Does anyone know dielectric constand for PEBAX?

It's "low" >:-}

This website has it, but you have to "create an account"...

A search on PEBAX + permittivity turned up a few things, e.g.

Cheers

Phil Hobbs

Ya well, I entered all my stuff and when clicking on create account nothing happens. Many web site designers aren't worth their salt these days.

It's unbelievable but in some such cases I actually have to get a sample and measure.

Thanks, didn't think about the word permittivity because that was never used at my schools. 13 would be ugly. The question is where does it begin to rise? I need to operate in the 150-400kHz range. Maybe I just assume 4 and knock on wood :-)

Given that it's a polyamide block copolymer, I'd be concerned about water absorption. (Think nylon.)

Cheers

Phil Hobbs

Agreed. My chemistry knowledge says it should behaves something like nylon. Not sure what the polyether part would do, electrically, but hey, it's in the ballpark. :) That would put the loss tangent around 1% and K around 4 or so. You wouldn't want to take it into the microwave, but I doubt it'll melt from 400kHz applied to bulk material.

Tim

It ain't my choice, and it's actually going into the blood stream. It's a sheath, a standard medical utensil in the world of catheters that goes in before anything else does. I already dread the lead vests during clinicals, those give me a back pain.

Note to self: Must lose weight before that.

I'm not sure what sort of polyether it is. My only experience with polyethers is with polyethersulfone, which is incredibly horrible stuff if there's any water around. If you try solvent-casting it, it makes a block structure with the water, i.e. it turns to very very fine pore foam. On the plus side, that's how most inexpensive ultrafilters are made--you just stir a bit of water into your PES+solvent mixture, and you can make a huge filter with very uniform ~20 nm pore sizes.

I discovered this independently while trying to find a material for a three-layer resist system for building antenna-coupled infrared tunnel junctions. Polyethersulfone worked beautifully the first time I tried it, on a cold day in January, when the indoor humidity was probably in the single digits, and never worked again. :(

Cheers

Phil Hobbs

El viernes, 1 de febrero de 2013 02:22:59 UTC+1, Joerg escribió:

Hello Joerg,

You may visit matweb

Depending on chemistry (formulation) Dielectric Constant seems to vary betw een 4 and 9.5 (general page on PEBA on matweb).

Move to Spain for the winter to escape the cold? :-)

Hmmm ... where did you find the dielectric constant in there?

I copied the wrong link...

The general data is in:

It mentions 4 to 9.5

From the list of products, click on of the products with the red dots (EMS Grivory).

This will show you product data.

You are right, the wheater in Spain is better then the rain over here (around 20 degr. C. in Malaga).

Datasheet E-mailed to you.

I didn't have any problems creating an account using a temporary E-mail address which I then deleted from my forwarding system >:-} ...Jim Thompson

Thanks, Jim. Got it.

I think I'll assume 7 for now and call it a day. If I provide enough margin in the calcs it should be ok.

Says "only available to premium members".

Wish I was there ...