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Melt spinning and pump speed conditions are described for five samples of staple polypropylene PP fibers of different fineness. The influence of fiber fineness or denier on the physical characteristics of staple PP fibers spun at different pump speeds was studied. Optical ani- sotropy was measured using two-beam interference mi- croscopy. Enthalpy and degree of crystallinity were measured using differential scanning calorimetry tech- nique for studied fibers. The relation between the fiber di- ameter, crimp ratio, tenacity, and degree of orientation with the fiber denier are given. A selection of microinter- ferograms of fibers is given for illustration. V C 2009 Wiley

Manufacturing of blend man-made fibers especially from polyolefins due to their new and expanded applications has attracted the researchers and technologists' attention. In this study, PP/LDPE blend filament yarn samples with various ratios of 100/0, 99/1, 97/3, 95/5, 93/7, 90/10 were melt spun and then drawn under industrial conditions. According to the results of the melt spinning process, convenient spinnability comparing to pure PP for various polyblend samples up to 10 wt.% of LDPE was observed. Results of microstructure measurements in both group i.e. as-spun and drawn samples showed that the presence of LDPE in blend samples did not deteriorate the density and crystallinity of PP. However, increasing the fraction of LDPE in blend gave rise to noticeable increase in the shrinkage values of drawn samples in comparing to pure PP. Although the tenacity of as-spun and drawn yarns displayed a downward trend by increasing the LDPE in blend, the obtained values for tenacity are still at an acceptable level for further processing or textile applications.

We evaluated home-range size and site tenacity of Le Conte's Sparrows (Ammodramus lecontii) during winter 2002–2003 at Brazoria National Wildlife Refuge, Texas. Twenty-six wintering Le Conte's Sparrows were radiomarked in 1- and 2-year post-burn units, and monitored for ∼10 days. Additionally, 1-ha plots on each 1-, 2- and 3-year (n = 15) post-burn units were flush-netted once monthly. Telemetry results indicated Le Conte's Sparrows were sedentary during winter with a 50% probability mean home-range of 2.41 ha (72% < 1 ha) and a 95% probability mean home range of 10.31 ha (44% < 1 ha and 55% < 1.5 ha). Home-range size did not differ between post-burn year 1 and 2 (P = 0.227). Le Conte's Sparrows appeared to exhibit a behavioral response to flush-netting (P < 0.001) with estimated capture probability of 0.462 and recapture probability of 0.056. Our findings suggest Le Conte's Sparrows remain fairly sedentary throughout the winter.

How much should we trust machines – and the algorithms they follow? To what extent should we blindly trust and follow rules?Several of the articles in this issue of the Journal of Military Ethics d...

Recycled fiber has a great potential as a solution to meet overgrowing synthetic fiber demand and reduce plastic waste in the same time. In the previous research, bottle cap waste is used as the material of the recycled fiber. The result shows that fiber tenacity of recyled fiber from bottle cap waste has low tenacity, different polymer. This phenomena may have been caused by the present of pigment molecule. This research focused on producing recycled fiber from straw waste which has low pigment content. Straw waste was washed and cleaned before the cutting process. Then, the waste was processed in the experiment melt spinning machine with plunger system and single hole orifice in various diameter, 4 mm, 10 mm and 15 mm. The processing temperature was 140° C temperature in three take-up speed, 3.00 m/minutes, 10.30 m/ minutes and 19.16 m/ minutes. The diameter and cross section shape of recycled polyethylene fiber were obtained by using electric microscope with software assistance. The linear density of the recycled fiber was analysed by calculating it with denier and the mechanical strength of the fiber was measured in accordance with the ASTM D 3379-75 standard. High take-up speed leads to higher linear density and take-up speed value is proportionally linear with the tenacity of fiber produced. Moreover, the spinneret diameter is proportionally linear with linear density but it is inversely linear with the tenacity of the fiber produced.

Polylactide stereocopolymer multifilament fibers were prepared by wet spinning and subsequent hot drawing. The stereocopolymers were poly-(L,D-lactide) [P(L,D)LA], L/D ratio 96/4, and poly-(L,DL-lactide) [P(L,DL)LA], L/DL ratio 70/30. They were dissolved in dichloromethane and coagulated in a spin bath containing ethanol. The hot-drawing temperature was 65°C. The draw ratios (DR) were upto 4.5 to the P(L,D)LA 96/4 filaments and upto 3 to the P(L,DL)LA 70/30 filaments. Wet spinning decreased crystallinities of both copolymers. Hot drawing increased the crystallinity of the P(L,D)LA 96/4 filament but not to the level of the original copolymer, whereas the as-spun and the hot-drawn P(L,DL)LA 70/30 filaments were amorphous. The filament diameter, tenacity, Young's modulus, and elongation at break were dependent on the DR. The maximum tenacity (285 MPa) and Young's modulus (2.0 GPa) were achieved with the P(L,D)LA 96/4 filament at the DR of 4.5. Respectively, the maximum tenacity of the hot-drawn P(L,DL)LA 70/30 filament was 175 MPa and Young's modulus 1.3 GPa at the DR of 3. Hot drawing slowed down in vitro degradation rate of both stereocopolymer filaments. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

