词条 | dammar |
释义 | dammar varnish resin also spelled damar, or dammer, any of a variety of hard varnish resins obtained from coniferous and hardwood trees characteristic of Southeast and East Asia. These include the conifer genus Agathis (family Araucariaceae), such flowering plants as Shorea (especially S. wiesneri) and other genera of the family Dipterocarpaceae, and a few species of the family Burseraceae. The resin obtained from S. wiesneri oozes from the tree in a soft viscous state. It is highly aromatic but loses its odour as it hardens upon exposure to form a transparent, brittle, straw-coloured film. Dammar is readily soluble in alcohol. It is much-esteemed in Asia for incense burning and is also used in plasters, varnishes, and lacquers. Rapid-drying lacquers are formulated using dammar in combination with nitrocellulose. A solution of dammar in chloroform or xylene is used to preserve and mount thin biological sections for microscopic examination. With oil of turpentine, dammar forms a fine varnish that dries clear, smooth, and hard; it is a widely used picture varnish. |
随便看 |
|
百科全书收录100133条中英文百科知识,基本涵盖了大多数领域的百科知识,是一部内容开放、自由的电子版百科全书。