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The goal of this paper was to establish a metric, which we refer to as the resilience parameter, to evaluate the ability of a material to retain tensile strength after damage recovery for shape memory polymer (SMP) systems. In this work, three SMP blends created for the additive manufacturing process of fused filament fabrication (FFF) were characterized. The three polymer systems examined in this study were 50/50 by weight binary blends of the following constituents: (1) polylactic acid (PLA) and maleated styrene-ethylene-butylene-styrene (SEBS-g-MA); (2) acrylonitrile butadiene styrene (ABS) and SEBS-g-MA); and (3) PLA and thermoplastic polyurethane (TPU). The blends were melt compounded and specimens were fabricated by way of FFF and injection molding (IM). The effect of shape memory recovery from varying amounts of initial tensile deformation on the mechanical properties of each blend, in both additively manufactured and injection molded forms, was characterized in terms of the change in tensile strength vs. the amount of deformation the specimens recovered from. The findings of this research indicated a sensitivity to manufacturing method for the PLA/TPU blend, which showed an increase in strength with increasing deformation recovery for the injection molded samples, which indicates this blend had excellent resilience. The ABS/SEBS blend showed no change in strength with the amount of deformation recovery, indicating that this blend had good resilience. The PLA/SEBS showed a decrease in strength with an increasing amount of initial deformation, indicating that this blend had poor resilience. The premise behind the development of this parameter is to promote and aid the notion that increased use of shape memory and self-healing polymers could be a strategy for mitigating plastic waste in the environment.
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Development and characterization of rigid polyester blends for 4D printing
Incorporating thermoplastic materials with shape memory properties into the fused filament fabrication process enables what is commonly referred to as 4D printing. When the blends are composed of one or more materials with inherent shape memory properties, the tailoring of critical parameters such as shape recovery temperature can be realized. Previous work by our group demonstrated the creation of shape memory polymer blends where one component was elastomeric. The following work entails the development and characterization of rigid polyester blends that are biocompatible and biodegradable in addition to having shape memory properties. Dynamic mechanical analysis (DMA) was used to determine the critical deformation and recovery temperatures. The effect of print raster patterns on the DMA results was also evaluated. Micro- tensile testing was used to characterize the physical properties of the materials at elevated temperatures. Finally, scanning electron microanalysis was used to examine the fracture surfaces of spent tensile specimens.
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- Award ID(s):
- 2227573
- PAR ID:
- 10565035
- Publisher / Repository:
- University of Texas at Austin
- Date Published:
- Subject(s) / Keyword(s):
- 4D Printing Shape memory polymers Digital image correlation Fused filament fabrication
- Format(s):
- Medium: X
- Location:
- Texas ScholarWorks/ University of Texas Libraries
- Right(s):
- open
- Institution:
- Austin, The University Of Texas At
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.26153/tsw/58052