The effects of pretreatment and mechanical modification on characteristics of jute fibre were evaluated in this paper. The experimental results show that pretreatments and mechanical modifications both have obvious effects on the characteristics of jute fibre. The blended agent used for pretreatment can form a thin film on the surface of jute fibre to make it smoother, so the fibre can be refined by further mechanical modification. Regarding the four process routes used for mechanical modification discussed in this study, the process of draft-cutting and speedily carding can produce jute fibre with finer diameter, lower average length, higher percentage of short fibre, and lower tenacity. The jute fibre pretreated with blended agent and mechanically modified by Process I has linear density of 16.1 dtex, average length of 35.2 mm, and tenacity of 3.4 cN/dtex, indicating that it is available for high value textile end uses.

Silicone fouling-release coatings represent a non-toxic alternative to biocide-containing ship hull paints. These coatings allow fouling organisms to attach to the hull surface, but prevent firm adhesion. Adhesive tenacity to fouling-release materials varies both among and within species. We quantified broad-sense genetic and environmental sources of intraspecific variation in tenacity to two silicone substrata, for the barnacle Balanus amphitrite. For both materials tenacity varied over an order of magnitude; however, the partitioning of this variation differed between the substrata. For International Veridian, a commercially-available fouling-release coating, removal stress varied significantly among maternal families and replicate barnacle cultures. Variation among the maternal families was associated with previously observed differences among these families in the condition of the adhesive plaque. Additional experiments suggested that variation among the replicate cultures arose from heterogeneity between replicate coatings in properties that affect tenacity. We could not attribute variation in removal stress for Dow Corning Silastic T-2, a silicone rubber used for mold-making, to any of the genetic or environmental sources tested. Instead, variation may have been due to measurement error or heterogeneity within replicate coatings in properties affecting tenacity. Differences among maternal families in removal stress may stem from variation in the interaction between the adhesive and the substratum, or in the viscoelastic properties of the adhesive plaque.

In this study, the effects of splicing parameters, fiber and yarn properties on the tenacity and elongation of spliced yarns were investigated in detail. For this purpose, yarns from eight different cotton types, having three different counts (29.5, 19.7 and 14.8 tex) and three different twist coefficients (α tex 3653, αtex 4038, αtex 4423) were produced. Fiber properties measured using an Advanced Fiber Information System fiber tester were evaluated. Artificial neural network and response surface models were used to analyze spliced yarn tenacity and elongation as dependent variables. As independent variables, fiber properties together with the machine settings such as opening air, splicing air and splicing time, yarn twist and yarn count were chosen. As a result of the study, equations and neural network models that predict the tenacity and elongation of the spliced yarns were obtained. The obtained equations and models are statistically important and have high coefficient of multiple determination ( R2).

The conditions for producing nanocomposite fibers composed of calcium alginate, containing a hydroxyapatite nanoadditive were devised and the rheological, sorptive, and strength properties of these fibers, as well as their porous and supramolecular structure were subjected to analysis. It has been concluded that the presence of the HAp nanoadditive in the material of alginate fibers decreases their susceptibility to distortion in the drawing stage, which results in their tenacity properties being lower by 2cN/tex than of the fibers with no nanoadditive. The obtained nanocomposite fibers are characterised by a tenacity value exceeding 26 cN/tex, accompanied by high sorptive and water-retention properties of 90% and the even distribution of the nanoadditive on the fiber surface. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

This study investigated the relationship between the mechanical properties and the sensorial optimal cooking time (OCT) of spaghetti. Three semolina spaghetti samples with an increasing radius and three non-conventional spaghetti samples (one wholemeal semolina and two maize-based spaghetti) were analyzed. Tenacity, elongation at break and phase shift angle (tan delta) were monitored during the cooking and overcooking of spaghetti using a dynamic mechanical analyzer. The sensorial OCT was also determined by a trained panel. Results highlight that the mechanical parameters are related with the OCT for all investigated spaghetti samples. In particular, a relationship was observed with elongation at break and tan delta.

This study surveys the optimum processing conditions of ATY for PET braiding for automotive hoses. For this purpose, high tenacity and low shrinkable PET filaments with three types of deniers are prepared. Twenty seven ATY specimens are manufactured with variation of feed speed and overfeed on the air jet texturing machine. The physical properties of various yam according to the ATY processing conditions are measured and analysed for deciding the optimum ATY processing condition. Two kinds of ATY filaments made under the optimum air texturing conditions are processed with variation of tpm, heat setting temperature and heat setting time on the 2-for-l twister and setting chamber, respectively. The optimum twisting and heat setting conditions are decided through analysis of the yam physical properties. Finally, the braiding fabric specimens are manufactured using conventional filament and newly developed filament made under optimum twisting and heat setting conditions. The bursting strengths of these braiding specimens are compared and discussed between two types of specimens.

