DuPont hired Randy L. Stone as president of its Performance Materials business effective immediately, succeeding Patrick E. Lindner who has resigned from the company to accept another position.  Stone will report to DuPont Executive Vice President Marc Doyle.   Stone joined DuPont in 2007 and has served in progressive leadership roles for the DuPont Dow Elastomers joint venture and DuPont Performance Elastomers business, the latter while located in Shanghai, China.  He also served as director,...