Very possible.
I have a good friend who was my JC class mate. We used to go out
together one on one (for movies, shopping, swimming etc.) during
our JC days, but there was no physical contact between us, and no
affection other then the normal "friend" affection. I treated her
as a 'normal' friend and both of us are comfortable in the
friendship and have no intention (and no urge!) of going
beyond.
In time, we got into our own separate relationships and got
married... and we attended each other's wedding. We both have our
own children now but we are still keeping close contact. Both
our families will meet every now and then. Her children and my own
children are also becoming close friends.
So to answer the TS question, yes platonic friendship is
possible, though admittedly rare.
