Solubility dammar

Batu n. East Indian semifossil resin, resembling the dammars. Soluble in aromatic or mixed aromatic-aliphatic hydrocarbons. Dissolves readily in warm vegetable oil. It is almost neutral. Acid value averages bout 30. 

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. 

East India. Resins. The East India resins are related to the dammars, although they are older and harder. They are not obtained by tapping trees, but are collected where they are found, principally in Indonesia. Because they are semifossil resins, their softening points are high, ranging from about 110—130°C. The East India resins [9000-16-2] have low (20—30) acid numbers. They are soluble only in aryl hydrocarbons and hydrogenated aUphatic hydrocarbons, and are used primarily in coatings. 

A number of important resins are composed of triterpenoids, including the dammar resins which derive from a sub-family of the family Dipterocarpaceae. Dammar resins are fluid, balsamic oleoresins highly suited for caulking and waterproofing. Frankincense (olibanum) is known as a gum-resin collected from various Boswellia spp. and contains amyrin epimers and triterpenoid acids. The gum component is polysaccharide in origin and is water soluble. The Anacardiaceae family contains the genus Pistacia (Mills and White, 1977 21 Mills and White, 1989). 

Other polymeric terpenes are also known in nature. One such material is the resin called dammar (recent or fossil), generated by the trees from the family Dipterocarpaceae. Pyrolytic studies were performed on this polymer [16] after separation in two fractions, one soluble in CH2CI2 and the other insoluble. Three different pyrolysis techniques were used to obtain information on the insoluble polymer, flash pyrolysis, open isothermal furnace pyrolysis and closed system isothermal pyrolysis. Several compounds separated and identified in pyrolysates by GC/MS are shown below ... 

Damdr or JTammar.—A gum obtained from the agathU or dammar tree, ed to the pine trees, growing in the East Indi. It is soluble is aloobol and in oil of turpentine. 

Acetanyl acetone, a diketone, is a water-white liquid with an agreeable odor. It is completely soluble in water, almost entirely soluble In such substances as toluene, kauri gum and rosin, and only partly soluble in raw linseed oil, shellac, dewaxed dammar and ester gum. It has been suggested as an intermediate In the manufacture af rubber accelerators, dyes, inhibitors, insecticides, and pharmoceuticals and for the preparotlr of derivatives of thiophene, furan and pyrrole. It may also be employed in tanning hides and skins. 

Glycol diocetote is a colorless liquid having a foint odor resembling that of ethyl acetate. It will dissolve a wide range of cellulose esters, camphor, dammar, ester gum, elemi, mastic, rosin and sandarac. When it is mixed with active solvents its range of solubility is increased far a wide variety of cellulose esters and ethers and for natural and synthetic resins. 

FIGURE A3.31 Solubility of fresh dammar. Data kindly provided by Dr Greg Smith and Classes of2009, 2010 and 2011 of the Art Conservation Department at Buffalo State College. 

FIGURE A3.32 Solubility of dark aged dammar. — indicates the approximate limit of solubility when exposed to light and oxidation equivalent to 100 years on a gallery wall (Feller and Curran, 1975 of A3.33). Data kindly provided by Dr Greg Smith and Classes of2009, 2010 and 2011 of the Art Conservation Department at Buffalo State College. 

Black East India n Dark colored resin collected in the East Indies. It resembles the dammars in several respects, notably in solubility and free acid content. Its alternative name is black dammar . 

Dammar (Damar) da-mor n [Malay] (1698) Natural resinous exudation from trees of the Dipterocarpaceae family, which grow chiefly in the East Indies (now Indonesia) and Malaya. Very pale in color (practically colorless to deep yellow). Soluble in hydrocarbons without the necessity of running. Average acid value of 30. A fossil resin used as an ingredient in printing ink varnishes. 

The identification of dammar and mastic resins that have been used as spirit-soluble varnishes on... 

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