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The work presented here describes a paradigm for the design of materials for additive manufacturing platforms based on taking advantage of unique physical properties imparted upon the material by the fabrication process. We sought to further investigate past work with binary shape memory polymer blends, which indicated that phase texturization caused by the fused filament fabrication (FFF) process enhanced shape memory properties. In this work, two multi-constituent shape memory polymer systems were developed where the miscibility parameter was the guide in material selection. A comparison with injection molded specimens was also carried out to further investigate the ability of the FFF process to enable enhanced shape memory characteristics as compared to other manufacturing methods. It was found that blend combinations with more closely matching miscibility parameters were more apt at yielding reliable shape memory polymer systems. However, when miscibility parameters differed, a pathway towards the creation of shape memory polymer systems capable of maintaining more than one temporary shape at a time was potentially realized. Additional aspects related to impact modifying of rigid thermoplastics as well as thermomechanical processing on induced crystallinity are also explored. Overall, this work serves as another example in the advancement of additive manufacturing via materials development.

Hybrid material systems, where two materials with similar melting temperatures are combined to form a new compound, represent a possible avenue to expand the materials palette available for 3-D printing platforms such as fused deposition modeling (FDM™). In general, the morphology of filler materials in thermoplastic composites is unchanged before and after combining with a polymer matrix. However, the processing of hybrid material systems in FDM™-type processing allows for the possibility of manipulating the morphology of the filler material. The work presented here demonstrates the development of three different hybrid (polymer–metal) blends for 3-D printing platforms based on FDM™ technology. Tin-bismuth (SnBi) alloy powder was combined with three thermoplastic materials: (1) acrylonitrile butadiene styrene (ABS), (2) polylactic acid, and (3) a polymer blend composed of ABS and styrene ethylene butylene styrene containing a maleic anhydride graft (SEBS-g-MA). A notable feature observed through the use of scanning electron microscopy (SEM) was the drawing of the spherical SnBi particles into wires, leading to an in situ reinforcement. The efficacy of a silane functionalization process was also noted, though the material processing temperatures were well above the melting temperature of the SnBi particles.

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