Boynton, a 10-year veteran, had eight points in 41 games on the season. Before sitting out Thursday's game in Nashville with an upper-body injury, Boynton had been a healthy scratch for the Blackhawks several times in recent weeks.
"I couldn't be happier," Boynton said in a statement released by the Flyers. "I was a little shocked and didn't realize that I was put on waivers until late last night, but I couldn't ask to be coming to a better team or organization. I've been around the league for a while and I hope to bring that experience, try to work hard and play solid defense and chip in with whatever the team needs."
Boynton's departure could be a precursor to another move for the Blackhawks. General manager Stan Bowman said Saturday that he was "optimistic" the team would make a trade.
Bowman has indicated that the team is looking to add another defenseman. Colorado's Matt Hunwick, Edmonton's Ladislav Smid, Tampa Bay's Brett Clark and Buffalo's Steve Montador are on the Blackhawks' radar, according to league sources.
"It was salary and roster flexibility," Bowman said of Boynton's departure. "We're at the full roster, 23. That gave us some flexibility and as it turns out we have the salary as well.
"We're not looking to change the core guys at all. We're trying to add."
The NHL's trade deadline is 3 p.m. ET Monday.
Jesse Rogers covers the Blackhawks for ESPNChicago.com.