Weathering applications

PVDF is the third most widely used fluoropolymer, after polytetrafluoroethylene (PTFE) and fluorinated ethylene-propylene (FEP). The worldwide consumption of PVDF was approximately 15,000 metric tons in 2001 and is growing at an annual rate of 6-8%. PVDF applications have been expanded over the past 40 years because of its unique physical properties, and have over 30 years of proven and field performance data on thermal, chemical, radiation, and weathering applications. PVDF applications include, but are not limited to, chemical processing of pipes and components, semiconductor, architectural finishes and coatings, electrical plenum, cable jacketing. 

The widest employment of these devices is in CCD imaging arrays in the visible, or for IR focal plan arrays in the 8-10 pm range. The 8-10 pm range is ideal for night vision and foul weather applications. Other materials used for photodetectors include InAs ( 3 pm), InSb (= 5 pm) and their alloys (to = 10 pm), HgCdTe (= 3-20 pm) and... 

A black pigment or filler produced by the incomplete burning of natural gas or oil. It is widely used in the rubber industry and for wire/cable applications. Since it possesses ultraviolet protective properties, it is also used in formulations intended for outside weathering applications. 

Paraloid KM 377 is an impact modifier for construction products, with improved impact and weather resistance and good gloss-holding properties and BTA 730 and 751 are MBS modifiers, respectively, for clear sheet and film and opaque non-weatherable applications. Paraloid BTA 780-S is a methyl methacrylate butadiene styrene (MBS) for PVC packaging applications, in particular for film and sheet, claiming a unique combination of impact, crease whitening resistance and clarity. 

Of the various chemical classes of UV stabilizers that have been developed, the benzophenone and benzotriazole UV absorbers, the hindered amine light stabilizers (HALS), and their combinations continue to satisfy the UV stabilization requirements of most of the large-volume outdoor polymer applications. In addition, many new stabilizer chemistries, such as UV absorbers based on hydrox-yphenyl triazines, have been developed for more demanding applications or to satisfy specific market needs. Light stabilizers together with other additives (qv), such as antioxidants (qv), impact modifiers, colorants (qv), fillers, heat stabilizers (qv) and plasticizers (qv), have enhanced the properties and extended the service life of polymeric materials, resulting in the replacement of traditional materials in a multitude of outdoor weatherable applications. 

Wu B, Bibeau EL. Development of 3-D anaerobic digester heat transfer model for cold weather applications. T ASABE 2006 49(3) 749-57. 

A preaccelerated, low shrink, low exotherm, resilient resin designed for cultured mait)le casting applications, being particularly recommended for hot weather application, tubs, shower pans, complicated parts or wherever a more forgiving resin is desirable. Offers resistance to warping and cracking. 

Today s high-visibiUty choices include waterproof, insulated Class 3 bomber jackets for the coldest weather applications. Other options include Class 3 multipurpose, breathable jackets that provide waterproof and windproof comfort. With removable liners and sleeves, these all-in-one jackets are designed for year-round use, taking the place of a vest, plus a windbreaker, winter jacket and rain jacket. 

Mustard-lewisite mixture (HL) is a variable mixture of HD and L. The mixture ratio varies according to weather conditions during an operation. L is added to the HD to increase volatility and to lower the freezing point of HD to permit cold-weather application. 

The recharge voltage on this type of cell is lower than that of other types of lead-acid battery. This is probably the most sensitive cell in terms of adverse reactions to overvoltage charging. Gel batteries are best used in very deep-cycle applications and may last a bit longer in hot weather applications. If the incorrect battery charger is used on a gel cell battery, poor performance and premature failure are certain. 

RTV silicone adhesive is a rubberlike polymer called polydimethsiloxane. RTV stands for room temperature vulcanizing, or simply a rubber that cures at room temperature. Silicone rubber adhesives are made using a complicated process that turns elemental silicon metal made from sand (silica) into a rubbery polymer. When cured, silicone rubber adhesives/sealants have excellent resistance to heat (500—600 °F) and moisture that makes them exceptionally suited for outdoor weathering applications such as sealant and caulking compounds in the construction industry. Because of its exceptional properties, silicone adhesive has been used in some exotic applications such as the soles of the boots worn by the first astronauts to walk on the moon. Silicone adhesive/sealants are used to seal windows, doors, and portholes on the space shuttle and many satellite missiles. A special silicone adhesive is used to bond the heat shield tiles on space shuttles. 

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