Chemical Finishing Research Articles

Effect of Di-ammonium Hydrogen Phosphate on Jute Fabric for Fire Resistance

Over the years, technologies have been used for the development of various textile products to meet the consumer demands in different fields as per their end-use specifications. The market sustainability of each new product mainly depends on the raw material as well as its functionality. A functional finishing dictates the end-use of the products as well as enhances the life of the products. There are important historical and economic reasons for the fact that, the science and technology of flame retardant for cellulose fibres are more advanced than for other fibres and polymers. Until perhaps 25 years ago, an overwhelming proportion of all textiles used were made of cellulose fibres. Jute is one of the important natural cellulosic fibers and used for diversified product. Similar to cotton, jute fiber has the potential to impart different functionality by different chemical finishing for its diversification. This project has been taken to improve the flameproof property of jute fabrics. Jute fabrics were treated with Di-Ammonium Hydrogen Phosphate by various concentrations under certain condition. The study was conducted at the Industrial Chemistry Department, Chemistry Division, Textile Physics Division and Pilot Plant and Processing Division of Bangladesh Jute Research Institute, Dhaka, Bangladesh during 2017-2019. It was found that desized jute fabric gives the best flame proofed (Completely resistance to both after flaming and after glowing) than the sized jute fabrics without undesirable loss of the tensile strength.

Chemical surface finishing of AlSi10Mg components made by additive manufacturing

One of the most critical issues of a component realized by Additive Manufacturing is the surface quality. In particular, in case of high levels of roughness, the functionality of the component and its mechanical properties are significantly affected. Chemical finishing offers the advantage of acting on the whole surface, without the need of tools. In this preliminary work several specimen of AlSi10Mg have been treated firstly by Chemical Machining to remove the gross irregularities, followed by Chemical Brightening to further smooth the surface.The results are promising; the surface parameters analyzed indicate that the treatment improves the surface quality.

Development and performance study of a new shrink-proof and non-iron cotton blended fabric

The approaches for cotton shrink-resistant finishing can be categorized into chemical finishing and physical finishing. In this research, a new approach to prevent cotton fabric from shrinkage and wrinkling without resin finishing was studied to reach an easy care effect of “wash-and-wear” for related end products. It was achieved by adding a certain proportion of fine denier polyester and memory polyester fibers. Unlike the previous chemical finishing methods, this physical finishing method does not cause yellowing, formaldehyde content increase or strong damage of tensile strength. It can reduce the shrinkage rate and increases the wrinkle recovery angle (WRA) through the shape memory formed by the memory polyester fiber in the heat setting stage. Our results were of better condition with significant improvements in WRA, anti-pilling effect, shrink-proofing and strength of the fabrics. The fabrics can be widely used in bedding textiles and shirting fabrics.

Catalysts based on Fenton reaction for SiC wafer in chemical magnetorheological finishing

Aiming at the chemical magnetorheological finishing (CMRF) of single crystal silicon carbide (SiC) based on the Fenton reaction, concentration of hydroxyl radical produced in Fenton reaction and its influence on chemical reaction rate of SiC were detected by visible spectrophotometry, and catalytic ability of different particles was detected by the method of immersion corrosion test. The experimental results showed that surface roughness is better when the carbonyl iron powder (CIP) is used as catalyst. The lower value of pH, the higher content of hydroxyl radicals. The hydroxyl radical can react with SiC surface to form a softer SiO 2 oxide layer. The acid environment can promote Fenton reaction and the polishing effect is better, while the oxidation layer of SiC surface is converted to silicate in the alkaline environmental. The SiC after CMRF can obtain the smooth surface of the surface roughness Ra 0.0817 nm when the pH value is 9.

Mathematical Modeling of the Extraction of the Target Component from Plate-Shaped Bodies in a Semicontinuous Process

The problem on the kinetics of extraction of the target component (technological contaminant) from plate-shaped bodies in an apparatus for a semi-continuous (periodic for the solid and continuous for the liquid phase) process in which the liquid phase is completely mixed was formulated and solved analytically. The process kinetics was analyzed by the numerical method at different specific consumptions of the liquid phase. Recommendations were given on the use of the solution for calculating the kinetics of extraction of technological contaminants from textile materials during washing in the chemical finishing technology.

