Melt Spinning Machine Research Articles

Fabrication and properties of precursor-derived SiBN ternary ceramic fibers

In this paper, polymer precursor polyborosilazane (PBSZ) was synthesized from hexamethyldisilazane, HSiCl3, BCl3 and CH3NH2 using a multi-step polymerization process. Continuous PBSZ fibers were prepared by a laboratory scale melt-spinning machine. SiBN ceramic fibers were then obtained by the pyrolysis of PBSZ fibers. The chemical structure character and its ceramic conversion of the polymer precursor were presented. After high temperature pyrolysis process at 1100°C, SiBN ceramic fibers were obtained with a diameter of about 14μm. Those fibers showed average tensile strength of 0.87GPa. The carbon content of the obtained SiBN ceramic fibers was less than 0.1wt%. SiBN ceramic fibers revealed excellent dielectric properties and structural stability at high temperatures.

Structure and properties of ethylene-tetrafluoroethylene fibers fabricated by melt spinning

Ethylene-tetrafluoroethylene (ETFE) fibers were fabricated by a single-screw melt spinning machine at different drawing roll speed ratios and different drawing roll temperatures. Thermogravimetric analyzer, differential scanning calorimetry, X-ray diffraction (XRD), digital fiber sound velocimeter and single fiber strength testers were used to discuss the impacts of spinning processes on the structure and performance of ETFE fibers. The results indicated that four different fibers showed a similar melting temperature at around 257℃. XRD results revealed that the largest crystallinity of four ETFE fibers was 41.1%. As the drawing temperature increased, the crystallinity of ETFE fibers decreased and the grain size increased. The breaking strength of four as-spun ETFE fibers reached up to 1.12 cN/dtex. The minimum shrinkage of ETFE fibers at 200℃ was 7%, and it was only 1% at most below 150℃. The maximum creep strain of ETFE fibers was 6% when the loading capacity was 20% of the breaking strength at room temperature and ETFE fibers had a high recovery ratio of >90% after the load was removed. Moreover, ETFE fibers showed exceptional corrosion resistance and good performance of irradiation resistance.

Polyester fabric with inherent antibacterial, hydrophilic and UV protection properties

Polyethylene terephthalate (PET) yarn with multifunctional properties such as UV protection, antimicrobial property and cotton-like moisture transport properties was fabricated in a semi-commercial melt spinning machine. Effects of chemical modifications and additives on PET yarn with polyethylene glycol (PEG) and zinc oxide (ZnO) were studied and reported. It was found that ZnO imparts UV protection and antimicrobial properties and PEG helps to improve moisture management. Bacteriostatic activity above 3.5 was observed with ZnO incorporation. High wicking length of 15 cm was obtained as against 2 cm for control PET fabric of same construction.

Effect of TiO2@SiO2 nanoparticles on the mechanical and UV-resistance properties of polyphenylene sulfide fibers

In order to avoid the inherent photo-catalysis and aggregation of TiO2 in PPS, TiO2 nanoparticles were coated with SiO2 layers, which were chosen as the UV absorbent to improve the UV stability of polyphenylene sulfide (PPS) fiber. The PPS–TiO2@SiO2 nanocomposites fibers were prepared via melt spinning, and the nanocomposites fibers displayed different crystallization behaviors on variation of the diameters of TiO2@SiO2 nanoparticles, as confirmed by Differential Scanning Calorimetry (DSC). The spinnability, breaking strength and UV-resistance properties of PPS nanocomposites fibers, as measured by homemade melt spinning machine, Xenon-lamp Weather Resistance Test Chamber and Yarn Tensile Tester, manifested the dependence on the diameters. The addition of nanoparticles with the diameter of 25nm improved the spinnability and the mechanical performance of PPS most, which is attributed to the heterogeneous nucleation effect of nanoparticles. The UV-resistance properties of the PPS nanocomposites were improved by the addition of TiO2@SiO2 nanoparticles. After aging for 180h, PPS nanocomposites fiber still maintained a high strength.

Comparison of the Morphological, Mechanical, and UV Protection Properties of TiO2/Polyamide 6 (PA6), and ZnO/PA6 Nanocomposite Multifilament Yarns

The properties of TiO2/polyamide 6 (PA6) and ZnO/PA6 nanocomposite filament yarns produced on a pilot-plant melt spinning machine were compared. Concentrated masterbatches were prepared using a twin screw extruder. Then continuous multifilament yarns were produced by blending nylon 6 chips and various amounts of the prepared masterbatches. Melt spinning was carried out at the spinning temperature of 265°C and take-up speed of 4000 m/min. As-spun multifilament yarns were then drawn and textured. Morphological properties of the produced yarns were studied. Thermal behavior and physical properties, including shrinkage and tensile properties, were measured. Weft-knitted fabrics were evaluated for their ultraviolet protection properties. Although both kinds of the nanoparticles had a positive effect on the ultraviolet protection properties of their nanocomposite fabrics as compared to pure PA6 fabric, the efficiency of the TiO2 nanoparticles was more than that of the ZnO ones for the same concentrations. The differences between the different properties of the two kinds of nanocomposites are discussed based on their interaction with the polymeric matrix, specific surface area, steric hindrance effect, and band gap energies.

