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Article
Publication date: 4 January 2013

Mazeyar Parvinzadeh Gashti, Mohammad Yousefpour Navid and Mohammad Hossein Rahimi

Silicone softeners are widely used in the textile industry to improve the performance of textile products. The thermal characteristics and flammability of polyester…

Abstract

Purpose

Silicone softeners are widely used in the textile industry to improve the performance of textile products. The thermal characteristics and flammability of polyester fabrics can be influenced by these compounds, which need to be considered, as important issues of human safety. The purpose of this paper is to investigate the changes induced on the polyester fibre by silicone softener treatment using a pad/dry/cure method.

Design/methodology/approach

The fibres were first treated with nano‐ and microemulsion silicone softeners. The influence of the silicone emulsion type on thermal properties and flammability of the resultant samples were investigated by various analytical techniques, namely, the differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), dynamical mechanical thermal analysis (DMTA) and horizontal flammability test (HFT).

Findings

Results showed that the silicone softeners increase the thermal degradation and flammability of the polyethylene terephthalate (PET) substrate.

Originality/value

The paper's study of thermal and flammability of the silicone‐treated sample is novel and can be used to optimize the properties of silicone polymers during production and consumption.

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Article
Publication date: 11 September 2019

Swapnil Vyavahare, Soham Teraiya, Deepak Panghal and Shailendra Kumar

Fused deposition modelling (FDM) is the most economical additive manufacturing technique. The purpose of this paper is to describe a detailed review of this technique…

Abstract

Purpose

Fused deposition modelling (FDM) is the most economical additive manufacturing technique. The purpose of this paper is to describe a detailed review of this technique. Total 211 research papers published during the past 26 years, that is, from the year 1994 to 2019 are critically reviewed. Based on the literature review, research gaps are identified and the scope for future work is discussed.

Design/methodology/approach

Literature review in the domain of FDM is categorized into five sections – (i) process parameter optimization, (ii) environmental factors affecting the quality of printed parts, (iii) post-production finishing techniques to improve quality of parts, (iv) numerical simulation of process and (iv) recent advances in FDM. Summary of major research work in FDM is presented in tabular form.

Findings

Based on literature review, research gaps are identified and scope of future work in FDM along with roadmap is discussed.

Research limitations/implications

In the present paper, literature related to chemical, electric and magnetic properties of FDM parts made up of various filament feedstock materials is not reviewed.

Originality/value

This is a comprehensive literature review in the domain of FDM focused on identifying the direction for future work to enhance the acceptability of FDM printed parts in industries.

Details

Rapid Prototyping Journal, vol. 26 no. 1
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 4 July 2016

Abhishek Das and Gautam Sarkhel

The purpose of this paper is to study the effect of various stoichiometric ratios for synthesised epoxy phenolic novolac (EPN) resins on their physicochemical…

Abstract

Purpose

The purpose of this paper is to study the effect of various stoichiometric ratios for synthesised epoxy phenolic novolac (EPN) resins on their physicochemical, thermomechanical and morphological properties.

Design/methodology/approach

In the present study, EPN (EPN-1, EPN-2, EPN-3, EPN-4 and EPN-5) resins were synthesised by varying five types of different stoichiometric ratios for phenol/formaldehyde along with the corresponding molar ratios for novolac/epichlorohydrin. Their different physicochemical properties of interest, thermomechanical properties as well as morphological properties were studied by means of cured samples with the variation of its stoichiometric ratios.

Findings

The average functionality and reactivity of EPN resin can be controlled by controlling epoxy equivalence as well as cross-linking density upon its curing as all of these factors are internally correlated with each other.

Research limitations/implications

Epoxy resins are characterised by a three-membered ring known as the epoxy or oxirane group. The capability of the epoxy ring to react with a variety of substrates imparts versatility to the resin. However, these resins have a major drawback of low toughness, and they are also very brittle, which limits their application in products that require high impact and fracture strength.

