DowDuPont (NYSE: DWDP), formed by the recent merger of Dow Chemical Co. and DuPont, announced Sept. 21 that its Materials Science business started up two recently completed projects in Freeport, south of Houston. The new integrated world-scale ethylene production facility and Elite enhanced polyethylene production facility will continue to ramp up and are expected to reach full rates in the final quarter of the year. Construction was complete on the ethylene facility in March and on the polyethylene…