Recognition of fault process parameters for diameter uniformity variation in melt spinning

This study focused on the abnormal condition of diameter variation in melt spinning, and attempted to recognize the machine processing parameter that deviates from the set value. The experiment used polypropylene as the experimental material. The machine processing parameters included nine factors, including temperatures in three extruder barrel sections, temperature of metering pump, die temperature, spinneret temperature, speed of an extruder screw, speed of metering pump and speed of take-up roll. The biaxial laser sensor measured the yarn diameter instantly, and the optimum parameter combination for minimum diameter variation was obtained by Taguchi method and analysis of variance (ANOVA). The degree of influence of various processing parameters on the diameter variation was determined. The optimum parameter combination was used as parameter setting value, and the processing parameters of various factors were changed for experiment, so as to obtain the signals of abnormal condition. Two methods were used for feature extraction. The minimum entropy of wavelet transform signal was used as eigenvector, and two features were selected by analyzing the statistical process control chart, which are skewness and kurtosis. The abnormal processing parameters and normal condition were recognized effectively and accurately by using the three eigenvalues and back-propagation neural network. With enough training samples, the recognition success rate was as high as 100 %. For complete abnormity diagnosis of melt spinning machine, a two-factor classification process was established by using the single-factor classification result and back-propagation neural network. The experimental results proved that the proposed method can recognize various abnormal conditions successfully and effectively.

Application of a fuzzy neural network to control the diameter and evenness of melt-spun yarns

In the melt-spinning process, evenness of melt-spun yarns will affect the appearance, hairiness, strength, and the production of yarns. Great variations in yarns may cause defects. Yarns with small variation can have a more stable quality. In this study, we applied the fuzzy neural network (FNN) control theory to the melt-spinning machine. By adjusting the speed of the take-up rollers, the average yarn diameter reached the target value, allowing a reduction in variations. Diameter error and diameter error variation were also used as input, and the increments in take-up roller speed were used as output. The FNN was used to adjust the mean and standard deviation of the membership function in the second layer and the connection weighted value of the third and fourth layers in order to achieve convergence and the learning effect. The experimental results showed that the FNN controller maintained the average diameter of yarns and reduced the variation of the yarn diameter. Therefore, the proposed method could be successfully applied to on-line control of yarn evenness.

Physical and Mechanical Properties of Nylon 6/ Titanium Dioxide Micro and Nano-Composite Multifilament Yarns

In this study, the effect of titanium dioxide particles (TiO2 micro and nano) on the physical and mechanical properties of Nylon 6–based multifilament yarns was investigated. For this reason, master-batches of Nylon 6/TiO2 micro and nano-particles were prepared by melt compounding before spinning and then multifilament composites incorporating 0.03, 0.33, 0.5 and 0.7% TiO2 micro and nano-particles were successfully spun in a melt-spinning machine. Characterization of these composite multifilament yarns was carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive x-ray (EDX), and X-ray diffraction (XRD) analysis. Characterization of mechanical strength properties including tenacity and elongation at break of the resultant composites are discussed as a function of filler loading. Through the application of scanning electron microscopy (SEM) and transmission electron microscopy (TEM), it was found that incorporating micro titanium dioxide caused severe aggregation at the nylon fiber surface. By contrast, the diffusion of nano-particles within bulk of multifilament yarns was much more consistent, although aggregation of the titanium dioxide nano-particles still appeared. The results manifested the improvement of mechanical properties of the nano-composites containing TiO2 nano-particles.

Investigation on the physical and structural properties of melt-spun multifilament yarns, drawn yarns and textured yarns produced from blend of PP and oxidized PP

In the present study, effect of OPP (oxidized PP) fraction on the mechanical and structural properties of produced fibers is investigated. Polypropylene powder without antioxidant materials was oxidized at the suitable thermal condition. The various fractions of OPP were blended with PP in the chips shape, and employed as starting material in a melt spinning machine for production of filament yarn. Then as-spun filaments were drawn and finally textured. Structural properties including density, birefringence and FTIR and physical properties consisting of shrinkage, tensile properties and crimp properties were measured. Results show that blending of OPP with virgin PP reduces tacticity and crystallinity, but it hasn’t any effect on orientation. Physical properties of drawn yarns and textured yarns were reduced with increasing of OPP fraction. Moreover, increasing of OPP fraction in blend, reduce crimp properties of textured yarn.