Thermal and surface characterization of ABS replicas made by FDM for rapid tooling applications

PurposeThis paper aims to focus on the changes in thermal and surface characteristics of acrylonitrile butadiene styrene (ABS) material when exposed to chemical vapours for surface finishing. The poor surface finish and the dimensional accuracy of the fused deposition modelling parts (of ABS material) because of the stair-stepping hinder their use for rapid tooling applications, which can be improved by vapour finishing process. The differential scanning calorimetry (DSC) tests are performed to investigate the thermal behaviour of ABS thermoplastic after vapour finishing.Design/methodology/approachThe hip prosthesis replica has been used to highlight the efficacy of chemical finishing process for intricate and complex geometries. The replicas are treated with chemical vapours for different durations. The DSC tests are performed along with surface roughness, surface hardness and dimensional measurements of exposed replicas and compared with unexposed replica.FindingsThe longer finishing time, i.e. 20 s, manifested higher melting peak temperature, higher melting enthalpy and higher heat capacity along with smoother and harder surface as compared with unexposed replica. The finishing process enhanced the bonding strength and the heat-bearing capacity of ABS material. The vapour finishing process enhanced the thermal stability of the material which may extend its sustainability at higher temperatures.Practical implicationsThe improved thermal stability of ABS thermoplastic after chemical vapour finishing has been demonstrated. This advancement allows the use of ABS in functional tooling suitable for small production runs with higher flexibility and lead time savings.Originality/valueThe heat effects associated with phase transitions as a function of temperature are studied in case of replicas finished with chemical vapours. The relationship between melting enthalpy and surface characteristics has been ascertained.

Aspects of the dimensional changes of jersey structures after knitting process

The study proposes a statistical analysis by applying a mathematical model for the study of the dimensional changes of jersey structures made of 100% cotton yarn, with 58/1 metric count of yarn. The Structures are presented as tubular knitted metrage and are designed for underwear and/or outer garments. By analysing the jersey structures, from dimensional stability point of view, there can be observed that values in the limits are within the ±2% interval, values which are considered appropriate. Following the experimental researches, there are proposed solutions for the reduction of dimensional changes on both directions of the knit, on the stich course direction and also on the stich courses in vertical direction, being analyzed the behaviour of the knitted fabrics during relaxation after knitting process. The problem of the dimensional stability of the knitted fabrics is extensive researched. The knitted structures are elastic structures, this being a reason for which dimensional stability will always be a topical theme. The jersey structures, due to the distribution of the platinum loop in the knit plane, due to the relative small number of yarn-yarn contact points that causes the threads to slide into the structure, due to the spiral of the tubular metrage structure, are among those whose dimensional stability is difficult to control. The technical characteristics of the yarns, the technical characteristics of the knitting machines and the technological parameters of the knitting machine are the elements which will be correlated in order to obtain structures with minimum dimensional changes. In order to obtain knitted structures with adequate dimensional stability, this means within ±2%, it is necessary that the dimensional changes during the relaxation periods after knitting and chemical finishing being minimum. For this, all the processes to be applied will be conducted with appropriate and uniform tensions throughout the technological flow. The relaxation periods of 72 hours should be strictly respected, folded and under standard atmospheric conditions, both after knitting and after chemical finishing. The jersey structures are plane structured made on knitting machines equiped with font. There will be analyzed the dimensional changes of the jersey structures made of 100% cotton yarn, Nm 58/1, after the relaxation after knitting process througout the corelation between the technical characteristics of the yarns, of the technological parameter of the knitting operation and of some technical characteristici of the knitting machine.

Sol-gel 3-glycidoxypropyltriethoxysilane finishing on different fabrics: The role of precursor concentration and catalyst on the textile performances and cytotoxic activity

