The Fused deposition modeling (FDM) process is highly non-equilibrated and often has inadequate thermal retention, posing problems, which can be addressed via binary blending. This work explores a binary polymer blend of polylactic acid (PLA) and isotactic polypropylene (iPP) with added graphene nanoplatelets (GNPs). Mechanical testing revealed that in comparison to a control sample of pure PLA, the addition of only 1% iPP resulted in a 66% increase in toughness, and a further increase to 2.5% resulted in an increase of only 16%. Further increase above 5% decreased the toughness by 45%. These results correlated with SEM and HD optical microscopy where the filament/filament interfaces were still visible in the pure PLA sample, while they appeared completely fused in the sample with 1% iPP. Water contact angle goniometry showed an increase from 66 degrees on the pure PLA sample to 88 degrees, the value of pure iPP, on the samples containing only 1% iPP. These results indicate that an iPP shell had formed at the filament surface, which is consistent with the segregation of iPP whose surface tension is significantly lower than that of PLA. The glass transition of iPP, also being lower than that of PLA, enables interdiffusion between filaments, leading to complete obliteration of the interface and enhanced mechanical properties. Blends of iPP/PLA containing 5% GNPs were also produced and drawn into filaments. While SEM imaging indicated nearly complete alignment of the GNPs along the extrusion direction, partial sequestration of the particles in the iPP shell and internal phase segregated regions were also evident. Infrared imaging (FLIR A300) of samples in contact with a well-defined heat flux indicated an increase of 159% over the pure PLA control sample with the addition of 5% GNP. Addition of 5% GNP, with 2.5% and 5% iPP yielded an increase of 272% and 245% respectively, indicating greater thermal conduction efficiency when graphene platelets are confined in the iPP domains.

Sequestration of graphene nanoparticles within a polypropylene shell at the surface of extruded phase-separated poly(lactic acid)/polypropylene fibers and its impact on FDM printed structures

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.