EVOLUTION OF NANOGRAINS AND SOFT MAGNETIC PROPERTIES OF Fe74Cu0.8Nb2.7Si15.5B7 BY ISOTHERMAL ANNEALING

Fe -based alloy of the composition, Fe 74 Cu 0.8 Nb 2.7 Si 15.5 B 7 has been studied thoroughly in order to research the evolution of nanograins and soft magnetic properties. The composition has been significantly deviated from FINEMET type composition given by Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9. It is hard to optimize composition to obtain equally good soft magnetic properties as FINEMET significantly deviating from conventional type alloy. Fe -based alloy of the composition, Fe 74 Cu 0.8 Nb 2.7 Si 15.5 B 7 has been prepared by single roller melt spinning machine. X-ray diffraction studies confirmed that the ribbon is in the amorphous state. Evolution of α- Fe ( Si ) nanograins from amorphous matrix were carried out by isothermal annealing in the temperature range from 550°C to 650°C for 1, 3, 5, 10, 20, 30, 40, 50 and 60 minutes. Frequency spectrum of real and imaginary part of complex initial permeability has been measured for the samples at different annealing conditions. Short time annealing has been proved to be more efficient than long time annealing for the samples of this composition for most of the annealing temperatures.

Investigating the production and properties of Ag/TiO2/PP antibacterial nanocomposite filament yarns

In this research, investigating the possibility of producing, processing and also characterization of antibacterial organic/inorganic nanocomposite polypropylene fiber has been presented. For this purpose, PP powder and inorganic nanocomposite filler were mixed using a twin screw extruder and modified granule was produced. After producing as-spun filament yarns by a pilot plant melt spinning machine at the take-up speed of 2000 m/min, samples were drawn, textured and finally weft knitted. Physical and structural properties of as-spun and drawn yarns with constant and variable draw ratios were investigated. The experimental results revealed that the crystallinity reduction of modified as-spun yarns could be compensated by drawing process. Tensile properties of modified drawn yarns with the variable draw ratio were higher than the pure PP, whereas the inverse observation was noticed in the case of constant draw ratio. The investigation of antimicrobial activity showed a high percentage of biostatic efficiency on the modified samples.

Fiber to Fabric Processability of Silver/Zinc-loaded Nanocomposite Yarns

In this research, investigating the possibility of producing, fiber to fabric processing and also characterization of antibacterial organic/inorganic polypropylene (PP) filament yarns for permanent antimicrobial efficiency has been presented. The development of bacteriostatic filament yarn has been realized from mixing of virgin PP granule and various blending contents of silver/zinc-concentrated masterbatch. After producing as-spun filament yarns by a pilot plant melt spinning machine at the take-up speed of 2,000 m/ min, samples were drawn, textured and finally weft knitted. Physical and structural properties of as-spun and drawn yarns with constant and variable draw ratios were investigated and also tensile and crimp properties of textured yarns were evaluated. Tenacity and modulus of modified as-spun and drawn yarns were significantly higher than the pure PP. The investigation of antimicrobial activity showed a high percentage of biostatic efficiency on the modified samples.

Comparing the effect of three processing methods for modification of filament yarns with inorganic nanocomposite filler and their bioactivity against staphylococcus aureus

This research compared three methods for producing and processing nanocomposite polypropylene filament yarns with permanent antimicrobial efficiency. The three methods used to mix antimicrobial agents based on silver nano particles with PP were as follows: 1) mixing of PP powder and inorganic nanocomposite filler with the appropriate concentration using a twin-screw extruder and preparing granules, 2) method 1 with a singlerather than twin-screw extruder, and 3) producing the masterbatch by a twin-screw extruder and blending it with PP in the melt spinning process. All pure polypropylene samples and other combined samples had an acceptable spinnability at the spinning temperature of 240 °C and take-up speed of 2,000 m/min. After producing as-spun filament yarns by a pilot plant, melt spinning machine, the samples were drawn, textured and finally weft knitted. The physical and structural properties (e.g., linear density, tenacity, breaking elongation, initial modulus, rupture work, shrinkage and crystallinity) of the as-spun and drawn yarns with constant and variable draw ratios (the variable draw ratio was used to gain a constant breaking elongation of 50%) were investigated and compared, while DSC, SEM and FTIR techniques were used to characterize the samples. Finally, the antibacterial efficiency of the knitted samples was evaluated. The experimental results revealed that the crystallinity reduction of the as-spun yarn obtained from method 1 (5%) was more than that of method 2 (3%), while the crystallinity of the modified as-spun yarns obtained with method 3 remained unchanged compared to pure yarn. However, the drawing procedure compensated for this difference. By applying methods 2 and 3, the drawing generally improved the tenacity and modulus of the modified fibers, whereas method 1 degraded the constant draw ratio. Although the biostatic efficiency of the nanocomposite yarns was excellent with all three methods, the modified fabrics obtained from methods 1 and 2 showed a higher bioactivity.

