Safety precautions on using trichlorosilanes
Safety precautions on using trichlorosilanes
(OP)
thread334-270573: Hydrophobic coating
This question is directed towards Chris (demon3) and your comment on creating your own hydrophobic coating. That sounds very neat! and I am thinking of trying it.
However, I have some questions from a safety point of view. How sensitive are the final coating solution (~5 wt% chlorosilane in hexane) to ambient moisture or retained water in the fabric? The chlorosilanes are listed as very reactive with water. Did you dry your fabric thoroughly before you applied the coating? I was thinking a hair-dryer treatment might be a good pre-coating step but I wonder if this is even necessary. Please let me know what your thoughts are.
Thanks.
This question is directed towards Chris (demon3) and your comment on creating your own hydrophobic coating. That sounds very neat! and I am thinking of trying it.
However, I have some questions from a safety point of view. How sensitive are the final coating solution (~5 wt% chlorosilane in hexane) to ambient moisture or retained water in the fabric? The chlorosilanes are listed as very reactive with water. Did you dry your fabric thoroughly before you applied the coating? I was thinking a hair-dryer treatment might be a good pre-coating step but I wonder if this is even necessary. Please let me know what your thoughts are.
Thanks.





RE: Safety precautions on using trichlorosilanes
We made up the solution and sprayed it right onto a Tenson brand jacket I bought at a second hand clothes store. The treatment was done with no pre-drying. Probably we had enough silane (5 weight%) in there to react with any surface water.
The hydrophobic treatment was stunning. You could literally hold a litre of water in that jacket for days and get a mirror like sheen where the water sat on the jacket. Then we did the same with an umbrella. It was hilarious because the water would literally bounce off the surface and jump several feet, hitting the person next to you.
Then we did the same on the cement outside and wrote in water-proof ink. This is the same as commercial water-proofing for cement like Ronson Water Shield or whatever it's called only they use the less reactive trialkoxy silanes.
Trichlorosilanes liberate hydrochloric acid vapor when they react so do it in a well ventilated area.
Chris DeArmitt PhD FRSC CChem
RE: Safety precautions on using trichlorosilanes
I have a follow up question on this coating method, I hope you don't mind :D.
Do you think these silane molecules chemically react with the surface of the fabric (I imagine this would require -OH groups presiding on the surface being coated...) or do these molecules only being physically adsorbed on the surface? I suppose to relate my question to real life, did you see a performance reduction with your jacket after you wash it multiple times? I think this would indicate whether the silane molecules are only physically adsorbed or chemically tethered to the surface. I love to hear your thoughts on this.
Thanks again!
Best,
Dawud
RE: Safety precautions on using trichlorosilanes
Chris DeArmitt PhD FRSC CChem
RE: Safety precautions on using trichlorosilanes
Cyclic azasilanes: "Meeting the environmental demands of
surface modified minerals"
Mr. Joel Zazyczny, Vice President - Silanes Silicones and
Metal-Organics
GELEST INC., United States
Chris DeArmitt PhD FRSC CChem