Developments in electrically conductive bio-composites for use in additive manufacturing

dc.contributor.advisorChairperson, Graduate Committee: Cecily Ryanen
dc.contributor.authorArroyo, Jesse Whitneyen
dc.contributor.otherCecily Ryan was a co-author of the article, 'Incorporation of carbon nanofillers tunes mechanical and electrical percolation in PHBV:PLA blends' in the journal 'Polymers' which is contained within this thesis.en
dc.date.accessioned2019-08-30T19:53:49Z
dc.date.available2019-08-30T19:53:49Z
dc.date.issued2019en
dc.description.abstractWith the growth of rapid production methods, such as additive manufacturing, petroleum derived plastics are becoming ever more prevalent in consumer homes and landfills. As the industry grows, research into a more circular approach to designing and using materials is critical to maintaining sustainability. Bioplastics such as poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and poly(lactic acid) (PLA) provide material properties comparable to petroleum derived plastics and are becoming more common in the additive manufacturing field. Biobased fillers, such as bio-derived cellulose, lignin byproducts, and biochar, can be used to modify the thermal, mechanical, and electrical properties of polymer composites. Biochar (BioC), in particular, is of interest for enhancing thermal and electrical conductivities in composites, and can potentially serve as a bio-derived graphitic carbon alternative for certain composite applications. In this work, we investigate a blended biopolymer system: PLA/PHBV, and addition of carbon black (CB), a commonly used functional filler as a comparison for Kraft lignin-derived BioC. We present calculations and experimental results for phase-separation and nanofiller phase affinity in this system, indicating that the CB localizes in the PHBV phase of the immiscible PHBV:PLA blends. The addition of BioC led to a deleterious reaction with the biopolymers, as indicated by blend morphology, differential scanning calorimetry showing significant melting peak reduction for the PLA phase, and a reduction in melt viscosity. For the CB nanofilled composites, electrical conductivity and dynamic mechanical analysis supported the ability to use phase separation in these blends to tune the percolation of mechanical and electrical properties, with a minimum percolation threshold found for the 80:20 blends of 1.6 wt.% CB. At 2% BioC (approximately the percolation threshold for CB), the 80:20 BioC nanocomposites had a resistance of 3.43x10 8 Omega as compared to 2.99x10 8 Omega for the CB, indicating that BioC could potentially perform comparably to CB as a conductive nanofiller if the processing challenges can be overcome. Investigations into alkaline and dealkaline lignin sources have shown that alkaline lignin experiences a significant effect on the thermal stability of PHBV eluding that alternate sources of lignin may provide a solution to the processing challenges mentioned. This work has helped to develop a understanding of the factors that aid in creating sustainable materials sourced from PLA,PHBV, and BioC.en
dc.identifier.urihttps://scholarworks.montana.edu/handle/1/15520en
dc.language.isoenen
dc.publisherMontana State University - Bozeman, College of Engineeringen
dc.rights.holderCopyright 2019 by Jesse Whitney Arroyoen
dc.subject.lcshComposite materialsen
dc.subject.lcshPolymersen
dc.subject.lcshBiomoleculesen
dc.subject.lcshHeaten
dc.subject.lcshElectricityen
dc.subject.lcshMechanicsen
dc.titleDevelopments in electrically conductive bio-composites for use in additive manufacturingen
dc.typeThesisen
mus.data.thumbpage69en
thesis.degree.committeemembersMembers, Graduate Committee: Stephan Warnat; Mark Owkes.en
thesis.degree.departmentMechanical & Industrial Engineering.en
thesis.degree.genreThesisen
thesis.degree.nameMSen
thesis.format.extentfirstpage1en
thesis.format.extentlastpage114en

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