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1 – 10 of over 1000
Article
Publication date: 6 March 2009

Pieter Samyn and Tony M. Tuzolana

The purpose of this paper is to verify, experimentally, the sliding stability of cast polyamide samples under dry sliding in contact with different steel counterface roughnesses…

Abstract

Purpose

The purpose of this paper is to verify, experimentally, the sliding stability of cast polyamide samples under dry sliding in contact with different steel counterface roughnesses. The effect of catalyser (sodium or magnesium) and addition of internal oil or solid lubricants is investigated and a classification for coefficients of friction in relation to the polyamide intrinsic mechanical properties is discussed.

Design/methodology/approach

A new tribotester is designed for meso‐scale testing according to the elastic loading region of polymers. The reliability of the tribotester is verified by preliminary determination of the stick‐slip characteristics. Sliding tests for polyamide are done at 1.15‐5.15 N normal load and 0.125‐20 mm/s sliding velocity on steel counterfaces with roughness Ra=4 and 1.6 μm.

Findings

Pure polyamides sliding against rough steel show severe stick‐slip. The stick‐slip motion is eliminated in contact with smooth steel counterfaces. Magnesium catalysed polyamide has weaker mechanical properties and shows lower friction with better sliding stability compared to sodium catalysed polyamide. Internal oil lubricant is more efficient in reducing coefficients of friction than internal solid lubricants are. Surface energy measurements are related to coefficients of friction, showing the effect of internal lubrication on adhesion.

Research limitations/implications

Present test results are very specific for the present tribotester configuration and should be further compared to macro‐scale testing. The choice of tribotest conditions strongly affects the sliding performance.

Originality/value

Present tests are done on the meso‐scale, being in between traditional macro‐scale testing and nano‐scale testing. It allows for low contact pressures avoiding the effects of frictional heating and relatively large surfaces areas including the effects of long‐range polymer structure such as internal lubrication.

Details

Industrial Lubrication and Tribology, vol. 61 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 20 October 2020

Lamiaa Kamal El-Gabry, Mohamed Fathy Nasr and Amira Adel Abou El-Kheir

This work aims to increase the dyeability of nylon 6 with basic dyeing through the treatment of the fibre with available and cheap nanomaterials, namely; nano bentonite using an…

Abstract

Purpose

This work aims to increase the dyeability of nylon 6 with basic dyeing through the treatment of the fibre with available and cheap nanomaterials, namely; nano bentonite using an economic and simple method.

Design/methodology/approach

Different amounts of nano clay, namely, nano bentonite were dispersed in distilled water using an ultrasonic homogenizer for 1 h. Nylon fabrics were treated with different concentrations of dispersed nano bentonite (1%, 2%, 3%, 4%, 5% wt/v). After half an hour, the samples were padded using SVETEMA laboratory padding system. The padding pressure was adjusted at 3 bar to allow a pickup of 100%. The padded samples were dried at 80°C for 5 min and cured at 160°C for 3 min using ROACHES laboratory thermos-fixation. The cured samples were then washed with running water and left to dry at room temperature.

Findings

The obtained results indicated that the modification of polyamide 6 fibres with nano bentonite had a great impact on their dyeing properties. The obtained shades, absorption behaviour and fastness properties were significantly enhanced. Based on these results, it was concluded that polyamide fabrics could be successfully dyed with basic dyes using economical dyeing conditions.

Originality/value

This paper introduces a new method the loaded the nano-clay on the synthetic fibres, which are nylon 6 to enhance the dyeability with cationic dyes using the physical method without changing the structure of the fibres.

Details

Research Journal of Textile and Apparel, vol. 25 no. 1
Type: Research Article
ISSN: 1560-6074

Keywords

Article
Publication date: 30 September 2013

Mengqi Yuan, Timothy T Diller, David Bourell and Joseph Beaman

The purpose of this paper is to acquire thermal conductivities of both fresh and preheated polyamide 12 powder under various conditions to provide a basis for effective and…

Abstract

Purpose

The purpose of this paper is to acquire thermal conductivities of both fresh and preheated polyamide 12 powder under various conditions to provide a basis for effective and accurate control during the laser sintering (LS) process.

