Fiber Tenacity Research Articles

The influence of pre-treatment of Spartium junceum L. fibres on the structure and mechanical properties of PLA biocomposites

Different chemical pre-treatments of Spartium junceum L. fibres using alkali (NaOH), nanoclay (MMT) and Citric acid (CA) with the aim of producing biodegradable composite material are discussed. As environmental requirements in processing technologies have been higher in recent years, the Polylactic acid (PLA) is used in this research as a matrix, due to its renewability, biodegradability and biocompatibility. Biocomposites are prepared by reinforcing PLA with randomly oriented, short Spartium junceum L. fibres in order to increase material strength. The effects of different pre-treatments of Spartium junceum L. fibres on the mechanical properties of final biocomposite material are examined. Fibre tenacity is studied using Vibroscop and Vibrodyn devices. Tensile strength of biocomposite material was measured on the universal electromechanical testing machine Instron 5584. The results indicate that biocomposites reinforced with fibres modified with MMT and CA show upgraded mechanical properties of the final composite material in comparison with the composite materials reinforced with referenced (nontreated) fibres. Infrared spectra of tested fibres and biocomposites were determined with Fourier transform infrared spectroscopy using Attenuated total reflection (FT-IR ATR) sampling technique and the influence of fibre modifications on the fibre/polymer interfacial bonding was investigated. The interface of Spartium/PLA composites was observed with scanning electron microscope (SEM) and it was clearly visible that biocomposites reinforced with fibres modified by MMT and CA showed better interaction of fibres and matrix.

Graphene reinforced regenerated cellulose nanocomposite fibers prepared by lyocell process

Nanocomposites of regenerated cellulose containing different amounts of graphene nanoplatelets (GNPs) (0.5, 1, and 2 wt%) have been prepared by wet spinning using Lyocell process. The thermal stability, mechanical, and electrical properties of the nanocomposite fibers were studied. The nanocomposite fibers were characterized by Fourier transform infrared (FTIR), Transmission electron microscopy, X‐ray diffraction, and Scanning electron microscopy (SEM). The tenacity and initial modulus of the nanocomposite fibers improved by 66% and 61%, respectively with the addition of 2 wt% GNPs. The T20 decomposition temperature of regenerated cellulose fibers improved with the addition of GNPs up to 2 wt%. The morphology by SEM revealed exfoliated dispersion of GNPs into the regenerated cellulose matrix which subsequently resulted in good interaction between the nanofillers and the matrix. The addition of exfoliated GNPs generated electrical conductivity. The nanocomposite fibers containing 2 wt% GNPs has a conductivity of 2.3 × 10−4 S/cm. The FTIR spectra showed that the addition of GNPs in regenerated cellulose did not result in any noticeable change in its chemical structure. The resulting nanocomposite may find potential applications in the areas of carbon fiber precursor, conductive fibers, electrical tools, and biodegradable composites. POLYM. COMPOS., 38:E81–E88, 2017. © 2015 Society of Plastics Engineers

Composition of ramie hemicelluloses and effect of polysaccharides on fiber properties

Ramie, which is one of the most important natural fibers, possesses distinctive characteristics and excellent properties. In this study, the chemical compositions of hemicelluloses in ramie fibers were thoroughly investigated. The effect of NaOH treatment on polysaccharides in hemicelluloses and the effect of polysaccharides on fiber properties were systematically explored. It was found that the components of galactoglucomannan, glucomannan, and xylan accounted for about 79.0% of total weight in ramie hemicelluloses. Galactoglucomannan was more easily soluble than glucomannan in 1% (w/w) NaOH solution. Xylan possessed the lowest solubility in the same concentration of NaOH solution compared to the other two. Furthermore, with an increase of galactoglucomannan, glucomannan, and xylan contents, the fiber linear density and unseparated fiber percentage showed an increasing trend, while the fiber tenacity exhibited a decreasing trend under the same conditions. In addition, it was demonstrated that the contents of these three components have an insignificant effect on friction coefficient, breaking elongation, modulus, and resilience of ramie fibers. This study could provide useful information in understanding the nature of hemicelluloses and polysaccharides within natural fibers, as well as theoretically guiding the degumming process of ramie fibers.

