Surface Of Polypropylene Fibers Research Articles

Surface-treated polypropylene fiber for reinforced repair mortar cementitious composites

The effects of surface treatment of polypropylene (PP) fiber on the mechanical and microstructure of fiber-reinforced cementitious (FRC) composites are investigated. Surface treatment of the PP fiber was performed with 3-aminopropyltrimethoxy silane (APS) and methyltriethoxy silane (MTES) in order to improve interaction between PP fiber and matrix. The effects of APS and MTES on the surface of PP fiber are studied by scanning electron microscopy, energy dispersive spectrometer, and Fourier transform infrared spectroscopy. The experiment results indicated that the treatment of PP fiber with APS and MTES can effectively increase the adhesion between fiber and matrix, and an improvement in the flexure and compressive strength of the cementitious composites was found in the samples containing treated PP fiber compared to the samples containing untreated PP fiber. The optimized mechanical properties could be obtained using 1.0% APS (by weight) and 1.0% MTES (by weight)-treated PP fiber at studied conditions, respectively.

Effects of Oxygen Plasma Treatment on the Wettability of Polypropylene Fabrics

The objective of this study is to give PP(polypropylene) fabric a good affinity for water. Oxygen plasma was treated to PP fabrics in a commercial glow discharge reactor with different RF power, discharge pressure, and reaction time. The PP fiber surfaces were characterized by the measurement of contact angle and ESCA. A JEOL scanning electron microscope was used to observe the surface morphology of fibers. The spontaneous water uptake amount of PP fabrics was determined by the demand wettability test. To determine the effect of aging on the surface properties of <TEX>$O_2$</TEX> plasma treated PP, all the above measurements of the samples were carried out after 1, 7, 30, 60, and 150 days. The results are as follows. The PP fiber surfaces treated by <TEX>$O_2$</TEX> plasma treatment have a chemical composition that consisted of various oxygen containing polar groups. Consequently, the contact angles of the treated PP fibers decreased, which improved the water uptake rate of PP fabrics. Surface roughness of the treated PP affected the fabric wettabiity as well. Wettability of the treated PP decreased and leveled off with aging. The <TEX>$O_2$</TEX> plasma treatment is a simple and effective method to increase the water uptake rate of PP fabrics.

Rapid removal of Cr(VI) ions using quaternary ammonium fibers functioned by 2-(dimethylamino)ethyl methacrylate and modified with 1-bromoalkanes

Abstract The quaternary ammonium fibers which could remove Cr(VI) ions rapidly were prepared by radiation-induced grafting of 2-(dimethylamino)ethyl methacrylate (DMAEMA) onto polypropylene (PP) fibers (PP-g-DMAEMA) and modifying with 1-bromoalkanes. The FTIR, FESEM, XPS and TG-DTG spectra manifested that the quaternary ammonium group was introduced onto the surface of PP fibers. The main factors influencing the adsorption of Cr(VI) ions including contact time, pH of the aqueous solution and adsorption dosage were investigated. The removal rate could reach 97% within 4 min and the kinetics study indicated that adsorption process was surface reaction controlled. Maximum adsorption capacities of Cr(VI) ions at 25 °C were 105.8 mg/g based on the Langmuir isotherms. These results suggested that the quaternary ammonium fibers have potential application for the removal of hazardous metal pollutants from wastewater highly and rapidly.

Effect of surface chemistry of polyethyleneimine-grafted polypropylene fiber on its CO2 adsorption

A high amino density of grafted solid amine adsorption fiber (PP-AM-PEI) for CO2 adsorption was prepared by grafting acrylamide (AM) onto the surface of a polypropylene (PP) fiber and subsequently modified with polyethylenimine (PEI). The grafting of AM on PP fibers was beneficial for introducing and assembling PEI onto the fibers. An examination by infrared and scanning electron microscopies confirmed that AM and PEI were successfully introduced onto the surface of PP fiber. PP-AM-PEI showed good thermo-stability, a high adsorption capacity for CO2 (5.91 mmol g−1). It also has good regeneration performance and could maintain almost the same adsorption capacity for CO2 after 5 recycle numbers. In addition, two other polypropylene-based adsorbents, PP-GMA-PEI (using glycidyl methacrylate (GMA) as the active monomer) and PP-AM-EDA (using ethylenediamine (EDA) as the functional monomer) were prepared. Compared with PP-GMA-EDA, PP-AM-PEI was more suitable for CO2 capture in the presence of moisture due to its hydrophilicity. The results also showed that the adsorption capacity of PP-AM-PEI was superior to PP-AM-EDA due to the high amino density of PEI.