Design/methodology/approach

A Hot Disk® TPS 500 thermal measurement system using a transient plane source (TPS) technology was employed for thermal conductivity measurements. Polyamide 12 powder was packed at different densities, and different carrier gases were used. Tests were also performed on fully dense laser sintered polyamide 12 to establish a baseline.

Findings

Polyamide 12 powder thermal conductivity varies with packing density and temperature, which is approximately one-third bulk form thermal conductivity. Inter-particle bonding is the primary factor influencing polyamide 12 thermal conductivity.

Research limitations/implications

Limited ranges of density were tested, and the carrier gas needed carefully control to prevent powder oxidation. Thermal properties obtained were not tested in the LS process.

Originality/value

This experimental result could be used to enhance thermal control during the LS process.

Details

Rapid Prototyping Journal, vol. 19 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 7 June 2019

Adam Gnatowski, Agnieszka Kijo-Kleczkowska, Rafał Gołębski and Kamil Mirek

The issues concerning the prediction of changes in properties of polymer materials as a result of adding reinforcing fibers are currently widely discussed in the field of polymer…

Abstract

Purpose

The issues concerning the prediction of changes in properties of polymer materials as a result of adding reinforcing fibers are currently widely discussed in the field of polymer material processing. This paper aims to present strengths and weaknesses of composites based on polymer materials strengthened with fibers. It touches upon composite cracking at the junction of a matrix and its reinforcement. It also discusses the analysis of changes in properties of chosen materials as a result of adding reinforcing fibers. The paper shows improvement in the strength of polymer materials with fiber addition, which is extremely important, because these types of composites are used in the aerospace, automotive and electrical engineering industries.

Design/methodology/approach

Comparing the properties of matrix strength with fiber properties is practically impossible. Thus, fiber tensile strength and composite tensile strength shall be compared (González et al., 2011): tensile (glass fiber GF) = 900 [MPa], elongation ΔL≈ 0; yield point (polyamide 66) = 70−90 [MPa], elongation Δ[%] = 3,5-18; tensile (polyamide 66 + 15% GF) = 80-125 [MPa], elongation Δ[%] ≈ 0; tensile (polyamide 66 + 30% GF) = 190 [MPa], elongation Δ[%] ≈ 0; yield point (polyamide 6) = 45-85 [MPa], elongation Δ[%] = 4-15; tensile (polyamide 6 + 15% GF) = 80-125 [MPa], elongation Δ[%] ≈ 0; tensile (polyamide 6 + 30% GF) = 95-130 [MPa] elongation Δ[%] ≈ 0. Comparison of properties of selected polymers and composites is presented in Tables 1−10 and Figures 1 and 2. The measurement methodology is presented in detail in the paper Kula et al. (2018). The increase in fiber content (to the extent discussed) leads to the increase in yield strength stresses and hardness. The value of yield strength for polyamide with the addition of fiberglass grows gradually with the increase in fiber content. The hardness of the composite of polyamide with glass balls increases together with the increase in reinforcement content. The changes of these values do not occur linearly. The increase in fiber content has a slight impact on density change (the increase of about 1 g/mm3 per 10 per cent).

Findings

The use of polymers as a matrix allows to give composites features such as: lightness, corrosion resistance, damping ability, good electrical insulation and thermal and easy shaping. Polymers used as a matrix perform the following functions in composites: give the desired shape to the products, allow transferring loads to fibers, shape thermal, chemical and flammable properties of composites and increase the possibilities of making composites. Fiber-reinforced polymer composites are the effect of searching for new construction materials. Glass fibers show tensile strength, stiffness and brittleness, while the polymer matrix has viscoelastic properties. Glass fibers have a uniform shape and dimensions. Fiber-reinforced composites are therefore used to increase strength and stiffness of materials. Polymers have low tensile strength, exhibit high deformability. Polymers reinforced by glass fiber have a high modulus of elasticity and therefore provide better the mechanical properties of the material. Composites with glass fibers do not exhibit deformations in front of cracking. An increase in the content of glass fiber in composites increases the tensile strength of the material. Polymers reinforced by glass fiber are currently one of the most important construction materials and are widely used in the aerospace, automotive and electro-technical industries.

