Printability Study of a Conductive Polyaniline/Acrylic Formulation for 3D Printing

[Abstract] There is need for developing novel conductive polymers for Digital Light Processing (DLP) 3D printing. In this work, photorheology, in combination with Jacobs working curves, efficaciously predict the printability of polyaniline (PANI)/acrylate formulations with different contents of PANI and photoinitiator. The adjustment of the layer thickness according to cure depth values (Cd) allows printing of most formulations, except those with the highest gel point times determined by photorheology. In the working conditions, the maximum amount of PANI embedded within the resin was ≃3 wt% with a conductivity of 10−5 S cm−1, three orders of magnitude higher than the pure resin. Higher PANI loadings hinder printing quality without improving electrical conductivity. The optimal photoinitiator concentration was found between 6 and 7 wt%. The mechanical properties of the acrylic matrix are maintained in the composites, confirming the viability of these simple, low-cost, conductive composites for applications in flexible electronic devices.Xunta de Galicia; ED481A-2019/001Xunta de Galicia; ED431C 2019/17Goretti Arias-Ferreiro thanks the financial funding received from the Xunta de Galicia and the European Union (Program to support the predoctoral stage at SUG 2019 (ED481A-2019/001)). The authors would like to thank the financial support from Xunta de Galicia-FEDER (Program of Consolidation and structuring competitive research units (ED431C 2019/17))

How to Achieve a Highly Toughened 70/30 PLA/PCL Blend by Using Nucleating Agents and Tailoring Processing Conditions

In this work, the toughening of a 70/30 polylactide (PLA)/poly(ε-caprolactone) (PCL) blend was achieved by the addition of nucleating agents (NAs) and by tailoring the processing conditions. To this end, different NAs (TMC200, TMC300, TMC306, and TMC328) were used to promote the crystallization of PLA. For comparison reasons, the effect of NAs on the PCL phase was also analyzed. From polarized light optical microscope (PLOM) observations and crystallization kinetics studies (performed by differential scanning calorimetry), it was concluded that TMC200 and TMC328 were the most efficient NAs for PLA, whereas TMC300 and TMC306 were the best in the case of PCL. Nucleation efficiency calculations showed, for the first time, a supernucleation effect of TMC200 and TMC328 NAs on PLA. However, the NAs did not produce any significant change in the mechanical properties of the blends when the samples were injection-molded into a cold mold. By contrast, PLA70/PCL30/NA blends with high impact strength values were achieved using a high mold temperature and a longer molding time. From PLOM and transmission electron microscope observations, it was concluded that the PLA/PCL blends must have a high PLA nucleation density and submicrometer spherulitic sizes along with a homogeneous PCL particle size distribution to achieve a PLA-based blend with high impact strength

Synthesis, structure, crystallization and mechanical properties of isodimorphic PBS-ran-PCL copolyesters

Isodimorphic behavior is determined by partial inclusion of comonomer segments within the crystalline structure and arises from the comparatively similar repeating chain units of the parental homopolymers. Isodimorphic random copolymers are able to crystallize irrespective of their composition and exhibit a pseudo-eutectic behavior when their melting point values are plotted as a function of comonomer content. At the pseudo-eutectic point or region, two crystalline phases can coexist. On the right-hand and the left-hand side of the pseudo-eutectic point or region, only one single crystalline phase can form which is very similar to the crystalline structures of the parent homopolymers. This article aims to study the synthesis method, structure, crystallization behavior and mechanical properties of isodimorphic random PBS-ran-PCL copolyesters. Moreover, this study provides a comprehensive analysis of our main recent results on PBS-ran-PCL random copolyesters with three different molecular weights. The results show that the comonomer composition and crystallization conditions are the major factors responsible for the crystalline morphology, crystallization kinetics and mechanical performance of isodimorphic random copolyesters. Our studies demonstrate that in the pseudo-eutectic region, where both crystalline phases can coexist, the crystallization conditions determine the crystalline phase or phases of the copolymer. The relationships between the comonomer composition and mechanical properties are also addressed in this work.Peer ReviewedObjectius de Desenvolupament Sostenible::3 - Salut i BenestarObjectius de Desenvolupament Sostenible::12 - Producció i Consum ResponsablesPostprint (published version