Thermoplastic Polyurea Elastomers

Title: MELT PROCESSIBLE POLYUREAS AND POLYUREA-URETHANES, METHOD FOR THE PRODUCTION THEREOF AND PRODUCTS MADE THEREFROM

 Number/Link: US2013/0331538

Applicant/Assignee: University of Akron

Publication date: 12-12-2013 (priority PCT)

Gist”: Polyurea is made melt-processable by incorporating hydrogen-bond accepting chain extenders (HACE)

Why it is interesting: It is well known that polyurea elastomers with a decent hardblock content (of e.g. 30-35%) are not melt-processable. Because of very strong (bi-dentate) H-bond formation in the hard domains the material will degrade sooner than flow when heated. In this invention it is proposed to incorporate a relatively small amount of HACE to disrupt the hard domain structure and reduce flow temperature.  In an example a few parts of OH-ended pentamethylenepolycarbonate with a MW of 500 to 800 was used next to the conventional 1,6-hexamethylene chain extender to drop the flow temperature by 50°C while not affecting the tensile strength. (I suppose a NH2-ended polycarbonate could have been used as well to make an all-polyurea material).

Bi-dentate H-bonds between polurea molecules (left) disrupted by a polycarbonate group (right)

Bi-dentate H-bonds between polurea molecules (left) dusrupted by a carbonate group (right)

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