Is there some sort of spray / paint protector i can use to protect plastics that i paint?

walmart sells a paind called ';fusion'; in spray cans, that can be sprayed on plastic. it mostly comes in colors, but clears may be available. Another product, that may work, is Minwax PolyCrylic. it is a waterbase clear drying product available in satin, semi-gloss and gloss sheens, in both cans, and spray.