Practical implications

Epoxy resins have been widely used as high-performance adhesives and matrix resins for composites because of their outstanding mechanical and thermal properties. Because of their highly cross-linked structure, the epoxy resin disables segmental movement, making them hard, and it is also notch sensitive, having very low fracture energy.

Social implications

Epoxy resin is widely used in industry as protective coatings and for structural applications, such as laminates and composites, tooling, moulding, casting, bonding and adhesives.

Originality/value

Systematic study has been done for the first time, as no exact quantitative stoichiometric data for the synthesis of EPN resin were available on the changes of its different properties. Thus, an optimised stoichiometric composition for the synthesis of the EPN resin was found.

Details

Pigment & Resin Technology, vol. 45 no. 4
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 30 May 2019

Pooria Khalili, Xiao Ling Liu, Kim Yeow Tshai, Ing Kong, Chris Rudd and Xiao Su Yi

The purpose of this paper is to fabricate and characterize the natural fibre (NF) reinforced epoxy composites containing flame retardants (FRs) and microcrystalline…

Abstract

Purpose

The purpose of this paper is to fabricate and characterize the natural fibre (NF) reinforced epoxy composites containing flame retardants (FRs) and microcrystalline cellulose (MCC) in terms of flammability, thermal properties and dynamic mechanical performances.

Design/methodology/approach

The FRs used in this study were ammonium polyphosphate and alumina trihydrate.

Findings

The results demonstrated that the addition of MCC particles into the flame retardant composite (control) further enhanced the self-extinguishing properties of composites, in particular, the burn length. Thermogravimetric analysis showed that the mass residue improved with every addition of MCC particles at 700 °C. For instance, the residual weight enhanced from 28.4 Wt.% to 33 Wt.% for the control and the composite with 7 Wt.% MCCs, respectively. As obtained from the dynamic mechanical analysis, the glass transition temperature of composites increased upon increasing inclusion of MCC particles. For example, this parameter was 77.1 °C and 86.8 °C for the control and composite loaded with 7 Wt.% MCC, respectively.

Originality/value

Thus, the combination of MCC and FR had been proved to be a promising flame retardant system for NF reinforced epoxy.

Details

World Journal of Engineering, vol. 16 no. 3
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 7 September 2015

Lilan Gao, Hong Gao and Xu Chen

This review paper aims to provide a better understanding of formulation and processing of anisotropic conductive adhesive film (ACF) material and to summarize the…

Abstract

Purpose

This review paper aims to provide a better understanding of formulation and processing of anisotropic conductive adhesive film (ACF) material and to summarize the significant research and development work for the mechanical properties of ACF material and joints, which helps to the development and application of ACF joints with better reliability in microelectronic packaging systems.

Design/methodology/approach

The ACF material was cured at high temperature of 190°C, and the cured ACF was tested by conducting the tensile experiments with uniaxial and cyclic loads. The ACF joint was obtained with process of pre-bonding and final bonding. The impact tests and shear tests of ACF joints were completed with different aging conditions such as high temperature, thermal cycling and hygrothermal aging.

Findings

The cured ACF exhibited unique time-, temperature- and loading rate-dependent behaviors and a strong memory of loading history. Prior stress cycling with higher mean stress or stress amplitude restrained the ratcheting strain in subsequent cycling with lower mean stress or stress amplitude. The impact strength and adhesive strength of ACF joints increased with increase of bonding temperature, but they decreased with increase of environment temperature. The adhesive strength and life of ACF joints decreased with hygrothermal aging, whereas increased firstly and then decreased with thermal cycling.

Originality/value

This study is to review the recent investigations on the mechanical properties of ACF material and joints in microelectronic packaging applications.

Details

Soldering & Surface Mount Technology, vol. 27 no. 4
Type: Research Article
ISSN: 0954-0911

Keywords

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Article
Publication date: 5 May 2015

Haibao Lu, Yongtao Yao, Shipeng Zhu, Yunhua Yang and Long Lin

The purpose of this paper is a study aimed at overcoming the interface issue between nanopaper and polymer matrix in shape-memory polymer (SMP) composite laminates caused…

Abstract

Purpose

The purpose of this paper is a study aimed at overcoming the interface issue between nanopaper and polymer matrix in shape-memory polymer (SMP) composite laminates caused by their large dissimilarity in electrical/thermal conductive properties. The study attempted to develop an effective approach to fabricate free-standing carbon nanofibre (CNF) assembly in octagon shape formation. The structure design and thermal conductive performance of the resulting octagon-shaped CNF assembly were optimised and simulated.