Originality/value

The paper presents the test results for polyethylene composites with 25 per cent and 50 per cent filler coming from recycled car carpets of various car makes. The tests included using differential scanning calorimetry, testing material hardness, material tensile strength and their dynamic mechanical properties.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 4 July 2016

A. Shams Nateri, E. Dehnavi, A. Hajipour and E. Ekrami

The aim of the paper was to study the effects of mordanting methods on the absorption behaviour of cochineal natural dye on polyamide fibres.

Abstract

Purpose

The aim of the paper was to study the effects of mordanting methods on the absorption behaviour of cochineal natural dye on polyamide fibres.

Design/methodology/approach

Iron sulphate and aluminium potassium sulphate salts were used as mordanting agents, and bottom mordanting, meta-mordanting and after mordanting methods were applied in the dyeing of polyamide samples with the cochineal natural dye. Colourimetric evaluations were carried out, and the principal component analysis was used to investigate the spectrophotometric properties of the dyed samples. Fastness properties of the dyed samples were also assessed.

Findings

The obtained results indicate that the method of mordanting has a great effect on the obtained shades, absorption behaviour and fastness properties. Based on the results, it was concluded that polyamide fabrics could be successfully dyed with cochineal and combination of dyeing with different mordanting methods, and different mordanting agents would develop the range of obtainable shades.

Originality/value

The textile and apparel industries have been widely criticised for their role in polluting the environment. So, the use of synthetic dyes has been limited and the use of natural dyes has increased. The literature survey indicates that there have been relatively few works investigating the dyeing of polyamide with cochineal natural dye. This research studies the effects of mordanting methods and mordant types on colourimetric and fastness properties of cochineal-dyed polyamide samples.

Details

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

Keywords

Article
Publication date: 1 February 2008

S.A. Shama, M.M. El-Molla, Riad F. Basalah and S. El-Sayed Saeed

Disappearing ink was prepared using different concentrations of thymolphthalein, phenolphthalein and their mixture, applying to different types of handwriting surfaces such as…

Abstract

Disappearing ink was prepared using different concentrations of thymolphthalein, phenolphthalein and their mixture, applying to different types of handwriting surfaces such as cotton, polyester and polyamide. The effects of thymolphthalein, phenolphthalein and alkali concentrations (i.e. pH) on the fading time were studied. The handwriting stability increased when the concentration of thymolphthalein or phenolphthalein was increased. At a high concentration of alkali with phenolphthalein and its mixture with thymolphthalein, the handwriting stability decreased with polyester or polyamide handwriting surfaces and the stability increased in the case of cotton. When the faded handwriting surfaces were subject to the thermal effect in a thermostatically controlled oven at 100°C for 10 minutes by hanging them with suitable hooks, there was no change in the faded handwriting. When they were at 150°C for 20 minutes, the faded phenolphthalein ink, which contained 0.5ml of 1N NaOH, was visible and shown red on the polyester and polyamide handwriting surfaces, but there was no change on the faded cotton handwriting surface.

Details

Research Journal of Textile and Apparel, vol. 12 no. 1
Type: Research Article
ISSN: 1560-6074

Keywords

Article
Publication date: 1 April 1997

Jean‐Louis Pey

The wide range of steel pipe sections with complex geometry, as well as that of their cast iron components (fittings, valves and pumps) poses a real problem to installation…

Abstract

The wide range of steel pipe sections with complex geometry, as well as that of their cast iron components (fittings, valves and pumps) poses a real problem to installation designers who must achieve a consistent level of long‐term corrosion resistance. In that case, Rilsan, Polyamide 11 coating gives the opportunity to engineering companies and subcontractors who are concerned both with the corrosion protection of pipes and with the quality of drinking water supplies to solve complex problems, such as the pipes which equip water treatment, purification and pumping stations. The application of specification and standards such as WIS 4‐52‐01(*) and NF A 49713 is the key for a long‐term solution.

Details

Anti-Corrosion Methods and Materials, vol. 44 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 12 November 2020

James Robert Wingham, Maha Omran, Joanna Shepherd and Candice Majewski

The use of laser sintering (LS) in the medical sector has increased dramatically in recent years. With the move towards direct use of these parts in clinical applications, there…

Abstract

Purpose

The use of laser sintering (LS) in the medical sector has increased dramatically in recent years. With the move towards direct use of these parts in clinical applications, there is a greater need to understand the effects of standard processes on the part properties. The purpose of this study is to determine the effect that steam sterilisation has on the mechanical properties of LS polyamide 12 parts.

