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1 – 10 of 353Abstract
Purpose
The purpose of this paper is to improve the anti‐sedimentation of the acrylic resin containing long afterglow phosphors (SrMgAl4O8:Eu2+, Dy3+).
Design/methodology/approach
The phosphors were first modified by the vinylsilane coupling agent MPS (3‐(methacryloxypropyl)‐trimethoxysilane). Then, the acrylic resin containing modified phosphors was synthesised by in situ polymerisation. Meanwhile, the compared blend sample was prepared by pure acylic resin with no modified phosphors in the same content. When the two resins were coated on glass, the films were characterised by ATR‐FTIR, SEM and TGA. The sedimentation performances of liquid resins were also observed.
Findings
Results showed that anti‐sedimentation of acrylic resin with phosphors by in situ polymerisation was enhanced greatly, because the phosphors have been connected with the macromolecule chain, and dispersed homogeneously with no aggregation, so preventing its sedimentation.
Research limitations/implications
Researchers are encouraged to test the proposed method and enhance the anti‐sedimentation further.
Practical implications
This method provides an idea to solve the problem of anti‐sedimentation in luminescent paint containing long afterglow phosphors in practical production and application.
Originality/value
This paper introduced the in situ polymerisation to enhance the anti‐sedimentation of acrylic resin containing long afterglow phosphors and it can be applied also to other inorganic powders.
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Keywords
Fatemeh Andami, Maryam Ataeefard, Farhood Najafi and Mohammad Reza Saeb
Printing toners are polymer composites accountable for transmission of digital images onto target substrates. Bearing in mind the ever increasing demand for high quality digital…
Abstract
Purpose
Printing toners are polymer composites accountable for transmission of digital images onto target substrates. Bearing in mind the ever increasing demand for high quality digital printing, modification and/or integration of existing techniques for manufacturing toners with favourable morphological and colour characteristics appears of vital importance. The present study aims to uncover the significance of in-situ polymerisation method, i.e. suspension, emulsion and mini-emulsion to control the microstructure of toner particles (particle size, particle size distribution and sphereness) while keeping the energy required for polymerisation along with reaction conversion at a reasonable level.
Design/methodology/approach
Assessment of particle size, particle size distribution and reaction conversion visualised the potential of suspension, emulsion and mini-emulsion polymerisation techniques to control microstructure, and colour characteristics of synthesized toners as well.
Findings
The results provided support for the fact that either the emulsion or mini-emulsion polymerisation routes will result in toners having an acceptable particle size and particle size distribution in the presence of a redox precursor. The higher monomer conversion at low temperature, as compared to the suspension polymerisation, was noticeable.
Practical implications
Analysing the glass transition temperature and colour characteristics of the resulting toners elucidated the superiority of mini-emulsion with respect to the other two cases which ranks this method on account of application.
Originality/value
For the first time, mini-emulsion route was put into practice and toners with acceptable colour and microstructure features were synthesised. In spite of lower polymerisation temperature and higher conversion of mini-emulsion compared to suspension and emulsion polymerisation techniques, further investigations are required to fine-tuning the properties of toners produced through this method.
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Monika Zawadzka, Jan Kulawik, Dorota Szwagierczak and Krzysztof Zaraska
The purpose of this paper is to present fabrication process of volatile organic compounds (VOCs) sensors based on polypyrrole material deposited on different substrates and to…
Abstract
Purpose
The purpose of this paper is to present fabrication process of volatile organic compounds (VOCs) sensors based on polypyrrole material deposited on different substrates and to show and compare the responses of the produced sensors to different VOCs.
Design/methodology/approach
Polypyrrole sensing layers were prepared by in situ chemical polymerisation on two different substrates: alumina and poly(ethylene terephthalate) (PET). The time of the polymerisation was varied. After film deposition, an interdigitated electrode was screen-printed on the material deposited on the substrate.
Findings
It was demonstrated that both polymerisation time and substrate type provide means to vary the sensitivity of polypyrrole-based sensors to VOCs.
Practical implications
VOCs, which are released in manufacturing or use of various products and materials, pose a threat to the environment and human health. Therefore, measures must be taken to control their concentration both in indoor and outdoor air.
Originality/value
Deposition of a conductive polymer film on the substrate via in situ chemical polymerisation followed by screen-printing of an interdigitated electrode on the polymer surface offers a fast and an effective method of chemiresistor-type sensor fabrication.
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Abstract
Purpose
The purpose of this paper is to investigate the effects of carbon nanotubes (CNTs) on the mechanical, thermal and colour properties of solvent-containing two-component polyurethane (PU) coating.
Design/methodology/approach
Fourier transform infrared spectroscopy and observation of dispersion stability were used to assess the effects of acid treatment on CNTs. The CNTs and PU composite coating was synthesised by in situ polymerisation and bending polymerisation, and the mechanical, thermal and colour appearance properties of coating were characterised.