Design/methodology/approach

The CNF nanopaper was prepared based on a filtration method. The SMP nanocomposites were fabricated by incorporating these CNF assemblies with epoxy-based SMP resin by a resin-transfer modelling technique. Thermal conductivity of the octagon-shaped CNF assembly was simulated using the ANSYS FLUENT software for structure design and optimisation. The effect of the octagon-shaped CNF on the thermomechanical properties and thermally responsive shape-memory effect of the resulting SMP nanocomposites were characterised and interpreted.

Findings

The CNF template incorporated with SMP to achieve Joule heating triggered shape recovery at a low electric voltage of 3-10 V, due to which the electrical resistivity of SMP nanocomposites was significantly improved and lowered to 0.20 O·cm by the CNF template. It was found that the octagon CNF template with 2 mm width of skeleton presented a highest thermally conductive performance to transfer resistive heat to the SMP matrix.

Research limitations/implications

A simple way for fabricating electro-activated SMP nanocomposites has been developed by using an octagon CNF template. Low electrical voltage actuation in SMP has been achieved.

Originality/value

The fabricated CNF template, the structure design and analysis of dynamic thermomechanical properties of SMP are novel.

Details

Pigment & Resin Technology, vol. 44 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 2 January 2018

Dario Puppi, Alessandro Pirosa, Andrea Morelli and Federica Chiellini

The purpose of this paper is to describe the fabrication and characterization of poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyexanoate] (PHBHHx) tissue engineering scaffolds…

Abstract

Purpose

The purpose of this paper is to describe the fabrication and characterization of poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyexanoate] (PHBHHx) tissue engineering scaffolds with anatomical shape and customized porous structure.

Design/methodology/approach

Scaffolds with external shape and size modeled on a critical size segment of a rabbit’s radius model and an internal macrochanneled porous structure were designed and fabricated by means of a computer-aided wet-spinning (CAWS) technique. Morphological, thermal and mechanical characterization were carried out to assess the effect of the fabrication process on material properties and the potential of the PHBHHx scaffolds in comparison with anatomical star poly(e-caprolactone) (*PCL) scaffolds previously validated in vivo.

Findings

The CAWS technique is well suited for the layered manufacturing of anatomical PHBHHx scaffolds with a tailored porous architecture characterized by a longitudinal macrochannel. Morphological analysis showed that the scaffolds were composed by overlapping layers of microfibers with a spongy morphology, forming a 3D interconnected network of pores. Physical-chemical characterization indicated that the used technique did not affect the molecular structure of the processed polymer. Analysis of the compressive and tensile mechanical properties of the scaffolds highlighted the anisotropic behavior of the porous structure and the effect of the macrochannel in enhancing scaffold compressive stiffness. In comparison to the *PCL scaffolds, PHBHHx scaffolds showed higher compressive stiffness and tensile deformability.

Originality/value

This study shows the possibility of using renewable microbial polyester for the fabrication of scaffolds with anatomical shape and internal architecture tailored for in vivo bone regeneration studies.

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Article
Publication date: 1 November 1985

J Boxall

Paints are dynamic systems which are in an almost constant state of change throughout their whole life. These changes are evident from the time of manufacture and…

Abstract

Paints are dynamic systems which are in an almost constant state of change throughout their whole life. These changes are evident from the time of manufacture and througout storage when the liquid paint can undergo major rheological changes due to binder adsorption, crosslinking or, with waterborne systems, biological attack, as well as associated problems such as pigment instability. When in service the dried film also exhibits progressive changes. These occur in both surface properties by erosion, loss of gloss colour change, and also in bulk properties by, for example, embrittlement. Both are often due to structural changes within the cured film and can be due to a variety of external causes such as solar radiation, oxidation or chemical attack.

