scholarly journals Influential Parameters of Starching Process on Mechanical Properties of Yarns Intended for Multifunctional Woven Fabrics for Thermal Protective Clothing

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 73
Author(s):  
Ivana Schwarz ◽  
Stana Kovačević ◽  
Ivana Vitlov

The investigation of influential parameters of the starching process on mechanical properties of yarns intended for multifunctional woven fabrics for thermal protective clothing was performed on four different yarn samples starched on an innovative starching machine, adapted to industrial starching conditions. The starching was conducted with two different processes with different starch mass concentrations: the standard starching process and a newer starching process (with yarn prewetting). Based on the results obtained, it can be concluded that starching positively affects all the properties of tested samples and that the increase of starch mass concentration is not accompanied by the improvement of those yarn properties. Synthetic polymer fibers that achieve satisfactory yarn strength need to be starched with lower starch mass concentrations in order to retain the breaking properties and to be protected from abrasion and static electricity, which occurs during the weaving process. The yarn prewetting starching process shows significantly better results than the standard starching process, especially for aramid yarns, where abrasion resistance increased from 42 to 135%. Therefore, we can conclude that the goal of starching such yarns is aimed at increasing the wear resistance. Linear regressions and correlations between the values of breaking properties and abrasion resistance obtained by the testing and their values that were estimated by the analysis show a high correlation coefficient.

2017 ◽  
Vol 88 (12) ◽  
pp. 1335-1344 ◽  
Author(s):  
Licheng Zhu ◽  
Maryam Naebe ◽  
Ian Blanchonette ◽  
Xungai Wang

This study focuses on the qualitative evaluation of the mechanical properties of bifacial fabrics, which have a knitted structure on one face and a woven structure on the other. Woven, knitted, and bifacial fabrics were produced on a purpose-built machine, using wool/acrylic and polyester yarns. The bifacial fabric was manufactured with the woven structure being a plain weave and the knitted structure being a single jersey. The results of load–extension test showed unique tensile behavior, with two breakages in both the warp and weft directions, representing the woven and knitted structures. The bending length of the bifacial fabric in the weft direction with its knitted face up was smaller than that in the warp direction, and the bending length in the warp direction with its knitted face up was similar to that in two directions with the woven face up. The bifacial fabric demonstrated unique abrasion resistance on two faces, combining the performance of the knitted and woven fabrics in abrasion resistance. The abrasion resistance on the woven face was better than that on the knitted face. The knitted face of the bifacial fabric generally pilled less than the knitted fabric after abrasion over a certain number of cycles.


2013 ◽  
Vol 709 ◽  
pp. 242-245
Author(s):  
Zheng Qin Liu ◽  
Wei Guo Liu ◽  
Xiu Li Qiu ◽  
Yu Qing Zhang ◽  
Fan Dong Kong

Phenolic fiber is a new fiber and has excellent flame retardant properties. In order to investigate the textile possibility of phenolic fiber and to develop protective clothing and decorative fabrics containing phenolic fiber, the mechanical properties of phenolic fiber were studied firstly, then the polyester fiber was chosen to blend with different portion of phenolic fiber to enhance the strength of the blended yarn and finally the fabrics were knitted with different blended yarns. The strength and wear resistance of different blending ratio of phenolic/polyester blended yarn, and the bursting strength, abrasion resistance and flame retardant properties of the blended fabrics were analyzed and compared. The experimental results shows that the breaking tenacity and elongation at break are low, only 1.3 cN/dtex and 9.4%, respectively, which is not suitable for 100% phenolic fiber to be processed in yarn. The strength and wear resistance of the phenolic/polyester blend yarns and their knitted fabrics increase while the contents of polyester are increased. The flame retardant of phenolic/polyester blend fabrics is improved greatly due to phenolic fiber. Therefore, it is necessary for phenolic fiber to modify its strength and extension in order to be able to get the 100% phenolic yarn and products and in order to give full play to the excellent characteristics of the phenolic fiber.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Adam K. Puszkarz ◽  
Waldemar Machnowski

AbstractIn this paper, the safety and thermal comfort of protective clothing used by firefighters was analyzed. Three-dimensional geometry and morphology models of real multilayer assemblies used in thermal protective clothing were mapped by selected Computer-Aided Design (CAD) software. In the designed assembly models, different scales of the resolution were used for the particular layers – a homogenization for nonwoven fabrics model and designing the geometry of the individual yarns in the model of woven fabrics. Then, the finite volume method to simulate heat transfer through the assemblies caused by their exposure to the flame was applied. Finally, the simulation results with experimental measurements conducted according to the EN ISO 9151 were compared. Based on both the experimental and simulation results, parameters describing the tested clothing protective features directly affecting the firefighter’s safety were determined. As a result of the experiment and simulations, comparable values of these parameters were determined, which could show that used methods are an efficient tool in studying the thermal properties of multilayer protective clothing.