Needle-punched nonwoven fabrics were made from 100% jute fiber using various levels of fabric weight, punch density, and depth of needle penetration. The number of variables and their combinations in the experimental plan were selected following a statistical experimental design technique. Various tensile responses or parameters (e.g., tenacity, breaking extension, initial modulus, work of rupture, permanent set on extension cycling, and stress decay) of needle-punched jute nonwoven fabric were studied. It was observed that at any level of fabric weight, with an increase in punch density and depth of penetration, fabric tenacity, initial modulus, and work of rupture initially increases and then decreases with further increases in punch density and depth of penetration. With the increase in fabric weight, tenacity, initial modulus, and work of rupture initially increase, but at greater fabric weight, though the tenacity becomes steady, initial modulus and work of rupture show a declining trend. Elongation ...

Poly(L,D-lactide) [P(L,D)LA], LL/D ratio 96/4, and poly(L,DL-lactide) [P(L,DL)LA], L/DL ratio 70/30, multifilament fibers were prepared by wet-spinning and the effects of the spin draw ratio and the coagulant on the morphological, thermal, and mechanical properties of the filaments were studied. The hydrolytic degradation of filaments was studied in vitro. The filament diameter and the mechanical properties of filaments were highly dependent on the spin draw ratio, whereas the coagulant had no or minor effect. The filament diameters were in the range of 11–36 μm and the maximum tenacity of 150 MPa was obtained at the spin draw ratio of 7.0 for both copolymers. The copolymer had the main importance on the crystallinity of filaments, but it was also affected by the duration of the coagulation process. The crystallinities of P(L,D)LA 96/4 filaments were in the range of 5–16%, whereas P(L,DL)LA 70/30 filaments were totally amorphous. The degree of crystallinity had effect on the hydrolytic degradation of filaments. The tenacity loss of P(L,D)LA 96/4 filaments was about 10% and that of P(L,DL)LA 70/30 filaments was as high as 50% after 24 weeks in vitro. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

This paper studies the effects of stretching slenderization on the structure and properties of yak hair using an optical microscope, scanning electron microscope (SEM), Raman spectroscopy, tensile curves and dyeability. The SEM results show that stretching slenderization can decrease the diameter of yak hair, and the scale of the fibres is elongated and thinner. As well, the structure of the fibre scale is looser after stretching, and some scale cells are damaged. The stretching process results in the structural transformation of yak hair from an α-keratin to a predominantly β-keratin crystalline structure by the Raman analysis. Through the tensile curves, the slenderizing of the yak hair at different stretching rates is analyzed. The breaking tenacity increases gradually in terms of the stretching rate and breaking elongation decreases. Optical microscope photographs and dyeing rate analysis are used to observe the changes in the dyeability of yak hair before and after the stretching. The results show that after stretching, there is a significant improvement in the dyeing properties of yak hair.

Core spun yarns are applied for various purposes that especially require the multi-functional performance. This research reports on the core spinning effect on the yarn strength. We prepared various core yarns by combining different kinds of high tenacity filaments in core with cotton staples in sheath with various twist levels in the ring spin system. And the tensile strength was tested to investigate the contribution of the core-sheath structure to the core yarn strength. The influence of the twist level was also checked up on the relationship between the core-sheath structure and the yarn strength. Results turned out that the core-sheath weight ratio had influence on the tensile properties of the ring core-spun yarns in different ways according to the core filaments used for the yarn. Increasing the twists yielded a monotone decreasing strength for the aramid and the basalt core yarns, while the PET core yarns showed almost unchanged strength, which could be ascribed to the extensional property of the filaments.

The soybean protein fiber is a new textile material. Thanks to its fine denier, light specific gravity, high strength and silk-like luster，it has so excellent cashmere handle, silk softness and heat resistant properties that it has been called manmade cashmere and found wide application. In order to understand the relationship between the inner structure and the mechanical property and the effect of bleaching and dyeing to the soybean protein fibers，four mechanical models are chosen. The tensile and relaxation property of the soybean protein fibers are analyzed. The tensile and relaxation cures are fitted with the suitable model. It shows that the relaxation property of SPF is in accordance with the standard linear solid model. Estimates of the Hookean spring modulus at 8% and at 10% are different, so some structural modifications could be produced by the strain. Bleached fibers show a higher level of relaxation than raw fibers and dyed fibers. Bleaching has a remarkable influence on decreasing tenacity at break for each test modality. Knotted and looped modalities decrease fiber tenacity remarkably in all three samples.

The aim of this work is to explore a new method for producing spun yarn on a modified ring spinning system which is called “clusterspun yarn”. Here, we describe the effects of the clustering of polyester multifilaments on the internal structure and properties of a composite yarn. Cotton fibers and polyester multifilaments were spun into 19 Ne cluster and core-spun yarns at five different twist levels. These yarns were then tested to compare their properties, including tenacity, elongation, and evenness. Surface morphology and structural variations of cluster and core-spun yarns were studied by scanning electron microscopy. Microtome and image-processing methods have been used to study the structure and packing of fibers in the cross-section of yarns. The results show that the special structure of a cluster-spun yarn results in pronounced enhancement in the structural mechanics and yarn properties. The statistical analysis results indicate that the tenacity and breaking elongation of cluster-spun yarn is significantly more than that in core-spun yarn. The results show that the twist factor at about 3.9(α e) gives the optimum properties. In addition, lower twist is needed to produce quality yarn in cluster-spun yarns as compared with normal core-spun yarns.

