Pure Polypropylene Fibers Research Articles

Sorption Capabilities of Polypropylene/Modified Polypropylene Fibers

The aim of this paper is to present the influence of the modification of polypropylene (PP) fibers on the sorption capabilities of the fibers. The physical modification of the PP fibers was made with inorganic nanoadditives in the mass, with a view to improving the properties of silicate composites used in the construction industry. The compositions of the modified PP fibers using two different nanoadditives were based on previous work, as well as the work presented in this paper. The prepared modified PP fibers were compared with pure PP fibers, and their mechanical and thermomechanical properties were evaluated. Another task of this work was to evaluate and compare the sorption capabilities of these fibers without the preparation of concrete blocks. Therefore, the Washburn method was used. However, the obtained results led us to the conclusion that the given method points to the excellent transport properties of PP fibers if such properties are used to evaluate the sorption of the fibers. However, the sorption of the prepared modified fibers could be associated with the nanoadditives used, which have a higher water sorption capacity compared to pure PP fibers, and this could also ensure the higher adhesion of the modified PP fibers with inorganic additives to the cement matrix compared to the adhesion of the hydrophobic PP fibers.

Effect of an Antioxidant and a Compatibilizer on the Mechanical Properties of Virgin and Thermally Aged Polypropylene Drawn Fibers

Polypropylene (PP), like all polymers, is susceptible to various forms of aging. Drawn fibers exhibit increased mechanical properties; however, the drawing results in non-equilibrium (decreased entropy) structures, due to the orientation of the polymer chains. Consequently, the drawn fibers are susceptible to an additional form of physical aging. In this work, the effect of common industrial additives on the mechanical strength of virgin and thermally aged PP fibers was studied. Thermogravimetry and tensile strength tests were used to characterize the drawn fibers, before and after physical thermal aging. PP drawn at 120 °C and at a drawing ratio of 7 exhibited a tensile strength of 549 MPa, while the incorporation of an antioxidant and a compatibilizer lowered the tensile strength down to 449 MPA. This reduction was related to the constraint of chain alignment due to the low molecular weight and poor dispersion of the additives. Depending on the aging temperature, shrinking occurred to different extents in pure PP fibers, accompanied by a 6–7% reduction in tensile strength. The fibers with incorporated additives exhibited higher rate and degree of shrinking. Briefly, the incorporation of such additives in drawn PP resulted in the deterioration of the fibers’ mechanical tensile properties. Since such additives have an indisputable value for non-drawn samples and their usage is necessary for various reasons also in drawn samples, e.g., for their protection from chemical aging/decomposition, additives specific for drawn samples should be developed.

IMPROVING MECHANICAL PROPERTIES OF OIL WELL CEMENT USING POLYPROPYLENE FIBERS AND EVALUATING A NEW LABORATORY METHOD FOR MEASURING THE CASING CEMENT BONDING STRENGTH

The main objective of this study is to enhance the poor performance of oil well cement in terms of mechanical properties by using pure polypropylene fibers. Polypropylene fibers were added in increasing concentrations from 0 to 0.1%, 0.3%, 0.5%, 0.7%, and 0.9% by weight of cement (BWOC). Rheological parameters, density, fluid loss, permeability, porosity, compressive strength, tensile strength, and flexural strength were all tested. A new method for measuring the tensile strength of cement samples in the presence of a casing is also evaluated in this research. In addition, the interfacial bonding shear strength, which represents the strength of cement adhesion to the casing, was measured using a new laboratory procedure. The influence of adding polypropylene fibers on rheology, density, and fluid loss can be ignored, according to the results of the experiments. The permeability and porosity of cement samples increased as the proportion of polypropylene fibers increased, according to the findings. Further, an increase in polypropylene fibers concentration up to 0.3% BWOC led to improving the mechanical properties at different curing times. The bonding strength of the casing cement interface improved with increasing polypropylene fibers concentration up to 0.5% BWOC.

Halogen-Free Flame Retardant Polypropylene Fibers with Modified Intumescent Flame Retardant: Preparation, Characterization, Properties and Mode of Action.