Photoinduced Bactericidal Activity of Titanium Dioxide Nanoparticles Attached to the Surface of Polypropylene Fibers

In work bactericidal properties of system "TiO2 nanoparticles - the polypropylene fibrous carrier" are defined at impact of ultra-violet radiation concerning gram-positive and gram-negative bacteria and conditions under which this property is realized are defined.

Polypropylene non-woven meshes with conformal glycosylated layer for lectin affinity adsorption: The effect of side chain length

The unique characteristics of polypropylene non-woven meshes (PPNWMs), like random network of overlapped fibers, multiple connected pores and overall high porosity, make them high potentials for use as separation or adsorption media. Meanwhile, carbohydrates can specifically recognize certain lectin through multivalent interactions. Therefore glycosylated PPNWMs, combing the merits of both, can be regarded as superior affinity membranes for lectin adsorption and purification. Here, we describe a versatile strategy for the glycosylation of PPNWMs. Two hydrophilic polymers with different side chain length, poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(oligo(ethylene glycol) methacrylate) (POEGMA), were first conformally tethered on the polypropylene fiber surface by a modified plasma pretreatment and benzophenone (BP) entrapment UV irradiation process. Then glucose ligands were bound through the reaction between the hydroxyl group and acetyl glucose. Chemical changes of the PPNWMs surface were monitored by FT-IR/ATR. SEM pictures show that conformal glucose ligands can be achieved through the modified process. After deprotection, the glycosylated PPNWMs became superhydrophilic and had high specific recognition capability toward Concanavalin A (Con A). Static Con A adsorption experiments were further performed and the results indicate that fast adsorption kinetics and high binding capacity can be accomplished at the same time. We also found that increasing the side chain length of polymer brushes had positive effect on protein binding capacity due to improved chain mobility. Model studies suggest a multilayer adsorption behavior of Con A.

Surface treated polypropylene (PP) fibres for reinforced concrete

Surface treatments on a polypropylene (PP) fibre have contributed to the improvement of fibre/concrete adhesion in fibre-reinforced concrete. The treatments to the PP fibre were characterized by contact angle measurements, ATR-IR and XPS to analyse chemical alterations. The surface topography and fibre/concrete interaction were analysed by several microscopic techniques, namely optical petrographic, and scanning electron microscopy. Treatment modified the surface chemistry and topography of the fibre by introducing sodium moieties and created additional fibre surface roughness. Modifications in the fibre surface led to an increase in the adhesion properties between the treated fibres and concrete and an improvement in the mechanical properties of the fibre-reinforced concrete composite as compared to the concrete containing untreated PP fibres. Compatibility with the concrete and increased roughness and mineral surface was also improved by nucleated portlandite and ettringite mineral association anchored on the alkaline PP fibre surface, which is induced during treatment.

Adhesion strength behaviour of plasma pre-treated and laminated polypropylene nonwoven fabrics using acrylic and polyurethane-based adhesives

The adhesion strength enhancement of oxygen plasma pre-treated laminated polypropylene nonwoven fabrics using two different types of adhesives was investigated in this study. Fabric surface modification was performed using low-pressure, radio-frequency oxygen plasma treatment. Effect of plasma treatment on fabric surface wettability was determined by vertical wicking measurements. Wettability of highly hydrophobic polypropylene nonwoven samples dramatically increased with increasing plasma power and exposure time. Plasma-treated polypropylene fibers showed rougher surfaces with increased plasma power and treatment times. X-ray photoelectron spectroscopy (XPS) analysis showed that oxygen plasma treatment of polypropylene fiber surface led to a significant increase in atomic percentage of oxygen compound responsible for hydrophilic surface. Peel strength enhancement of produced laminated fabrics was observed for plasma-treated samples compared to untreated samples. PU-based adhesive attached on the surface of both plasma-treated and untreated polypropylene nonwoven, filling the spaces between the fibers due to the penetration of the adhesive agent. The improvement in surface wettability of polypropylene nonwoven and the introduced sites through oxygen plasma treatment resulted in good adhesive bonding. For both adhesives, peel strength improvement of produced laminated fabrics was observed for plasma-treated samples compared to untreated ones. After lamination with polyurethane-based adhesive and 20 wash cycles, decrease in peel bond strength was between 22% and 25% for plasma-treated samples, while it was 36% for untreated fabrics. Laminated samples using acrylic-based adhesives showed much lower peel strength values and washing resistance than samples laminated with polyurethane-based adhesives.

