Casting compounds commercially available

Currently, one of the most important commercially available materials today are the urea-formaldehyde (U-F) resins. Their applications include coatings, adhesives, castings, moulding compounds and textiles. Maciel et al. have produced a series of extensive papers in this area concentrating on both and CP/MAS [13-16]. 

Ground/cracked cast acrylic and PE-based materials are the main purging agents, but others also are commercially available for certain machines and materials. Cast acrylic, which does not melt completely, is suitable for virtually any resin. About one pound for each ounce of injection capacity will be needed (5-10 Ib/in. of screw diameter in an extruder). With extruders, special conditions and preparations are required, which suppliers of the purging compound can recommend (remove dies, screen packs, etc.). 

In 1963, Heacock, Mattok and Wilson reported the results of a study carried out on the stability of adrenochrome in the dry state and in solution and on the purity of various commercial samples of this compound [153], The results of this work cast some doubt on the purity of commercial samples of adrenochrome, available at that time, and on the long-term stability of even the purest crystalline samples of this compound (153). The potential value of either some commercial or old samples of adrenochrome in pharmacological work is thus open to question. It was further pointed out that pharmacological results may be invalidated when the adrenochrome solutions being examined were contaminated by trace quantities of metallic ions [153]. 

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