Details

Pigment & Resin Technology, vol. 14 no. 11
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 7 November 2016

Abolfazl Darvish, Reza Naderi and Mohammad Reza Mohammadzadeh Attar

This research aims to provide a comparative study of the effect of conventional zinc phosphate (ZP) and zinc aluminium phosphate (ZPA) representing second generation of…

Abstract

Purpose

This research aims to provide a comparative study of the effect of conventional zinc phosphate (ZP) and zinc aluminium phosphate (ZPA) representing second generation of phosphate-based anticorrosion pigments on the protective performance and physical mechanical properties of a solvent-borne polyurethane (PU) coating.

Design/methodology/approach

The two pigments were incorporated into the coating at optimum pigment volume concentration. To evaluate the protective performance, electrochemical impedance spectroscopy (EIS) was used. The effect of modification of ZP on the physical–mechanical properties of the coatings was studied through dynamic mechanical thermal analysis. Moreover, Micro Vickers hardness and pull-off tests were used to evaluate the hydrolytic coating degradation.

Findings

EIS revealed the superior protective function of coatings incorporated with ZPA compared to those formulated with ZP. This behaviour might be attributed to the release of sufficient inhibiting species because of partial dissolving of the anticorrosive pigments when an electrolyte penetrates into the coating. In addition, the effectiveness of modification of ZP on the physical–mechanical properties of coatings was shown.

Research limitations/implications

As a classical replacement for the toxic chromates, ZP has been widely used in the formulation of protective coatings. However, undesirable inhibitive function of the pigment arising from its low solubility has made modification necessary. Because of the modified solubility, second generation of phosphate-based anticorrosion pigments has been reported to reveal superior performance.

Originality/value

According to the literature, no report can be found studying the effect of the second generation of phosphate-based anticorrosion pigments on the physical–mechanical properties of PU coatings. The main goal of this work is to study the correlation between physical–mechanical properties and anticorrosion performance of the PU coatings.

Details

Pigment & Resin Technology, vol. 45 no. 6
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 10 July 2019

Adam Gnatowski and Agnieszka Kijo-Kleczkowska

The main purpose of polymeric mixtures manufacturing is wish to eliminate or reduce drawbacks which polymers are characterised by and also to strive for reduction of the…

Abstract

Purpose

The main purpose of polymeric mixtures manufacturing is wish to eliminate or reduce drawbacks which polymers are characterised by and also to strive for reduction of the price of expensive polymers with particular very precious properties by mixing them with cheaper polymers but without significant deterioration of their properties. In the work some investigation results have been presented for PA6 which is miscible in viscoelastic state with polymer, with ability to create physical bounds with substances of inorganic as well as organic origins. For this purpose, polyvinylpyrrolidone (PVP) has been used with law molecular weight (10 ± 2,5 thousand). The functionalactive material was prepared with sharp tuning sorption ability across physical modification polycapramide mixed from bipolar polyvinylpyrrolidone in batch – free state, which characterises high ability complex. In the paper, some results of chosen properties of PA with the addition of polyvinylpyrrolidone (PVP) have been presented. In chance of mixing PA6 with PVP forms solution PVP in PA6, to which proper are large intermolecular influence, in this case hydrogen bond. It is possible to foresee that under the influences of large tangent stresses and intermolecular interaction colloidal solution PVP in PA forms with sure homogeneity, after cooling of it the inversion of winding phases is not noticeable In the mixtures on the basis of such polymers the intermolecular interactions occur, and they differently influence parameters of the modified materials. Conducted investigations have proved opportunity of physical modification of PA6 during mixing, in viscoelastic state, with polyvinylpyrrolidone. The modified polymer has dielectric properties and a reduced susceptibility to water absorption. It can be used as an insulation material, in all industrial sectors, including the energy sector.

