Melgar - 31-7-2017 at 01:47
I became interested in flexible foams recently, and figured that foam rubber would be a good place to start. Liquid latex is rather cheap, and can
apparently be used for all sorts of different things. It came as an opaque white liquid with no directions though. I know it can be hardened with
acids, but I guess I'm unfamiliar with how that reaction actually works. And I know about vulcanization too, but I don't know if that's needed for
making foam rubber.
Also, to make the bubbles, you need a blowing agent (I think that's the correct term), but the rubber blowing agents that I found when searching for
information, all seemed like they were industrial chemicals that aren't the least bit OTC.
So, is foam rubber something that can be made by an amateur chemist or not? And if so, how might one go about it? So far, the best results I've had
were by blending the latex very well with H2O2, and then mixing with a small amount of chlorine bleach. But even those results weren't very good.
XeonTheMGPony - 31-7-2017 at 06:50
R-152a can be used as a blowing agent for some foams, it is Diflouro Ethan, which happens to be what they used in so called "Caned Air"
Butane can be used as well, as has carbon dioxide, basically you want some thing that wants to be a gas at atmospheric pressure but liquid when under
pressure, rest comes down to miscibility and reactivity (IE will it burn in air more so then the polymer or does it all have to be non flammable)
If it is miscible in liquid state it will expand the foam on release of the external pressure, so you'd need a modified pressure cooker to be your
mixing vessel under pressure.
it is doable but you'll need to invest in valves and regulators and then build a beefy pressurized blender to mix the expanding agents and viscosity
modifiers.
then need to figure out what your making with it in terms of the molds n such.
[Edited on 31-7-2017 by XeonTheMGPony]
Melgar - 31-7-2017 at 08:38
First of all, are you sure you're not thinking of R-134a?
The problem I see with that is that the bubbles would form too fast. There's also the issue of latex needing a curing agent or else it stays liquid.
CO2 might work though, since it's an acid when dissolved in water.
Another thing I'm trying to figure out: what's the difference between the latex in rubber cement, and the stuff in the white water-based latex
solution? They don't seem very similar at all.
XeonTheMGPony - 31-7-2017 at 09:41
134a is 1,1,1,2, tetraflouroethan R152a is DiflouroEthan so yes quite sure! Diflouroethan has a lower GWP then 134a and so it has mostly been phased
out of use in "Caned Air" in most the world so yes quite certain (Refrigerants was my main job in the past)
The amount of foaming is controlled by pressure so higher volume lower density foams is expanded faster and cured faster then high density low volume
foams exctra.