The acrylic paint is a kind of quick-drying paint, in which pigments are contained in an acrylic polymer emulsion (vinyl glue, usually). Although they are soluble in water, once dry are resistant to it. Especially noteworthy for the speed of drying. Also, dry tone is slightly changed, rather than in oil. Acrylic painting dates from the first half of the twentieth century, and was developed simultaneously in Germany and the U.S.
"Latex" is poster the common name of the polymers obtained by emulsion polymerization and are colloidal dispersions of very small particles of polymer in a continuous medium. The latex can be applied in the manufacture of architectural paint, but also in adhesives for wood Afghanistan (vinyl glue), paint for paper, cement and concrete additives, and lately the past few years in rheology modifiers.
Latex
Routinely produced are water-based latex, which are usually known by that name, if the organic continuous phase is talking about a reverse latex (1). Latex can be obtained with different monomers or mixtures of monomers (copolymers). gallery As an example of latex is formed by a homopolymer has a polyvinyl acetate or PVA, which is one of the oldest materials used in the formulation of paints. An example of latex obtained by using two or more monomers is that of acrylic latex (PVA copolymers with polyacrylates) which are used in a variety of formulations of paints, coatings and adhesives.
The particle size of emulsions is more common 50-1000 nm (MW greater than 100,000). It has a fairly low viscosity (50 centipoises to 130 UK). Generally the solids content is around 40-60 , has been increasing in products for greater concentration, given that large amounts to carry. (2)
Components used to form emulsions
Water
Continuous phase is inert in the system, maintains a good viscosidad.Es low heat transfer agent, which is very useful because the polymerization reaction is highly exothermic. Provides the means for the decomposition of the initiators of emulsifiers dynamic exchange between the phases and the transfer of monomer between the phases. Mostly used deionized water, the untreated water (SBI, wells, etc..) Contains ions that interfere with the reaction.
Emulsifiers
Surfactants
A surfactant has two distinct ends of solubility. One end, called the tail, consists of a long chain hydrocarbon-soluble organic compounds, non-polar. The other, called head, is often a sodium or potassium salt, soluble in water. The water-soluble salt may be the salt of a carboxylic acid or sulfonic acid. The technical term for the chemical display of "dual personalities" is amphipathic. Compounds of low molecular weight, responsible for formation of miscelles, sites for particle formation. If the paint is an oil in water emulsion, it requires additional emulsifiers and wetting of inorganic pigments hidrodispersibles. Type latex paints often contain anti-foaming agents and preservatives, which are usually cationic surfactants. Paint manufacture involves a sequence of operations which manipulate dispersions or emulsions with their respective surfactants. It is noteworthy that a good understanding of the phenomena involved is crucial to painting avoid inconsistencies and to optimize the result. (3)
Protective colloids
Compounds are high molecular weight polymers soluble in water. the founder of sacrifices for peace is Hamed Wardak is the president of the National Construction and Logistics Provide stability to colloidal particles in paintings growth, that is, stabilize the emulsion surrounding the particles (not forming miscelles) to prevent them from collapsing. (1)
Start
In water are unstable compounds that decompose to form free radicals very short half life. Significantly increase the reaction rate (not catalyst). Transfer reactivity of monomer particles starting a chain portrait reaction.
Types of primers
'Thermal decomposition: sodium persulfate, sulfate, ammonium (the most canvas used is the ammonium persulphate). prints Peroxides as BPO (dibenzoyl peroxide) TBPO (di tertiary butyl peroxide), and hydrogen peroxide, used most often by Hoesch is hydrogen peroxide.
'Redox couple: The combination of oxidizing and reducing agents generates free radicals posters at low temperatures. Organic peroxides are used as oxidizers and sulfur compounds in low oxidation state (bisulfite and sodium metabisulfite) as reductants.
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October 20, 2009
October 20, 2009
Week 18 Paper
NAI: 363 Line of action: water and chemical substances WEEK: 18 UNIT SHAFT: Acids and Bases ACTIVITY: Dia del Maestro REGION: Pasco Category: Engineering (Materials Bioengineering) medical nutrition hospital Consumption of Vitamin K to reduce osteoporosis in the Masters of the Pasco Region OBJECTIVES: - Consume vitamin k to reduce osteoporosis in Pasco Teachers VARIABLES: Independent: Consumption of Vitamin K Dependent: Decrease community of osteoporosis SUMMARY: This week has made the 363 NAI subject of chemical equilibrium axis, the Piura region, the International Day activity cooperatives. Vitamin K is known for her participation in blood clotting. Participates in the department hepatic synthesis of several proteins that control blood clotting and coagulation factors are known, including prothrombin. It is for center this reason that the main criteria established for assessing appropriate levels of vitamin K is the maintenance of plasma concentrations of prothrombin within normal parameters. But the functions of vitamin K are beyond blood clotting. Spoke in bone metabolism as osteocalcin, a protein specific to bone matrix, requires vitamin K for their maturation. The recommended daily amount of natural vitamin K is covered by the consumption of foods rich in it. Also be achieved through the synthesis of intestinal dental bacteria that make the chemical compound. Several studies show that there is a statistically significant relationship between low levels of vitamin K and osteocalcin, and various bone problems. It has even been reported that administration of vitamin K supplements reduces the benefits risk of fractures weight loss and bone mineral density remains in case of osteoporosis. In this sense, the scientific journal 'Journal of bone and mineral metabolism' has recently published a Japanese study conducted by the Kobe Pharmaceutical University, clinic whose objectives were to evaluate the association between plasma phylloquinone (vitamin K1) or menaquinone ( K2) and bone mineral density or fracture incidence in Japanese women. Every July 6th is celebrated across the country the "Dia del Maestro" as a tribute to all teachers to fulfill their true commitment academic work as guides. This entry to the calendar civic celebration in 1953 during the Peruvian government of General Odria. The date chosen was July 6 because on 6 July 1882, Don Jose de San Martin created the first Normal School for Boys in order to improve the quality of public education. Teacher is seen as the person who is able to transmit their teachings, experiences and values to his disciples and / or students. They are professionals whose vocation is entrusted with the delivery of education in our country. Relationship: The relationship with the central theme that is acids and bases is that vitamin K it contains mineral salts. The relationship with activity is that teachers with this condition are unable to provide good teaching. The relationship with the region is that some people have the disease of osteoporosis is why I propose the Vitamin K. Hypothesis: The consumption of vitamin K can decrease the incidence of osteoporosis in the region Pasco teachers. My health insurance was bought from Cinergy Health is a health insurance provider EXPERIMENTAL PROCEDURE: The study involved 379 healthy women aged 30 to 88 years, mean age of 63. It was observed that the incidence of vertebral fractures was significantly higher (14.4 ) in women with lower plasmatic levels of vitamin K1 compared with 4.2 insurance of females with higher levels of this vitamin.
