Talk Composites - The Forum for Advanced Composites

PU240 Medium Density Polyurethane (or similiar) as a core for a prepreg construction?

http://www.talkcomposites.com/Topic25412.aspx

By AndersES - 3/12/2018 8:15:43 PM

Hello!

I am making a rather complex model where making a mould is extremely difficult, and not necessary because it is a one time only. 
There fore, I wonder if it is possible to make the the core out of some kind of polyurethane, and proceed to wrap it in pre-preg and then cure it as usual? Does anyone have any experience on this topic? 
Would the polyurethane handle the heat?
Would it bend or deform under vacuum? (The construction is about 40mm wide at thinnest and about 600mm long)

Best Regards, 
Anders
By AndersES - 3/13/2018 12:50:00 PM

 
Hanaldo - 3/12/2018 10:52:04 PM
Polyurethanes will inhibit the cure of epoxies at high temperatures unfortunately. 

Thank you for your answer - but the heat in this case would not be higher than 90-100 degrees celsius. Is this still too high?
If it is, do you have any suggestions or recommendations on what I should use instead?
Maybe the EB700 High Temperature Epoxy Tooling Board would work for example?
- A
By Warren (Staff) - 3/13/2018 2:42:31 PM

PU will inhibit the cure even at relatively low temperatures.  By far the better choice would be an Epoxy Tooling block such as our EB700
By Hanaldo - 3/14/2018 12:20:11 AM

Tooling board would work, but it wouldn't be lightweight at all, especially the EB700 tooling board as it is a 700kg/M3 density - extremely heavy for use in a final component. You ideally want something no heavier than a 90-100kg/M3 density, but can also take high temperatures without inhibition... There aren't many options that spring to mind for me, but I would suggest it will be an aerospace product. 

As Scott suggested, pre-preg may not be the most suitable choice for this one?
By Tony2125 - 4/2/2018 12:53:16 PM

Yes
I ve looking for foam core solution for a project.
I know some guys use EPS polystyrene, but I don’t know if this require a preparation for using it with preg
What I found was
Rohacell
Soluble foam core from http://www.acmtucson.com/
sold by aeroconsultant.ch
Expandable foam core from https://www.tencatecomposites.com/products/adhesives-and-core
Epoxy foam for Sicomin http://www.sicomin.com/datasheets/product-pdf_fr19.pdf
I will give a try with the last one available in small qty and relatively cheep