This paper surveys the mechanical properties of nylon high tenacity coarse yarn and fabric for military and technical textiles. For this purpose, 6 kinds of yarns and 2 kinds of fabrics are prepared. The yarn physical properties such as yarn count, thermal shrinkages, and tensile properties are measured and discussed with the characteristics of the domestic and imported yarns. And, the physical and mechanical properties of these fabrics are also measured and discussed with the usage of these fabrics in the military and technical textiles fields. Hereafter, the differences of physical properties between domestic and foreign yarn specimens for high functional military and technical fabrics are estimated through this study.

The effects of different factors, namely spinning technologies (ring, rotor and DREF-II, i.e. Group A yarns), position of shrinkable acrylic feed sliver in DREF-II friction spinning system (Group B yarns) and proportion of shrinkable acrylic core fibre in core-sheath type DREF-III friction spun yarns (Group C yarns) on various properties of cotton-acrylic–blended bulked yarns have been studied. The bulk in the yarns was developed by relaxing shrinkable acrylic component of the yarns using boiling water treatment. All the above factors have a significant impact on various properties of cotton–acrylic blended bulked yarns. For all the yarns, after boiling treatment, there is lengthwise shrinkage of yarns and the specific volume also increases. Tenacity and breaking elongation of all the yarns of Group A and Group B increase after hot water treatment, whereas in case of core-sheath type DREF-III yarns (Group C yarns) there is drop in tenacity and breaking elongation after similar treatment. In general, for a...

The authors determined conditions for manufacturing PAN precursor fibers containing a system of two nanoadditives, montmorillonite (MMT), and hydroxyapatite (HAp) in their structure. The PAN precursor fibers thus obtained are characterized by a tenacity of more than 30 cN/tex and a total volume of pores at the level of 0.29 cm3/g. Furthermore, it was found that the use of nanoadditives entails the remodeling of the paracrystalline structure of PAN fibers into a strictly crystalline one. This is accompanied by a decrease in spacing between MMT layers combined with their partial exfoliation. The fibers thus obtained, after being carbonized, will be used for medical applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

The goal of this review is to provide an overview of existing research on the environmental tenacity of avian influenza (AI) viruses, to identify gaps in our current understanding, and discuss how this information relates to AI control, eradication, and prevention. We are just beginning to understand the environmental factors that affect infectivity and the extent of variation in environmental tenacity that is present among these viruses. Because the environment can provide a bridge for AI virus transmission between many diverse hosts, including wild and domestic animals and man, understanding the importance of environmental transmission and identifying important points of contact are critical steps in preventing the spread of infection especially related to the introduction of these viruses to new host species.

This study investigated the tensile properties of a rotating or ballooning staple yarn. The results indicated that the effect of rotating speed on the tensile properties of a ballooning staple yarn was significant. As the yarn rotating speed increased, the tenacity of the rotating or ballooning yarn decreased, while the yarn breaking elongation increased. The effect of rotating speed on the tenacity of a ballooning staple yarn varied for different yarns. These results demonstrated that the breaking force of a ballooning yarn was much lower than the yarn breaking force obtained from normal tensile tests. These results provide new insight into the problems of yarn breakage in yarn spinning and twisting processes.

Heat-set bulked continuous filament (BCF) polypropylene yarns constitute one of the most important pile yarns used in the production of machine-woven carpets. As carpets made from non-heat-set BCF polypropylene yarns lack resiliency and loss of appearance, heat setting of BCF yarns has proved to be very useful in overcoming these deficiencies. This work aimed to investigate the effects of dry steam heat setting on the structure, properties and structural–property relationship of industrially produced heat-set BCF polypropylene yarns. It was ascertained that while tenacity, initial modulus, bending rigidity, crimp contraction and shrinkage decrease as a result of heat setting process, there is an increase in the yarn linear density. Because of these mechanical changes, the resiliency of BCF polypropylene yarns is positively affected by heat-setting process, and as a result, a better wear and look for the carpet pile yarns. Changes in mechanical properties result from microstructural changes, namely, recrys...

This paper reports the variability of mechanical properties of banana fibers with respect to diameter, testing speed and gauge length. We report interesting findings on banana fibers. Tenacity of the fibers significantly improved for the fibers with lower linear density. An increase in speed resulted in improvement of fiber properties to a certain degree. Higher gauge lengths resulted in poor properties due to an increase in flaws in the structure. The banana fibers showed very high variability in linear density and mechanical properties.