Dissolution of enzyme-treated cellulose using freezing–thawing method and the properties of fibres regenerated from the solution

The rapid coagulation of NaOH-based cellulose solution during the wet spinning process leads to a low stretching ratio and, consequently, the low mechanical properties of the fibres. The aim of this work was to slow down the coagulation by replacing the sulphuric acid spin bath with an acetic acid bath. The spin dope was prepared by dissolving the enzyme-treated dissolving pulp in aqueous sodium zincate using a freezing–thawing method. The optimal zinc oxide and sodium hydroxide concentrations were studied first. The most thermally stable cellulose solution contained 6.5 wt% NaOH and 1.3 wt% ZnO with 6 wt% enzyme-treated dissolving pulp. The spin dope was prepared accordingly. Coagulation of the cellulose solution slowed down in the acetic acid bath, resulting in a significantly higher stretching ratio for the fibres than with the sulphuric acid bath. However, the acetic acid spun fibres shrunk strongly during drying, and the possibly aligned order of the molecular chains due to the high stretch was partly lost. As a consequence, the high stretch was not transferred to high tenacity of the fibres in this study. However, the result suggests attractive potential to develop processing conditions to increase fibre tenacity.

Effect of fiber geometry and tenacity on the mechanical properties of fine aggregates concrete

The effect of fiber cement interactions and its influence on flexural and tensile properties of cementitious composites are well known. In this research, acrylic fibers with different cross sectional and longitudinal shapes and different tensile strengths were selected as reinforcement of the specific fine aggregates concrete. Three point bending test, pullout test, and scanning electron microscopy were used to investigate flexural and pullout behavior of the composites. It was found that flexural toughness and pullout strength were increased 20% and 34%, respectively, by application of kidney shaped acrylic fibers in comparison to dog bone shaped acrylic fibers. It was also found that the flexural and pullout strength of composites containing non-crimped fibers are 33% and 26.5% higher than specimens with crimped fibers, respectively. Results showed that the flexural toughness and pullout strength of high tenacity fiber is 75% and 131% higher than regular fiber as well, respectively. The effect of fine aggregates on the adhesion of fibers to cement matrix was evaluated.

Stab resistance of triaxial woven fabrics for soft body armor

Protective body armors, providing protection against stab threats, have long been in a focus of substantial interest. Lightweight fabric for flexible body armors that satisfy the customized fit, comfort, and protection should be considered. Sharp impact experiments were conducted on single and multilayer fabrics of Kevlar29, Vectran, and Polyester triaxial woven fabrics and compared with polyester woven and knitted fabrics. The experimental results evaluate the energy absorption of the different triaxial woven fabrics for stab resistance. An index was developed to evaluate the capability of fibers to absorb the impact energy which indicated that high fiber tenacity and Young’s modulus and low density lead to high rate of punching resistance force. The present work indicates that Vectran triaxial weave fabrics propose to improve the impact performance when used in developing multilayer fabrics for designing lightweight soft body armor with enhanced stab performance adding flexibility and comfort.

Improvement of degummed ramie fiber properties upon treatment with cellulase secreting immobilized A. larrymoorei A1.

Degummed ramie fiber is widely used in the textile industry. Cellulase enzyme can be effectively used for bio-polishing of the ramie fiber. We immobilized Agrobacterium larrymoorei A1, a potent extra-cellular cellulase producing bacteria, in Ca-alginate. The production of enzyme significantly increased with increasing alginate concentration and reached a maximum activity of 0.28 IU/ml at 20 g/l, which was 32% higher as compared to free cells. These immobilized cells were used on ramie fibers. Scanning electron micrograph (SEM) and differential interference contrast (DIC) studies showed increased smoothness and orientation of surface structure of the fibers after 19.5 h. The single fiber tenacity was almost same as compared to non-treated fiber and the initial modulus increased by 24.01%. The remarkable reusability of these immobilized cells provides a cost effective method for treatment of natural fibers containing cellulose.

