Is is possible/recommended to put an epoxy such as Rust-Oleum Epoxy Garage Floor Coating on particle board? Any help would be appreciated!
Possible, yes. Recommended - probably not. What purpose to you intend it to serve? Why do you think epoxy coating (intended for application to concrete) makes it better for the purpose? With or without coatings, is particle board even remotely suitable for the purpose?
Responding to comment: Marine plywood would have been a much better choice of material - if the business lasts long enough for you to discover why that's the case, remember that when you have to replace the particleboard. Particleboard falls apart when it gets wet, and it will, no matter what you cover it with. Given that it's a food truck your choice of flooring will have to pass the health department inspection applicable to to the locale where it operates, and they may well have a preference, or even a list of approved materials; check with them before proceeding. Properly applied vinyl tile flooring is very likely more durable than epoxy - epoxy can be chipped. The solid vinyl tiles common in commercial kitchens take a lot of abuse, and if they are too badly damaged, can be replaced individually.
As is the case in almost any situation you have two choices:
1- Do it right
2- Get it done
The first road involves tearing out the particle board. Encerwal is right, particle board is not suited to that application. Not to mention that most pb's gas off formaldehyde (when not sealed properly) which is, shall we say...less than great for the people eating the food coming out of the truck.
The second road requires sealing the ever-loving bejesus out of the pb flooring in the hopes of preserving it long enough to get you to the time when you can fix it proper. I don't see any reason the product in your link won't work but if it were me I'd be looking at a deck restorer like this: http://www.olympic.com/products/olympic-rescue-it-wood-and-concrete-resurfacer
Its made to stick to wood, which is more or less what pb is , and its thick enough to withstand most of the slings and arrows your going to throw at it. If at all possible get the edges and the underside too. Give plenty of time to air out with active ventilation or the fumes might taint the food.
I don't know if this qualifies as "good" advice but I think its the best you can do with the situation. Good Luck
If the particle board is in good condition, and is structurally sufficient for the task, using epoxy seems like a good idea. But you're looking at it the wrong way: instead of thinking floor paint, think flooring surface.
First you'd want to use an epoxy that is really "runny" and meant to penetrate well into wood. Ideally something like Git-Rot or as a backup, a 2-part epoxy primer made for brushing. If that is not feasible, I'd look at just going straight in with West System epoxy.
Next I would coat with West System epoxy, a very versatile epoxy system with 100 uses. They make a series of gluing and fairing fillers that let you use it for anything from bondo to laminating wood to building boats. In this case I'd coat the floor with several layers, giving an overnight drying interval, in much the way you might do "tabletop epoxy".
I was reluctant to recommend West System owing to the rather expensive upfront cost for a gallon of base and 1/5 gallon of hardener, and the pump kits. But then I looked at the price of Rustoleum garage paint! West is cheaper and infintely more useful, with excellent shelf life. (6 year old epoxy is performing fine for me). You'll never buy a hardware store epoxy pack again.
If you're going to be walking on it, mix the last coat with a traction additive, such as sand, or those sold with the Rustoleum systems.