Priamine 1075 and catechol carbonate, a perfect match for ecofriendly production of a new renewable polyurea for sustainable flexible food packaging

New homopolyurea with enhanced functional properties was synthesized by combining a bio-based vegetable oil derived diamine, Priamine 1075, with catechol carbonate as carbonylating agent employing an ecofriendly synthetic strategy. The synthesis, carried out in catalyst-free and solventless conditions, allowed obtaining a transparent rubbery material soluble in chloroform and processable in form of film. The polyurea was firstly subjected to molecular characterization by 1H, 13C NMR, ATR-FTIR spectroscopy and GPC analysis, to check molecular structure and weight ensuring the good control of synthesis process. Afterwards, the film was subjected to thermal characterization, DSC analysis confirming the amorphous rubbery nature and TGA revealing the outstanding thermal stability. Tensile tests showed low elastic modulus and exceptional elongation at break together with shape-recovery capability. Permeability tests revealed good gas-barrier properties regardless the amorphous rubbery nature, in particular to CO2 molecules. The measured values were better than polyolefins ones, to date the most used materials in food packaging.