In this paper, the influence of 3-glycidoxypropyltriethoxysilane (GPTES) based organic-inorganic coatings on the properties of treated textile fabrics was studied. All experimental results were deeply analyzed and thereafter correlated with the employed silica precursor concentration and with the presence of the BF3OEt2 (Boron trifluoride diethyl etherate), used as epoxy ring opening catalyst. SEM analysis, FT-IR spectroscopy, X-ray Photoelectron Spectroscopy (XPS), thermogravimetric analysis (TGA) and washing fastness tests of the sol-gel treated cotton fabric samples were firstly exploited in order to characterize the morphological and structural features of the achieved coatings. Finally, the influence of the resulting nanohybrid coatings was explored in terms of abrasion resistance, tensile strength and elongation properties of treated cotton, polyester and silk fabrics. The catalyst amounts seem to strongly improve the formation of coatings, but still they do not influence the wear resistance of treated textile fabrics to the same extent. Indeed, it was found that increasing catalyst/GPTES ratio leads to a more cross linked inorganic 3D-network. GPTES itself was not found to affect the bulk properties of the selected textile and the resulting coatings were not so rigid to hardly modify the mechanical properties of the treated samples. Finally, it is worth mentioning that in all case the obtained 3-glycidoxypropyltriethoxysilane-based chemical finishing have shown no cytotoxic effects on human skin cells.

High performance polymer binders inspired by chemical finishing of textiles for silicon anodes in lithium ion batteries

Inspired by the chemical finishing method for textile, theN-methylol acrylamide functionalized carboxymethyl cellulose binder has been developed for Si anodes. This binder can help maintain integration of the Si electrodes, leading to significant improvement in cycling performance of the Si based lithium ion batteries.

Surface polish of PLA parts in FDM using dichloromethane vapour

Fused deposition modelling has become one of the most diffused rapid prototyping techniques, which is widely used to fabricate prototypes. However, further application of this technology is severely limited by poor surface roughness. Thus it is necessary to adopt some operations to improve surface quality. Chemical finishing is typically employed to finish parts in fused deposition modelling (FDM). The purpose of this paper is to decrease the surface roughness for polylactic acid (PLA) parts in FDM. The chemical reaction mechanism during the treating process is analysed. Then NaOH solution and dichloromethane vapour are used to treat FDM specimens respectively. A 3D laser microscope has been applied to assess the effects in terms of surface topography and roughness. The experimental results show that treatment using dichloromethane vapour performs much better than NaOH solution. Compared with the untreated group, surface roughness obtained through vapour treatment decreases by 88 per cent. This research has been conducted to provide a better method to treat PLA parts using chemical reagents.

Preliminary study on atmospheric-pressure plasma-based chemical dry figuring and finishing of reaction-sintered silicon carbide

Reaction-sintered silicon carbide (RS-SiC) is a research focus in the field of optical manufacturing. Atmospheric-pressure plasma-based chemical dry figuring and finishing, which consist of plasma chemical vaporization machining (PCVM) and plasma-assisted polishing (PAP), were applied to improve material removal rate (MRR) in rapid figuring and ameliorate surface quality in fine finishing. Through observing the processed RS-SiC sample in PCVM by scanning white-light interferometer (SWLI), the calculated peak-MRR and volume-MRR were 0.533 μm/min and 2.78×10−3 mm3/min, respectively. The comparisons of surface roughness and morphology of the RS-SiC samples before and after PCVM were obtained by the scanning electron microscope and atomic force microscope. It could be found that the processed RS-SiC surface was deteriorated with surface roughness rms 382.116 nm. The evaluations of surface quality of the processed RS-SiC sample in PAP corresponding to different collocations of autorotation speed and revolution speed were obtained by SWLI measurement. The optimal surface roughness rms of the processed RS-SiC sample in PAP was 2.186 nm. There were no subsurface damages, scratches, or residual stresses on the processed sample in PAP. The results indicate that parameters in PAP should be strictly selected, and the optimal parameters can simultaneously obtain high MRR and smooth surface.

Impact of chemical finishing on laser-sintered nylon 12 materials

Additive Manufacturing offers many potential benefits including reduced tooling costs and increased geometric freedom. However, the surface quality of the parts is typically below that of conventionally-processed materials. This paper evaluates a new chemical post-processing method to reduce the roughness of laser-sintered Nylon 12 components. This process is called the PUSh™ process. The treatment reduced the surface roughness of sample parts from 18μm to 5μm Ra and largely eliminated roughness with length scales below 500μm. Treatment did not affect the flexural modulus, flexural strength, or dimensions of 3.2mm thick bending specimens, but it did significantly impact the mechanical properties of thin tensile specimens that are one to eight layers thick. The post processing reduced the breaking force of the samples, but it increased the ultimate tensile strength and elongation at break. The impact was largest on the thinnest parts. Significant sample shrinkage (12–20%) and weight gain (3.7–7%) from treatment was also observed in the tensile specimens. The results show that the PUSh™ process dramatically increases surface smoothness and elongation at break in thin specimens. It decreases the surface strength, but effects are negligible in larger samples.

