Recycled, Bio-Based, and Blended Composite Materials for 3D Printing Filament: Pros and Cons—A Review

In recent years, additive manufacturing (AM), known as “3D printing”, has experienced exceptional growth thanks to the development of mechatronics and materials science. Fused filament deposition (FDM) manufacturing is the most widely used technique in the field of AM, due to low operating and material costs. However, the materials commonly used for this technology are virgin thermoplastics. It is worth noting a considerable amount of waste exists due to failed print and disposable prototypes. In this regard, using green and sustainable materials is essential to limit the impact on the environment. The recycled, bio-based, and blended recycled materials are therefore a potential approach for 3D printing. In contrast, the lack of understanding of the mechanism of interlayer adhesion and the degradation of materials for FDM printing has posed a major challenge for these green materials. This paper provides an overview of the FDM technique and material requirements for 3D printing filaments. The main objective is to highlight the advantages and disadvantages of using recycled, bio-based, and blended materials based on thermoplastics for 3D printing filaments. In this work, solutions to improve the mechanical properties of 3D printing parts before, during, and after the printing process are pointed out. This paper provides an overview on choosing which materials and solutions depend on the specific application purposes. Moreover, research gaps and opportunities are mentioned in the discussion and conclusions sections of this study.

Hydrometallurgical recovery of lithium carbonate and iron phosphate from blended cathode materials of spent lithium-ion battery

The recycling of cathode materials from spent lithium-ion battery has attracted extensive attention,but few research have focused on spent blended cathode materials.In reality,the blended materials of lithium iron phosphate and ternary are widely used in electric vehicles,so it is critical to design an effective recycling technique.In this study,an efficient method for recovering Li and Fe from the blended cathode materials of spent LiFePO_(4)and LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)batteries is proposed.First,87%A1 was removed by alkali leaching.Then,91.65%Li,72.08%Ni,64.6%Co and 71.66%Mn were further separated by selective leaching with H_(2)SO_(4)and H_(2)O_(2).Li,Ni,Co and Mn in solution were recovered in the form of Li_(2)CO_(3)and hydroxide respectively.Subsequently,98.38%Fe was leached from the residue by two stage process,and it is recovered as FePO_(4)·2H_(2)O with a purity of 99.5%by precipitation.Fe and P were present in FePO_(4)·2H_(2)O in amounts of 28.34%and 15.98%,respectively.Additionally,the drift and control of various components were discussed,and cost-benefit analysis was used to assess the feasibility of potential application.

Research on Thermal Properties of Nomex Fiber and Nomex/Viscose Blended Fabric

Based on the analysis of the properties of Nomex 450 and Nomex 462,the thermal properties of Nomex 462/Lenzing Viscose Flame retardent(FR)blending materials were analyzed.It was discovered through burning test and Thermal Gravity(TG)analysis that the blended material was superior in thermal behaviors to the material made from either Nomex or Viscose FR filament,when the ratio of Nomex and Lenzing Viscose FR reached 80∶20,and excellent thermal properties were achieved with the value of Limiting Oxygen Index(LOI)up to 36.1%.Blending Nomex and Viscose FR filaments may be recommended for better fire retardant property of related fabric.

Thermal stability of LiFePO_4/C-LiMn_2O_4 blended cathode materials

Safety is important to lithium ion battery materials. The thermal stability of LiFePOa/C-LiMn204 blended cathode materials is characterized by using TG, XRD, and SEM etc. The results show that LiFePO4/C-LiMn2O4 possesses a worse thermal stability than pure spinel LiMn2O4 and pure olivine LiFePO4/C. When LiFePO4/C-LiMn2O4 blended cathode materials are sintered at 500℃ under Ar atmosphere, the sintered cathode materials emit O2, and appear impurity phases （Li3PO4, Fe2O3, Mn3O4）. It is deduced that some chemical reactions take place between different materials, which leads to a worse discharge specific capacity. LiFePO4/C-LiMn2O4 blended cathode materials, therefore, need to be managed and controlled strictly for the sake of ther- mal stability and safety.

Synergetic effects of blended materials for Lithium-ion batteries

LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2, LiMn_2O_4 and LiCoO_2 are paired to make the blended materials for the cathode of lithium-ion batteries. The factors impacting on the characteristics of blended materials are studied using constant current charge/discharge measurement and electrochemical impedance spectroscopy. The results show that the three pairs of blended materials exhibit very different synergetic effects in high C-rate discharging. The mechanism of particle synergetic effect has a physical root on the compensating material property of blending components, which fundamentally correlates with their similarity and difference in crystalline and electronic structures. The AC impedance show the obvious changes that alternate the high C-rate performance, due to reduced particle impedance in blended materials. The pairs of LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2-LiMn_2O and LiCoO_2-LiMn_2O_4 present obvious increases in high C-rate reversible capacities than does the pair LiCoO_2-LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2.

Small Molecule:Polymer Blends for N-type Organic Thin Film Transistors via Bar-coating in Air

Fabricating n-type organic thin film transistors(OTFTs)based on small molecules via solution processing under atmospheric conditions remains challenging.Blending small molecules with polymer is an effective strategy to improve the solution processibility and air stability of the resulted devices.In this study,polystyrene was chosen to blend with n-type small molecule DPP1012-4F to enhance the continuity of the semiconductor layer and maintain a favorable edge-on stacking of semiconductors.The introduction of high-boiling point 1-chloronaphthalene as a solvent additive in the blending system can reduce the grain boundary defects in the microscopic morphology.These changes in aggregation behavior are confirmed by X-ray diffraction,atomic force microscopy and polarized optical microscopy analyses.Via bar-coating of the semiconductor layers in air,the electron mobility of the resulted OTFTs under the optimal condition is 0.73 cm2·V–1·s–1,which is amongst the highest n-type small molecule-based OTFTs with active layers prepared in air up to now.These results show a great potential of the blending strategy in industrial roll-to-roll manufacture of high-mobility n-type OTFTs.

Computational and conceptual blends: Material considerations and agency in a multi-material design workflow

The assimilation of functionally graded (or multi-) materials into architecture is deemed to enable the rethinking of current architectural design practice and bring back material considerations at the heart of the early design process. In response, the paper outlines a functionally graded material (FGM) design workflow that departs from standard early-stage CAD, which is typically performed via computer elements devoid of materiality. It then analyses this workflow from a theoretical perspective, namely through Edwin Hutchins’ materially anchored conceptual blending, Lambros Malafouris’ Material Engagement Theory (MET) and John Searle’s concepts of intentionality. The aim is to demonstrate that due to the superimposition of material considerations that precede and succeed the CAD operation, working with material-less entities during early-stage FGM design is not logically sustainable. Additionally, multi-materiality allows for the questioning of authorship in the design process and leads to a repositioning of agency from the subject to the locus of engagement with digital materials and their affordances.