BC post-processing mechanical comparison protocols


#1

Hello everyone!

(small re-intro of what I’m doing: I’m an architectural engineering student at VUB researching bacterial cellulose’s mechanical properties in an architectural context for my master thesis under @Elise’s supervision .)
First growings and experiments:


Other experiments:

my last post was about my first cellulose growing experiments (and issues). Still had a lot of contaminations since then but 2 weeks ago for some magical reason 4 large plates started developing cellulose instead of yeast for the first time! So now I’m finally facing my first mechanical tensile tests on BC-sheets, which will be in two weeks.

For these mechanical tests I want to compare a range of post-processing protocols. I have collected some ideas and protocols from different sources (this forum, some academic papers, from the web or from Elise). I placed the protocols in this googles sheet link and screenshot so that you can consult it and give comments. A first sheet has a broader literature overview of production routines, the second sheet (=screenshot) has the protocols I selected from this literature which I want to try for my tests.
By the end of the week I will harvest the sheets of BC, then I have one week to apply the post processing before the testing week


I’m working on making this post-processing overview a bit larger and making the protocols more precise, but I have some questions

  • @Gammarra I have two processes which I found on one of your posts on post-processing of mycelium. Unfortunately I cant see the links you placed there, could you enlighten me a bit more on what you did there, how you did it and what the results were? And whether I could try them for bacterial cellulose too?

  • has anyone some input on other post-processing ideas which I could include? I mainly aim at producing a ductile and strong material, ways to achieve water-resistance or to improve mechanical strength.

If someone is interested in spending some time reading more on what I’m doing, in this google drive link I placed a pdf of my WIP (beware, very WIP!!) writing. Also not everything I did up untill now is included yet, but comments are of course very welcome.
https://drive.google.com/open?id=1_QZPnoEDVlzX3L2gP8EKU91jyyccp4Ej

thank you for reading me and looking forward to some input!
Bastien

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
Master Thesis by Bastien Damsin, Under supervision of Elise Elsacker, Prof. Lars De Laet and Prof. Eveline Peeters / Vrije Universiteit Brussel / Department of Architectural Engineering and Bioengineering Sciences.


BC - creating seams between cellulose sheets
Bacterial cellulose in architecture - culture comparison, composites, contamination
#2

Sure so here it goes

ethylene glycol: I submerged mycelium pieces in ethyleneglycol for 48 hours, took out rinsed and dried at 65C in a convection oven for another 48h
(this is the standard glassware drying setup in my lab)

Mycelium pieces: were grown on aligned fibers and all post po0rcessign was done after that mycelium was already baked dry, I think.

After the treatment pieces were more pliable.

Suggested changes:
Do a weight before and after to measure uptake.
Dont rinse dry, but press dry if you can ( mechanical, several Pascals kind of pressing, hot press is even better), this will promote more crosslinking if any is happening.

Ethylene glycol: choline chloride is a mixture done in molar equivalents 2:1 (120:140 in g) this is stirred and heated at 60 degrees until a clear liquid is produced.

The same procedure as for ethylene glycol was done.

I did try at home for bacterial cellulose, there is an increase in plasticity but I couldnt get it to fully dry.

since you are doing BC, there is a popular paper on lignin removal using high pressure and and temperature NaOH bath. ( cannot find it now)


#3

super, thanks. I’ll post the results on the forum later on.


#4

Hi,

I don’t know if this categorizes under post-processing, but here’s what I tried:

I airdried the BC, ground it up, resoaked it and made shapes with it. I then let it airdry again. I’ve read that this causes hornification (forming more irreversible H-bonds), thus creating harder but more brittle shapes with each time this cycle is repeated. Scroll down to my post/log here to see the little experiments:

Make sure you reduce the sugar content in the liquid. I suspect it to inhibit the properties I found earlier, as my recent BC’s remained quite malleable and sticky and did not dry properly.


#5

Hi @bdamsin,

Wow, what a great work! Really well documented.

Could you link all your posts together, maybe by starting with a link to your previous posts:


And your follow up post:

It’s easier for us to follow all your work when you connect it :wink:

I’ll take some time in the upcoming days to read it all.


#6

thanks! Good idea, I placed the links in all posts now :slight_smile: