What is the difference between dispersions and proper solutions?
While in the case of a proper solution, the dispersion of the binder in the solvent is molecular and below the size 0,0001 /im (0,0000001 mm), in the case of dispersion, the particles of the binder consist of many particles and have a size 0,1 4 μm. In dispersion varnishes, however, the fragmentation of the binder is already in the colloidal range, that is below 0,1 μm. Of course, the variation in particle size affects this, that they have different flow and gloss.
Please explain the term "homopolymer dispersions" and give examples
Homopolymer dispersions are prepared by polymerizing identical monomers (homo – equal). The homo-polymer dispersions include polyvinyl acetate (PYAC), vinyl polypropionate (PVP), polymethacrylate (PMA) and ethyl polyacrylate (PEA).
How copolymer dispersions are made?
Copolymer dispersions are prepared by co-polymerizing various monomers, i.e. combining various double-bonded molecules into macromolecules; the double bonds are broken in the process, which allows different molecules to combine into one giant molecule.
What are the advantages of copolymer dispersions compared to homopolymer dispersions??
These properties can be imparted to the dispersion by copolymerization, what else could be obtained only by using additives, e.g. plasticizers. Because a chemical bond is formed in the copolymerization process, the combined substances will not separate easily due to the action of physical factors, e.g. warm.
Materials are needed to produce the dispersion, which later in the coating cause its swelling to increase. What substances are involved here?
Cellulose ether is used as a protective colloid and thickening agent (more known as cellulose glue). Protective colloids prevent the separation of individual molecules during production. In addition, they prevent, together with thickeners, separation of ingredients during storage. Cellulose glue always dissolves in water and swells strongly under its influence.