I'm installing a panel with the feed conductors entering via 1-1/2" PVC. Is an end bushing, as shown here (for example), required by the U.S. NEC for PVC?
From the NEC:
352.46 Bushings. Where a conduit enters a box, fitting, or other enclosure, a bushing or adapter shall be provided to protect the wire from abrasion unless the box, fitting, or enclosure design provides equivalent protection.
The important part is bolded above - you need a bushing unless your fitting provides equivalent protection - that is, equivalent to the protection a bushing provides.
You'll probably terminate your conduit in your panel with either a PVC male terminal adapter:
or a PVC box adapter:
I think anyone would agree the box adapter provides protection equivalent to a bushing.
I believe it's generally accepted that a PVC male adapter does provide equivalent protection, but you might find someone that disagrees, and some of them are pretty sharp. I usually ream them with lineman's pliers to take the edge off and do without the bushing.
The box adapters make a great connection but since they are cemented on, they are a pain if you have to remove and replace them.