A novel intumescent flame retardant (IFR) agent designated as Dohor-6000A has been used to prepare halogen-free flame retardant polypropylene (PP) fibers via melting spinning. Before being blended with PP resin, a surface modification of Dohor-6000A was carried out to improve its compatibility with the PP matrix. The rheological behavior of flame retardant Dohor-6000A/PP resin, the structure, morphology, mechanical properties, flammability of the Dohor-6000A/PP fibers were studied in detail, as well as the action mode of flame retardant. X-ray diffraction (XRD) showed that the addition of Dohor-6000A did not damage the crystal as well as the orientation structure of PP matrix, which was helpful to the maintenance of mechanical properties. The presence of the IFR significantly improved the flame retardant performance and thermal stability of PP fibers. When the content of Dohor-6000A reached 25%, the fibers displayed a limiting oxygen index (LOI) value of 29.1% and good melt-drop resistance. Moreover, the peak heat release rate (PHRR) and total heat release (THR) from microscale combustion colorimetry (MCC) tests were decreased by 26.0% and 16.0% in comparison with the same conditions for pure PP fibers. In the condensed phase, the IFR promoted a carbonization process and promoted the formation of a glassy or stable foam protective layer on the surface of the polymer matrix. In addition, the IFR decomposed endothermically to release of non-combustible gases such as NH3 and CO2 which dilutes the combustible gases in the combustion zone.

Surface Hydrophilic Modification of Polypropylene Fibers and Their Application in Fiber-Reinforced Cement-Based Materials

Among the various polymer fibers available, polypropylene (PP) fibers are often used to improve the impermeability, impact resistance, anti-wear and crack resistance of concrete. In order to improve the interfacial adhesion between PP fibers and cement a series of PP composite fibers were prepared by melt spinning with micro-silica (MSi) as a hydrophilic modifier and the structure and properties of the composite fibers were studied. The results showed that the composite fibers displayed rougher and more hydrophilic surfaces than the pure PP fibers. As revealed by single fiber pull-out tests, the interfacial adhesive strength between the PP fibers and a cement matrix increased obviously after adding the MSi to the PP fibers. The flexural strength and compressive strength of the cement mortar blended with the composite fibers were much better than those of the cement modified by pure PP fibers. The cement mortar enhanced by the composite fibers containing 10 wt.% of MSi showed the best mechanical strength, which we suggest was caused by a balance between fiber strength and interfacial adhesive strength. In general, our research indicated that the mechanical properties of PP fiber reinforced cement-based materials could be further enhanced by mixing appropriate amounts of MSi in the PP fibers which provides a novel strategy to design high-ρperformance materials for modern architecture.

Study on bonding ability of melt-spun polypropylene/polyethylene blend fibers

This article investigates melt spinning of polypropylene (PP) with high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) blend fibers at different compositions, as well as the effects of HDPE and LLDPE on the bonding ability of blend fibers in thermal bonding process at different temperatures have been studied. HDPE and LLDPE were added to PP at 3, 5, 7, and 10 wt% to measure the upper threshold of such blends. While HDPE was added up to 7 wt%, PP/LLDPE blend fibers were only spun up to 3 wt% of LLDPE. Differential scanning calorimetry (DSC) revealed that increasing both HDPE and LLDPE contents lead to higher crystallinity values due to polyethylenes nucleating effect on PP. By adding HDPE and LLDPE, the tensile strength of blend fibers before and after bonding was decreased drastically compared to pure PP fibers. On the other hand, the addition of HDPE to PP and increasing bonding temperature enhanced bonding strength.

Synthesis of Super Hydrophobic Disperse Dyes Having Long Alkyl Substituents and Their Dyeability onto Unmodified Polypropylene Fibers

The new series of super hydrophobic disperse dyes having different length of alkyl substituents was synthesized to dye pure polypropylene fibers. From butyl to dodecyl groups were introduced to an anthraquinoid chromophore. The adsorption interaction of the dyes toward the polypropylene fiber was increased with the increase of the length of alkyl chains due to enhancement of hydrophobicity of the dyes. The optimum alkyl group was determined as the longest dodecyl group in this study. Their absorption spectra in the visible range appeared almost the same regardless of the length of alkyl groups, which meant that the length of alkyl groups did not influence on optical properties of the dyes relating to color appearances. The color fastnesses of the dyed fabrics to washing, rubbing, and light were good enough for practical application.