Radiation synthesis of polypropylene-acrylate grafted fiber and its remediation in the spillage of water-insoluble organic chemicals

A new kind of functionalized polypropylene(PP)-acrylate grafted fiber were prepared by radiation-induced graft polymerization of methyl acrylate (MA), ethyl acrylate(EA) and butyl acrylate (BA) monomer onto the PP fiber matrix, as a recovery adsorbent for insoluble organic chemicals. The grafting conditions of monomer concentration and irradiation time on the grafting degree were optimized. The obtained grafted fiber sample was identified by Fourier transform infrared (FT-IR) spectrometer and scanning electron microscopy (SEM) to characterize the chemical and morphological changes of the polypropylene fiber surface. The adsorption results indicated that the grafted fiber could be used to remove organic chemicals from water surface. The adsorption capacity of grafted fiber with different acrylate monomer was obviously different for the same chemicals, therefore, investigations with respect to organic removal, dynamic oil retention, and reusability, the effect of monomer polarity on the adsorption capacity of grafted fiber was especially highlighted in this study.

Synthesis of the azide derivative of cobalt tetra(carboxy)phthalocyaninate and its immobilization on nonwoven polypropylene

Methods of the synthesis of cobalt tetra(carboxy)phthalocyaninate azide derivative and its immobilization on nonwoven polypropylene and the structure of the phthalocyaninate on a polypropylene fi ber surface were studied.

Effect of removing polypropylene fibre surface finishes on mechanical performance of kenaf/polypropylene composites

Natural fibre/polypropylene thermoplastic composites are often produced by compression moulding of a blended preform of polypropylene fibre and natural fibre treated by chemicals or enzymes. Two preform processing routes may be adopted: (1) treating the natural fibre first and then blending it with the polypropylene fibre (the pre-treatment route), and (2) forming a blended preform of the natural fibre and polypropylene fibre first and then carrying out the chemical/enzyme treatment on the blended preform (the post-treatment route). The kenaf/polypropylene composites produced according to the post-treatment route show up to 36% higher flexural strength and up to 63% higher flexural modulus than the composites produced according to the corresponding pre-treatment route. These differences were attributed to the chemical surface finishes of the polypropylene fibre, which have been removed in the post-treatment processing route, but persisted into the final composites in the pre-treatment processing route.

Comparative Studies of Silver Nanocomposite Fibers

Functional silver-polypropylene nanocomposite fibers are prepared using melt-compounding and sputter coating techniques. The functional nanostructures formed on the fiber surfaces are characterized by Atomic force microscopy. The Environmental Scanning Electron Microscopy equipped with an energy dispersive X-ray analysis system is employed to examine the chemical compositions of the nanocomposite fibers. It is found that incorporating the silver nanoparticles by melt-compounding caused severe aggregation of the nanoparticles at the polypropylene fiber surface. By contrast, the coverage of the sputter coated fiber surfaces is much more consistent. The anti-bacterial properties of the nanocomposite fibers are also investigated and compared. The antibacterial tests revealed the better performance of silver sputter coated fibers.

Preparation and characterization of titanium dioxide nanocomposite fibers

Titanium dioxide and polypropylene fibers were prepared by melt-compounding and sputter coating, respectively. Energy dispersive x-ray analysis (EDX) confirmed the presence of titanium dioxide in the fibers. Through the application of environmental scanning electron microscopy (ESEM) and scanning probe microscopy (SPM), it was found that incorporating the titanium dioxide by melt-compounding caused severe aggregation of the titanium dioxide nanoparticles at the polypropylene fiber surface. Indeed, coverage of the fiber surface by titanium dioxide was poor. By contrast, the coverage of the sputter coated fiber surfaces was much more consistent, although aggregation of the titanium dioxide nanoparticles still appeared quite extensive. The behavior of the nanocomposite fiber surfaces was investigated using dynamic contact angle measurements by the Wilhelmy technique. Only a small increase in hydrophilicity of the polypropylene fibers was observed after melt-compounding with titanium dioxide, but a larger increase was noted after sputter coating. UV irradiation appreciably enhanced the hydrophilicity of the fiber surfaces in both cases.