Processing and Properties of Nanocomposite Filament Yarns with Various Filler Concentrations from Two Different Modification Methods

AbstractIn this research, the possibility of producing and processing nanocomposite polypropylene filament yarns with permanent antimicrobial efficiency has been assessed by comparing two different methods. Therefore two approaches were used to mix various blending contents of antimicrobial agents based on silver/TiO2 nano particles with PP: 1) mixing of PP powder and inorganic nanocomposite powder as an antibacterial agent with the appropriate concentration in a twin screw extruder, preparing modified granules and feeding them to the melt spinning machine, 2) producing masterbatch by a twin screw extruder and blending it with PP in the melt spinning process. In both methods, pure PP and all other combined samples had an acceptable spinnability at the spinning temperature of 240 °C and take‐up speed of 2000 m/min. After producing as‐spun filament yarns by a pilot plant melt spinning machine, samples were drawn, textured and finally weft knitted. Physical and structural properties of as‐spun and drawn yarns with constant and variable draw ratios were investigated and compared. Moreover, the DSC, SEM and FTIR techniques have been used for samples characterization. Finally antibacterial efficiency of knitted samples was evaluated. The experimental results indicated that the maximum crystallinity reduction of modified as‐spun yarns reached 5%. But by applying method 2 (masterbatch), crystallinity of modified as‐spun yarns remained unchanged compared to pure yarn. However, drawing procedure has compensated this difference. By applying the second method, the drawing generally improved the increase of tenacity and modulus of modified fibers, whereas in method 1 the opposite effect was noticed in the case of constant draw ratio. Although the biostatic efficiency of nanocomposite fibers was excellent in both methods, modified fabrics obtained from method 1 showed higher bioactivity.

Investigating the effect of various blend ratios of prepared masterbatch containing Ag/TiO2 nanocomposite on the properties of bioactive continuous filament yarns

In this research, possibility of producing and processing antibacterial organic/inorganic nanocomposite polypropylene filament yarns for permanent antimicrobial efficiency has been investigated. First PP powder and inorganic nanocomposite filler were mixed in a twin screw extruder and modified masterbatch was produced. Continuous filament yarn was made by a pilot plant melt spinning machine from the blend of PP granule and various blending contents of the prepared masterbatch. Pure PP and all other combined samples showed acceptable spinnability at the spinning temperature of 240 °C and take-up speed of 2000 m/min. After producing as-spun filament yarns, samples were drawn, textured and finally weft knitted. Physical and structural properties of as-spun and drawn yarns with constant and variable draw ratios were investigated and also tensile and crimp properties of textured yarns were evaluated. Moreover, the DSC, SEM, FTIR techniques have been used for characterization of samples. Finally antibacterial efficiency of knitted samples was evaluated. The experimental results indicated that the maximum crystallinity reduction of modified drawn yarns has reached to 5 %. The observed improvement in the tensile properties of modified as-spun yarns compared to the pure PP was significant. Drawing process improved generally the tensile properties of as-spun yarns. Tensile properties of modified textured and drawn yarns were higher than the pure PP. An optimum of antibacterial activity has been observed in the sample containing 0.75 wt% of nano-filler. It is interesting that the optimum of tensile properties has been also obtained for the sample with maximum bioactivity.

Isotactic polypropylene hollow microfibers prepared by CO2 laser‐thinning

AbstractAn isotactic polypropylene hollow microfiber was continuously produced by using a carbon dioxide (CO2) laser‐thinning method. To prepare the hollow microfiber continuously, the apparatus used for the thinning of the solid fiber was improved so that the laser can circularly irradiate to the hollow fiber. Original hollow fiber with an outside diameter (OD) of 450 μm and an internal diameter (ID) of 250 μm was spun by using a melt spinning machine with a specially designed spinneret to produce the hollow fiber. An as‐spun hollow fiber was laser‐heated under various conditions, and the OD and the ID decreased with increasing the winding speed. For example, when the hollow microfiber obtained by irradiating the CO2 laser to the original hollow fiber supplied at 0.30 m min−1 was wound up at 800 m min−1, the obtained hollow microfiber had an OD of 6.3 μm and an ID of 2.2 μm. The draw ratio calculated from the supplying and the winding speeds was 2667‐fold. The hollow microfibers obtained under various conditions had the hollowness in the range of 20–30%. The wide‐angle X‐ray diffraction patterns of the hollow microfibers showed the existence of the highly oriented crystallites. Further, the OD and ID decreased, and the hollowness increased by drawing hollow microfiber obtained with the laser‐thinning. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2600–2607, 2006

