4.14.
SELECTRON, RIGOLAC, AND VIAPALE EMBEDDING
119
4.14. Selectron, Rigolac, and Viapale Embedding
Low and Clevenger (1962) no doubt were influenced partly by the
problems of readily obtaining Vestopal in America to seek similar polyester resins that might be available from local sources. They settled upon
Selectron. This is a proprietary name for a family of resins manufactured
by the Pittsburg Plate Glass Co., which is marketed through the Plastic
Sales, Paint and Brush Division of this company, Pittsburgh, Pennsylvania. Compatible casting resins are available which allow the final
hardness of the plastic to be varied over wide limits. It is evident that a
properly chosen blend might be expected to resemble Vestopal, and
other blends would allow a flexible determination of physical properties.
Low and Clevenger (1962) have not chosen to report upon the use of
Selectron alone. Instead, for special reasons discussed later (Chapter 4.17)
they have blended Selectron with substantial quantities of methacrylate.
This is not at all necessary. In our own laboratory we have worked with
Selectron 5003 which produces a hard plastic, and Selectron 5208 which
produces a tough flexible plastic. [The latter replaces the Selectron 5214
originally recommended by Low and Clevenger (1962), which is no
longer available.] Blends of equal parts of these resins, or a 3:2 ratio of
5003:5208 section well.
The resin mixture is catalyzed with 1% benzoyl peroxide, and then it
has a pot life of many hours at room temperature before it begins to gel.
Low and Clevenger (1962) recommended using 1%
tert-butylhydroperoxide, but in our hands the pot life of such a mixture was a matter of only
an hour or so. This must be regarded as entirely inadequate for impregnation. Indeed the manufacturer recommends
ter£-butylhydroperoxide
cannot be used for storage purposes as this plastic is affected by the
Vestopal.
In a pamphlet distributed by the Martin M. Jaeger Company the following difficulties are anticipated. If the activator becomes thick or
changes color it should be discarded. If cracks appear in the blocks either
the initiator or the activator was not mixed well enough, or the polymerization was too rapid from too high temperature. If the tissue is shrunken,
the passages from acetone into plastic were made too quickly. If the material in the section has a spongy appearance, acetone was not entirely
removed from the tissue.
SELECTRON, RIGOLAC, AND VIAPALE EMBEDDING
119
4.14. Selectron, Rigolac, and Viapale Embedding
Low and Clevenger (1962) no doubt were influenced partly by the
problems of readily obtaining Vestopal in America to seek similar polyester resins that might be available from local sources. They settled upon
Selectron. This is a proprietary name for a family of resins manufactured
by the Pittsburg Plate Glass Co., which is marketed through the Plastic
Sales, Paint and Brush Division of this company, Pittsburgh, Pennsylvania. Compatible casting resins are available which allow the final
hardness of the plastic to be varied over wide limits. It is evident that a
properly chosen blend might be expected to resemble Vestopal, and
other blends would allow a flexible determination of physical properties.
Low and Clevenger (1962) have not chosen to report upon the use of
Selectron alone. Instead, for special reasons discussed later (Chapter 4.17)
they have blended Selectron with substantial quantities of methacrylate.
This is not at all necessary. In our own laboratory we have worked with
Selectron 5003 which produces a hard plastic, and Selectron 5208 which
produces a tough flexible plastic. [The latter replaces the Selectron 5214
originally recommended by Low and Clevenger (1962), which is no
longer available.] Blends of equal parts of these resins, or a 3:2 ratio of
5003:5208 section well.
The resin mixture is catalyzed with 1% benzoyl peroxide, and then it
has a pot life of many hours at room temperature before it begins to gel.
Low and Clevenger (1962) recommended using 1%
tert-butylhydroperoxide, but in our hands the pot life of such a mixture was a matter of only
an hour or so. This must be regarded as entirely inadequate for impregnation. Indeed the manufacturer recommends
ter£-butylhydroperoxide
cannot be used for storage purposes as this plastic is affected by the
Vestopal.
In a pamphlet distributed by the Martin M. Jaeger Company the following difficulties are anticipated. If the activator becomes thick or
changes color it should be discarded. If cracks appear in the blocks either
the initiator or the activator was not mixed well enough, or the polymerization was too rapid from too high temperature. If the tissue is shrunken,
the passages from acetone into plastic were made too quickly. If the material in the section has a spongy appearance, acetone was not entirely
removed from the tissue.