Fabrication of Polypropylene (PP)/Poly Trimethylene Terephthalate (PTT)/Nanoclay Nanocomposite Fibers with Tailored Properties

The main aim of this study was to deal with one of the major drawbacks of polypropylene (PP) fibers, i.e., low resiliency and low dyeability, by incorporating polytrimethylene terephthalate (PTT) fibrils, as a dispersed material, and organoclay, as a nano-filler, into the PP polymer matrix. The presence of 10 wt% of PTT and 0.5–1 wt% organoclay in the PP nanocomposite fibers led to an approximately 18.5% and 45.5% increase in the resilience behavior and dye uptake, respectively, compared to pure PP fibers, without using highly toxic carriers. The lowest mean diameter of the nano-fibrils was 75 nm for the hot drawn nanocomposite fiber samples as measured by scanning electron microscopy (SEM). The results of DSC indicated that the presence of both PTT and organoclay significantly influenced the crystallinity of the PP which also confirmed their nucleating effects in the nanocomposite fiber.

Fabrication of Polypropylene/Poly (TrimethyleneTerephthalate) Blend Fibers with Highly Improved Resiliency and Preserved Mechanical Properties

The main aim of this study was to deal with one of the major drawbacks of polypropylene (PP) fibers, i.e. low resiliency, by incorporating poly (trimethylene terephthalate) (PTT) nano-fibrils as a dispersed material into the PP polymer matrix. Thanks to the special helical shape of the PTT polymer backbone, the incorporated nano-fibrils of the PTT polymer strengthened the resiliency of the blend fibers. The presence of 10 and 15 wt% of PTT in the blend fibers led to an approximately 20% increase in the resilience behavior, compared to pure PP fibers, with the mechanical properties of the PP matrix preserved. The development of the fibrillar structures during the different steps of the melt spinning process was confirmed by scanning electron microscopy (SEM), and the lowest mean diameter of the nano-fibrils was 64 nm for the hot drawn blend fiber samples consisting of 10 wt% of PTT. In summary, we suggest the optimized blend fiber samples produced in this research will be a promising candidate for a wide range of engineering applications.

Preparation and Characterization of Melt Spun Polypropylene / Montmorillonite Nanocomposite Fibre for Ibuprofen Drug Delivery application

Polypropylene /Montmorillonite clay nanocomposite was prepared after modification of Montmorillonite (MMT) clay using Dimethyl di (hydrogenated tallow) ammonium chloride modifier. The prepared nanocomposite was characterized using scanning electron microscope (SEM), Fourier-transform infrared (FTIR) and thermal gravimetric analysis (TGA). Fibers of pure polypropylene (PP) and polypropylene/montmorillonite clay nanocomposite (PP/MMT) were produced using melt spinning technique and the prepared fibers were characterized using mechanical properties, water absorption in addition to SEM analysis. The results show that the nanocomposite fibers have higher thermal stability, higher mechanical properties, and lower water absorption than pure polypropylene fibers in addition to high degree in homogeneity between polypropylene and MMT clay in polypropylene/montmorillonite nanocomposite. Ibuprofen drug (IBU) was successfully loaded into polypropylene and polypropylene/montmorillonite clay nanocomposite fiber via solvent immersion method with different drug fiber ratio in presence of glyoxal cross linker. Drug release profile was studied for 120 min and the results showed that about 33% from the initial loaded drug was released from the fiber after one hour of release starting time.

Effect of multi walled carbon nanotube on the crystalline structure of polypropylene fibers

Polypropylene fibers containing varying amounts of multi walled carbon nanotube (MWCNT) have been spun using a conventional melt spinning and drawing apparatus. Changes in morphology and crystalline structure of composite fibers induced by addition of MWCNT were studied by small angle X-ray scattering (SAXS), wide angle X-ray scattering (WAXS), Fourier transform infrared spectroscopy (FTIR) and birefringence measurements. The results of SAXS experiments showed an increase in lamellar thickness, long period and crystallinity of the composite fibers in comparison to pure polypropylene fibers. Molecular orientation and helical content of the fibers were increased due to the addition of MWCNT to the polypropylene matrix. WAXS results, being in agreement with the SAXS results, also showed an increase in crystallinity of the composite fibers due to the increase in MWCNT content. This is probably because of nucleating effect of nanotubes in the fiber matrix, causing more crystallization and orientation of molecules to take place around them.

