Ultraviolet resistance

Reiaforced plastics may also iaclude fillers (qv), which are iaexpeasive materials such as calcium carboaate used to displace resia and reduce cost curing agents (catalysts), promoters, inhibitors, and accelerators, which affect thermosetting resia cure colorants release agents (qv) to faciUtate removal from the mold and other additives which can impart a wide variety of properties to the finished part, such as fire resistance, electrical conductivity, static dissipation, and ultraviolet resistance. 

Both fiber-glass mats and polyester mats are used either individually or combined in SBS membrane sheets. Because of the elastomedc properties of the asphalt, SBS sheets have developed a reputation as being very tough and abuse-resistant. However, they do not have any better ultraviolet resistance than conventional asphalts, so most of the SBS sheets come with a factory-appHed surfacing of granules. 

In broad tonnage terms the injection moulding markets for high-density polyethylene and polypropylene are very similar. The main reasons for selecting polypropylene have been given above. In favour of HDPE is the inherently better oxidation and ultraviolet resistance. Whilst these properties may be greatly improved in polypropylene by the use of additives these may increase the cost of polypropylene compounds to beyond that which is considered economically attractive. It is for this reason that HDPE has retained a substantial part of the crate market. 

In contrast to the above use PMMA sheet has been used as the bed in indoor ultraviolet lamp operated solaria. Here the ultraviolet radiation is so intense as to require the use of special formulations with adequate ultraviolet resistance. 

Plackett, D.V. and Dunningham, E.A. (1991). Ultraviolet resistance and colour stability of esterified wood. In Proceedings of the International Symposium on Chemical Modification of Wood, Kyoto, Japan, Takahashi, M. (Ed.), pp. 136-141. 

Other properties of lignocellulosic composites can be improved by changing the basic chemistry of the furnish (fQ). Acetylation has been shown to improve ultraviolet resistance of flakeboards. 

Ultraviolet Stability of PMMA—PVdF Poly blends. The potential ultraviolet resistance of this polyblend was of considerable interest. Let us first consider what is known of the photochemical stability of the components. 

Permanent Adhesives—Provides high tack, ultraviolet resistance and strong ultimate adhesion. 

L.M. Buchmann, and W. Finkelstein, Chemically amplified deep ultraviolet resist for positive tone ion exposure, J. Vac. Sci. Technol. B 15, 2355 (1997). 

Itani, H. Yoshino, S. Hashimoto, M. Yamana, N. Samoto, and K. Kasama, Acid and base diffu sion in chemically amplified DUV resists, Microelectron. Eng. 35, 149 (1997) T. Itani, H. Yoshino, and S. Hashimoto, Photoacid hulkiness effect on dissolution kinetics in chemically amplified deep ultraviolet resists, J. Vac. Sci. Technol. B. 13(6), 3026 (1995). 

For above-ground installations of the pipe track. I d check out 2-inch polypropylene pipe. It s black, comes in 100-foot coils, is reportedly better in UV (ultraviolet) resistance to sunlight than white PVC pipe, and is less expensive. It s definitely worth cheeking out. 

The compatibility of a colorant is assessed not only on the basis of the ease with which it can be mixed with the base resin to form a homogeneous mass but also on the requirement that it neither degrades nor is degraded by the resin. In relation to product functional properties, incompatibihty of a colorant can affect mechanical properties, flame retardancy, weatherability, chemical and ultraviolet resistance, and heat stability of a resin through interaction of the colorant with the resin and its additives. Flame retardancy, for example, may impinge directly on the performance of a colorant. Pressure to produce materials with lower levels of toxic combustion products can involve organic fire retardant additives that interact with the colorant either to negate the effect of the additives or affect the color. 

A number of investigations have indicated that the introduction of zinc oxide can improve ultraviolet resistance and endow antimicrobial properties to PP materials. 

They are synthesized from polymers of primarily polymethacrylate, acrylate esters, and polyethyl acrylate (Fig. 13.2). Acrylate resins are very stable in oxygen and UV light and are resistant to weathering and frequently used in the automobile industry as topcoats. Water-based acrylics are used as household paints. For ultraviolet resistance and improved weathering, acrylic resins are used as modifiers for epoxy and alkyd coatings. 

The ultraviolet resistance of poly( 1,3,4-oxadiazole) fibers can be improved, by the addition of 4,4 -azodibenzoic acid [50]. The tensile strength retention of the oxadiazole fibers containing 4,4 -azodibenzoic acid is much higher than that of the fibers without the azo groups after accelerated irradiation by an iodine-gallium lamp. Also the fibers with 4,4 -azodibenzoic acid in the molecular chain by copolymerization show a better UV stability than the fibers simply blended with the same amount of 4,4 -azodibenzoic acid. 

Zhou W, Yang X, Jia E, Wang X, Xu J, Ye G. Ultraviolet resistance of azo-containing poly(l, 3,4-oxadiazole) fibres. Polym Degrad Stab 2013 98(3) 691-6. 

Ultraviolet resistance n. Ability to retain strength and resist deterioration on exposure to sunlight. Zaiko GE (ed) (1995) Degradation and stabilization of polymers. Nova Science Publishers Inc., New York. 

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