Search results
1 – 10 of 10Christian Mauricio Cobos, Octavio Fenollar, Juan López Martinez, Santiago Ferrandiz and Luis Garzón
This paper aims to describe the influence of maleinized linseed oil (MLO), when used as a lubricant, on the thermal and rheological properties of PLA/MWCNTs (polylactic…
Abstract
Purpose
This paper aims to describe the influence of maleinized linseed oil (MLO), when used as a lubricant, on the thermal and rheological properties of PLA/MWCNTs (polylactic acid/multi-walled carbon nanotubes) and PLA/HNT (halloysite nanotubes) nanocomposites, as a reference for application in 3D printing processes.
Design/methodology/approach
Nanocomposites were obtained by melting in a twin-screw extruder, mixing PLA with MWCNTs and HNTs in different percentages of 0.5, 0.75 and 1 Wt.% for subsequent mixing by the same process with 5 phr MLO, for application in additive manufacturing, as analyzed by means of differential scanning calorimetry (DSC), capillary rheometry, melt flow rate (MFL) and field emission scanning electron microscopy (FESEM).
Findings
The results obtained for thermal characterization by using DSC indicate the non-variation of glass transition temperature Tg = 62 ± 2°C and a melting temperature (Tm) around 170°C. Crystallization temperature dropped by approximately 12°C, which should be kept in mind during the transformation processes. The values obtained by capillary rheometry indicate that the material’s viscosity is reduced by the influence of the MLO plasticizer’s lubricant effect on the PLA’s molecular structure. The melt flow index values confirm a rise of approximately 46% in the flow index and back up the capillary rheometry results. The values obtained were as follows: PLA/0.5 Wt.% MWCNT/MLO 5 phr 54.07, PLA/0.75 Wt.% MWCNT/MLO 5 phr 53.46, PLA/1 Wt.% MWCNT/MLO 5 phr 51.84y PLA/0.5 Wt.% HNT/MLO 5 phr 61.8, PLA/0.75 Wt.% HNT/MLO 5 phr 68.3 and PLA/1 Wt.% HNT/MLO 5 phr 71.2 g/10 min. Apart from the nanocharge distribution, the information obtained from the FESEM shows the existence of a cluster, which could have been avoided by more energetic stirring during the nanocompound manufacturing process.
Social implications
This paper presents an analysis of the insertion of plasticizer in nanocomposites for the application in additive manufacturing processes in fusion deposition modelling (FDM) system.
Originality/value
This is a novel original research work.
Details
Keywords
Andrea Mantelli, Marinella Levi, Stefano Turri and Raffaella Suriano
The purpose of this study is to demonstrate the potential of three-dimensional printing technology for the remanufacturing of end-of-life (EoL) composites. This technology will…
Abstract
Purpose
The purpose of this study is to demonstrate the potential of three-dimensional printing technology for the remanufacturing of end-of-life (EoL) composites. This technology will enable the rapid fabrication of environmentally sustainable structures with complex shapes and good mechanical properties. These three-dimensional printed objects will have several application fields, such as street furniture and urban renewal, thus promoting a circular economy model.
Design/methodology/approach
For this purpose, a low-cost liquid deposition modeling technology was used to extrude photo-curable and thermally curable composite inks, composed of an acrylate-based resin loaded with different amounts of mechanically recycled glass fiber reinforced composites (GFRCs). Rheological properties of the extruded inks and their printability window and the conversion of cured composites after an ultraviolet light (UV) assisted extrusion were investigated. In addition, tensile properties of composites remanufactured by this UV-assisted technology were studied.
Findings
A printability window was found for the three-dimensional printable GFRCs inks. The formulation of the composite printable inks was optimized to obtain high quality printed objects with a high content of recycled GFRCs. Tensile tests also showed promising mechanical properties for printed GFRCs obtained with this approach.
Originality/value
The novelty of this paper consists in the remanufacturing of GFRCs by the three-dimensional printing technology to promote the implementation of a circular economy. This study shows the feasibility of this approach, using mechanically recycled EoL GFRCs, composed of a thermoset polymer matrix, which cannot be melted as in case of thermoplastic-based composites. Objects with complex shapes were three-dimensional printed and presented here as a proof-of-concept.
