Transparent plastic

The chemical resistance and excellent light stabiUty of poly(methyl methacrylate) compared to two other transparent plastics is illustrated in Table 5 (25). Methacrylates readily depolymerize with high conversion, ie, 95%, at >300° C (1,26). Methyl methacrylate monomer can be obtained in high yield from mixed polymer materials, ie, scrap. 

ASTM D1044, Test Methodfor Resistance of Transparent Plastics to Su face Abrasion, Vol. 8.01, ASTM, Philadelphia, Pa., 1993. 

Fig. 10. Free2e drying profiles for A, whole milk, and B, nonfat milk. Heat was transmitted by radiation from heated wires above the fro2en milk which rested in a transparent plastic tray. (-----------------------) is the induction period. Total pressure was 33 Pa (0.25 mm Hg).

Note that diaphragm-type accumulators can be checked more easily and are more reliable than the less expensive bladder type. Here, a rubberized nylon diaphragm separates the nitrogen charge from the oil. An indicator rod protrudes into a transparent plastic dome and gives accurate, visual indication of tlie true volumes of nitrogen and lube oil. 

For transparent plastics materials transparency may be defined as the state permitting perception of objects through or beyond the specimen. It is often assessed as that fraction of the normally incident light transmitted with deviation from the primary beam direction of less than 0.1 degree. 

There are a number of occasions where a transparent plastics material which can be used at temperatures of up to 150°C is required and in spite of its relatively high cost, low impact strength and poor aging properties poly-(4-methylpent-1 -ene) is often the answer. Like poly(vinyl chloride) and polypropylene, P4MP1 is useless without stabilisation and as with the other two materials it may be expected that continuous improvement in stabilising antioxidant systems can be expected. 

In consequence of a Tg of 104 C with its amorphous nature, commercial poly(methyl methacrylate) is thus a hard transparent plastics material in normal conditions of use. 

Terpolymers based on methyl methacrylate, butadiene and styrene (MBS) have been increasingly used in recent years both as tough transparent plastics materials in themselves and as additives for PVC (see also Chapters 12 and 16). 

This faintly amber, transparent plastic has toughness, tensile strength, ductility, and din 1... 

In principle, the velocities c and ti can be determined by taking a series of pictures at a very high frequency of the flow through a transparent plastic tube. Because of the particle size distribution, each particle moves at a different velocity, and this makes this method difficult to apply in practice. We have therefore used an indirect method, where we have measured the pressure losses of pneumatic conveying for two mixture ratios and then fit the parameters so that Eq, (14.126) coincides as accurately as possible with measured pressure losses. 

H CHS V-c" / H C—OCHo A F F =C/ F F Styrene Polystyrene Cast articles using a transparent plastic... 

There are several ways to handle Petri dishes. The standard dishes are 15-20 mm deep and 12-15 cm in diameter. They are normally available in glass and also transparent plastic. Petri dishes are individually wrapped. The media is separately sterilised while we add the sterilised media to the Petri dishes in front of a flame. It is recommended to use 20-25 ml... 

Allyl diglycol carbonate (CR-39) is the most highly scratch resistant of the transparent plastics. Unlike most of the other transparent plastics that are TP, CR-39 is a TS plastic that has been in use for over a half century in applications such as bullet-proof shields, high temperature steel blast furnace eye and face guards, aircraft window side panels, etc. Processing methods include injection molding and casting. 

Photoelastic measurement is a very useful method for identifying stress in transparent plastics. Quantitative stress measurement is possible with a polarimeter equipped with a calibrated compensator. It makes stresses visible (Fig. 5-2). The optical property of the index of refraction will change with the level of stress (or strain). When the photoelastic... 

This photoelastic stress analysis is a technique for the nondestructive determination of stress and strain components at any point in a stressed product by viewing a transparent plastic product. If not transparent, a plastic coating is used such as certain epoxy, polycarbonate, or acrylic plastics. This test method measures residual strains using an automated electro-optical system. 

These qualities are considered in most applications for transparent plastics, forming a basis for directly comparing the transparency of various grades and types of plastic. The data are of value when a material is considered for optical purposes. Many transparent plastics do not have water clarity, and, for this reason, the data should indicate whether... 

Opacity or transparency is important when the amount of light to be transmitted is a consideration. These properties are usually measured as haze and luminous transmittance. As reviewed haze is defined as the percentage of transmitted light through a test specimen that is scattered more than 2.5° from the incident beam. Luminous transmittance is the ratio of transmitted light to incident light. Table 5-7 provides the optical and various other properties of different transparent plastics. 

