Month: June 2022

Organic/inorganic nanocomposites formed by inorganic fillers dispersed in a general plastic matrix with nano size are called nanoplastics. In nanocomposites, nanoplastics have excellent properties such as high strength, heat resistance, high barrier properties, flame retardancy and excellent processability because of the nano size effect, large specific surface area and strong interfacial bonding of the dispersed phase, which is a new high-tech new material.

Application of nano materials in plastic modification:

(1) Anti-aging properties of reinforced plastics
The anti-aging performance of polymer directly affects its service life and working environment, especially for agricultural plastics and plastic building materials, which is an indicator that requires high attention. The ultraviolet wavelength in sunlight is 200~400nm, and the ultraviolet light in the 280~400nm band can break the polymer molecular chain, and never make the material age. Nano oxides powder, such as nano alumina(Al2O3), titanium dioxide(TiO2), silicon dioxide(SiO2), etc., have good absorption characteristics for infrared and microwave. Proper mixing of nano-SiO2 and TiO2 can absorb a large amount of ultraviolet rays, thereby making the material anti-aging.

(2) Improve the processing performance of plastics
Some high polymers, such as ultra-high molecular weight polyethylene with a viscosity average molecular weight of more than 150, have excellent comprehensive performance, but due to their extremely high viscosity, it is difficult to form and process, thus limiting their popularization and use. Taking advantage of the small friction coefficient between the layers of layered silicate sheets, the ultra-high molecular weight polyethylene and layered silicate are fully mixed to make nano rare earth / ultra-high molecular weight polyethylene composite material, which can effectively reduce the ultra-high molecular weight polyethylene. The entanglement of ethylene molecular chains reduces the viscosity and plays a good lubricating role, thus greatly improving its processing performance.

(3) Improve the toughness and strength of plastics
The emergence of nano materials provides a new method and approach for the enhancement and toughening of plastics. Small particle size dispersed phase has relatively few surface defects and more unpaired atoms. The ratio of the number of atoms on the surface to the total number of atoms increases sharply with the decrease of the particle size. The crystal field environment and binding energy of the surface atoms are different from those of the internal atoms, and they have great chemical activity. The micronization of the crystal field and the increase of active surface atoms greatly increase the surface energy, so it can be closely combined with the polymer substrate and has good compatibility. When subjected to external force, the ions are not easily separated from the substrate, and can better transmit the external stress. At the same time, under the interaction of the stress field, more micro-cracks and plastic deformation will be generated inside the material, which can cause the substrate to yield and consume a large amount of impact energy, thereby achieving the purpose of strengthening and toughening at the same time. Commonly used nanomaterials include nano silicon carbide(SiC), silicon carbide whiskers(SiC-W), nano aluminum oxide(Al2O3), multi-walled carbon nanotubes(MWCNTs), etc.

(4) The addition of nanomaterials enables the functionalization of metal nanoparticles have heterogeneous nucleation, which can induce the formation of certain crystal forms that impart toughness to the material. Polypropylene was filled with low melting point metal nanoparticles, and it was found that it can act as a conductive channel and strengthen and toughen the polypropylene. At the same time, its low melting point also improves the processing performance of the composite material.