Details
Keywords
Chaduvula Vijaya Lakshmi, Ch. Ravi Kiran, M. Gowrisankar, Shaik Babu and D. Ramachandran
The paper aims to throw light on the interactions taking place between the different chemical compositions at various temperatures. P-methylacetophenone is a polar dissolvable…
Abstract
Purpose
The paper aims to throw light on the interactions taking place between the different chemical compositions at various temperatures. P-methylacetophenone is a polar dissolvable, which is positively related by dipole–dipole co-operations and is exceptionally compelling a direct result of the shortfall of any critical primary impacts because of the absence of hydrogen bonds; hence, it might work an enormous dipole moment (μ = 3.62 D). Alcohols additionally assume a significant part in industries and research facilities as reagents and pull in incredible consideration as helpful solvents in the green innovation. They are utilized as pressure-driven liquids in drugs, beauty care products, aromas, paints removers, flavors, dye stuffs and as a germ-free specialist.
Design/methodology/approach
Mixtures were prepared by mass in airtight ground stopper bottles. The mass measurements were performed on a digital electronic balance (Mettler Toledo AB135, Switzerland) with an uncertainty of ±0.0001 g. The uncertainty in mole fraction was thus estimated to be less than ±0.0001. The densities of pure liquids and their mixtures were determined using a density meter (DDH-2911, Rudolph Research Analytical). The instrument was calibrated frequently using deionized doubly distilled water and dry air. The estimated uncertainty associated with density measurements is ±0.0003 g.cm−3. Viscosities of the pure liquids and their mixtures were determined by using Ostwald’s viscometer. The viscometer was calibrated at each required temperature using doubly distilled water. The viscometer was cleaned, dried and is filled with the sample liquid in a bulb having capacity of 10 ml. The viscometer was then kept in a transparent walled water bath with a thermal stability of ±0.01K for about 20 min to obtain thermal equilibrium. An electronic digital stop watch with an uncertainty of ±0.01 s was used for the flow time measurements for each sample at least four readings were taken and then the average of these was taken.
Findings
Negative values of excess molar volume, excess isentropic compressibility and positive values of deviation in viscosity including excess Gibbs energy of activation of viscous flow at different temperatures (303.15, 308.15 and 313.15 K) may be attribution to the specific intermolecular interactions through the hetero-association interaction between the components of the mixtures, resulting in the formation of associated complexes through hydrogen bond interactions.
Originality/value
The excess molar volume (VE) values were analyzed with the Prigogine–Flory–Patterson theory, which demonstrated that the free volume contribution is the one of the factors influencing negative values of excess molar quantities. The Jouyban–Acree model was used to correlate the experimental values of density, speed of sound and viscosity.
Details
Keywords
Witold Nawrot and Karol Malecha
The purpose of this paper is to review possibilities of implementing ceramic additive manufacturing (AM) into electronic device production, which can enable great new…
Abstract
Purpose
The purpose of this paper is to review possibilities of implementing ceramic additive manufacturing (AM) into electronic device production, which can enable great new possibilities.
Design/methodology/approach
A short introduction into additive techniques is included, as well as primary characterization of structuring capabilities, dielectric performance and applicability in the electronic manufacturing process.
Findings
Ceramic stereolithography (SLA) is suitable for microchannel manufacturing, even using a relatively inexpensive system. This method is suitable for implementation into the electronic manufacturing process; however, a search for better materials is desired, especially for improved dielectric parameters, lowered sintering temperature and decreased porosity.
Practical implications
Relatively inexpensive ceramic SLA, which is now available, could make ceramic electronics, currently restricted to specific applications, more available.
Originality/value
Ceramic AM is in the beginning phase of implementation in electronic technology, and only a few reports are currently available, the most significant of which is mentioned in this paper.
Details
Keywords
Ming Gao, Anhui Pan, Yi Huang, Jiaqi Wang, Yan Zhang, Xiao Xie, Huanre Han and Yinghua Jia
The type 120 emergency valve is an essential braking component of railway freight trains, but corresponding diaphragms consisting of natural rubber (NR) and chloroprene rubber…
Abstract
Purpose
The type 120 emergency valve is an essential braking component of railway freight trains, but corresponding diaphragms consisting of natural rubber (NR) and chloroprene rubber (CR) exhibit insufficient aging resistance and low-temperature resistance, respectively. In order to develop type 120 emergency valve rubber diaphragms with long-life and high-performance, low-temperatureresistant CR and NR were processed.