순수 폴리프로필렌 섬유용 안트라퀴논계 마젠타 염료의 합성과 응용

A new series of anthraquinoid magenta dyes having alkylphenyl substituents was synthesized and applied toward pure polypropylene fibers. The affinity of the dyes toward polypropylene fibers was increased gradually with the increase of the length of alkyl substituents. The optimum length of alkyl group was determined as heptyl substituents from the practical point of view. The color values of the dyes on polypropylene fabrics displayed slight bluish red, namely magenta which is more practical than primary red in color matching. The good fastness ratings to washing, rubbing and light were obtained for the dyes having longer alkyl groups than hexyl substituents. Expecially they exhibited ratings 4 of light fastness, which is higher than primary red dyes previously reported.

Processing Science of Isotactic Polypropylene Fiber Reinforced with Halloysite Nanotubes Based on Masterbatch Dilution Technique

The properties of nanocomposites can be improved significantly by the addition of nanoparticles into polymer. Nanocomposites of isotactic polypropylene (iPP) and Halloysite Nanotubes (HNT) at 100/0 and 99.2/0.8 weight ratios were prepared in a co-rotating twin screw extruder using masterbatch dilution technique. IPP/HNT fibers were obtained in a single-screw extruder with extrusion temperature of 231°C, screw speed of 1.38 rpm and 0.6mm diameter die L/D of 6. The effect of processing variables, such as pick-up speed (0.05m/s, 0.15m/s and 0.45m/s), horizontal distance (0, 0.5m and 1m),and annealing (120°C), were investigated. The air cooling time was crucial for fiber processing and exhibited a linkage with crystal morphology, degree of crystallinity as well as the mechanical performance of the fiber. More importantly, the incorporation of HNT into isotactic polypropylene reduced the deficiencies of the annealing process on the toughness and elongation at break of the pure polypropylene fibers, and significantly enhanced the tensile strength of the fiber.

헥실기 이상의 알킬치환기를 가지는 디아미노안트라퀴논계 청색 분산염료의 합성과 순수폴리프로필렌 섬유에 대한 염색성

As a subsequent research of the previously reported<TEX>$^{9)}$</TEX>, a series of diaminoanthraquinoid blue dyes having hexyl, heptyl and octyl substituents were newly synthesized in order to investigate dyeability toward polypropylene fibers. As the length of alkyl groups introduced to the chromophore increased, the dyeability of the dyes toward polypropylene fibers also increased and then gradually decreased. From the result of dyeing, the hexyl-substituted dye showed the highest color strength and deep shade on pure polypropylene fibers. The good fastness rates to wash, rubbing and light were also obtained for all of the synthesized dyes.

Improved soiling resistance of polypropylene fibers on the addition of synthetic compounds

With the aim of enhancing the soil resistance of polypropylene (PP) fibers, polydimethylsiloxane (PDMS) and/or oleamide (OA) were added, and the soiling and wear resistances of the obtained fibers were evaluated. Films made from PP with the addition of PDMS and/or OA were fabricated and their water repellencies were evaluated by using droplets to measure their contact angles. The water contact angle increased with increasing amount of PDMS and/or OA added to PP. These blended resins were then used to produce fibers, which were in turn used to form fabrics. The soil resistances of these fabrics were evaluated by immersing them in aqueous solutions of a water-soluble artificial soiling substance for 1 min. Fiber G, for which both PDMS and OA had been added to PP, had a soiling ratio that was about 8–15% lower than that of pure PP fibers to which nothing had been added. Longer immersion of 24 h resulted in Fiber E, for which only PDMS had been added, having the lowest soiling ratio. In contrast, Fibers L and G (produced by adding OA) had relatively high soiling ratios when immersed for a long time. The wear resistances of knitted fabrics were evaluated using an abrasion tester. Fabric made from pure PP fibers had holes after 20 cycles of abrasion, whereas fabrics formed from fibers to which PDMS and/or OA had been added did not have holes even after 100 cycles of abrasion, which represents a remarkable improvement in wear resistance.

Synthesis of Red Disperse Dyes with Various Diazo Components and Coloration of Unmodified Pure Polypropylene Fibers

The five new red disperse dyes for unmodified pure polypropylene fibers were synthesized. As a coupling component, a di-n-hexyl substituent was used in common, while various substituents were used for the diazo component. The dye having electron donating group at diazo component showed hypsochromic shift compared to the unsubstituted dye, while the dyes having electron withdrawing groups showed bathochromic shift. Owing to their extreme hydrophobicity caused by the di-n-hexyl substituent, all dyes exhibited very high affinity toward pure polypropylene fibers. Fastness to washing was very good for all dyes and fastness to light was good except two purplish red dyes.