Findings
It was found that desirable modifications to CNTs occurred after acid treatment; thus, mainly carboxylic acid groups were introduced onto the surface of CNTs. And the acid-treated CNTs could improve the mechanical and thermal properties of PU coating, and the properties of composite coating was improved more successfully by in situ polymerisation than by blending polymerisation.
Practical implications
The investigation established a method to synthesise CNTs and PU composite coating. The mechanical and thermal properties of PU coating could be improved by the inclusion of CNTs.
Originality/value
This study established a method to synthesise CNTs and PU composite coating by in situ polymerisation and blending polymerisation; the effects of CNTs on modifying mechanical, thermal and colour properties of PU coating were investigated and compared in detail.
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Bahareh Babaie, Mohsen Najafi and Maryam Ataeefard
Toner is a crucial dry colorant composite used in printing based on the electrophotographic process. The quality of printed images is greatly influenced by the toner production…
Abstract
Purpose
Toner is a crucial dry colorant composite used in printing based on the electrophotographic process. The quality of printed images is greatly influenced by the toner production method and material formulation. Chemically in situ polymerization methods are currently preferred. This paper aims to optimize the characteristics of a composite produced through emulsion polymerization using common raw materials for electrophotographic toner production.
Design/methodology/approach
Emulsion polymerization provides the possibility to optimize the physical and color properties of the final products. Response surface methodology (RSM) was used to optimize variables affecting particle size (PS), PS distribution (PSD), glass transition temperature (Tg°C), color properties (ΔE) and monomer conversion. Box–Behnken experimental design with three levels of styrene and butyl acrylate monomer ratios, carbon black pigment and sodium dodecyl sulfate surfactant was used for RSM optimization. Additionally, thermogravimetric analysis and surface morphology of composite particles were examined.
Findings
The results indicated that colorants with small PS, narrow PSDs, spherical shape morphology, acceptable thermal and color properties and a high percentage of conversion could be easily prepared by optimization of material parameters in this method. The anticipated outcome of the present inquiry holds promise as a guiding beacon toward the realization of electrographic toner of superior quality and exceptional efficacy, a vital factor for streamlined mass production.
Originality/value
To the best of the authors’ knowledge, for the first time, material parameters were evaluated to determine their impact on the characteristics of emulsion polymerized toner composites.
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Abstract
Purpose
The purpose of this paper is to investigate the effects of multi‐walled carbon nanotubes (MWNTs) on the mechanical, thermal and electrical conductivity properties of polyurethane (PU) by in situ polymerisation of MWNTs and PU.
Design/methodology/approach
A number of analytical techniques, including Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy, were employed to assess the effects of acid treatment on MWNTs. The mechanical and thermal properties of PU, MWNTs and PU composites were characterised using a tensile tester machine and dynamic mechanical analysis. The electoral conductivity properties of the materials were characterised by ohmmeter.
Findings
It was found that desirable modifications to MWNTs occurred after acid treatment, thus mainly carboxylic acid groups were introduced onto the surface of MWNTs. And the acid‐treated MWNTs could improve the mechanical, thermal and electrical conductivity properties of PU by in situ polymerisation of MWNTs and PU successfully.
Practical implications
The investigation established a method to synthesise MWNTs and PU composites by in situ polymerisation. The mechanical, thermal and electrical conductivity properties of PU could be improved by the inclusion of MWNTs.
Originality/value
The paper establishes a method to synthesise MWNTs and PU composites by in situ polymerisation; and the effects of MWNTs on modifying mechanical, thermal and electrical conductivity properties of PU by in situ polymerisation are investigated in detail.
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Arthur de Carvalho Cruzeiro, Leonardo Santana, Danay Manzo Jaime, Sílvia Ramoa, Jorge Lino Alves and Guilherme Mariz de Oliveira Barra
This study aims to evaluate in situ oxidative polymerization of aniline (Ani) as a post-processing method to promote extrusion-based 3D printed parts, made from insulating…
Abstract
Purpose
This study aims to evaluate in situ oxidative polymerization of aniline (Ani) as a post-processing method to promote extrusion-based 3D printed parts, made from insulating polymers, to components with functional properties, including electrical conductivity and chemical sensitivity.
Design/methodology/approach
Extrusion-based 3D printed parts of polyethylene terephthalate modified with glycol (PETG) and polypropylene (PP) were coated in an aqueous acid solution via in situ oxidative polymerization of Ani. First, the feedstocks were characterized. Densely printed samples were then used to assess the adhesion of polyaniline (PAni) and electrical conductivity on printed parts. The best feedstock candidate for PAni coating was selected for further analysis. Last, a Taguchi methodology was used to evaluate the influence of printing parameters on the coating of porous samples. Analysis of variance and Tukey post hoc test were used to identify the best levels for each parameter.
