I'm wanting to create a display container to hold some of our products (pellets and tablets).  My original intension was to fill a clear perspex tube, however the pellets moved around and started breaking.  Hence to hold them into position I was intending on using the water clear polyester resin.... which worked pretty well... but I found the resin reacts with the persex.  Is there an easy and simple means of lining the perspex tube with something to stop it reacting with the resin or would you have an alternative suggestion?  Many thanks.

Use an epoxy casting resin

This ^^

I second that ! Use epoxy casting resin, it won't react to anything that I have tried.
Once you have placed the articles into the container put it into a painters pressure pot (40 psi) if you have one and you will have zero air bubbles.
Hope this helps.
Fred

Epoxy as mentioned above is the solution to avoid the inhibiting effect you have had.  or change the tubes and carry on using the cheaper polyester.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant