Acrylic polymer is derived from the monomer methyl metharcrylate or MMA

When modern man discovered plastic and its myriad of uses, there was no turning back. Today, plastics figured prominently in the lives of 21st century people. It is almost impossible to live comfortably without this substance. And among the many kinds of polymer there is perhaps nothing more versatile and very much in demand than acrylic polymers. This paper will look into the chemical properties and the myriad of uses for the compound normally designated as PMMA or Polymethyl methacrylate. Chemistry Acrylic acid (H2C – CHCOOH) was synthesized in 1843 according to Charles Carraher (2003, p. 160). Then he goes to add that ethyl methacrylate (H2C – C(CH3)COOC2H5) was synthesized and polymerized in 1865 and 1877, respectively (2003). With regards to polymerization e.g. acrylic or methacrylic acid, it must be done in an aqueous solution at less than 20-30% concentration (Feldman Barbalata, 1996). â€Å"Besides water, a conventional recipe involves an initiating system (potassium persulfate and sodium thiosulfate) and chain transfer agent† (Feldman Barbalata, 1996). Acrylic polymer is derived from the monomer methyl metharcrylate or MMA. Polymers can be divided into two groups: thermoplastics and thermosets. And that majority of them are thermoplastics meaning once the polymer is formed it can be heated and reformed over and over again (see American Chemistry Council, 2007). This major attribute alone is enough to make scientists and businessmen to be very interested in the application of the product. But interestingly there are many more surprises up the sleeves of the thermoplastic polymer.Properties The following attributes can be seen in most polymers and especially so to acrylic polymers: 1.  Ã‚  Ã‚  Ã‚  Ã‚   Has a light transmittancy of about 92% with particular clarity at lower wavelength of 270 to 350 nm (Whitaker, 1996) 2.  Ã‚  Ã‚  Ã‚  Ã‚   Has good resistance to weathering 3.  Ã‚  Ã‚  Ã‚  Ã‚   Good mechanical strength 4.  Ã‚  Ã‚  Ã‚  Ã‚   Dimensional stability along with high tensile and flexural strength (Whitaker, 1996) 5.  Ã‚  Ã‚   Chemical resistance – including salts, bases, aliphatic hydrocarbons, fats and oils, most common gases, and inorganic chemicals as well as dilute and concentrated solutions of most alkali Applications According to Feldman and Barbalatat, the most important usage of acrylic polymer is in the manufacture of adhesives, thickeners, coatings, flocculants, dispersants, fluidizers, in cosmetics, pharmaceuticals, ion exchange processes and textile processing (1996). Now, a few years after acrylic polymer was first introduced by the scientific community, the said substance was first used as interlining for automobile windshields (Carraher, 2003). Since acrylic polymers exhibit good resistance to weathering it is widely used in thermoformed signs, aircraft windshields, and bathtubs. Acrylic polymers have long been used in the manufacturing of cuvettes, tubing connectors, speculums,and many other medical devices requiring impact strength, chemical resistance, biocompatibility, and clarity. In fact it occupies a, â€Å"†¦prominent place in the market for clear, disposable plastic – only glass transmits light as well† (Whitaker, 1996). In the medical field, acrylic polymers have shown its versatility and all around usefulness. From the start medical professionals were already well acquainted with the substance because it was used in the manufacture of incubators. In 1955 its range of usage was expanded when the first acrylic prosthesis was implanted. This probably came after its success as a primary material for aircraft canopies during World War II – pilots suffered fewer infections from shards of acrylic than they had from glass (Whitaker, 1996). Aside as an important component of cuvettes and tubing connectors, it is also used to produce test kits, luers, drainage wands, syringes, blood filters, blood pump housings, fluid silos, surgical blade dispensers, surgical trays etc. Finally, acrylic polymers is not only superior in terms of chemical resistance, clarity as a thermoplastic, and durability which is highly prized in the medical field. This substance is also easily recyclable, â€Å"Acrylic burns extremely clean [†¦] with end products of carbon dioxide and water. In addition, the material offers superior recyclability: acrylic can be reground and reused, which results in less material waste during molding† (Whitaker, 1996). But there is more. The said material can be depolymerized back to its monomer, thoroughly purged of its impurities, and then can go full circle back into PMMA. This is a true recycling process, whereas most other recycling processes involve crushing the material and using it in applications with lower specifications (Whitaker, 1996). In the world of plastic, acrylic polymers belong to the top shelf. The range of its applications is a great help in the development of many industries especially in the medical field. Among other things it has provided cost-efficiency and safety concerning the medical practice and other industrial purposes. References American Chemistry Council. (2007). The Basics – Polymer Definition and Properties. PlasticResource.com [online] Accessed 08 May 2007 from http: www.plasticresource.com/s_plasticresource/sec.asp? TRACKID=CID=124DID=226 Carraher, C. (2003). Giant Molecules: Essential Materials for Everyday Living and Problem Solving. New Jersey: John Wiley Sons, Inc. Feldman, D. Barbalata, A. (1996). Synthetic Polymers: Technology, Properties, Applications.    New York: Chapman and Hall. Whitaker, W. (1996). Acrylic Polymers: A Clear Focus. Medical Device Industry [online] Accessed 08 May 2007 from http: www.devicelink.com/mpb/archive/06/01/001.html.