Design/methodology/approach

For examinations, the following mixtures were made out: PA 99%/PVP 1%, PA 98%/PVP 2%, PA 90%/PVP 10%. Making mixtures out was begun with weighing elements out on numerical Sortorius AG GO TTINGEN scales and CAS MODEL: SW-1 (PA, PVP). Next elements of mixture were mixed with themselves mechanically. The process of drying was carried out in the ZELMET drier with the thermal kc-100/200 chamber in the temperature 80 °C for 12 h. The process of mixing up was carried out in the arrangement plasticising injections moulding machine of the voluted KRAUSS MAFFEI company KM 65-1600C1 (D screw = 30 mm and the L = 27D, the nozzle about d = 4 mm and the l = 2d) at the following parameters: is the nozzle temperature 230 °C, the speed of turnovers of the screw 210 obr/min. Granulated product of mixtures were get on the rotor grinder. Samples for examinations were made on the computer-operated injection moulding machine of type of KM 65-1600C1 of the KRAUSS MAFFEI company. The conditions which complement the homogeneity of a mixture – these include mixing processes with high shear stresses with the range of temperatures for viscoelastic state for the individual polymers. Such conditions are met by multiple mixing in the injection machine cylinder with extended perpetual screw length (L/D = 25 ÷ 42). Permanent conditions of injecting samples for the research on physical properties were the following: nozzle temperature – 230°C; worm area I temperature – 190°C; worm area II temperature – 210°C; worm area III temperature – 230-245°C, mould temperature 40°C, injection pressure – 60 MPa, clamping time – 5 s, cooling time – 30 s The research on chosen physical properties of getting polymer materials was carried out: hardnesses on hardness testing machine, impact resistance by Charpy’s method, mechanical properties while tension over the endurance machine the INSTON with tension speed of 90 mm/min, softening point by Vicat’s method was determined using testing machine type HAAKE N8, the investigation of DSC method and DMTA method using testing machine type Netzsch, water absorbing power test. The research on the structure was also carried out on the optical microscope type NIKON ECLIPSE E200.

Findings

In the paper, for the physical modification of PA 6, the polyvinylpyrrolidone (PVP) – amorphous polymer which is capable of ionisation and creation of complexes with the transition of the charge with many electrophilic compounds and also proton donors have been used. PVP does not change into the viscoelastic state but it is easily soluble in organic and inorganic solvents and the best in water. Its characteristic is high sorption capacity. As a result of ionisation changes PVP preserve the conformation changes. In case of mixing of polar PA6 polymers with PVP, a PVP solution is being created in PA, to whom big intermolecular interactions are proper for, in it hydrogen bonds. Reducing of polarity occurs of both polymers as a result of hydrogen bonds in created macromolecules. Macromolecule so they are interfering easily in fused condition creating the mixture about reliable homogeneity. An effect is applying to mixing with PA6 in case of dissolving PVP in the PA6 stop under the influence of big adjacent tensions in screw extruder what is calling changes of the supermolecular structure and properties of the material after chilling of stop in the form during injecting. The resultant homogeneous mixture is marked by one reflex narrowed in comparison with output PA6 of melting visible on DSC thermogram with moving to the page of higher tmmax temperatures. PA6/PVP mixtures are also providing effects of examinations about the homogeneity with DMTA method which shows results that the mixture is marked by one reflex of mechanical losses on the plot from (Tg) from the maximum at bigger than PA6 Tg (about 10 ÷ 15°C), and it is possible at the same time to reason that the mixture has not very thick frictional network as a result of the exchange of intermolecular bonds what is displayed itself in the increase in Tg intensity. The results of investigations show that PA with PVP additions create more stable material with visible homogeneity (due to strong intermolecular interactions) which is characterised by satisfactory mechanical properties which insignificantly differ from PA6 properties, but which shows higher deformability and sorptive power.

Originality/value

The results of investigations show that PA with PVP additions create more stable material with visible homogeneity (due to strong intermolecular interactions) which is characterised by satisfactory mechanical properties which insignificantly differ from PA6 properties, but which shows higher deformability and sorptive power. The modified polymer has dielectric properties and a reduced susceptibility to water absorption. It can be used as an insulation material, in all industrial sectors, including the energy sector.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

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