Sarah,
            the polymethacrylate is to pre polymerize the methacrylate
monomer and when you add this powder to the solution will become a bit
more viscous. If you use straight monomer for the final stages of
infiltration and hardening, you are susceptible to the generation of
bubbles due to focal areas of polymerization starting especially with
mineralized tissues and metal from implants. A "pre polymerized"
solution in which the methacrylate has started to polymerize is much
less likely to do this.
The dibutyl phthalate is, I believe, is added as a plasticizer.
The benzoyl peroxide is the catalyst
I am not sure about the N,N dimethyl aniline but it is probably used as
an accelerator for polymerization, as it is sometimes used in epoxy
resin mixtures  for this purpose.
Barry

Sarah Christo wrote:

> Dear Histonetters,
>    I'm making my first batch of MMA and have a
> few questions.  I see so many different
> formulations for the infiltration and embedding
> mixtures, I'm confused.
>   Diane Sterchi's formula for embedding is
> 95 ml MMA
> 1.5-5.0 gm benzoyl peroxide
> 5 ml dibutyl phthalate
> 10 gm polymethylmethacrylate
>
>   Peter Jackson & David Blythe's formula is
> 15 ml MMA
> 5 ml dibutyl phthalate
> 1gm benzoyl peroxide
> 125 ul N-N dimethyl aniline
>
> I see a greater amount of the dibutyl phthalate and
> benzoyl peroxide in Jackson's formula.  Also,
> what does the dimethyl aniline and the
> polymethylmethacrylate do?
> thanks for the help,  Sarah Christo, Texas A&M

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