Synthesis and characterization of ring-type and branched polymers including polyethylene glycols by “click” chemistry

Abstract

Synthesis of ring-type (or branched) polymers including polyethylene glycols was archived via “click” chemistry of 5,6-diazido-2-benzyl-1H-benzimidazole (Di-N3) [or triazidoacetohydrazide derivative (Tri-N3)] and terminally dipropargyl polyethylene glycols (PEG-dipropargyl) with different molecular weights. Di-N3 was obtained by reaction of 5,6-dichloro-2-benzyl-1H-benzimidazole (Di-Cl) and sodium azide. 2-(2-benzyl-5,6-dichloro-1H-benzimidazol-1-yl)-N′-(4-chlorobenzylidene)acetohydrazide (Tri-Cl) was synthesized by using Di-Cl. Synthesis of Tri-N3 was archived by means of reaction of Tri-Cl and sodium azide. PEG-dipropargyl was synthesized by using reaction of PEGs with different molecular weights and propargyl chloride. By using Di-N3 (or Tri-N3) and PEG-dipropargyl, ring-type (or branched) polymers including polyethylene glycols were synthesized. The polymers were relatively acquired in high yields and low dispersities. The primary parameters for example concentration and time were assessed. The characterization of products was accomplished by using multi instruments such as 1H-NMR, FT-IR, GPC, TGA, DSC, and elemental analysis techniques. The multi instruments studies of the obtained polymers show that the ring-type and branched polymers easily formed as a result of “click” chemistry.