Modeling of the chemical finishing process for polylactic acid parts in fused deposition modeling and investigation of its tensile properties

Fused deposition modeling has become one of the most diffused rapid prototyping techniques, which is widely used to fabricate prototypes. However, further application of this technology is severely affected by poor surface roughness primarily due to staircase effect. It is necessary to adopt post-treatment operations to improve surface quality. Chemical finishing is typically employed to finish parts in fused deposition modeling. The purpose of this paper is to provide a universal finishing method or solution for FDM parts made up of PLA, and to represent the evolution of surface topography between adjacent layers during the chemical finishing operation by building a geometrical model of the deposited filament. Case study was used to validate the proposed model by an experimental observation using a 3D laser scanning microscope. The comparison between theoretical computed values and observed data shows a significant reliability by means of statistical analysis. Subsequently a number of specimens are tested to determine the changes in tensile properties of fused deposition modeling parts building in different orientations. The results show that the horizontal build directions have little influence on the tensile strength. And, untreated specimens of polylactic acid show brittle behavior due to the inherent material properties. Because of the thin transparent film formed on the appearance, the tensile mechanical properties of specimens after chemical finishing are obviously changed, with the result that the tensile strength reduces by 63% and elongations at break improve by 50%. This chemical finishing not only decreases the roughness of parts manufactured in fused deposition modeling significantly, but also improves the toughness of polylactic acid parts.

Experiment on Chemical Magnetorheological Finishing of SiC Single Crystal Wafer

Experiment was performed to examine the plane polishing of SiC single crystal wafer by using the chemical magnetorheological finishing (CMRF) technique. The influence of some process parameters such as the concentration of diamond abrasive particles, the concentration of carbonyl iron powder and the machining gap in CMRF were studied comparing with the magnetorheological finishing (MRF) method. The results show that the surface roughness of polished SiC single crystal by the CMRF is slightly lower than that by the MRF. Polishing liquid with different components and processing parameters affects the coupling effect of mechanical removal and chemical removal in CMRF, and a better coupling effect can produce a better surface quality in CMRP. In the MRF, the surface roughness of SiC single crystal is lower for a higher concentration of carbonyl iron powder (CIP). However, in the CMRF, the CIP’s concentration may change the contact state between the catalyst and SiC, and the CIP’s concentration of about 20% can produce a better surface roughness of SiC. The machining gap between the polishing disk and the workpiece surface determines the processing effect, and the machining gap of 1.0 mm is suitable for the polishing of SiC in the MRF and CMRF.

3D プリンタ造形物の形状に対応可能な改質処理機構の開発

The 3D printed object is suffering by the layer grooves. We developed the 3D Chemical Melting Finishing (3D-CMF). It can remove the layer grooves effectively and 3D-CMF is able to improve mechanical strength of the 3D printed structure. However there is no suitable process for the complex shape of the 3D printed structure. Therefore we developed the mechanism of the 3D-CMF that can adjust the amount of the processing. In this paper, we developed the automation mechanism of the 3D-CMF that is suitable for the complex shape of the 3D printed structure.

Microwave curing for applying polymeric nanocapsules containing essential oils on cotton fabric to produce antimicrobial and fragrant textiles

Application of encapsulated essential oils in the chemical finishing of textiles is rapidly developing because of their versatility and flexibility. In this work, alginate nanocapsules containing peppermint oil were prepared by the microemulsion method and applied on cotton fabric by a microwave curing process. Effective parameters on antimicrobial activity of finished cotton fabric were optimized to obtain a good antimicrobial and fragrant textile. FT-IR spectroscopy and TGA were used to quantify the presence of nanocapsules on the cotton fabric. Also, the surface distribution, attendance and preferred position of the nanocapsules on the textile fibers were investigated by SEM images. The releasing behavior of peppermint oil from the finished cotton fabric in different washing cycles measured by GC-MS analysis indicated that the percent of peppermint oil reached 16 % after 25 washing cycles. Antimicrobial activity of the finished fabric showed 100 % bacterial reduction for both E. coli and S. aureus bacteria in optimum conditions.

