I'm guessing you want something between the drawbar and pintle tongue ?

https://www.maywes.com/products/draw-bar-savers

http://www.lundellplastics.com/harvest-products/hitchsaver.asp

https://www.tractorpartsasap.com/poly-hitchsaver-38-x-6-od-1-12-id-new-126929.html

If you mean an actual poly bushing the hitch pin passes through to take up slack in the pintle tongue I'm not sure that poly would hold up too well.

If you are wanting to take up pin slop consider a Terog Bull Pull

https://blackaceparts.com/hitches.php