preparing these polyamides are well known and described in numerous patents and trade journals the poly dioxa amide portion of the molecule contains both a double oxygen linkage i e r o r o r and amide linkage i e n c the following repeating structural formula depicts the composition used in this invention wherein the 34 y 34 radical is the poly dioxa amide portion str1 wherein r 1 r 2 and r 3 are selected from the group consisting of h c 1 c 10 alkyls and c 3 c 10 isoalkyls r 4 is selected from the group consisting of c 6 c 12 aryls c 1 c 10 alkylenes and c 3 c 10 isoalkylenes r 5 is selected from the group consisting of c 0 c 10 alkylenes and c 3 c 10 isoalkylenes and y 4 200 and z 4 300 examples of c 1 c 10 alkyls are methyl propyl butyl pentyl etc examples of the c 3 c 10 isoalkyls are isopropyl isobutyl isopentyl and the like examples of c 1 c 10 alkylenes are as follows methylene dimethylene trimethylene and the like examples of c 3 c 10 isoalkylenes are as follows methyltrimethylene 2 methyltetramethylene and the like the molecular weight of the copolymer is about 5000 100 000 preferably 10 000 50 000 the poly dioxa amide portion of the composition can be prepared by the following generalized scheme str2 examples of hor 4 oh of reaction 1 are as follows ethylene glycol propylene glycol and trimethylene.