Resins, fossilized

Fossil copal Fossil flour Fossil-fuel furnaces Fossil fuel prices Fossil fuels Fotoform/Fotoceram Fougere Royal Foundry alloys Foundry core binders Foundry furnaces Foundry resins Fountains Fourcault process... 

A varnish is often appHed on top of the paint layers. A varnish serves two purposes as a protective coating and also for an optical effect that enriches the colors of the painting. A traditional varnish consists of a natural plant resin dissolved or fused in a Hquid for appHcation to the surface (see Resins, natural). There are two types of varnish resins hard ones, the most important of which is copal, and soft ones, notably dammar and mastic. The hard resins are fossil, and to convert these to a fluid state, they are fused in oil at high temperature. The soft resins dissolve in organic solvents, eg, turpentine. The natural resin varnishes discolor over time and also become less soluble, making removal in case of failure more difficult (see Paint and FINNISH removers). Thus the use of more stable synthetic resins, such as certain methacrylates and cycHc ketone resins, has become quite common, especially in conservation practice. 

Natural resins are generally described as solid or semisolid amorphous, fusible, organic substances that are formed in plant secretions. They are usually transparent or translucent yeUow-to-brown colored, and are soluble in organic solvents but not in water. The principal uses for natural resins are in varnishes, printing inks, adhesives, paper size, and polymer compositions. The term natural resins includes tree and plant exudates, fossil resins, mined resins, and shellac. They often have been altered from their original state during isolation and processing. For some appHcations, the resins have been chemically modified to increase their industrial utiUty. 

Pontia.na.k. This resin is a copal and is similar to the alcohol-soluble Manilas. It is partially fossilized, so it melts at a higher temperature. Softening points range from 99—135°C, and acid numbers from about 112—120. Pontianak [9000-14-0] is used in specialty coatings and adhesives. 

Ka.un. This fossil resin, classified as a copal, is found in the South Pacific, primarily in New Zealand. It formerly was used in protective coatings. It is still used in the Kauri-butanol test (ASTM D1133) to determine the volume of thinner that can be added to a varnish formulation without causing turbidity. 

In Ancient Rome, Pliny the Elder (c. a.d. 23-79) dedicated 37 volumes of Natural History to the emperor Titus. In the last of these books, dealing with gems and precious stones, he describes the properties of the fossil resin, amber. The ability of amber to attract dust was recognised and in fact the word electricity is derived from elektron, the Greek for amber. 

One resin, however, can be considered as an exception to this. Although rarely recognised as a plastics material it can be fabricated into pipe mouthpieces, cigarette holders and various forms of jewellery. It may also be compression moulded and extruded. It is the fossil resin amber. 

Erdharz, n. asphalt, bitumen fossil resin. — gelbes —, amber,... 

Amber Organic Origin Fossil resin Yellow//brown/red... 

Poinar, G. O. and R. Milki (2001), Lebanese Amber The Oldest Insect Ecosystem in Fossilized Resin, Oregon State University, Corvallis, OR. 

Ceresine is the white end-product of the purification of the fossil wax ozokerite, which is found in Miocene lignite deposits at considerable depths, by the separation of foreign and resinous matter and decolorisation by active agents. It is harder than paraffin wax, and has linear and cyclic hydrocarbons with high molecular weight [2]. It is used for waterproofing and oil absorption. 

Resins older than 40 000 years are considered to be fossil resins. The fossilization of resins begins with polymerisation and forms ambers and copals. Most of the ambers are derived from components of diterpenoid resins with a labdanoid structure other ambers are based on polymers of sesquiterpene hydrocarbons such as cadinene, and may include triterpenoids less common ambers from phenolic resins derive from polymers of styrene. Figure 1.4 shows the skeletal structures of the components which make up the polymers occurring in fossil resins [141]. 

Figure 1.4 Main structures of polymeric fossil resins...

Copals, sometimes referred to as immature amber, originate from Africa, Asia or central American countries and derive from the Araucariaceae and Leguminosae families. Polymerised communic acid and agathic acid are found as the main compounds in these fossil resins. The extreme hardness of copal results from polymers of resin acids such as ozoic acid, an enantiomer of communic acid that can polymerize and thus enable fossilization [86]. They are still commonly used today for varnishing and protecting wood. 

I. Pastorova, T. Weeding, J.J. Boon, 3 Phenylpropanylcinnamate, a copolymer unit in siegbur gite fossil resin a proposed marker for the Hamamelidaceae, Organic Geochemistry, 29, 1381 1393 (1998). 

K.B. Anderson, J.C. Crelling (Eds), Amber, Resinite, and Fossil Resins, American Chemical Society, Washington, DC, 1995. 

B.G.K. Van Aarssen, H.C. Cox, P. Hoogendoorn, and J.W. De Leeuw, A Cadinene Biopolymer Present in Fossil and Extant Dammar Resins as a Source for Cadinanes and Bicadinanes in Crude Oils from South East Asia, Geochim. Cosmochim. Acta, 54, 3021 3031 (1990). 

Some high molecular weight substances, such as highly polymerized terpenic resins or fossil resins, cannot be directly analysed by GC/MS. In these cases online analytical pyrolysis combined with GC/MS can be used. Pyrolysis-GC/MS applications are described in Chapters 11 and 12. 

K.B. Anderson, New evidence concerning the structure, composition, and maturation of Class I (polylabdanoid) resinites, in Amber, Resinite and Fossil Resins, K.B. Anderson and J.C. Crelling (Eds), vol.617, American Chemical Society, Washington, DC 105 129 (1995). 

Liptinites were made up of hydrogen-rich hydrocarbons derived from spores, pollens, cuticles, and resins in the original plant material. Vitrinites were made up of wood, bark, and roots and contained less hydrogen than the liptinites. Inertinites are mainly oxidation products of the other macerals and are consequently richer in carbon. The inertinite group includes fusinite, most of which is fossil charcoal, derived from ancient peat fires. 

Grimalt, J.O., Simoneit, B.R.T. and Hatcher, P.G. (1989). Chemical affinities between the solvent extractable and bulk organic matter of fossil resin associated with an extinct podocarpaceae. Phytochemistry 28 1167-1171. 

Simoneit, B.R.T., Grimalt, J.O., Wang, T.G., Cox, R.E., Hatcher, P.G. and Nissenbaum, A. (1986). Cyclic terpenoids of contemporary resinous plant detritus and of fossil woods, ambers and coals. Organic Geochemistry 10 877-889. 

---