Encapsulation natural history

Soon after their introduction in the 1940s, UP resins were used for encapsulating natural history objects (Purves and Martin, 1950). This use has probably been abandoned for objects that must be preserved. One example has been published of a transparent resin that went opaque (Meurgues, 1982). Polyester resins deteriorate when exposed to weathering (Beloto, 1994), though it is possible to specify grade and application methods to reduce the tendency. 

Natural history (and other) specimens were encapsulated in PMMA (Hibben, 1937 Organ, 1963) or PEMA (Puckett, 1940) blocks by both ultraviolet and chemically initiated polymerization. PMMA/MMA slurries have been used for restoration of glass (Technovit 4004a Kulzer) (Jackson, 1983), Plastogen G (Schmidt) and other materials. The two parts are a PMMA powder that contains an initiator and MMA hquid. The slurry sets to a translucent solid. The initial viscosity of the slurry, rate of setting and total shrinkage depend on the proportion of powder added. 

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