Solar adhesives

Sodium nitrate is also used in formulations of heat-transfer salts for he at-treatment baths for alloys and metals, mbber vulcanization, and petrochemical industries. A mixture of sodium nitrate and potassium nitrate is used to capture solar energy (qv) to transform it into electrical energy. The potential of sodium nitrate in the field of solar salts depends on the commercial development of this process. Other uses of sodium nitrate include water (qv) treatment, ice melting, adhesives (qv), cleaning compounds, pyrotechnics, curing bacons and meats (see Food additives), organics nitration, certain types of pharmaceutical production, refining of some alloys, recovery of lead, and production of uranium. 

Many grades of interlayer are produced to meet specific length, width, adhesion, stiffness, surface roughness, color (93,94), and other requirements of the laminator and end use. Sheet can be suppHed with vinyl alcohol content from 15 to about 23 wt %, depending on the suppHer and appHcation. A common interlayer thickness for automobile windshields is 0.76 mm, but interlayer used for architectural or aircraft glaring appHcations, for example, may be much thinner or thicker. There are also special grades to bond rear-view mirrors to windshields (95,96) and to adhere the components of solar cells (97,98). Multilayer coextmded sheet, each component of which provides a separate property not possible in monolithic sheet, can also be made (99—101). 

For photochemical aging, it is well known that photooxidation affects only a thin superficial layer directly exposed to solar radiation - a few dozens of micrometers in the case of epoxies (Bellenger and Verdu, 1983). Thus the aging mode cannot control the material s lifetime in most cases (composites, adhesives), except for applications such as, for example, varnishes of automotive bodies (Bauer et ah, 1992). 

Now, consider stability. If a satisfactory initial system or component performance and cost are assumed, then in many cases the critical issue is to maintain the physical behavior of materials adjoining an interface for up to 30 years. The physical behavior may include properties that directly influence solar device performance, such as reflectance, transmittance, absorptance, emittance, and photovoltaic efficiency or solar device performance may be indirectly affected by properties such as adhesion, permeability, photo-oxidative stability, or interdiffusion. The required stability of interfaces in SECS components is counter to basic physics and chemistry, because atoms at interfaces must be more reactive and thermodynamically less stable than when in the bulk of materials (2). Yet, the density of solar energy requires deploying systems with large interfacial... 

Table 1 of a paper by Murr (2) lists problems and/or concerns related to specific interface materials and specific components of SECS. In Table 2 of the same work, he related topical study areas and/or research problems to S/S, S/L, S/G, L/L, and L/G interfaces. It is also useful to divide interface science into specific topical areas of study and consider how these will apply to interfaces in solar materials. These study areas are thin films grain, phase, and interfacial boundaries oxidation and corrosion adhesion semiconductors surface processes, chemisorption, and catalysis abrasion and erosion photon-assisted surface reactions and photoelectrochemistry and interface characterization methods. The actual or potential solar applications, research issues and/or concerns, and needs and opportunities are presented in the proceedings of a recent Workshop (4) and summarized in a recent review (3). 

The ability of an adhesive to withstand long periods of exposure to a vacuum is of primary importance for materials used in space travel or in the fabrication of equipment that requires a vacuum for operation. The outgassed constituents can also become a source of contamination and be highly objectionable in certain applications, such as with electronic products, optical equipment, and solar arrays. 

Pizzi A (1989) Wood adhesives chemistry and technology. Marcel Dekker, New York Plumtre RA (1979) Simple solar heated lumber dryers design, performance and commercial viability. Commonwealth Forestry Review, 46(A) 298-309 Plumtre RA ( 9 >A) Pinus Caribaea, Volume 2 Wood Properties. Tropical Forestry Paper 17. 

Major polymer applications aerospace, electronics (mostly films and coatings), photosensitive materials for positive imaging, solar cells, hollow fiber membranes, composites. unclear power plants, space shuttle, microprocessor chip carriers, structural adhesives... 

Another possibility of decomposing a C=C-double bond is supplying energy. Radiation contains energy in different forms the heat radiation of a heater or an electric light bulb is known as well as the radiation of an X-ray tube able to penetrate body tissue. Particularly suitable for curing, thus the polymerization of the C=C-monomers, is ultraviolet radiation (UV-radiation), known as a part of solar radiation. If these ultraviolet rays meet with the adhesive monomers to which so-called photoinitiators are added, the double bonds included in the monomers will be decomposed and polymerization proceeds in a way similar to that described in Section 4.3. 

---