Latest Developments on Crease Resistance Processes for Cellulosic Fabrics

Cellulosic fabrics generally exhibit tendency to crease during usage, laundering and drying processes and this fact leads to deformation in the appearance properties of these fabrics. This problem can be eliminated by crease resistance finishing process. For this aim, various chemical finishing materials have been used, however; they may not find broad usage area due to their uneconomical, unecological nature and their damage to physical properties of fabrics while conferring anti-creasing performance. Thereby, there is still demand and need for related studies and suggestions. In this review study, development of the crease resistance processes for cellulosic fabrics from past to present, encountered problems and new approaches to solve these problems have been explored and examined. In addition to these, test methods to evaluate crease resistance have been discussed.

EFFECT OF CHEMICAL TREATMENTS ON THE CHARACTERISTICS OF REGULAR AND COMPACT COTTON SPUN YARNS

An investigation on the physical properties of compact and conventional spun yarns following chemical treatments is reported. In this research, the effect of chemical finishing treatments namely, scouring, hypochlorite bleaching, peroxide bleaching, mercerising and dyeing on the yarn characteristics of 30 Ne regular and compact ring spun yarns has been studied. The results showed that whilst tenacity of treated yarns rose, elongation fell with the exception of slack mercerising treatment. Work of rupture was significantly higher than that of control for slack mercerised samples. With the exception of slack mercerised yarns there was no measurable difference in initial modulus of yarns. While bleached yarns samples showed somewhat poor abrasion resistance, the other treated yarns did not show any change in abrasion resistance. All the treatments had led to an increase in yarn friction. Slack mercerisation treatment had led to a significant increase in shrinkage and the shrinkage values were identical in both conventional and compact yarns. The other treatments had resulted in lower shrinkage values. Compression was found to be greater for compact yarns in untreated state and all the treatments had lowered the compression. Compressional energy (WC) was found to be the highest for compact mercerised yarn. Scanning electron micrographs showed clearly the improved hairiness and bulk in compact yarns.

Wood as Material Suitable for Health Care and Therapeutic Facilities

Paper deals with features important for creating healthy microclimate in health care and therapeutic facilities. It presents basic facts about visual, tactile, behavioural, somatic, acoustic and socio-cultural comfort particularly important for spatial design of these facilities.It focuses especially on choice of materials and their surfaces for built-in elements and furnishings which plays crucial role for well-being - comfort. It sets hypotheses that using wood as phenomena by humanisation of microenvironment, it is possible to reach high level of complex comfort.It also shows main disadvantages of using wood in the healthcare and wellness facilities, where belongs particularly more demanding maintenance to keep the surfaces clean and disinfected and water resistant. To prevent these problems, the high resistant chemical /artificial finishing is needed. But with chemical finishing there are lost many positive effects of wood on healthy microclimate.Despite of it there are two hypotheses that are contributing to the statements that wood is suitable for the healthcare facilities. First is that natural wood without additional chemical finishing has antibacterial (antimicrobial) effect. And second is that it is possible to provide a surface modification with the aim to reach the state that wood can be hydrophobic or even superhydrophobic and thus easy to maintain such as adjustment by plasma or by finings based on nanotechnologies and biomimetic. The paper presents examples and own tests supporting these hypotheses.

The Analysis of Acoustic Characteristics and Sound Absorption Coefficient of Needle Punched Nonwoven Fabrics

Control of acoustical related phenomenon in environments, such as work place and residential homes, using various textile materials has gained paramount importance. Nonwoven fabrics in general are ideal acoustical insulator due to their high volume-to-mass ratio. This research examined acoustic characteristics of structured needle punched floor coverings in relation to fiber fineness, surface effect, punch density, areal density, and chemical bonding process. Sound absorption of the test samples was measured using the impedance tube method. Results indicate that fabrics produced from finer fibers absorb sound waves more efficiently. It was found that, samples with no surface effect enjoy the maximum sound absorption. This is followed by velour and cord surface effect samples. It was established that, higher levels of punch density and higher areal density caused the noise reduction coefficient (NRC) of the fabrics to be increased. It was also found that chemical finishing adversely affected the sound absorption property of the samples.