Design/methodology/approach

The research presented here focusses on the effect of a single steam sterilisation cycle on the mechanical properties of polyamide 12 parts manufactured using LS. The influence of water content on the properties was investigated, with additional drying steps trialled to establish the potential to reverse any changes observed and to determine their root cause.

Findings

The results show that steam sterilisation has a significant effect on the mechanical properties of LS polyamide 12 parts, with a 39% reduction in elastic modulus, a 13% decrease in ultimate tensile strength and a 64% increase in the elongation at break. These properties were also all found to correlate with the water content, suggesting that this was the cause of the difference. The original properties of the parts were able to be recovered after oven drying.

Practical implications

These results show that with an additional drying step, LS polyamide 12 parts can be steam sterilised with no effect on the mechanical properties.

Originality/value

This is believed to be the first investigation into the effects of steam sterilisation in isolation on LS polyamide 12 parts, the first instance of drying parts to recover mechanical properties and the first instance of multiple water content measurements being directly linked to the mechanical properties.

Details

Rapid Prototyping Journal, vol. 27 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 27 February 2009

Bengi Kilic, Aysun Cireli Aksit and Mehmet Mutlu

Plasma polymerization is a very promising technique to produce functional textile materials for any textile end uses as well as for high performance clothing. It can be possible…

Abstract

Purpose

Plasma polymerization is a very promising technique to produce functional textile materials for any textile end uses as well as for high performance clothing. It can be possible to obtain highly cross‐linked, pinhole free and very thin polymer films up to 1 μm thickness with unique physical and chemical properties. These films can be used as very effective barriers. The purpose of this paper is to investigate the influences of plasma polymerization of hexamethyldisilane (HMDS) and hexamethyldisiloxane (HMDSO) on the surface properties of cotton and polyamide fabrics.

Design/methodology/approach

The methodology is based on the surface modification of the cotton and polyamide fabrics by plasma polymerization of HMDS and HMDSO. The fabrics are modified by low pressure low temperature RF (radio frequency −13.56 MHz) plasma polymerization system under different power and time conditions. The changes in surface structure and morphology of the fabrics are investigated by Fourier transform infrared spectroscopy‐attenuated total reflectance (FTIR‐ATR) analysis and atomic force microscopy (AFM).

Findings

Water repellency of polyamide fabrics is strongly enhanced after plasma polymerization of both HMDS and HMDSO monomers. In addition to this, the treatments are found to slow down the vertical flame spread in cotton fabrics.

Originality/value

Increased water repellency and decreased vertical flame spread are achieved using plasma polymerization technique in a very short time with very little amount of chemical and without water and auxiliary agent.

Details

International Journal of Clothing Science and Technology, vol. 21 no. 2/3
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 15 June 2015

Mengqi Yuan and David L. Bourell

The purpose of this paper is to report selected optical properties of laser sintered polyamide 12 blank plates under different monochromatic and white light conditions and to…

Abstract

Purpose

The purpose of this paper is to report selected optical properties of laser sintered polyamide 12 blank plates under different monochromatic and white light conditions and to apply these properties in production of laser sintered lithophanes.

Design/methodology/approach

A UNICO 1201E spectrophotometer was used to measure the transmittance of laser sintered polyamide 12 plates as a function of plate thickness. Monochromatic light-emitting diodes were used to assess the wavelength dependence on the transmission and contrast as captured by a SONY DSC-W55 camera.

Findings

The transmittance decreased with increasing plate thickness which varied significantly depending on the monochromatic wavelength. Highest transmission was observed using green light (525 nm) and poorest transmission was measured for yellow light (589 nm).

Research limitations/implications

There is a limit to the amount of contrast obtained in polyamide lithophanes because the thickness of the plates is limited to less than about 5 mm. Greater thickness results in discernible topology on the lithophane which impairs the quality of the image.

Originality/value

Light transmittance of polyamide 12 plates under different lighting conditions is reported and applied to optically defined laser sintered lithophanes.

Details

Rapid Prototyping Journal, vol. 21 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

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