Design/methodology/approach
The physical properties of the low-temperature-resistant CR and NR were tested by low-temperature stretching, dynamic mechanical analysis, differential scanning calorimetry and thermogravimetric analysis. Single-valve and single-vehicle tests of type 120 emergency valves were carried out for emergency diaphragms consisting of NR and CR.
Findings
The low-temperature-resistant CR and NR exhibited excellent physical properties. The elasticity and low-temperature resistance of NR were superior to those of CR, whereas the mechanical properties of the two rubbers were similar in the temperature range of 0 °C–150 °C. The NR and CR emergency diaphragms met the requirements of the single-valve test. In the low-temperature single-vehicle test, only the low-temperature sensitivity test of the NR emergency diaphragm met the requirements.
Originality/value
The innovation of this study is that it provides valuable data and experience for future development of type 120 valve rubber diaphragms.
Details
Keywords
Chau Thi Ngoc Pham, Hung Ngoc Phan, Thao Thanh Hoang, Tien Thi Thuy Dao and Huong Mai Bui
The health and environmental hazards associated with synthetic dyes have led to a revival of natural dyes that are non-toxic, environmentally benign and coupled with various…
Abstract
Purpose
The health and environmental hazards associated with synthetic dyes have led to a revival of natural dyes that are non-toxic, environmentally benign and coupled with various functions. The study aims to investigate and develop the potentiality of a popular herb called Chromolaena odorata (C. odorata) as a sustainable and stable dyestuff in textiles.
Design/methodology/approach
Natural colorant extracted from C. odorata leaves is used to dye the worsted fabric, which is one of the premier end-use of wool in fashion, via the padding method associated with pre-, simultaneous and post-mordanting with chitosan, tannic acid and copper sulfate pentahydrate. The effects of extraction, dyeing and mordanting processes on fabric’s color strength K/S and color difference ΔECMC are investigated via International Commission on Illumination’s L*a*b* color space, Fourier transform infrared spectroscopy, scanning electron microscope, color fastness to washing, rubbing, perspiration and light.
Findings
The results obtained indicate extraction with ethanol 90% with a solid/liquid ratio of 1:5 within 1 h, and coloration with a liquor ratio of 1:5 (pH 5) within 2 h under padding pressure of 0.3 MPa are the most effective for coloring worsted fabric.
Practical implications
The C. odorata’s application as a highly effective dyestuff possessing good colorimetric effectiveness has expanded this herb's economic potential, contributing partly to economic growth and adding value to wool in global supply chain.
Originality/value
C. odorata dyestuff has prevailed over other natural colorants because of its impressive color fastness against washing, rubbing, perspiration and especially color stability for pH change.
Details
Keywords
Kai Zhuang, Jieru Xiao and Xiaolong Yang
The purpose of this paper is to show that the droplet impact phenomenon is important for the advancement of industrial technologies in many fields such as spray cooling and ink…
Abstract
Purpose
The purpose of this paper is to show that the droplet impact phenomenon is important for the advancement of industrial technologies in many fields such as spray cooling and ink jet printing. Droplet bouncing on the nonwetting surfaces is a special phenomenon in the impact process which has attracted lots of attention.
Design/methodology/approach
In this work, the authors fabricated two kinds of representative nonwetting surfaces including superhydrophobic surfaces (SHS) and a slippery liquid-infused porous surface (SLIPS) with advanced UV laser processing.
Findings
The droplet bouncing behavior on the two kinds of nonwetting surfaces were compared in the experiments. The results indicate that the increasing Weber number enlarges the maximum droplet spreading diameter and raises the droplet bounce height but has no effect on contact time.
Originality/value
In addition, the authors find that the topological SHS and SLIPS with the laser-processed microwedge groove array produce asymmetric droplet bouncing with opposite offset direction. Microdroplets can be continuously transported without any additional driving force on such a topological SLIPS. The promising method for manipulating droplets has potential applications for the droplet-based microfluidic platforms.
Details
Keywords
Francesco Sillani, Dominik Wagner, Marvin Aaron Spurek, Lukas Haferkamp, Adriaan Bernardus Spierings, Manfred Schmid and Konrad Wegener
Powder bed-based additive manufacturing (AM) is a promising family of technologies for industrial applications. The purpose of this study is to provide a new metrics based on the…
Abstract
Purpose
Powder bed-based additive manufacturing (AM) is a promising family of technologies for industrial applications. The purpose of this study is to provide a new metrics based on the analysis of the compaction behavior for the evaluation of flowability of AM powders.