Preliminary Study of Linear Density, Tenacity, and Crystallinity of Cotton Fibers

An investigation of the relationships among fiber linear density, tenacity, and structure is important to help cotton breeders modify varieties for enhanced fiber end-use qualities. This study employed the Stelometer instrument, which is the traditional fiber tenacity reference method and might still be an option as a rapid screening tool because of its low cost and portable attributes. In addition to flat bundle break force and weight variables from a routine Stelometer test, the number of fibers in the bundle were counted manually and the fiber crystallinity (CIIR) was characterized by the previously proposed attenuated total reflection-sampling device based Fourier transform infrared (ATR-FTIR) protocol. Based on the plots of either tenacity vs. linear density or fiber count vs. mass, the fibers were subjectively divided into fine or coarse sets, respectively. Relative to the distinctive increase in fiber tenacity with linear density, there was an unclear trend between the linear density and CIIR for these fibers. Samples with similar linear density were found to increase in tenacity with fiber CIIR. In general, Advanced Fiber Information System (AFIS) fineness increases with fiber linear density.

Effects of Fiber Spinning on the Morphology, Rheology, Thermal, and Mechanical Properties of Poly(trimethylene terephthalate)/Poly(ethylene terephthalate) Blends

ABSTRACTThe morphology, thermal behavior, rheological, and mechanical properties of poly(trimethylene terephthalate) (PTT)/poly(ethylene terephthalate) (PET) blend fibers were investigated. The scanning electron microscopy studies revealed the formation of a microfibrillar network of the PET within the PTT matrix after the fiber‐spinning process. Differential scanning calorimetry results demonstrated that although the thermal characteristics of the amorphous phase were unaffected by the fiber‐spinning process, the melting and crystallization behavior of the blends was altered by the elongation flow imposed during the melt spinning. The viscoelastic behavior of the PTT/PET blends was also studied by a steady shear rate and dynamic sweep rheological experiments before and after the spinning process. The induced morphology and crystallization reordering resulting from the fibrillation process are shown to have a remarkable effect on the complex viscosity profile of the PTT/PET fibers, particularly in the blend containing 30 wt% PET. The mechanical testing showed that tenacity and Young's modulus of the PTT fibers increased with the addition of PET up to 30 wt%.

Fabrication and properties of dope-dyed Poly(m-phenylene isophthalamide) fibers via wet spinning

Poly(m-phenylene isophthalamide) (PMIA) fibers play an irreplaceable role in the area of high-temperature resistance. It is usually difficult to dye PMIA fibers due to their rigid molecular structure and high crystallinity. In this study, the dope-dyed PMIA fibers with different amounts of pigment were fabricated by wet spinning. The properties of the pigment were analyzed, including size distribution and dispersive properties. The results showed that the pigment was easy to disperse in the fibers when the average diameter of the pigment was smaller than 500 nm. The color fastness of the colored PMIA fibers was tested, and their thermal properties and mechanical properties were also analyzed. The results of thermal gravity analysis (TGA) indicated that the colored PMIA fibers maintained good thermal performance. Compared to uncolored PMIA fibers, the colored PMIA fibers became lighter after exposing to simulated sunlight for 50 h. The breaking tenacity of fibers exceeded 2.0 cN/dtex, and the retentivity was above 80 % after being exposed to simulated sunlight for 50 h. These suggested the good mechanical performance of colored PMIA fibers. Dope-dyed PMIA fibers with good mechanical properties and thermal performance were successfully developed.

Preliminary study of relating cotton fiber tenacity and elongation with crystallinity

A fundamental understanding of the relationship between cotton fiber strength (or tenacity)/elongation and structure is important to help cotton breeders modify varieties for enhanced end-use qualities. In this study, the Stelometer instrument was used to measure the bundle fiber tenacity and elongation properties of different cotton fibers. This instrument is the traditional fiber strength reference method and could be still preferred as a screening tool owing to its significant low cost and portability. Fiber crystallinity ( CIIR) and maturity ( MIR) were characterized by the previously proposed attenuated total reflection (ATR)-based Fourier transform infrared protocol that has microsampling capability and is suitable for the tiny Stelometer breakage specimens (2 ∼ 5 mg), which cannot be readily analyzed by a conventional X-ray diffraction pattern. Relative to the distinctive increase in fiber tenacity with either CIIR or MIR for Pima fibers ( Gossypium barbadense), there was an unclear trend between the two for Upland fibers ( G. hirsutum). Although fiber elongation increases with elevated CIIR and MIR for Pima fibers, it generally decreases as CIIR and MIR increase for Upland fibers. Furthermore, small sets of Upland fibers with known varieties and growth areas were examined, and their responses to both CIIR and MIR are discussed briefly.