The structuring effects of the core and sheath on the tensile properties of core-spun yarns need to be systemized in order to meet potential application requirements. In this study, the core— sheath structuring effect was modeled theoretically, using a spring and damper as mechanical elements. Core-spun yarns with high tenacity filaments as the core and cotton staples as the sheath were prepared and tested to determine their tensile properties. Results demonstrated that the tensile system of the ring core-spun yarn could be described with four mechanical elements, two elements for the core-sheath geometry and two elements for the structuring effect. The core-spun yarns had a lower elastic modulus than the core filaments, and an easy viscous deformation of the core-spun yarn occurred with core spinning. Increasing the number of twists led to a consistent decrease in the strength of aramid core-spun yarn, while the high tenacity PET core-spun yarn had almost unaffected tenacity for various twist levels. The basalt core-spun yarn, however, demonstrated a twist factor level that indicated a potential maximum yarn tenacity. The breaking elongation of the aramid core-spun yarn had an increasing tendency with the number of twists. The high tenacity PET core-spun yarn remained in a limited range of elongation with twists. The basalt core-spun yarn had noticeably greater elongation as the number of twists increased.

Nonwoven materials have been used in ballistic protection applications because they offer the advantages of light and flexible fabrics. This study examined the ballistic protection efficacy of a nonwoven structure with high tenacity polyamide staple fiber as its main component. The nonwoven structure was reinforced with low-melt polyester fiber. High tenacity filaments were laid between two layers of polyamide webs and bonded via needle punching. The impact-resistant properties were assessed using dropped weight and bullet-shooting impact tests. The results of the dropped weight-impact test were used to examine the optimum processing conditions for composite nonwoven fabrics. Furthermore, the results of the bullet-shooting test were used to examine the ballistic protection performance of composite nonwoven fabrics. The experiment's results demonstrated that the cushion structure of composite nonwoven fabric could reduce non-penetration damage and increase the ballistic-resistant properties of bullet-resistant vest.

It is well-known that one of the principal difficulties which limit the development of ceramics is their intrinsically brittle nature. In this work we were interested to the study of the single crystal alumina tenacity measured by the Vickers indentation technique in the aim to highlight certain factors responsible for this brittleness. After having defined a reliable protocol of measurement on pure sapphire, we studied the effect on tenacity of the structural defects introduced into the same single crystal by friction and by both X-rays and UV irradiations. The obtained results reveal the importance of these defects which behave, in this case, like trapping sites of electric charges and affect in an important way tenacity of material.

The photooxidative degradation of acrylic fibers was investigated with two different fiber-spinning processes, that is, dry spinning and wet spinning. Several analytical methods were used in this study: viscometry, X-ray diffraction, Fourier transform infrared spectroscopy, optical measurements, and mechanical testing. Viscometry was used to determine the molecular weight as a monitoring factor for degradation. X-ray diagrams showed lower changes in the crystallinity of wet-spun fibers during a weathering process by irradiation. The results from mechanical testing indicated that the tenacity of dry-spun fibers had less deterioration than that of wet-spun fibers. Degraded wet-spun and dry-spun fibers showed similar trends in optical and spectroscopy analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Combining the two basic techniques used for the preparation of single polymer composites (SPCs), hot com- paction and film stacking, a polyamide 6 (PA 6) single polymer composite was manufactured. The starting materials were PA 6 high tenacity yarn (reinforcement) and PA 6 film prepared via melt quenching (matrix), both expected to be the two principal polymorphic modifications of PA 6 and thus differing in their melting temperatures. The prepared single polymer composite is characterized by a layered structure and shows superior mechanical properties due to the good wetting - ten- sile modulus is improved by 200% and the ultimate tensile strength - by 300-400% as compared to the isotropic matrix film. Improvement of the interfacial adhesion via transreactions promoted by Sb2O3 as a catalyst was also undertaken.

This work presents an analysis of a mechanical model for cotton plied yarns' tenacity. Results show that the tenacity of a plied yarn depends on the parameters of twisting and the linear density. For verification of the theory, we have also applied this model for the ring and Open End plied yarns. Comparison between experimental data and theoretical predictions showed that the predicted yarn tenacity is in reasonable agreement with experiment results.

In raw materials of dromedary hair, there are two distinct fibre populations: the fine one is of textile relevance and the coarse one is rather worthless and must be as a rule separated prior to spinning and subsequent processing. The paper reports an investigation into the effects of fibre passage sequence throughout the Shirley Analyser on the efficiency, the mean fibre diameter and the mean fibre length of the dehairing dromedary hair. Also, it presents the effect of dehairing dromedary hair process on the yield samples. The results show that the most important effect on percentage yield, mean fibre diameter and mean fibre length is caused by the first passage throughout the Shirley Analyser. Following these experiments, we determined an optimal number of passages which is 4. So, the paper discusses the effect of opening operation for dromedary fleece before dehairing on the percentage yield and efficiency of dehairing.