Design/methodology/approach
In this work, a novel qualification methodology based on a camera mounted onto a commercially available tap density meter allowed to assess the compaction behavior of a selection of AM materials, both polymers and metals. This methodology automatizes the reading of the powder height and obtains more information compared to ASTM B527. A novel property is introduced, the “tapping modulus,” which describes the packing speed of a powdered material and is related to a compression/vibration powder flow.
Findings
The compaction behavior was successfully correlated with the dynamic angle of repose for polymers, but interestingly not for metals, shedding more light to the different flow behavior of these materials.
Research limitations/implications
Because of the chosen materials, the results may lack generalizability. For example, the application of this methodology outside of AM would be interesting.
Originality/value
This paper suggests a new methodology for assessing the flowing behavior of AM materials when subjected to compression. The device is inexpensive and easy to implement in a quality assurance environment, being thus interesting for industrial applications.
Details
Keywords
Zrinka Buhin Šturlić, Mirela Leskovac, Krunoslav Žižek and Sanja Lučić Blagojević
The purpose of this paper is to prepare stabile emulsions with 0–15% of colloidal silica and high monomer/water ratio and to investigate the influence of silica addition and…
Abstract
Purpose
The purpose of this paper is to prepare stabile emulsions with 0–15% of colloidal silica and high monomer/water ratio and to investigate the influence of silica addition and surface modification on the polyacrylate properties.
Design/methodology/approach
Improving the properties of the composite can be achieved by optimizing the compatibility between the phases of the composite system with improving the interactions at the matrix/filler interface. Therefore, the silica surface was modified with nonionic emulsifier octylphenol ethoxylate, cationic initiator 2,2'-azobis-(amidinopropane dihydrochloride) and 3-methacryloxypropyltrimethoxysilane and polyacrylate/silica nanocomposites were prepared via in situ emulsion polymerization. Particle size distribution, rheological properties of the emulsions and morphology, thermal properties and mechanical properties of the film prepared from the emulsions were investigated.
Findings
Polyacrylate/silica systems with unmodified silica, silica modified with nonionic emulsifier and cationic initiator have micrometer, while pure PA matrix and systems with silica modified with silane have nanometer particle sizes. Addition and surface modification of the filler increased emulsion viscosity. Agglomeration of silica particles in composites was reduced with silica surface modification. Silica filler improves thermal stability and tensile strength of polyacrylate.
Originality/value
This paper provides broad spectrum of information depending on filler surface modification and latex preparation via in situ emulsion polymerization and properties with high amount of filler and monomer/water ratio with the aim that prepared latex is suitable for film formation and final application.
Details
Keywords
Silvia Rita Sedita, Silvia Blasi and Andrea Ganzaroli
This paper explores how exaptive innovation process might be considered a useful innovation model in constraint-based environments. Through an in-depth case study, it illustrates…
Abstract
Purpose
This paper explores how exaptive innovation process might be considered a useful innovation model in constraint-based environments. Through an in-depth case study, it illustrates clearly the antecedents of exaptation processes, which are particularly relevant in rapidly changing environments requiring new solutions under time and resource constraints.
Design/methodology/approach
The authors adopt a single case study approach that is particularly suitable in case of an inductive research design, which is required because of the novelty of the topic. The research is inspired by the use of the snorkeling mask EASYBREATH, commercialized by the giant Decathlon, as a medical device, a respirator to treat patients affected by coronavirus in Italy. The authors organized the evidence according to a novel taxonomy grounded in the literature.
Findings
The case study stimulates reflections on the existence of some antecedents to the exaptive innovation process in constraint-based environments: (1) the availability of specific actors in the innovation process; (2) the creation of platforms of interaction between people with different competences, nurtured by collective bottom-up financing systems; (3) the role of the community of makers, in particular, and of the 4th industrial revolution, in general, for creating enabling technologies; (4) multidisciplinary individual background of key actors in the innovation process is crucial to ensure the exaptive path to be in place.
Research limitations/implications
This work has some limitations, due to the choice of limiting the analysis to a single case, nevertheless, it offers a first glance on a new technological trajectory available in constraint-based environments.
Originality/value
The case study results underline the importance of new digital collaboration platforms as knowledge multipliers, and illuminate on the potential of the fourth manufacturing revolution, which, through new technologies, creates opportunities for distributed forms of innovation that cross long distances.
Details