Search results
Results From The WOW.Com Content Network
Titanium dioxide nanoparticles, also called ultrafine titanium dioxide or nanocrystalline titanium dioxide or microcrystalline titanium dioxide, are particles of titanium dioxide (TiO 2) with diameters less than 100 nm. Ultrafine TiO 2 is used in sunscreens due to its ability to block ultraviolet radiation while remaining transparent on the ...
The addition−fragmentation chain-transfer process was first reported in the early 1970s. [3] However, the technique was irreversible, so the transfer reagents could not be used to control radical polymerization at this time. For the first few years addition−fragmentation chain-transfer was used to help synthesize end-functionalized polymers.
In the environment, titanium dioxide nanoparticles have low to negligible solubility and have been shown to be stable once particle aggregates are formed in soil and water surroundings. [103] In the process of dissolution, water-soluble ions typically dissociate from the nanoparticle into solution when thermodynamically unstable.
In polymer chemistry, chain transfer is a polymerization reaction by which the activity of a growing polymer chain is transferred to another molecule: [1] [2] + + where • is the active center, P is the initial polymer chain, X is the end group, and R is the substituent to which the active center is transferred.
Protein nanotechnology is a field of research that integrates the diverse physicochemical properties of proteins with nanoscale technology. This field assimilated into pharmaceutical research to give rise to a new classification of nanoparticles termed protein (or protein-based) nanoparticles (PNPs).
Titanium dioxide nanoparticles imparts what is known as the self-cleaning effect, which lend useful water-repellant and antibacterial properties to paints and other products. Zinc oxide nanoparticles have been found to have superior UV blocking properties and are widely used in the preparation of sunscreen lotions, [ 171 ] being completely ...
By definition, condensation liberates a small molecule, such as water or alcohol. This type of reaction can continue to build larger and larger silicon-containing molecules by the process of polymerization. Thus, a polymer is a huge molecule (or macromolecule) formed from hundreds or thousands of units called monomers. The number of bonds that ...
In order to perform the in situ polymerization of precursor polymer molecules to form a polymer nanocomposite, certain conditions must be fulfilled which include the use of low viscosity pre-polymers (typically less than 1 pascal), a short period of polymerization, the use of polymer with advantageous mechanical properties, and no formation of ...