This report deals with the drying of paint, with the main focus on latex paint. Evaporation and polymerisation are the two main processes in drying paint. These are described and the effects that the environment has on evaporation is discussed. Furthermore, an attempt was made to create a theoretical model to predict the evaporation of paint and an experiment was carried out to test this model. Several plates were prepared with different mixtures and two were coated in paint. The experimental data of the evaporation of water agrees with the theoretical model. The drying of the latex paint however, does not coincide with the theoretical model.
INTRODUCTION
In this project we take a look at the drying process of paint. At first this may not seem
…show more content…
Water is a commonly used solvent, because it is more environmental friendly and healthier than organic solvents. In water based paints there are usually organic co-solvents present to help the film forming process.
In oil-based paint, the solvent is a mixture of organic substances, wherein toluene or xylene are usually the largest components (> 50%). In addition, a whole range of other organic compounds are used, which are usually ketones or alcohols[1][2].
Paint often contains a colouring material and that is either a pigment or a dye. The main difference between these is that a pigment is insoluble and a dye is either a liquid or soluble in the paint. Acrylic paints contain only pigments, so dyes will not be discussed further.
Pigments are used since ancient times and are originally extracted from plants, animals or minerals, but today most pigments are synthetic. The biggest disadvantage of using pigments is that they are insoluble in water and do not attach to the surface the paint is applied on. To overcome this, manufacturers use different additives in their paints to keep the pigment in suspension and improve dispersion. In order to attach the pigment to the surface, the binding agent is
…show more content…
In physical drying, no chemical reaction takes place. The binding agent’s long polymers have been dissolved in a solvent. During drying, the solvent evaporates and the long polymer chains remain unaltered as a film. Some paints dry only by means of evaporation of the solvent, but the majority of paints dry chemically[1].
Chemical drying is usually slower. This is because in addition to the evaporation of the paint’s solvent, there is also a chemical reaction that takes place. In this reaction polymers form which provide the binding in the paint’s film. In most cases organic molecules crosslink themselves through oxidation reactions to form a polymer network of large macromolecules. The energy required for this chemical oxidation process is often provided by ultraviolet light[1][3].
The less ventilation and amount of light, the slower this type of paint generally will dry. To accelerate this process, a catalyst is usually added. Paints which dry by means of oxidative crosslinking are catalysed by metal compounds such as cobalt naphtenate[1].
There are also coatings which consist of two different components, a base and a hardener. These paints do not dry by means of oxidation with the air, but by a polymerization reaction between the two
The paint is spread thinly along the surface showing no raised areas for texture. The objects within the painting have similar line weights. There are different directional lines as well
There are three main areas of paintball that I will be analyzing. First the way in which a paintball leaves the barrel of a paintball marker. Second the way in which a paintball fly's through the air and lastly how to determine optimum ranges for paintballs.
Pentane was observed to have the highest evaporation rate. Isopropanol had the lowest evaporation rate. Pentane is nonpolar and it’s strongest intermolecular force is London Dispersion Force. Because Isopropanol is polar and has strong hydrogen bonds, the bonds are harder to break and the evaporation rate was lower because it took more time to break this force. Pentane has a weaker molecular force than the hydrogen bonds so it evaporated faster than the Isopropanol.
The Bob Ross oil paints are specially formulated to meet the consistencies he prefers in the various colors on his palette. He also has a specific range of colors he uses. There are soft and firm versions of many of his colors. That is how important the liquidity is in his painting style. The thinner paints are used in the early stages of painting, while the thicker paint is used in the latter stages. This is known as thick over thin. If a thin layer of paint is applied over thick, there is a danger of cracking, unless it has been made more supple with the appropriate oil medium.
PURPOSE: The purpose of the experiment is to determine the specific types of pigments found in water-soluble marker pens by using paper chromatography and water as a solvent.
Multiple layers of paint add depth of color, as well as shading and highlights. When the paint is dry, remove the Mylar. The piece is ready for the next segment of painting.
Unlike acrylics and watercolors, which are mixed and blended before being applied to a painting surface, pastel is applied dry, directly to the paper, without any tonal preparation. This results in a sense
History of drying and wetting: soil suction is less during wetting time than it is during drying time.
www2.careercruising.com. web. 25 Nov 2013. “A BRIEF HISTORY AND TRENDS IN VEHICLE PAINTS”. www.protect.all.com/art paints.
Under normal operating conditions, Mattel requires that their manufacturing partners use paint from approved and certified suppliers with specific procedures in place to test and verify the validity of the products; in this particular instance however, procedures were not followed. It would appear that Mattel’s code of conduct called “Global Manufacturing Principles” which requires all busi...
In a similar transpiration lab, performed by an AP student, the results showed that controlled was the fastest, wind the second, light and heat the third, and humidity the slowest. These results occurred because all four environments played a role in increasing evaporation which therefore increased the rate of evaporation. In the controlled environment, the room temperature helped increase the rate of evaporation (1.67mL/m²). In the wind environment, the blowing of air on the leaves increased the rate of evaporation (0.76 mL/m²). In the light and heat environment, the heat hitting the plant increased the rate of evaporation therefore increasing amount of water being transpired (0.93 mL/m²). In the humidity environment, the moist ...
It decreases the chances for caking of partially hygroscopic materials, in case of storage as a powder. This is achieved since the moisture is adsorbed onto the surface of the granulated particles and they can still maintain their flowability due to its size(1).
In ancient China nail paint was made from egg whites and waxed gelatin’s. The most popular colors were silver and gold. A bit later in time b...
As air humidity is in an instance of increasing, its ability to absorb water vapor decreases and evaporation rate slows down. For evaporation to undergo there must be a difference in humidity (Tenalem Ayenew and Tamiru Alemayehu, 2001; Fetter C.W, 1994).
Freeze drying, otherwise known as lyophilization, is a form of drying that is done by freezing a wet substance and allowing the ice to directly sublime to vapor by exposing it to a low-pressure amount of water vapor. This method of drying takes place in a special type of vacuum desgned for this method. Freeze drying is used in many instances, often as a means to preserve material or decrease the weight of that material; thus allowing transportation of certain substances to become less difficult.