What happens if you varnish laminate flooring
It depends on the type of laminate. Some of the early styles were glued t&amp;g if this is the style you have I might try a poly coat depending on the surface material, some are not wood and may not play well with poly, oil or latex. Of the wood and bamboo glued floors I installed poly did help. 
Note do not sand with a drum sander the veneer is very thin. If it is a snap lock floor I would not try to use poly as this kind of floor flexes and the poly in the gaps will probably chip along the lines and look worse but I do not know this as a fact, the one house that the renter tried to fix the floor tried to sand it prior to varnishing but had taken the surface layer off , then left knowing their deposit was less than the damage they caused.