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Dynamic Semicrystalline Networks of Polypropylene with Thiol-Anhydride Exchangeable Crosslinks.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Saed, Mohand O 
Lin, Xueyan 
Terentjev, Eugene M  ORCID logo  https://orcid.org/0000-0003-3517-6578

Abstract

Thermoplastic polyolefins (TPOs) crosslinked by dynamic covalent bonds (xTPOs) have the potential to be the most utilized class of polymer in the world, with applications ranging from household and automotive to biomedical devices and additive manufacturing. xTPO combines the benefits of thermoplastics and thermosets in a "single material" and potentially avoids their shortcomings. Here, we describe a new two-stage reaction extrusion strategy of TPOs with a backbone consisting of inert C-C bonds (polypropylene, PP), and thiol-anhydride, to dynamically crosslink PP through thiol-thioester bond exchange. The degree of PP crosslinking determines the rubber plateau modulus above the melting point of the plastic: the modulus at 200 °C increases from zero in the melt to 23 kPa at 6% crosslinking, to 60 kPa at 20%, to 105 kPa at 40%. The overall mechanical strength of the solid xTPO plastic is 25% higher compared to the original PP, and the gel fraction of xTPO reaches 55%. Finally, we demonstrate that the crosslinked xTPO material is readily reprocessable (recycled, remolded, rewelded, and 3D printed).

Description

Keywords

Polypropylene, Thermoplastic, 3D Printing, Plastic Recycling, Vitrimer, Thiol-anhydrate, Thiol-thioester

Journal Title

ACS applied materials & interfaces

Conference Name

Journal ISSN

1944-8244

Volume Title

13

Publisher

Sponsorship
European Research Council (786659)