Calculation and Analysis of Hydrophobicity of the Dyes Synthesized for Unmodified Polypropylene Fibers Using Molecular Descriptors

In order to analyze numerically the hydrophobicity of the new dyes synthesized for unmodified pure polypropylene fibers, the octanol-water partition coefficient (logP), which is one of molecular descriptors representing hydrophobicity of organic compounds, was obtained by a semi-empirical method using Chem3D software. For the dyes of higher logP than around 5, the affinity of the dyes towards unmodified polypropylene fiber was substantial. In contrast to the new dyes for polypropylene, conventional disperse dyes have logP values lower than 5 and exhibited poor affinity.

Properties of polypropylene/layered-silicate nanocomposites and melt-spun fibers

Polypropylene (PP)/layered-silicate organoclay nanocomposites and their fibers were prepared by melt compounding and melt spinning, respectively, in the presence or absence of compatibilizer (PP-based maleic anhydride compatibilizer) to examine the effects of the organoclay dispersion and rheological behavior on the internal structure and tensile properties of the nanocomposite fibers. The compatibilized nanocomposites showed solidlike plateau behavior and strain hardening due to a three-dimensional network structure in the shear and uniaxial elongational flows. The tensile properties of the nanocomposite fibers were reduced compared with those of the pure PP fibers because some of the layered silicates were present as partially aggregated forms and the molecular weight of the compatibilizer was lower than that of the pure PP matrix. It was also found that the tenacity of the nanocomposite fiber increased and then decreased as the compatibilizer content increased because the compatibilizer affected the internal structure of the nanocomposite fibers. The positive effect of the compatibilizer was to generate a more effective exfoliated structure of organoclay in the polymer matrix. The negative effect was that the melt-spun nanocomposite fiber had a lower molecular weight than the pure PP fiber because the compatibilizer had a lower molecular weight. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Polypropylene-Clay Nanocomposites Fibers Structure and Performance

Abstract Fibers from Polypropylene (PP) and polypropylene nanocomposite (PNC) were produced using a fiber spinning process. Various amounts of different clays were added to the PP matrix. The structure of PP and PNC fibers was evaluated using field emission scanning electron microscopy (FE-SEM) and X-ray diffraction. The crystalline axes orientation factors were determined from wide-angle X-ray diffraction pole figures of (110) and (040) reflections for PP and of (001) for clay. The d-spacing of the (001) clay crystalline plane, indicative of the clay dispersion, was determined from the intensity −2 θ plots superimposed on the two dimensional X-ray diagrams. The results obtained for the d-spacing at small angles indicated that the clay in the PNC maintained its intercalated distance at low loadings whereas at higher loadings, some aggregation was observed. Results on orientation of the clay (001) axis (normal to the clay platelets plane) indicated that it was oriented perpendicular to the machine direction, which is expected. Its orientation in the normal and transverse directions was different, suggesting that clay platelets were not randomly distributed in the transverse plane, which was confirmed from SEM observations. The orientation of PP c-axis in the fibers was slightly higher for the nano-composite that the pure resin. Tensile modulus, strength and elongation at break for both PP and PNC fibers increased with increasing draw ratio. Flexural modulus and strength of laminates made by consolidation of the PNC fibers were higher than those of consolidated pure PP fibers as well as those of bulk PP or PNC.

EFFECT OF POLYPROPYLENE FIBERS ON THE MECHANICAL PROPERTIES OF NORMAL CONCRETE

The present work investigates the effect of addition of pure polypropylene fibers to concrete in order to diminish some poor performances particularly in case of ductility and tensile strength. The effect of the addition of polypropylene fibers on the mechanical properties of normal strength concrete is studied. The polypropylene fibers were added at concentration of 0.25, 0.5, 1.0 and 1.5% by volume. Compression, pullout and bending tests were carried out to determine the mechanical properties such as maximum compressive strength, modulus of elasticity, splitting strength, ductility, bond strength, modulus of rupture and the percentage of absorption. On the basis of the experimental results, it can be concluded that, ductility of concrete significantly increased and maximum compressive strength slightly increased with increasing the content of polyproplylene fibers materials. Further increase of polypropylene fibers (higher values than 0.5 vol. %) did not increase the ultimate bond strength, but it provided much more ductile bond behaviour. Besides, the addition of polypropylene fibers caused a significant increase in the percentage of water absorption for the tested concrete specimens.