In this study, the interaction between blended rotor-spun yarns of cotton and polyester fibers has been investigated using the hybrid model. Various blends of PET/CO were produced and tensile and evenness properties of yarns were examined. The migration index of yarns has been calculated to study how migration affects the yarn properties. The difference between the experimental values and predicted values has been studied statistically using the rule of mixtures. The results of the tenacity of yarns have been compared with Hamburger's model. The results show that elongated and thin places have no significant difference in the rule of mixtures model. Tenacity, work of rupture, and hairiness are decreased in blended yarns while the uniformity, thick places, and neps are increased. The tenacity of the yarns does not follow the Hamburger's model. The migration index shows that cotton fibers tend to migrate inwards and the migration index of this fiber is minimum at 75:25 and maximum at 50:50 PET/CO b...

The effect of nanoclay concentration on the molecular orientation and drawability of poly(ethylene terephthalate) PET was examined using thermal and vibrational spectroscopic analysis. Although drawability at 83 °C in hot air increased by the addition of nanoclay, the maximum draw ratio was independent of nanoclay concentration. The average molecular orientation of the PET chain was found to mimic the trend in mechanical property improvements. Both Young's modulus and tenacity (i.e. strength) showed the maximum improvement at a 1 wt% loading of clay, which was shown to coincide with the maximum amount of molecular orientation. Nanoclay was shown to intercalate with PET and enhanced amorphous orientation that led to modulus and strength improvements. However, at higher concentrations of nanoclay the presence of large agglomerates prevented efficient orientation to the fiber axis and acted as stress concentrators to aid in cavitation and failure during testing. Raman spectroscopy showed that the as-spun unfilled PET fibers possessed significantly more trans rotamer content of the ethylene glycol moiety than the nanocomposite fibers.

BACKGROUND: Some of the problems with electrospun zein fiber are that it has very low tenacities in the dry and wet states and that mats of the fiber become films when immersed in water. The fibers are therefore unusable for various applications despite their good biocompatibility and biodegradability. This research was conducted to overcome these problems by electrospinning novel fibers containing various concentrations of zein, citric acid (CA) and sodium hypophosphite monohydrate (SHP) and by crosslinking the zein with CA and with SHP serving as a catalyst. RESULTS: The CA-crosslinked electrospun zein fiber has as much as 10-fold greater wet tenacity and 15-fold greater dry tenacity than regular electrospun zein fiber. The average diameter of these fibers is 451 nm, which is the smallest diameter ever reported for zein-based electrospun fiber. A mat of this fiber retains its fibrous structure when immersed in water, and the fiber retains about 70% of its tenacity after 16 days at 50 °C and 90% relative humidity. CONCLUSION: The high dry and wet tenacities, good water stability and small diameter of the novel CA-crosslinked electrospun zein fiber make it attractive for biomedical and other applications that expose zein to water or that require high surface area. Copyright © 2008 Society of Chemical Industry

BACKGROUND: Although several cereal proteins have been used to develop fibers and films, it has not been possible to obtain protein materials with good mechanical properties and water stability, even after crosslinking. Previously, high concentrations of glutaraldehyde were used to improve the mechanical properties of protein fibers but the effect of crosslinking conditions on the properties of the crosslinked materials has not been studied in detail. RESULTS: Low concentrations of glutaraldehyde can be used to improve the mechanical properties and water stability of gliadin fibers. Quantitative relationships that can predict the breaking tenacity of the fibers at various crosslinking conditions are developed. Glutaraldehyde crosslinking is more resistant to hydrolysis in neutral pH than under acidic conditions in terms of increasing and retaining the breaking tenacity. The crosslinked fibers show improved resistance to hydrolysis over poly(lactic acid) fibers in aqueous dispersions at pH = 4 and 7 at 50 and 90 °C, respectively. CONCLUSIONS: This study shows that low concentrations of glutaraldehyde can impart excellent mechanical properties to gliadin fibers. The quantitative relationships developed can be used to select the crosslinking conditions such low glutaraldehyde concentration and high temperature or vice versa to obtain the desired improvement in mechanical properties or water stability. Copyright © 2008 Society of Chemical Industry

As pilling in textiles originates from many factors, the kinetic of pilling formation play an important role in the investigation and approaches of pilling. The single jersey-knitted lyocell fabrics were treated with different alkaline solution concentrations and submitted to Rapid Pilling Test—a wet-state Martindale test for cellulosic fabrics performed with increasing abrasion cycles. After each type of cycles, the pilling density was microscopically counted, and then pilling was visually rated. The changes in fiber properties were followed by water retention values (WRV), fibers swelling, fiber wet abrasion resistance (NSF), and fibers tenacity/elongation in wet and in dry states. The kinetics of pill formation—quantified by pills/cm2—occurred in the following steps: pills are promptly formed at first abrasion cycles, reached the pill plateau cycles, and are self-removed from the fabric surface. The untreated and alkali-treated lyocell fabrics followed a similar trend of pill formation. However, the pilling propensity is distinct depending on the concentrations. The changes in the swollen state of fiber properties and fiber–fiber friction mainly determined the pill kinetics in lyocell fabrics. The kinetic model aims to figure out the pilling mechanism and the appropriate treatment for pilling resistance. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Although high performance fibers possess higher thermal resistant properties, they show very low sunlight stability. In this paper, a new sol-gel treatment method was used to enhance their light-resistant properties. Their mechanical property retention ratios (tenacity, extension, modulus) of fibers treated with titanium hydrosol were higher than those of the original Kevlar®129, PBO, and Kermel® fibers after light irradiation. Moreover, Kermel® fiber showed the highest improvement among the three kinds of fibers.

