Clear plastics

Plexiglas, a clear plastic used to make many molded articles, is made by polymerization of methyl methacrylate. Draw a representative segment of Plexiglas. 

This concept has been known for over a century. Expressed as Brewster s Constant law, it states that the index of refraction in a strained material becomes directional, and the change of the index is proportional to the magnitude of the stress (or strain) present. Therefore, a polarized beam in the clear plastic splits into two wave fronts in the X and Y directions that contain vibrations oriented along the directions of principal stresses. An analyzing filter passes only vibrations parallel to its own transmitting plane (Chapter 4, TRANSPARENT AND OPTICAL PRODUCT, Polarized Lighting). 

Any piece of equipment under pressure is a potential hazard and must be properly shielded. Shields of clear plastic, properly anchored, will often suffice. Vacuum has its problems too. More than one glass flask with an almost imperceptible fault has imploded under vacuum, with an effect much the same as an explosion. Here, too, shielding is recommended. 

The polymerization of methyl methacrylate produces poly(methyl methacrylate), an exceptionally clear plastic sold under the names Plexiglas or Lucite as a shatter-proof substitute for glass in windows, doors, and other glazing applications. 

Table 2 presents the results of tests to measure the calorific power, ash content, and chlorides concentration of some of the materials obtained from the separation process, such as polystyrene, aluminum foil, plastic foam, and other plastics (general, clear, colored, black, and vinyl). Polystyrene and clear plastic have very high calorific power and low levels of chlorides, but polystyrene has very high ash content. Figures 10-17 present the samples of waste components from the separation and composting plant of Cantagalo. 

First find the two wires in the rocket tail section which disappear through a plastic plug into the rocket motor. (In the current model of the 3.5, these are the two wires covered with clear plastic.)... 

L-glutamic acid and 30 mM malic acid under the same experimental condition as for the pre-culture. The 150 ml-capacity of a serum bottle was used for the pre-cultures and for the hydrogen production. Two types of 2.5 L-capacity flat-rectangular and vertical photo-bioreactors, which were made of glass for both flat sides and stainless steel for the edges or made of clear plastic acryl material, were used for the production of hydrogen and P-D-hydroxybutyrate. 

A four-choice star maze, similar to that used by Kubie and Halpern (1978, 1979), was used as a two-choice Y maze for training the snakes. Snakes were trained to follow earthworm extract trails (IX = 6 gm earthworm per 20 ml dH20) in the apparatus until their performance exceeded chance behavior. (See Kubie and Halpern 1978 for details). At the termination of testing, snakes were videotaped during trailing at each earthworm concentration (IX, 1/9X, 1/8IX, Dry). Trials were repeated until a minimum of one minute of good, analyzable film had been obtained at each concentration. This usually involved one to three trials. For filming of animals from the side, a clear plastic maze of similar dimensions was used. 

Wear your goggles. Eye injuries are extremely serious and can be mitigated or eliminated if you keep your goggles on at all times. And I mean over your eyes, not on top of your head or around your neck. There are several types of eye protection available, some of it acceptable, some not, according to local, state and federal laws. I like the clear plastic goggles that leave an unbroken red line on your face when you remove them. Sure, they fog up a bit, but the protection is superb. Also, think about getting chemicals or chemical fumes trapped under your contact lenses before you wear them to lab. Then don t wear them to lab. Ever. 

The refractive index of these pigments is about 1.5, which means that they give a transparent blue when used in paints and clear plastics. Opacity can be increased by adding small amounts of titanium dioxide. The principal failing of ultramarine is its lack of resistance to acid, which can even decompose the pigment if there is sufficient available. Coated grades are made with substantially improved acid resistance. 

Different demands are placed on a pigment which is targeted for covered or laminated printing. In this technique, a reverse impression is printed onto a plastic film and laminated by means of one or two component adhesives, laminating resins and wax onto another substrate such as paper, aluminum foil, or polymer foil. These substances may adversely affect pigment performance. For high gloss applications, a normal impression is covered with a clear plastic film. 

Using insights contributed to by Mark, his laboratory group was steadily concocting new polymers, turning them over to the development department. Toward the end of 1929, word was rushed about the plant that one of these showed great promise. This polymer was formed from the common liquid styrene and could be transformed into a clear plastic from which cigar holders, toys, handles, etc. could be constructed. About a month later the first order for polystyrene was placed. The crisis was past. 

Kept in the dark Just as potatoes are earthed up while growing (seep.249)—or grown under mulches—to prevent the tubers from being exposed to the light, so they must be protected in storage. Clear plastic bags are the worst form of storage. Always close the sack once you have taken what you need. 

The chemistry of polycarbonates is similar to the chemical behavior of polyesters. We can think of a carbonate as being a diester of carbonic acid, H2CO3, which is unstable itself. Polycarbonate is a strong, clear plastic used in automobiles (25%), glazing and sheet (20%), optical media (15%), appliances (8%), computers (7%), medical industry (7%), and recreation and... 

We must remember that the information is closest to the label side of the CD, not the clear plastic side the data is read from. It is fairly easy to scratch the top surface of the CD, thus rendering it unusable. Some CDs have a special hard top coating that helps resist surface damage. Dust, minor scratches, and fingerprints are generally not harmful because the laser assemblies are designed to focus beyond the disc surface. 

The monomer can be heated in the presence of an initiator giving a clear plastic shaped like the container, but a little smaller because of shrinkage. The volume of the monomers is generally larger than the final polymers thus, the density of the polymer is greater than that of the original monomer. 

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