Flying From Chicago to Thailand via Shanghai and Guangzhou

Hi, I am traveling from Chicago to Shanghai and then I am traveling from Shanghai to Guangzhou and making a connecting flight to Phuket

It's all less than 24hours I'll be in PRC at the airport and I am not leaving the airport.

Also just to add, I'm flying united to Shanghai and then flight China southern to Guangzhou and then Phuket. Same thing when returning.

Will I still need a visa?