P. Kalenda, D. Veselý, A. Kalendová and V. Št'áva
To study the siccativation effects of metallocenes based on ferrocene and its derivatives as siccatives supporting their catalytic effects during meshing reactions proceeding…
Abstract
Purpose
To study the siccativation effects of metallocenes based on ferrocene and its derivatives as siccatives supporting their catalytic effects during meshing reactions proceeding during the creation of an alkyd resin film.
Design/methodology/approach
Siccatives are used as catalysts of auto‐oxidation reactions between a binder dried by oxidation and atmospheric oxygen. Without these substances, the auto‐oxidation of the binder would be slow and paint film drying would take too long. The cobalt salts of organic acids are currently the most efficient and most widely used siccatives. Present‐day ecological efforts are aimed at reducing the content of volatile organic substances in paints. One way to achieve this goal is the application of the so‐called high solids of binders that create thicker paint films. However, fast meshing throughout the whole paint layer remains their downside.
Findings
Ecological efforts are aimed at searching for the highly efficient catalysts of hardening reactions for paints dried by oxidation. This paper investigates the possibility of using metallocenes based on ferrocene and its derivatives as siccatives for paints dried by oxidation. Their catalytic properties, mainly their synergic effects with cobalt siccative, were monitored in model binders by means of Fourier‐transform infrared spectroscopy and by measuring the hardness of created paint films. The data found in regard with the catalytic effects of ferrocene and some of its derivatives were compared with the activity of cobalt siccative alone.
Practical implications
The siccatives under scrutiny can be conveniently used to accelerate the formation of alkyd paints modified with natural oils, be it for industrial or decorative purposes. It was discovered that acetylferrocene has excellent siccativation effects that can be realistically used in industry. Its application allows for reducing the cobalt salt content in paint as much as ten times, which has major ecological significance.
Originality/value
The method of detecting the kinetic parameters of the meshing reactions of alkyls described in the paper is relatively new and facilitates identification of siccatives that are optimum for specific paints formulations. Research into ecologically acceptable ferrocene and its derivatives as catalysts of paints dried by oxidation is also beneficial.
Details
Keywords
Eujin Pei, Giselle Hsiang Loh, David Harrison, Henrique de Amorim Almeida, Mario Domingo Monzón Verona and Rubén Paz
The purpose of this paper is to extend existing knowledge of 4D printing, in line with Khoo et al. (2015) who defined the production of 4D printing using a single material, and 4D…
Abstract
Purpose
The purpose of this paper is to extend existing knowledge of 4D printing, in line with Khoo et al. (2015) who defined the production of 4D printing using a single material, and 4D printing of multiple materials. It is proposed that 4D printing can be achieved through the use of functionally graded materials (FGMs) that involve gradational mixing of materials and are produced using an additive manufacturing (AM) technique to achieve a single component.
Design/methodology/approach
The latest state-of-the-art literature was extensively reviewed, covering aspects of materials, processes, computer-aided design (CAD), applications and made recommendations for future work.
Findings
This paper clarifies that functionally graded additive manufacturing (FGAM) is defined as a single AM process that includes the gradational mixing of materials to fabricate freeform geometries with variable properties within one component. The paper also covers aspects of materials, processes, CAD, applications and makes recommendations for future work.
Research limitations/implications
This paper examines the relationship between FGAM and 4D printing and defines FGAM as a single AM process involving gradational mixing of materials to fabricate freeform geometries with variable properties within one component. FGAM requires better computational tools for modelling, simulation and fabrication because current CAD systems are incapable of supporting the FGAM workflow.
Practical implications
It is also identified that other factors, such as strength, type of materials, etc., must be taken into account when selecting an appropriate process for FGAM. More research needs to be conducted on improving the performance of FGAM processes through extensive characterisation of FGMs to generate a comprehensive database and to develop a predictive model for proper process control. It is expected that future work will focus on both material characterisation as well as seamless FGAM control processes.
Originality/value
This paper examines the relationship between FGAM and 4D printing and defines FGAM as a single AM process that includes gradational mixing of materials to fabricate freeform geometries with variable properties within one component.
Details
Keywords
Zizhao Wang, Hongyao Shen, Senyang Wu and Jianzhong Fu
Fused filament fabrication (FFF) is a common additive manufacturing method that is widely used owing to its low cost, environmental friendliness and safety. Colour models are…
Abstract
Purpose
Fused filament fabrication (FFF) is a common additive manufacturing method that is widely used owing to its low cost, environmental friendliness and safety. Colour models are needed because of their ability to express more information, but high printing quality and efficiency are difficult to achieve with the existing FFF colour printing methods because of the “inertia” of printing. Inertia refers to the feature of the former colour material remaining in the molten cavity when switching colours in colour FFF printing. The purpose of this paper is to propose a new FFF colour printing method to reduce printing material usage and printing time.
Design/methodology/approach
A new FFF colour printing method that uses transitioning waste to construct the part is proposed. Based on the freedom of the colour surface model’s interior space, the internal fill and support of the print model are generated using the transitioning waste to reduce printing material usage and printing time and to achieve environmentally friendly colour printing. The modified elite ant system (EAS) algorithm is used to construct and optimize this method based on the colour surface model.
Findings
A colour printing experiment is performed using a colour-mixing FFF printer platform with a special waste extrusion module. The experimental results show that this method can significantly reduce material and time consumption compared to the commonly used method. The printed part produced by this method also has high surface quality.
Originality/value
A new FFF colour printing method that uses transitioning waste to construct the part is proposed. Based on the freedom of the colour surface model’s interior space, the internal fill and support of the print model are generated using the transitioning waste to reduce printing material usage and printing time and to achieve environmentally friendly colour printing. The modified EAS algorithm is used to construct and optimize this method based on the colour surface model. A special waste extrusion module is developed.