recrystallizable from water m p 252 4 u00b0 c lit 240 245 u00b0 c the ethylenebisdiimidazolidone which comprises 2 functional groups 1 is very pure and therefore crystallizes the fraction which is soluble in methanol evaporated to dryness and dissolved in water at 33 by mass this aqueous solution is referred to as the mother solution and it comprises the monomer of the invention comprising the functional groups 1 this fraction does not crystallize because of a molecular disorder caused by impurities in the triethylenetetramine analysis shows that this fraction is predominantly composed of ethylenebisdiimidazolidone a n piperazinoethyl imidazolidone b bisaep n n u2032 bis 2 aminoethyl piperazine c and branched teta tris 2 aminoethyl amine d u2022 note 1 the grade used is a mixture of linear cyclic and branched ethyleneamines with similar boiling points teta n n u2032 bis 2 aminoethyl 1 2 ethanediamine bisaep n n u2032 bis 2 aminoethyl piperazine peeda n 2 aminoethyl 2 aminoethyl piperazine branched teta tris 2 aminoethyl amine the crosslinking of polyacrylic acid by the polymer of the invention is illustrated 150 mg mass on a dry basis of polyacrylic acid paa in the form of an aqueous solution are added to 3 g of mother solution example 1 the mixture is poured into a circular ptfe mould u00f8 50 mm after a time of three weeks in a climate controlled chamber t 23 u00b0 c rh 50 the films obtained thickness appr 0 4 mm can be detached from the mould and handled the glass transition temperatures tg measured by differential scanning colorimetry dsc are recorded in the following table 10 5 g 41 mmol of triethylenetetramine dow chemicals appr 60 purity u2022 note 1 and 50 ml of ethanol are placed.