Controlling of threadline dynamics via a novel method to develop ultra-high performance polypropylene filaments

A detailed study was conducted to investigate the effects of horizontal isothermal bath (hIB) on the production of ultra-high performance polypropylene filaments. Two different commercial PP polymers were used with the melt flow rate of 4.1 and 36 g/10 min. The optimum process conditions depended on polymer molecular weight. Fibers showed distinct precursor morphology for each at each optimum process condition. However, two sets of filaments demonstrated similar fiber tenacity and modulus of about 7 and 75 g d−1, respectively, for as-spun and more than 12 g d−1 for tenacity and more than 190 g d−1 for modulus values of drawn fibers after just 1.49 draw ratio. The mean value for the modulus after the drawing process for the high melt flow rate was 196 g d−1. The theoretical modulus of PP is 35–42 GPa19, (275–330 g d−1), shows the hIB fiber's modulus performance is approaching its theoretical maximum value. Fibers had greatly improved thermal properties, degree of crystallinity, crystalline and amorphous orientation factors. The hIB spinning system produced highly oriented and predominantly amorphous structure for as-spun fibers and a well-defined, highly oriented crystalline fibrillar and amorphous structure after drawing process with the draw ratios lower than 1.5. POLYM. ENG. SCI., 55:327–339, 2015. © 2014 Society of Plastics Engineers

Alternate Relationship between Single Fiber Properties and Both of Fiber Microscopic and Physical Properties

Current study was carried out in Cotton Research Institute, Agricultural Research Center, Egypt and Textechno company labs Monchengladbach, Germany during 2013 season. The materials used in this study comprised 16 different genotypes produced by cotton research institute. In addition to, two upland cotton varieties from Sudan. Aiming to study the effect of environmental conditions, genotypes and thier interaction on each characters under study beside studyig the relationship between single fiber prroperties and bundle properties. Giza 93 variety showed the lowest micronaire, fineness and area of cross section. On contrast, it showed the highest upper half mean. Giza 87 variety exhibited the highest bundle strength, the lowest reversals number per mm and the narrowest convolution angle. As for single fiber properties. Giza 45 variety followed by Giza 87 variety exhibited the lowest single fiber linear density readings. Single fiber strength is a little bit lower than bundle strength. Giza 87 variety surpassed the other genotypes on single fiber strength. Upland cotton varieties showed the worst bundle and single fiber properties. As maturity ratio increased bundle and single fiber properties improved and vice versa. According to, the relationship between single fiber prroperties and bundle properties, there was a nearly linear relation¬ship between fiber properties and single fiber properties. After excluding the weak correlated characters 3 linear multiple regression models for single fiber tenacity, single fiber linear density and single fiber elongation were produced. Fineness and degree of thickness were the predictor variables for single fiber strength parameters. However, fiber fineness per mtex and micronaire values were the most important factors for single fiber linear density, both of them proportionate directly with single fiber linear density. While, single fiber elongation contains 7 predictors i.e. Micronaire reading, UI, area of cross section, theta, fiber strength, fiber elongation and UHM characters. Nevertheless, it showed the weakest relation, UI, area of cross section, and fiber Strength proportionate inversely with single fiber elongation. The model is not reliable enough for single fiber elongation prediction.

