Follow-up to the IR thread 1

[cluelessone]

I am trying to do temperature measurement through a sheet plastic window.
I have the electronics portion working well in my lab but all the "IR" windows I put in front of it pass so little energy that the unit is useless. ("windows glass" and clear polycarb)
The supplier of the sensor says that I am looking to pass 5 to 15 um. These windows seem pitched to near IR and my range extends deep into mid IR.
I have been trolling the net and found recommendations to use polyethylene so I grabbed some clear poly parts bags and they work very well.
While these work from an optical point to view I need a rigid window on the production machine.
I tried some sheet HDPE from a local plastic shop and that did pass some signal but the losses were unacceptable high.
Any suggestions on what I should be looking for?
Thanks in advance.

 

[Demon3]

Another tip is that the simplest plastics have the lowest IR adsorption. What I mean is that the fewer types of chemical bond, the less the IR adsorption. So, polyethylene has very little adsorption as it only has 2 types of chemical bond. Polycarbonate would have lots of IR adsorption peaks as it has lots of different types of chemical bonds.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[Demon3]

Here's a really nice guide to plastic IR windows.

http://www.infra-com.com/files/7068219edb10524f7a7b398b56f705a0.pdf

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry

 

[cluelessone]

Follow-up: I just completed testing with the Evonik Acrylite FF sample in a IR temperature sensing application.

The test was performed with the Black 9K020 GT (was 1146-0 IRT) material, 2.9 mm thickness.

The transmission was in the few percent range which means that material is unusable for this application.

The search continues.

 

[Demon3]

The problem was likely not the sheet but the black colorant. The most common of which is carbon black that blocks everything including IR light.

Try another color, or start with colorless. If you need IR transparent black colorant contact BASF.

Chris DeArmitt PhD FRSC CChem

http://www.phantomplastics.com

Consultant to the plastics industry