Energy light stabilizers

Grelier etal. (1997) synthesized a variety of UV stabilizers based upon hydroxy-phenylbenzotriazoles incorporating an isocyanate functionality. These were reacted with wood using microwave energy. The modified woods were exposed to UV irradiation and the photoinduced discolouration determined. It was found that the best protection was obtained when the UV stabilizer was used in conjunction with polyethylene glycol, or hindered amine light stabilizers. 

The high prices, frequently long and energy-intensive production cycles, processing difficulties, and health safety considerations during manufacture are justified by the high performances. The light stability, arc resistance and base and acid behaviours can be limited. 

In Part III of this series titled, "A Light Stability Cabinet for Evaluating the Photosensitivity of Pharmaceuticals," authored by Lachman et al. (38) they discussed the history of photostability testing in allied fields, the different sources that had been used along with their benefits and short-comings, and the rationale for the source they selected. The authors also presented some of the basic theory involved in this field, e.g., the relationship between wavelength and energy. 

Light Stabilizers Energy (KLy) Received to 50% Retained Tensile Strength for PP Tapes in Florida12 Time (h) to 50% Retained Tensile Strength for PP Tapes in a Xenontest 1200 (BPT 50°C, Without Rain Cycle) Time (h) until Carbonyl Absorbance = 0.2. for PP Plaques in a Weather Ometer (BPT 63°C, Without Rain Cycle) ... 

TABLE 17.10 Influence of Phenolic Antioxidants and a Phosphites on the Light Stability (Energy or Time Reached to Reduce the Tensile Strength 50% in KJ/cm2) of PA6 and 12 [133,134]... 

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