Fiberglass Products
Although fiberglass products have the advantages of light weight, high strength and corrosion resistance, they have low hardness and poor wear resistance. Relevant experts added nano-SiO₂ to gel coat resin by ultrasonic dispersion method, and conducted performance comparison experiments with gel coat without nano-SiO₂. It was found that its Mohs hardness increased from the original 2.2 (equivalent to the hardness of gypsum) to 2.8~2.9 (grade 3 is the hardness of natural marble), and the wear resistance increased by 1~2 times. Because nano-particles produce grafting and bonding with organic polymers, the toughness of the material is increased, so the tensile strength and impact strength are increased by more than 1 time, and the heat resistance is also greatly improved.
Drug Carriers
With the rapid growth of urban domestic waste and the increasingly serious environmental pollution, it is urgent to strengthen the efforts to eliminate the "four pests" and prevent the spread of diseases. Brushing lime on tree trunks and spraying liquid medicine on garbage bins have little effect. Nowadays, large cities have adopted spraying central nervous system anesthetic pesticides to eliminate insect pests such as mosquitoes, flies and cockroaches. However, most of these pesticides are imported from abroad, with high prices and short validity periods (only one month) after spraying. Using nano-SiO₂ as a carrier to adsorb such pesticides has a good sustained-release effect. According to measurements, its validity period after spraying is as long as more than one year.
Cosmetics
For cosmetics, strong UV shielding ability is required, preferably to protect against the harm of UV medium wave (UVB) to human body and also protect against UV long wave (UVA). In essence, UV shielding includes two aspects: one is the absorption of UV as mentioned above, and the other is the reflection of UV. At present, no UV-resistant agents developed from the perspective of UV reflection performance have been reported in the world. In the past, organic compounds were mostly used as UV absorbers in sunscreen products, but there were problems such as increased risk of skin cancer and chemical allergy after increasing the addition amount to protect the skin from UV exposure as much as possible. Nano-SiO₂, as an inorganic component, is easy to be compatible with other components of cosmetics, non-toxic, tasteless, without the above problems, and is white in color, which can be easily colored. Particularly valuable is that nano-SiO₂ has strong UV reflection ability and good stability, does not decompose or discolor after being irradiated by UV, and does not react chemically with other components in the formula. These outstanding characteristics of nano-SiO₂ have laid a good foundation for the upgrading of sunscreen cosmetics.