2 O 3 /PP nanocomposites increase with the particle content increasing, suggesting that the interfacial interaction between the nanoparticles and PP matrix is relatively strong. Under quasi-static loading rate, the fracture toughness (K IC ) of the Al 2 O 3 /PP nanocomposites was found to be insensitive to nanoparticle content. Under impact loading rate, the Izod impact strength and the impact fracture toughness (G c ) indicate that the impact fracture toughness increases initially with the addition of 1.5 wt % of the Al 2 O 3 nanofillers into the PP matrix. However, with the further addition of up to 3.0 and 5.0 wt % nanoparticles, both the Izod impact strength and impact G c change very little. By observing the single-edge-double-notch (SEDN) specimens with optical microscopy after four point bending (4PB) tests, it was found that numerous crazes and microcracks form around the subcritical crack tip, indicating that crazing and microcracking are the dominant fracture mechanisms. Scanning electron microscopy (SEM) observation confirms this result. In addition, when the strain rate of 4PB tests was increased, some wave-like branches were formed along the fractured edge for the Al 2 O 3 /PP nanocomposites.

Crystallization, mechanical, and fracture behaviors of spherical alumina‐filled polypropylene nanocomposites

Results on the effect of water absorption on the mechanical and dielectric properties of nano-size spherical alumina (Al2O3) filled epoxy are presented in this paper. The results from tensile tests indicate that incorporation of the Al2O3 nanoparticles into the epoxy can improve the stiffness of the matrix. DMA results show that the stiffness improvement is more pronounced at the rubbery region of the matrix. The alumina nanoparticles can increase the dielectric constant of the epoxy resin due to the increase in the total interfacial area. Upon water absorption, the mechanical properties of the alumina/epoxy nanocomposites decrease evidently, because of the damages induced by water on the epoxy resin. However, the ductility of epoxy can be improved by the water absorption process. In addition, the dielectric constant of the alumina/epoxy nanocomposites increased greatly after water absorption treatment.

Hongxia Zhao

Papers

A study on the photo-degradation of zinc oxide (ZnO) filled polypropylene nanocomposites

Effect of water absorption on the mechanical and dielectric properties of nano-alumina filled epoxy nanocomposites

Crystallization, mechanical, and fracture behaviors of spherical alumina‐filled polypropylene nanocomposites

Effect of Water Absorption on the Mechanical and Dielectric Properties of Nano-Alumina Filled Epoxy Nanocomposites

Fracture behaviour of poly(ether ether ketone) films with different thicknesses