Introduction
Polymers of methyl methacrylate (PMMA) are used in the manufacture of acrylic plastics. The first plastic polymer was developed in 1843. The process makes involves two reactants, methacrylic acid and methyl alcohol to produce an ester called methyl methacrylate. Fittig and Paul were the first chemists to discover the polymerization process of turning methyl methacrylate into polymethyl methacrylate in 1877. Later on, in 1936 the process was used to manufacture acrylic plastics for commercial purposes. PMMA is highly resistant to ultraviolet radiation and weathering and is an ideal material for making airplane windshields, automobile taillights, and skylights (Riegel et al 72-88).
Acrylic plastics are made through a process known as polymerization. The manufacture of acrylic plastic occurs through the reaction of monomers (methyl methacylate) with a catalyst such as organic peroxide. The catalyst only starts the reaction and maintains its process but is not part of the final polymer (Shreve, Randolph and Joseph 125-144). Production process follows two steps.
Step I- Production of the monomer.
The process occurs from the reaction between acrylic acid and alcohol as shown in equation below.
Step II – Polymerization
In this process a radical is added to one end of the double bond of a alkyl acrylate to form a radical monomer that eventually polymerizes. The final acrylics vary depending on the nature of alkyl groups in the reactants. Other ingredients include:
Surfactants: These are substances composed of repellent polar and non-polar ends that surround each monomer droplet forming a micelle.
Water: Water acts as a medium for dispersing micelles. Water is a solvent for surfactants and initiators and a heat transfer medium.
Initiator: These are the catalysts made of water soluble peroxide salts, example; ammonium.
The figure below shows the manufacture process of acrylic plastics (PMMA).
Figure 1: acrylic plastics manufacturing flow process diagram.
Environmental and/or Safety concerns
The emulsion process takes place in water that might cause problems in relation to the solvent used. In addition, all fumes coming from the manufacturing process vessels pass through a treatment unit before discharge to the atmosphere. The process produces a lot of heat and the water used for cooling is recycled in the cooling towers to minimize waste. The process water is thoroughly treated in compliance with local body regulations.
Product Use
Acrylic plastics find use in a wide range of industries. The list below shows some common uses of the products:
- Used as adhesives,
- Used in the textile industry to make sponge fill,
- Used in paper coatings,
- Used in the paint industry especially for making paints used for road marking and
- Used as cement modifiers.
Economics
The manufacturing process of Acrylic plastics is costly and risky making the products a bit expensive. The cost of producing one pound of acrylic plastic is $500, and the sale price for one pound is $600. The demand for acrylic plastics is extremely high since most companies prefer them to glass. The demand for acrylic plastic materials has had a significant growth due to the high rate of construction projects going on. Initially, few companies produced acrylic plastics, but with the growing demand the number has increased to about 100 companies in Europe. The increased number of acrylic plastic manufacturing companies has affected the market due to increased supply. The issue has affected the prices of plastic materials since every company uses different production processes at varying costs. Eventually, the price offer in the market is not common affecting the profitability of other companies (ICIS 2013).
Works cited
ICIS. Polymethyl methacylate: Market overview. 2013. Retrieved from:
http://www.icis.com/chemicals/polymethyl-methacrylate/?tab=tbc-tab2
Riegel, Emil R, James A. Kent, and James A. Kent. Riegel's Handbook of Industrial Chemistry.
New York: Kluwer Academic/Plenum Publishers, 2003. Print.
Shreve, Randolph N, and Joseph A. Brink. Chemical Process Industries. New York [usw.],
Düsseldorf: McGraw-Hill, 1977. Print.