Air-jet texturing of conventional poly(ethylene terephthalate) (PET) yarns, having the same chemical structure with high modulus and tenacity PET yarns, are studied in order to improve their adhesion to rubber. Air-jet texturing of these yarns is performed without any visible loop formation in order to minimize the mechanical loss, and an improvement in the adhesion to rubber of conventional PET yarns is achieved. This improvement is investigated by means of surface changes of single. laments and yarn geometry changes due to air-jet texturing. Changes of the cross-sectional structure of the yarns after air-jet texturing and therefore a higher surface area is found to be the main reason for this improvement. (C) 2008 Elsevier B. V. All rights reserved.

Orbiculariae consists of two major clades: the cribellate Deinopoidea and the much more diverse ecribellate Araneoidea. It has been hypothesized that the higher diversity of Araneoidea is a consequence of the superiority of the viscid orb web. However, this explanation seems incomplete; for example, cribellate silk may perform better than viscid silk in some contexts. Here, we consider the hypothesis that the diversification of Araneoidea was facilitated by changes in microhabitat occupation behavior due to the cheaper viscid orb web. In the present work we investigate the idea that the reduction in site tenacity caused by the emergence of the viscid orb web has led to an increase in the exploration of different resources and to a greater diversification of the Araneoidea through the evolutionary time. To test this idea, we evaluated the response of one cribellate orb web spider (Zosis geniculata Olivier 1789, Uloboridae) and one ecribellate orb web spider (Metazygia rogenhoferi Keyserling 1878, Araneidae) to abrupt prey absence. The changes in site tenacity and the day-to- day investment in web silk were evaluated. Spiders with three-dimensional webs tend to exhibit greater site tenacity than spiders making orb webs. Zosis geniculata and M. rogenhoferi show similar site tenacity when prey is ample. When prey is unavailable, the tenacity of the cribellate species increases while the tenacity of the ecribellate remains unchanged, and the silk investment of both species decreases. However, this decrease in silk investment is more extensive in Z. geniculata. These results coincide with the idea that a less costly ecribellate orb web leads to a lower tenacity and suggest that more frequent microhabitat abandonment in a context of insect radiation (Neoptera) leads to more diverse and opportunistic exploration of microhabitats that, in the long term, may be one explanation for the greater Araneoidea diversification.

Characterization of modified jute fibres treated with selective mixed enzyme and aminosilicone compound has been reported earlier. This part of the study relates to assessment of the effectiveness of such chemical (aminosilicone) and biochemical (mixture of cellulase, xylanase, and pectinase enzymes) modifications of raw jute fibres (with or without selective pretreatments using dilute NaOH, H2O2, and a combination of H2O2 and K2S2O8) on process performance during yarn making and property parameters of such yarns. Usually, jute fibres are spun into yarns applying 1.5% to 3% mineral oil-in-water emulsion prior to carding. 0.5% aminosilicone treatment of jute fibres under specified condition makes them suitable for yarn making without the use of mineral oil, and produces a softer yarn having substantially lower yarn mass irregularity and yarn imperfection values, though with some lowering in tenacity values. Some advantages accrued in regard to process performance (energy efficiency and less fibre ...

The present study relates to broad-based assessment of softening of raw jute and selectively pretreated jute fibres under the action of mixed enzymes (cellulase, xylanase and pectinase) and a textile grade aminosilicone softener and to further assess how such selective treatments finally contribute in enhancing some textile-related properties. Application of 4% mixed enzyme on jute fibre at 55°C for 2 h at pH 4.8 offers much finer, softer, cleaner and brighter jute fibre with some lowering of bundle tenacity. However, pretreatment of jute fibre under combined oxidative action of 3% H2O2 and 0.75% K2S2O8 for 2 h at 30°C (pH 11) followed by subsequent treatment with 1% mixed enzyme offers a better balance of textile-related properties covering moisture regain, fineness, bundle tenacity, flexural rigidity, surface reflectance, whiteness index, yellowness index and brightness index. Treatments of jute fibre with 0.5–1% aminosilicone softener under a specified condition also make jute fibre much softe...

Enzymatic treatment of fabrics is known to have a negative impact on the fabrics' tensile characteristics. The strength loss problems would be more severe in the case of nonwovens, since cellulase could attack bonded areas of the fabric. To prevent the fabric strength loss, a study was undertaken to treat cotton fibers as opposed to the final fabric. Raw cotton fibers were hydrolyzed with Cellusoft L and endoglucanase without a cellulose— binding domain. Factors such as the reducing end group, fiber length and tenacity were followed throughout the enzymatic hydrolysis. The results showed that if the concentration of Cellusoft L cellulase mixture was minimized to 0.25 % owf, extensive weakening of cotton fibers could be prevented. Endoglucanase demonstrated a moderate reduction in fiber strength; most of the reduction occurred at the beginning of hydrolysis. The concentration of reducing ends was observed to have a maximum for both enzyme solutions. The location of enzymatic attack and changes in surface morphology were monitored by Congo red staining and scanning electron microscope, respectively.