Michelangelo Merisi da Caravaggio The Calling of Saint Mathew Research Paper

Michelangelo Merisi da Caravaggio The Calling of Saint Mathew - Research Paper Example It is understood that a painting is incomplete without knowledge of its background. Further, interpretations of a painting vary between people and with time and it is the contradictory interpretations in paintings that makes the painting interesting and often lend an element of mystery towards it. The painting discussed in this paper is also not without its special context and interpretations. Discussion The painting, The Calling of Saint Mathews is a masterpiece that was commissioned by the church to be hanged within the Contraelli Chapel located inside the Church of San Luigi Dei Francesi. The chapel was meant to be an ode for Saint Mathews and for this Caravaggio was selected when the first choice of the church, Cavalier D’Arpino became busy with the royal patronage. This was probably the biggest church commission that Caravaggio got at that time. Therefore, he put all this time and energy into the creation of this masterpiece along with two others painting, the Martyrdom o f Saint Matthews and The Inspiration of Saint Mathews. The painting till date hangs with other paintings depicting important moments in the life of Saint Mathews. The painting was completed in 1600. We have to understand that this was a time when the church was in power. It had the money to fund biblical paintings. The Calling of Saint Mathews is a painting representing an important biblical sense. The painting takes reference from Luke 5:27-28, which reads: ‘And after that He went out and noticed a tax collector named Levi sitting in the tax booth, and He said to him, ‘Follow me’. And he left everything behind, and got up and began to follow him’ (Benner, 124) The painting, quite like many produced in the same era, is full of religious symbols. The painting, primarily, symbolizes the difference between Christ and Matthews. In this respect, the picture can be divided into two parts: one part showing Christ and Peter while the other depicting Mathews and his companies. Both these parts are in stark contrast with each other. Christ and Peter represent spirituality. They do so through their simple clothing and the fact they do not wear any shoes. The absence of footwear reflects on the fact that these men are down to earth without any love for material objects. Mathews and his companions reflect the worldly life. This is apparent in the way they dress: fashionably in the attire that was trend during the time period when the painting was created. Also the presence of the coins and the preoccupation of some companions with the coins reflect on the worldly life enjoyed by Mathews and his companies (Benner, 129). Another symbol apparent in the painting is the way the painting has been divided into two parts. Here Caravaggio uses his typical style of chiaroscuro where he paints a stark contrast of light and dark in the painting (Cunningham and Reich, 360). Between Christ and Mathews, Caravaggio has painted a dark area and the hand of Christ e xtending towards the dark spot. The light in the picture comes from the side where Christ is standing. This play of light seems to be intentional on the part of the painter as he depicts Christ as a beacon of hope and light for Mathews while taking him away from a life of materialistic love and wastage. Also the dark spot between the two important figures symbolizes the fact that before Christ, people were left in darkness with no way to reach

Why Mall of America Is My Favorite Hangout Essay

Why Mall of America Is My Favorite Hangout - Essay Example I have to admit that this mall is special at least going by the number of visitors it receives annually. Perhaps a fascinating feature about this facility is that besides being the leading mall in North America, it also an entertainment enthusiasts’ establishment [ALLITERATION]. In fact, it hosts a number of high-class restaurants and attractions including nostalgic memorials and artifacts [PERSONIFICATION]. [BACKGROUND]. This essay using imagery and three rhetorical devices intensively describes the Mall of America, particularly why it is a special and favorite place to me [THESIS SENTENCE]. Essentially, the mall contains a number of facilities ranging from stores to restaurants that are as vibrant as those found in New York City. In fact, The Theme Park Food Court, LEGO and The Hooters restaurant on levels two and four respectively, provide customers with finger licking meals [METAPHOR] that would make one a slave to the restaurants [METAPHOR]. As one passes by the pavement of the eateries, all they see are sumptuous and savory meals [ALLITERATION] inviting them for a taste [PERSONIFICATION]. When it comes to the attractions at the Mall of America, the mall is a tourists’ heaven [METAPHOR] considering the numerous theme parks and roller coasters. Additionally, the mall Sea Life Minnesota Aquarium is a sight to behold [METAPHOR] for anyone who loves watching sea animals. Principally, the sea animals in the aquarium are as proud as peacocks [SIMILE], judging by the way the manner in which they swim across the thick glass wall. Concerning the memorials and artifacts found in the mall of America, I feel it earnest to note that the United Airline flight 93 memorial that was laid after the September 11 attack is both a nostalgic and melancholic sight [METAPHOR]. Nonetheless, the stadium seat in honor one that was hit by Harmon Killebrew greets all [PERSONIFICATION] that enter through the door.