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


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
3D printing, plastic recycling, polypropylene, thermoplastic, thiol-anhydrate, thiol-thioester, vitrimer
Journal Title
ACS Appl Mater Interfaces
Conference Name
Journal ISSN
1944-8244
1944-8252
Volume Title
13
Publisher
American Chemical Society (ACS)
Rights
All rights reserved
Sponsorship
European Research Council (786659)
European Research Council H2020 (AdG 786659)