referred to as tetraglycol dichloride 3c), are preferred; i.e. since starch is a renewable and inexpensive starting material and some polyglycol dichlorides are commercially available or easily prepared from polyethylene glycol of formula 2b above by reaction at reflux with thionyl chloride in benzene or dichloromethane in the presence of pyridine. [0063] In accordance with the present invention