E.I. du Pont de Nemours & Co. Inc., Wilmington, Del., expects to contribute $50 million to its pension plans, according to an SEC filing. The company contributed $377 million to the plans in 2004 through Sept. 30. The company has voluntarily contributed $300 million to its principal U.S. pension plan in the third quarter but company officials have not decided whether to make additional contributions, according to the filing. DuPont has $18 billion in pension assets.