Textile fibers reinforced with carbon nanotubes (CNT) show significant improvement in mechanical properties. Being lightweight and stronger than ordinary textile grade fibers, they can be used for different reinforcement applications. This paper reports a study on the comparison of the mechanical properties of composite fibers made of polypropylene (PP) and CNT obtained from different sources. A single walled nanotube from Carbolex USA, mutiwalled nanotubes from Iljin, Korea and DMSRDE Kanpur are used for the study. The composite fibers are made in two varieties viz. 0.5wt% and 1wt% concentration of CNT. It is observed that the mechanical properties, such as tenacity and modulus, increased with increased concentrations of the CNT irrespective of the brand and nature of the synthesis. The composite fibers made of multi walled CNT produced by DMSRDE give the best results in terms of spinnability and mechanical properties. The tenacity of the DMSRDE fibers is as high as ∼9gpd and modulus as high as 114gpd.

Nylon textured yarn is usually manufactured by disk type false twist texturing. Dyeing properties of nylon textured yam have not been studied yet. In this study, dyeing properties of nylon textured yam according to draw ratio out of process parameters were investigated. The fact that microstructure of nylon textured yarn in amorphous region particularly is transformed by draw ratio was confirmed indirectly by measurement of dyeing rate because dyeing rate was affected by the structure of amorphous region. Dyeing rate at draw ratio 1.29 was the lowest because the higher draw ratio increase amorphous orientation and disturb dye diffusion into amorphous region. The microstructure according draw ratio was indirectly confirmed by 5% strength, tenacity, elongation. But difference in K/S value and fastness was insignificant.

Summary. Adult Buller's Mollymawks Diomedea bulleri banded in 1948 and 1961 at the Snares Islands south of New Zealand have been recovered between 1961 and 1971. Survival curves are presented which indicate the existence of a constant annual mortality rate of not more than 11.1 % with a mean expectation of further life at the time of banding of not less than 8.5 years. Breeding birds show a strong tendency to retain both the pair bond and the nest-site. One pair was still breeding in 1971 at the same nest at which it bred 23 years earlier. No re-matings were recorded while the original partner was known to be still alive. The dimensions of eggs laid over the years by particular females are presented. These enable some general indications to be given of the effects of the age of the female on the dimensions of the eggs which she lays.

The effect of various characteristics of Canada Goose Branta canadensis females and clutch size on their nest defence intensity during incubation was studied in the field during five nesting seasons. Nests were approached by a human, and the leaving distance was measured. Risk-taking in post-encounter behaviour was categorized at three levels. Nesting success was significantly associated with nest tenacity, a variable derived from leaving distance, but not with post-encounter behaviour. Nest tenacity, as well as post-encounter behaviour, differed significantly between individuals. Intensity of post-encounter behaviour, but not nest tenacity, increased with increasing age of the female. Nest tenacity, standardized over the incubation period, increased with increasing clutch size, but post-encounter behaviour intensity did not. None of the nest defence variables was correlated with the structural size of the female. Nest tenacity, but not post-encounter behaviour intensity, increased during incubation. Nest tenacity did not differ between early and late breeders, but post-encounter behaviour was more intense in late breeders. There was no evidence of positive reinforcement of nest defence through repeated visits. Nest defence did not differ between lakes, lake types or nest site types, nor was it affected by the distance to the nearest neighbouring nest. The results supported several of the predictions extracted from parental investment theory.

Thermoplastic starch materials are often based on a combination of starch, glycerol and water. In the present study, two potato starch grades were employed; a native (natural) grade and an oxidised and hydroxypropylated grade of the native material, in order to produce the thermoplastic material. The primary aim of the study was to identify possible routes for film blowing thermoplastic starch on a laboratory scale by a suitable choice of processing conditions, amount of glycerol and moisture content. With an appropriate combination of these parameters, the thermoplastic material based on the modified starch could be film blown in a satisfactory manner. Film blowing of material based on the natural starch was significantly more difficult. The difficulties encountered were mainly related to a sticky surface of the film, insufficient tenacity and foaming. The processing window for thermoplastic starch (related to film blowing) is briefly outlined and discussed.

The new paint of environment-friendly was fabricated that TDE-85 and other materials incorporation into epoxy resin enhanced tenacity, strength, thermal stability, humidity resistance and corrosion resistance due to its inherent flexibility. The paint’s viscosity is less 1000mPa·s in 25°C, can spread directly. Result of the corrosion velocity test indicates the coating’s corrosion velocity in 3.5% salt-liquor less than 0.02 g/m2h. The bending and shearing strength of EW-200 buildup epoxy resin is 649MPa and 57MPa in 25°C. The strength is stable after placing -30°Cfor 12h and 65°C for 12h. The scanning electro photomicrograph shows the type of failure breaking is a tough fracture.