Characterization of conductive poly(acrylonitrile-co-vinyl acetate) composites: Matrix polymerization of pyrrole derivatives

Lignin macromolecules are potential precursor materials for producing electrospun nanofibers for composite applications. However, little is known about the effect of lignin type and blend ratios with synthetic polymers. This study analyzed blends of poly(acrylonitrile-co-methyl acrylate) (PAN-MA) with two types of commercially available lignin, low sulfonate (LSL) and alkali, kraft lignin (AL), in DMF solvent. The electrospinning and polymer blend solution conditions were optimized to produce thermally stable, smooth lignin-based nanofibers with total polymer content of up to 20 wt % in solution and a 50/50 blend weight ratio. Microscopy studies revealed that AL blends possess good solubility, miscibility, and dispersibility compared to LSL blends. Despite the lignin content or type, rheological studies demonstrated that PAN-MA concentration in solution dictated the blend’s viscosity. Smooth electrospun nanofibers were fabricated using AL depending upon the total polymer content and blend ratio. AL’s addition to PAN-MA did not affect the glass transition or degradation temperatures of the nanofibers compared to neat PAN-MA. We confirmed the presence of each lignin type within PAN-MA nanofibers through infrared spectroscopy. PAN-MA/AL nanofibers possessed similar morphological and thermal properties as PAN-MA; thus, these lignin-based nanofibers can replace PAN in future applications, including production of carbon fibers and supercapacitors.

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Fabrication and Characterization of Electrospun Poly(acrylonitrile-co-vinylidene Chloride) Copolymer/Poly(n-tetradecyl acrylate-co-n-hexadecyl Acrylate) Sheath/Core Nanofiber-wrapped Thermo-regulated Filaments

ACS Applied Energy Materials ◽

10.1021/acsaem.1c01038 ◽

2021 ◽

Author(s):

Sai Chen ◽

Lijuan Tao ◽

Wenhua Cai ◽

Haihui Liu ◽

Xuechen Wang ◽

...

Keyword(s):

Vinylidene Chloride ◽

Fabrication And Characterization ◽

Copolymer Poly ◽

Poly Acrylonitrile

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Design and Characterization of a Screw Extrusion Hot-End for Fused Deposition Modeling

Molecules ◽

10.3390/molecules26030590 ◽

2021 ◽

Vol 26 (3) ◽

pp. 590

Author(s):

Tim Feuerbach ◽

Markus Thommes

Keyword(s):

Vinyl Acetate ◽

Fused Deposition Modeling ◽

Ethylene Vinyl Acetate ◽

Direct Printing ◽

Fused Deposition ◽

Screw Extrusion ◽

Deposition Modeling ◽

Feedstock Material ◽

Material Form

The filament is the most widespread feedstock material form used for fused deposition modeling printers. Filaments must be manufactured with tight dimensional tolerances, both to be processable in the hot-end and to obtain printed objects of high quality. The ability to successfully feed the filament into the printer is also related to the mechanical properties of the filament, which are often insufficient for pharmaceutically relevant excipients. In the scope of this work, an 8 mm single screw hot-end was designed and characterized, which allows direct printing of materials from their powder form and does not require an intermediate filament. The capability of the hot-end to increase the range of applicable excipients to fused deposition modeling was demonstrated by processing and printing several excipients that are not suitable for fused deposition modeling in their filament forms, such as ethylene vinyl acetate and poly(1-vinylpyrrolidone-co-vinyl acetate). The conveying characteristic of the screw was investigated experimentally with all materials and was in agreement with an established model from literature. The complete design information, such as the screw geometry and the hot-end dimensions, is provided in this work.

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