Absorbent alginate fibres modified with hydrolysed chitosan for wound care dressings – II. Pilot scale development

Fibres have been used extensively in wound dressing applications as they provide a high surface area for absorption, ease of fabrication and softness. It is common practice for commercial wound dressings to be produced from natural materials, such a marine polysaccharides, as they are predominantly biocompatible, non-toxic, and often display bioactive properties, such as inherent antimicrobial activity. In this study hydrolysed chitosans were utilised as a sole coagulant for the production of alginate–chitosan fibres via a one-step, direct wet-spinning extrusion process. The levels of chitosan incorporated into the fibres were analysed quantitatively via elemental analysis and qualitatively by staining using Amido Black 10B. It was estimated that the fibres contained between 4.50 and 5.10% (wt.%) chitosan. The presence of chitosan improved tensile properties such as elongation and tenacity of the base alginate fibres. The increased incorporation of chitosan into the fibres also improved the absorption of the fibres in both saline and distilled water; reaching maximum of >30g/g and >50g/g, respectively. This work suggests that the observed hydrolysed chitosan content within the fibre may be optimal for the preparation of a novel fibre for wound care application.

Grafting of Methyl Acrylate and Methyl Methacrylate onto Jute fiber: Physico-Chemical Characteristics of the Grafted Jute

The graft copolymerization of methyl acrylate and methyl methacrylate vinyl monomers onto jute fiber using potassium persulfate and ferrous sulfate redox system was investigated in an aqueous medium. Optimized reaction conditions for the graft copolymerization were established for parameter variables, of monomer concentration, initiator concentration, catalyst concentration, reaction time, and reaction temperature. The grafting degrees were found to depend on the above mentioned variables. A maximum graft yield of 17.3% for MA and 19.4% for MMA was obtained under effective optimized conditions for grafting. The attachment of the monomer on the grafted fiber was confirmed by FTIR studies. Dyeing was affected by monomer characteristics, and due to the development of hydrophobic nature on jute fiber by grafting, a lower amount of dye absorption occurred. Grafting has a favorable influence on tenacity, color fastness, and other properties of jute fiber.

Improved production of alkaline polygalacturonate lyase by homologous overexpression pelA in Bacillus subtilis

A polygalacturonate lyase (PGL), PelA, was purified from the culture broth of Bacillus subtilis 7-3-3, with a molecular weight, optimal temperature, and pH of approximately 45kDa, 55°C, and 9.4, respectively. The PGL gene (pelA) was homologously overexpressed in B. subtilis 7-3-3 to increase the gene copies and enhance the PGL production. The resulting PGL activity was 2138UmL−1 at 44h, and the productivity reached 48.58U(mLh)−1 through the homologous overexpression of strain B-pN-pelA in a 7.5L fermentor, the highest PGL production compared to those reported in literature to the best of our knowledge. Crude enzyme has high PGL and PGase activity, which can remove 50.58% of pectin in unpretreatment ramie fibers at 50°C for 4h. Meanwhile, the enzyme system with a low level hemicellulase and almost no cellulase will further help in enhancing the efficiency of degumming besides maintaining tenacity of plant fiber. The B. subtilis B-pN-pelA shows high genetic stability and has great potential in the textile industry.

The Tensile and Surface Frictional Property of Soybean Protein Fibers

In order to understand the mechanical properties of the soybean protein fibers (simply called SPF) in different processing condition, the tensile and frictional properties of the SPF are measured with different instruments. By the analysis of the results, the following conclusions can be deduced: bleaching has an influence on decreasing tenacity at break for each test modality. Knotted and looped modalities decrease fiber tenacity remarkably in all three samples, and the same occurs with elongation at break. Looped modalities show lower tenacity and elongation at break, the lowest being the bleached fibers in looped modalities.

Degumming of ramie fiber and the production of reducing sugars from waste peels using nanoparticle supplemented pectate lyase

Banana, citrus and potato peels were subjected to treatment with hydroxyapatite nanoparticle (NP) supplemented purified pectate lyase (NP-PL), isolated from Bacillus megaterium AK2 to produce reducing sugar (RS). At both 50 and 90°C production of RS by NP-PL was almost twofold greater than that by untreated pectate lyase (PL) from each of the three peels. The optimal production of RS from banana and citrus peels were after 24 and 6h of incubation while it was 24 and 4h for potato peels at 50 and 90°C, respectively, on NP-PL treatment. NP-PL could degum raw, decorticated ramie fibers as well as enhance fiber tenacity and fineness. The weight loss of the fibers were 24% and 31% better (compared to PL treatment) after 24 and 48 h of processing. These findings have potential implications for the bio-ethanol, bio-fuel and textile industries.