2020 ◽  
Vol 32 (3) ◽  
pp. 412-429 ◽  
Author(s):  
Meng Deng ◽  
Miao Tian ◽  
Yunyi Wang ◽  
Min Wang

Purpose The purpose of this paper is to determine the effect of flash fire exposure on the mechanical properties of single-layer thermal protective clothing. Design/methodology/approach The full-scale flame manikin tests were performed to simulate flash fire exposure. Two typical fire-resistant fabrics were investigated. The manikin was divided into seven body parts and the specimens meeting the requirements of tensile and tear strength standards were sampled. Fabric thickness, mass per unit area, tensile strength and tear strength were measured and analyzed. Findings The results revealed the significant influence of heat flux on both of tensile and tear strength. However, the regression analysis indicated the low R2 of the liner models. When the tensile and tear strength retention were reorganized based on the body parts, both of the multiple linear regression models for tensile and tear strength showed higher R2 than the one-variable linear regressions. Furthermore, the R2 of the multiple linear regression model for tear strength retention was remarkably higher than that of the tensile strength. Practical implications The findings suggested that greater attention should be paid to the local part of human body and more factors such as the air gap should be considered in the future thermal aging of firefighters’ clothing studies. Originality/value The outcomes provided useful information to evaluate the mechanical properties of thermal protective clothing and predict its service life.


2021 ◽  
pp. 096739112110239
Author(s):  
Sheedev Antony ◽  
Abel Cherouat ◽  
Guillaume Montay

Nowadays natural fibre composites have gained great significance as reinforcements in polymer matrix composites. Composite material based on a polymer matrix reinforced with natural fibres is extensively used in industry due to their biodegradability, recyclability, low density and high specific properties. A study has been carried out here to investigate the fibre volume fraction effect of hemp fibre woven fabrics/PolyPropylene (PP) composite laminates on the tensile properties and impact hammer impact test. Initially, composite sheets were fabricated by the thermal-compression process with desired number of fabric layers to obtain composite laminates with different fibre volume fraction. Uniaxial, shear and biaxial tensile tests were performed and mechanical properties were calculated. Impact hammer test was also carried out to estimate the frequency and damping parameters of stratified composite plates. Scanning Electron Microscope (SEM) analysis was performed to observe the matrix and fibre constituent defects. Hemp fabrics/PP composite laminates exhibits viscoelastic behaviour and as the fibre volume fraction increases, the viscoelastic behaviour decreases to elastic behaviour. Due to this, the tensile strength increases as the fibre content increases. On the other hand, the natural frequency increases and damping ratio decrease as the fibre volume fraction increases.


Author(s):  
Antao Deng ◽  
Bin Ji ◽  
Xiang Zhou

A new geometric design method for foldcores based on the generalized Resch patterns that allow face-to-face bonding interfaces between the core and the skins is proposed. Based on the geometric design method, a systematic numerical investigation on the quasi-static mechanical properties of the generalized Resch-based foldcores made of carbon fiber-reinforced plastic (CFRP) woven fabrics subjected to compression and shear loads is performed using the finite element method that is validated by experiments. The relationships between the mechanical properties and various geometric parameters as well as laminate thickness of the generalized Resch-based CFRP foldcores are revealed. Additionally, the mechanical properties of the generalized Resch-based CFRP foldcore are compared to those of the standard Resch-based, Miura-based foldcore, the honeycomb core, and the aluminum counterpart. It is found that the generalized Resch-based CFRP foldcore performs more stably than the honeycomb core under compression and has higher compressive and shear stiffnesses than the standard Resch-based and Miura-based foldcores and absorbs as nearly twice energy under compression as the Miura-based foldcore does. When compared with the aluminum counterpart, the CFRP model has higher weight-specific stiffness and strength but lower energy absorption capacity under shearing. The results presented in this paper can serve as the useful guideline for the design of the generalized Resch-based composite foldcore sandwich structures for various performance goals.


2011 ◽  
Vol 70 ◽  
pp. 405-409 ◽  
Author(s):  
Emrah Demirci ◽  
Memiş Acar ◽  
Behnam Pourdeyhimi ◽  
Vadim V. Silberschmidt

Having a unique microstructure, nonwoven fabrics possess distinct mechanical properties, dissimilar to those of woven fabrics and composites. This paper aims to introduce a methodology for simulating a dynamic response of core/sheath-type thermally bonded bicomponent fibre nonwovens. The simulated nonwoven fabric is treated as an assembly of two regions with distinct mechanical properties. One region - the fibre matrix – is composed of non-uniformly oriented core/sheath fibres acting as link between bond points. Non-uniform orientation of individual fibres is introduced into the model in terms of the orientation distribution function in order to calculate the structure’s anisotropy. Another region – bond points – is treated in simulations as a deformable bicomponent composite material, composed of the sheath material as its matrix and the core material as reinforcing fibres with random orientations. Time-dependent anisotropic mechanical properties of these regions are assessed based on fibre characteristics and manufacturing parameters such as the planar density, core/sheath ratio, fibre diameter etc. Having distinct anisotropic mechanical properties for two regions, dynamic response of the fabric is modelled in the finite element software with shell elements with thicknesses identical to those of the bond points and fibre matrix.


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