The S10 Technique

The S 10 technique is the standard technique in Plastination. Specimen Impregnation with S 10 results in opaque, more or less flexible, and natural looking specimens. The procedure consists of the four main steps of Plastination, besides the specimen preparation and dissection before.


FIXATION

Fixation can be achieved by all usual fixatives as formaldehyde solution, Kayserling solution etc. Hollow organs must be dilated during fixation as well as during dehydration and gas curing.

DEHYDRATION

Dehydration removes the specimen fluid, as well as some fat. In this step tissue fluid is replaced with an organic solvent. Either alcohol or acetone may be used as a dehydrant for Plastination. Acetone is used in most cases because acetone also serves as the intermediary solvent during the next step - forced impregnation. To minimize specimen shrinkage, dehydration is done in cold (- 15 ° C to 25 ° C) acetone. If the removal of fat is also desired the dehydrated specimen must be kept in acetone at room temperature for some time. An acetone amount of 10 times the specimen weight is best for good results. Dehydration is finished when the water content is less than 1 %.
dehydration

Equipment: deep freezer (explosion proof or motor and compressor removed and placed in a different room), acetonometer (to measure the content of water).


FORCED IMPREGNATION

Forced impregnation is the central step of Plastination. In this step the intermediary solvent (acetone) is replaced with a curable polymer (BIODUR® S 10). The silicone polymer S 10 is mixed with a curing agent BIODUR® S 3 (1 part S 3 and 100 parts S 10) which commences the process of end-to-end linkage of the molecules. This linking is enhanced at room temperature, however, it is very slow when kept in the freezer at -15 ° C to -25 ° C. The dehydrated specimen is submerged in the cold 8-15 ° C to -25 ° C) polymer mixture. After some days of immersion, vacuum is applied to it. Vacuum is increased gradually to boil the intermediary solvent (acetone), which has a lower boiling point (+56 ° C) out of the specimen. Impregnation is monitored by watching the bubble formation on the surface of the mixture and by a vacuum gauge. Vacuum is complete when the pressure is around 5 mm Hg. Equipment: deep freezer (explosion proof or motor and compressor removed and placed in a different room), vacuum chamber (e.g. Heidelberg plastination kettle), vacuum pump (with a pumping speed of 1,5 m³/min. for 15 l polymer mixture or 3 m³/min. for 30 l polymer mixture)

impregnation

GAS - CURING (HARDENING)

Finally the polymer inside the specimen has to be cured (hardened). This is achieved by exposing the impregnated specimen to a gaseous hardener (BIODUR® S 6). S 6 is a liquid that vaporizes at room temperature. The impregnated specimen and a bowl filled with S 6 is placed in an tightly closed chamber for several weeks. To keep the environment for curing dehumidified a bowl with a desiccant (e.g. calcium chloride) is also placed in the curing chamber. To enhance the curing procedure air may be bubbled through the fluid S 6. For complete curing inside the specimen the specimen should be kept in a plastic bag for several weeks.

Equipment:plastic box, stretch foil, membrane (aquarium) pump.
gas cure