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Examination of Forensic Evidence
Published in Karen D. Sam, Thomas P. Wampler, Analytical Pyrolysis Handbook, 2021
John M. Challinor, David A. DeTata, Kari M. Pitts, Céline Burnier
Oleoresinous varnishes contain vegetable drying oils such as linseed and tung oils. Wood rosins comprise a mixture of rosin acids. Shellac is the flaked form of purified lac, the natural secretion of the insect laccifer lacca kerr; it contains 46% aleuritic acid (a trihydroxy substituted hexadecanoic acid), and 27% shelloic acid (a dihydroxy polyacyclic aliphatic dicarboxylic acid), together with other components, many of which are undetermined. The main components of oriental lacquer are urushiol, laccol, and thitsiol—which are C15- and C17- alkyl and alkenyl substituted benzene-1,2 diol compounds. Printing inks on questioned document letterheads may also contain natural resins in combination with contemporary synthetic modifiers including phenol formaldehyde resins.
Naturally Occurring Polymers—Plants
Published in Charles E. Carraher, Carraher's Polymer Chemistry, 2017
Shellac, which was used by Edison for molding his first photograph records and is still used as an alcoholic solution (spirit varnish) for coating wood, is a crosslinked polymer consisting largely of derivatives of aleuritic acid (9,10,16-triphydroxyhexadecanoic acid). Shellac is excreted by small coccid insects (Coccus lacca), which feed on the twigs of trees in Southeast Asia. Over 2 million insects must be dissolved in ethanol to produce 1 kg of shellac. HOCH2−(CH2)5−CH(OH)−CH(OH)−(CH2)7−COOHAleuritic acid
Dual-functional anti-adhesion barrier prepared using micro-hierarchical structured and neutralized shellac films for drug release
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Shellac is a natural, nontoxic, biocompatible, and biodegradable polymer that is generally recognized as a safe substance by the FDA. The polymer is a resinous exudate from the Laccifer lacca insect inhabiting tropical forests. Commercially, shellac is available as an alkaline aqueous solution, which is applied as an enteric or sustained-release coating polymer. Formerly, shellac was used mostly as an alcoholic solution. In recent years, it has gained considerable attention as a biomaterial with diverse applications in tissue engineering owing to its low cost, large-scale availability and biocompatibility [13–15].