Hi, the following text is the experimental section of a paper. I cannot understand what is happening exactly, and when I follow the experimental route, there are not any polymers in my round bottom flask. any ideas?

"As shown in Scheme1 A, polymers were prepared based on the protocol reported previously with minor modification.19 In brief, 3.5 g of 1,4-butanediol diacrylate (17.7 mmol) and 1.5 g of 6-amino caproic acid (11.4 mmol) were firstly mixed in 10 mL of 50% (v/v) DMSO aqueous solution, followed by vigorously stirring for 12 h at 90 °C in a safe dark place. Subsequently, an end-capping reaction was performed by the addition of 10% (v/v) amino solution, ethylenediamine, into the polymer/DMSO solution."