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Subject: Didecyldimethyl ammonium chloride

Didecyldimethyl ammonium chloride

From: Phil Geis <geis.pa>
Date: Thursday, June 21, 2007
Karin von Lerber <karin.vonlerber [at] prevart__ch> writes

>I therefore suggested drying the object between two layers of
>blotting paper, the lower one being sprayed with 70% Ethanol, which
>would seep through the textile. 70% Ethanol is not *really* a
>biocide, as it is not 100% effective, however the amount of living
>spores can again be reduced quite drastically. (this I conclude from
>Mary-Lou Florian: Fungal Facts, London 2002.) This suggestion of
>Ethanol then lead to the mold specialist's proposal of quaternary
>ammonium salt treatment, as in his view, Ethanol is not a biocide.

Although I am not a textile expert, my knowledge of chemistry draws
my attention tp your intention to use ethanol on textile. It seems
to me that you should be aware of the ability of ethanol to open the
textile fiber up to a point where access to oxygen could be a
spontaneous reaction.

In other words, your textile after receiving such a treatment may be
susceptible to spontaneously catch fire. I will strongly recommend
further investigation on this specific topic.

I am not qualifed to address the concern for fiber opening effect
but doubt spontaneous combustion in the absence of signficant heat
addition is a reality here.

I am a microbiologist/mycologist and need to correct the
misinformation offered re biocides. No biocide is "100% effective".
70% ethanol (or isopropanol) is a very effective
biocide--especially. vs. vegetative (growing) bacteria and yeasts.
It has limited efficacy vs. bacterial and fungal spores.

Dialkyl quats like didecyldimethyl ammonium Cl are also very
effective biocides and can have a greater effect on bacterial and
mold spores--both in killing and preventing their germination.  The
efficacy "gap" for quats is typically vs. a group of water-born
bacteria casually termed "pseudomonads".  Though commercial quat
solutions from less than careful manufacturers can themselves arrive
contaminated, the bigger problem will be in use.  If you prepare a
bath of dilute quat, it will become contaminated over time.  So
change the baths often.


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                  Conservation DistList Instance 21:14
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Received on Thursday, 21 June, 2007

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