Heterosis Performance of Seed Cotton Yield and Physiological Parameters in F<sub>1</sub> Inter Specific Hybrids in Cotton

In order to known better the heterosis performance, yield and physiological parameters in 112 hybrids (F 1 ) and their parents the study initiated to create recombinational variability for combining ability, the elite barbadense lines DB 533 and DB 534 were crossed during 2007~2008. During two seasons 2008~2009 and 2009~2010 these barbadense crosses were advanced to F 2 and F 3 generations, respectively. The F 3 lines were evaluated for productivity and fiber quality parameters realizing the emphasis laid on developing ELS (Extra Long Stable) cotton hybrids out of 171 F 3 lines, only those F 3 lines with acceptable fiber strength were utilized in the study on recombinational variability of combining ability. During 2010~2011 those twenty eight F 4 lines of barbadense cross DB 533 × DB 534 depending on the higher value of fiber tenacity, were crossed with the selected four hirsutum testers viz., DH 98-27 (T 1 ), ZCH 8 (T 2 ), 178-24 (T 3 ) and DH 18-31 (T 4 ) selected based on earlier study. The derived F 1 crosses (28 barbadense lines x 4 hirsutum testers) were compared with the bench mark crosses (two barbadense lines x 4 hirsutum testers) of the heterotic box, best Bt check hybrid (MRC 6918) and non Bt check (DCH 32). Many derived F 1 crosses were found to be more productive than non Bt check DCH 32 (48 hybrids) and the Bt check MRC 6918 (35 hybrids). The potential crosses like DH 98-27 X (DB 533 x DB 534 F 4 IPS 49), DH 98-27 X (DB 534 x DB 533 F 4 IPS 22) and DH 98-27 X (DB 533 x DB 534 F 4 IPS 52) recorded highest per se performance for seed cotton yield. These potential crosses recorded highly significant heterosis over mid parent for seed cotton yield. They also recorded significant heterosis for other physiological parameters. Apart from showing high productivity the potential cross DH 98-27 X (DB 533 x DB 534 F 4 IPS 49 showed higher value of photosynthetic rate and stomatal conductance. This potential cross is example for blending of yield characters and physiological parameters.

Association Analysis of Seed Cotton Yield Components and Physiological Parameters in Derived F1 Inter Specific Crosses of Cotton

The measure of association and path coefficient analysis was done in the study of derived F 1 crosses study. It is necessary to work out path coefficient analysis which partitions the observed correlation into direct and indirect effects and also reveals the cause and effect relationship between yield and their related traits. During 2010~2011 twenty eight F 4 lines of barbadense cross DB 533×DB 534 depending on the higher value of fiber tenacity, were crossed with the selected four hirsutum testers viz., DH 98-27 (T 1 ), ZCH 8 (T 2 ), 178-24 (T 3 ) and DH 18-31 (T 4 ) selected based on earlier study. Each barbadense F 4 line was involved in a set of crosses (112 crosses refer to as derived F 1 crosses) were subjected to Line x Tester analysis. It has been observed that seed cotton yield exhibited highly significant positive correlation with plant height (0.349 5), number of monopodia per plant (0.405 8), number of sympodia per plant (0.350 6), number of bolls per plant (0.401 3), mean boll weight (0.420 0), seed index (0.299 9), ginning outturn (0.215 4), lint index (0.444 8) and photosynthetic rate (0.232 7) in derived F 1 crosses. Among these, seed cotton yield exhibited highly significant positive strong association with lint index compare to other characters. The direct effect on seed cotton yield was positive in plant height (0.028 9), number of monopodia per plant (0.177 1), number of sympodia per plant (0.043 4), number of bolls per plant (0.105 3), mean boll weight (0.185 2), sympodial length at 50% plant height (0.119 2), seed index (0.039 3), ginning outturn (0.078 6), lint index (0.239 4) and photosynthetic rate (0.158 8), while the direct effect on seed cotton yield was negative in reproductive points on sympodia (-0.141 1), inter branch distance (-0.074 6), stomatal conductance (-0.030 9) and transpiration rate (-0.193 7)