In this test for transparent plastics, the loss of optical effects is measured when a specimen is exposed to the action of a special abrading wheel. In one type of test the amount of material lost by a specimen is determined when the specimen is exposed to falling abrasive particles or to the action of an abrasive belt. In another test, the loss of gloss due to the dropping of loose abrasive on the specimen is measured. The results produced by the different tests may be of value for research and development work when it is desired to improve a material with respect to one of the test methods. The variables that enter into tests of this type are... 

Table 5-7 Notable behaviors of some transparent plastics...

Polycarbonate It is a tough, transparent plastic that offers resistance to bullets and thrown projectiles in glazing for vehicles, buildings, and security installations. It with stands boiling water, but is less resistant to weather and scratching than acrylics. It is notch-sensitive and has poor solvent resistance in stressed molded products. Use includes coffee makers, food blenders, automobile lenses, safety helmets, lenses, and many nonburning electrical applications. 

These are usually self-adhesive, precut, printed patterns on a substrate that are simply adhered to the surface of a product. Decals generally use a transparent plastic film while labels are usually on an opaque plastic, metallic and multilayer sandwich base. Labels of sufficient thickness are useful for hiding unavoidable appearance problems such as gate and sprue removal areas, sink marks, blushes, splays, and weld lines. 

Redner, A. S., et al., Measure Stress in Transparent Plastics, ASTM 4093-86. 

In a block copolymer, a long segment made from one monomer is followed by a segment formed from the other monomer. One example is the block copolymer formed from styrene and butadiene. Pure polystyrene is a transparent, brittle material that is easily broken polybutadiene is a synthetic rubber that is very resilient, but soft and opaque. A block copolymer of the two monomers produces high-impact polystyrene, a material that is a durable, strong, yet transparent plastic. A different formulation of the two polymers produces styrene-butadiene rubber (SBR), which is used mainly for automobile tires and running shoes, but also in chewing gum. 

Photographic film is a transparent plastic coated with a gelatinous film containing a silver salt, usually AgBr. When the film is exposed to light, individual photons absorbed by the Ag ions cause an electron-transfer reaction that produces neutral silver atoms ... 

For a completely symmetrical curve, the end-point can be easily established as the inflection point through which a tangent can be drawn here for convenience the "rings method (Fig. 2.23) can be used, where the inflection point is obtained by intersection of the titration curve with the line joining centres of fitting circles (marked on a thin sheet of transparant plastic see ref. 61). 

Cold flow studies have several advantages. Operation at ambient temperature allows construction of the experimental units with transparent plastic material that provides full visibility of the unit during operation. In addition, the experimental unit is much easier to instrument because of operating conditions less severe than those of a hot model. The cold model can also be constructed at a lower cost in a shorter time and requires less manpower to operate. Larger experimental units, closer to commercial size, can thus be constructed at a reasonable cost and within an affordable time frame. If the simulation criteria are known, the results of cold flow model studies can then be combined with the kinetic models and the intrinsic rate equations generated from the bench-scale hot models to construct a realistic mathematical model for scale-up. 

The entrance window is a relevant part of the sensor. Common glasses as well as most transparent plastics block UV radiation. Standard UV-transmitting materials like quartz and sapphire are expensive. For UVA and to some extent the UVB special glasses but also plastics like some PMMA-derivatives or some silicon gels are available with a reasonable transmittance down to about 330 nm. For UVC applications with the important 254 nm line of Hg, quartz remains the standard solution. 

Completely dissolved pigments should be referred to as dyes and be tested as such. This concerns features such as the extraction properties in the finished article. In PS, SAN, and other transparent plastics with a high glass transition temperature, they afford transparent, glass clear colorations. 

The proportioning pump controls the rate of advancement, viz 10 inch/minute, of each sample through the analysis stream. Hence, a fixed length of tubing is equivalent to a fixed amount of time. Each analysis stream is made of transparent plastic flexible tubing, and each patient-sample is separated from one another by an air-bubble. 

Pentagons are facilitated by the help of a stencil made of transparent plastic material, and (Hi) Sample mixture are applied to the narrow portion of the wedge to get the best results. 

Compared with other transparent plastics, they can be more resistant to stress cracking for some chemicals and sometimes less resistant for others. 

The importance of prefragmentation to the probability or violence of an explosion is not clear. Hess and Brondyke (1969) describe one incident where motion pictures were taken for a transparent plastic water vessel that had a steel bottom ... 

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