Findings
Colorimetry measurements showed significant color shifts in PP samples and no shifts in PETG samples upon pullout testing. The incorporation of PAni content and electrical conductivity were, respectively, 41% and 571% higher for PETG in comparison to PP. Upon coating, the surface energy of both materials decreased. Additionally, the dynamic mechanical analysis test showed minimal influence of PAni over the dynamic mechanical properties of PETG. The parametric study indicated that only layer thickness and infill pattern had a significant influence on PAni incorporation and electrical conductivity of coated porous samples.
Originality/value
Current literature reports difficulties in incorporating PAni without affecting dimensional precision and feedstock stability. In situ, oxidative polymerization of Ani could overcome these limitations. However, its use as a functional post-processing of extrusion-based printed parts is a novelty.
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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.
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Fukang Yang, Wenjun Wang, Yongjie Yan and YuBing Dong
Polyethylene terephthalate (PET) as a fiber molding polymer is widely used in aerospace, electrical and electronic, clothing and other fields. The purpose of this study is to…
Abstract
Purpose
Polyethylene terephthalate (PET) as a fiber molding polymer is widely used in aerospace, electrical and electronic, clothing and other fields. The purpose of this study is to improve the thermal insulation performance of polyethylene terephthalate (PET), the SiO2 aerogel/PET composites slices and fibers were prepared, and the effects of the SiO2 aerogel on the morphology, structure, crystallization property and thermal conductivity of the SiO2 aerogel/PET composites slices and their fibers were systematically investigated.
Design/methodology/approach
The mass ratio of purified terephthalic acid and ethylene glycol was selected as 1:1.5, which was premixed with Sb2O3 and the corresponding mass of SiO2 aerogel, and SiO2 aerogel/PET composites were prepared by direct esterification and in-situ polymerization. The SiO2 aerogel/PET composite fibers were prepared by melt-spinning method.
Findings
The results showed that the SiO2 aerogel was uniformly dispersed in the PET matrix. The thermal insulation coefficient of PET was significantly reduced by the addition of SiO2 aerogel, and the thermal conductivity of the 1.0 Wt.% SiO2 aerogel/PET composites was reduced by 75.74 mW/(m · K) compared to the pure PET. The thermal conductivity of the 0.8 Wt.% SiO2 aerogel/PET composite fiber was reduced by 46.06% compared to the pure PET fiber. The crystallinity and flame-retardant coefficient of the SiO2 aerogel/PET composite fibers showed an increasing trend with the addition of SiO2 aerogel.
Research limitations/implications
The SiO2 aerogel/PET composite slices and their fibers have good thermal insulation properties and exhibit good potential for application in the field of thermal insulation, such as warm clothes. In today’s society where the energy crisis is becoming increasingly serious, improving the thermal insulation performance of PET to reduce energy loss will be of great significance to alleviate the energy crisis.
Originality/value
In this study, SiO2 aerogel/PET composite slices and their fibers were prepared by an in situ polymerization process, which solved the problem of difficult dispersion of nanoparticles in the matrix and the thermal conductivity of PET significantly reduced.
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Muneer Umar, Michael Ikpi Ofem, Auwal Sani Anwar and Abubakar Garba Salisu
This study aims to fabricate and study the effect of five cumulative graphite (G) and graphite nanoplatelets (GNP) filler loading composites by polymerising PA6 precursor; monomer…
Abstract
Purpose
This study aims to fabricate and study the effect of five cumulative graphite (G) and graphite nanoplatelets (GNP) filler loading composites by polymerising PA6 precursor; monomer epsilon caprolactam with the two carbons in situ while taking cognisance of the mixing effects (simultaneous stirring and sonication at varying amplitudes and duration). Different aspect ratios will be used to model the two streams of polymerisations.
Design/methodology/approach
High viscosity extrusion grade PA6 and synthetic G of less than 2 µm particle size were used as fillers. GNP and G are dried for 6 h in vacuum oven at 90°C. Prior to in situ polymerisation, probe sonication was applied to disperse fillers in molten ɛ-caprolactam, the PA6 monomer. Five carbon loadings were made, that is 5–25 Wt.% for G and 0.5–2.5 Wt.% for GNP composites. Two different sonification regimes were applied 20% sonication amplitude for 20 min (20/20) and 40% sonication amplitude for 10 min (40/10).
Findings
Better tensile properties were achieved using the 20/20 processing streams for both G and GNP. The G- and the GNP-based composites systems of the 20/20 processing stream had tensile modulus and yield strength retained or improved above the unfilled PA6 value. The highest modulus obtained in the 20/20 streams are 1,878 and 1,201 MPa, respectively, for GNP and G at the highest loading levels, while the 40/10 processing streams had 963 and 1,247 MPa, respectively, for the GNP and G.
Originality/value
To the best of the authors’ knowledge, nobody has ever used sonification amplitude to compare mechanical properties.
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