Production and Characterisation of Multifilament Yarns Made from Polypropylene Containing Small Amounts of Oxidised Polypropylene

In the present work, oxidation of fibre grade polypropylene granules in the melt phase using oxygen gas has been performed. Then, virgin polypropylene granules were mixed with up to 10% by weight of oxidised granules and multifilament yarns from the blends were spun by a pilot-plant melt spinning machine. The characterisation of as-spun yarns was performed by FTIR and DSC analysis. Also the density, shrinkage and mechanical properties of the samples were evaluated. The results show that the as-spun blend fibre containing 10% by weight of oxidised polypropylene has the lowest crystallinity, density and melting temperature while it shows the highest shrinkage and mechanical property faults.

Melt spinning of poly(L‐lactic acid) and its biodegradability

AbstractThe melt spinning and melt drawing of poly(L‐lactic acid) (PLLA) were carried out with a melt‐spinning machine, and the mechanical properties, structure, and biodegradability of PLLA fiber were investigated. PLLA fiber with a tensile strength of 0.81 GPa was successfully obtained through two steps of drawing at a draw ratio of 18 in hot water. This fiber had enough tensile strength for common engineering use. The fiber could be degraded under controlled composting conditions at 70°C for 1 week. In scanning electron microscopy observations of the fiber, a regular pattern of cracks running along the vertical direction to the fiber axis was clearly observed. This suggested that the PLLA fiber built up a highly ordered structure arranged along the direction of the fiber axis. After the fiber was left to lie in the ground for 1 year, however, the surface of the fiber was still smooth, and the tensile strength did not decrease much. This PLLA fiber could not be hydrolyzed after 1 month of steeping in a buffer solution at 37°C, but it was rapidly hydrolyzed at more than 60°C. It was suggested that the degradation (hydrolysis) rate of PLLA depended on the glass‐transition temperature. Upon hydrolysis at 80°C for 48 h, a regular crack along the vertical direction to the fiber axis was found that was very similar to that observed in degradation under composting conditions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2118–2124, 2005

Melt Spinning of Tetrafluoroethylene Copolymer.

Melt spinning experiments of tetrafluoroethylene copolymers, whose components are hexafluoropropylene (FEP), ethylene (ETFE) and perfluoroalkoxy vinyl ether (PFA), respectively, were carried out. When the conventional melt spinning machine with gear pump was used, desirable filaments were difficult to be obtained probably due to the degradation of polymers. The screw structure was designed to decrease the degraded polymer and to keep constant through-put of the polymer without using the gear pump. By the study of melt fracture, the diameter of the orifice was determined. The thinning of the filament during the spinline was controlled by the equipment of heated sleeve under the spinneret.

Crystal Modification in Polypropylene Fibers Containing .BETA.-form Nucleating Agent.

Sample fibers were prepared with a multi-filament melt-spinning machine, from polypropylene (hereafter PP) to which β-form nucleating agent had been added. The relations between melt-spinning conditions and crystal modification of obtained fibers were studied. Wide-angle X-ray diffraction measurement of fibers yielded the following results: The diffraction peaks of α-form crystal were clearly observed in undrawn fiber to which β-form nucleating agent had been added in an amount of 0.05 wt%. The diffraction peaks of β-form crystal were observed in undrawn fiber to whichβ-form nucleating agent had been added in an amount of more than 0.10wt%. Also, the effects of spinning temperature on PP to which β-form nucleating agent had been added in an amount of 0.10 wt% were studied. Only crystalline reflections of α-form were found in the sample produced at a spinning temperature lower than 250°C. However, the reflections of β-form appeared when spinning temperature was increased to 280°C. When the draft ratio was more than 3100, the diffraction peaks of β-form crystal were not observed. When the samples were drawn with a heated roller at 110°C, a few diffraction peaks of β-form crystal were found when the draw ratio was set at 4.0, but the peaks were never found when the draw ratio exceeded 5.0. The results indicate that crystal transformation from β-form to α-form takes place in samples for which the crystallite-orientation factor ofβ-form, fC(β), reaches about 0.788.