Effects of Helium Atmospheric Pressure Plasma Treatment on Low-Stress Mechanical Properties of Polypropylene Nonwoven Fabrics

Polypropylene nonwoven fabrics are treated by He atmospheric pressure glow discharge plasma. After plasma treatment, weight loss (%), surface properties (wettability, morphology, and chemical composition changes), tensile strength, low-stress mechanical properties, and air permeability of the fabrics are examined. Scanning electron microscopy analysis shows significant surface morphology changes in plasma-treated polypropylene fiber surfaces, corresponding to reductions in fabric weight. X-ray photoelectron spectroscopy analysis reveals that surface oxidation by the formation of hydrophilic groups enhances the surface wettability of the fabrics. Surface morphology changes with plasma treatment increase fiber-to-fiber friction, playing an important role in enhancing their tensile strength, low-stress mechanical properties, and air permeability.

Effect of Ar+ Ion Irradiation of Polymeric Fiber on Interface and Mechanical Properties of Cementitious Composites

The values of fracture energy and mechanical flexural strength of Fiber Reinforced Cement (FRC) with polypropylene (PP) fiber modified by Ion Assisted Reaction (IAR), by which functional groups were grafted on the surface of PP fiber, was improved about 2 times as those of fracture energy and flexural strength of cement reinforced by untreated PP fiber. PP fiber was irradiated in O₂ environment by Ar + ion. The contact angle of PP treated by IAR decreased largely when compared with untreated PP. From this result, we expected that surface energy and interfacial adhesion force of treated PP fiber increased. The strain hardening occurred in the strain-stress curve of FRC including PP treated by IAR when compared with that of FRC with untreated PP. These enhanced mechanical properties might be due to strong interaction between hydrophilic group on modified PP fiber and hydroxyl group in cement matrix. This hydrophilic group on surface modified PP fiber was confirmed by XPS analysis. We clearly observed hydration products that were fixed at modified PP fiber due to the strong adhesion force of interface in cement reinforced modified PP by SEM (Scanning Electron Microscopy) study.

Investigation of gravity-spun, melt-spun, and melt-blown polypropylene fibers using atomic force microscopy

The morphology exhibited in a polymer depends on the particular process and processing conditions used to shape and modify the polymer. This morphology has an important influence on the final polymer product (sheet, molded part, etc.). Ten years ago, atomic force microscopy (AFM) was applied for the first time on polymer materials. Since then, AFM has been used extensively on polypropylene (PP) surfaces, but still very little has been reported on the use of AFM for analyzing PP fibers. The purpose of our work was to show the modifications of (a) the morphology and (b) the microstiffness of PP fiber surfaces processed under different operating conditions. Three fiber production processes were used: gravity spinning, melt spinning, and melt blowing. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1921–1937, 2000

Surface modified polypropylene fibres for use in concrete

The research project reported on is concerned with the effect of modification of the surface of polypropylene fibre by a new chemical treatment process, oxyfluorination, on the properties of polypropylene fibre reinforced concrete. As a world first, the interfacial bond of polypropylene fibres with the cementitious matrix is improved by increasing the surface free energy of the fibre surface. The reasons for the poor bonding between untreated polypropylene fibre and cementitious matrix are discussed, using the fibre surface free energy and Lewis acid–base interaction concept. The contact angle of water on the polypropylene fibre surface as well as fibre surface free energy components were measured. This showed reduced contact angles, as well as increased acid–base components of the surface free energy because of oxyfluorination. Mechanical properties such as compressive strength, flexural properties and impact resistance of the fibrous concrete, reinforced with different types of oxyfluorinated polypropylene fibres, were determined and compared with those of untreated polypropylene fibre reinforced concrete. The results confirmed that the surface modification largely improves the mechanical performance of the fibrous concretes. Restrained plastic and drying shrinkage cracking tests, using restrained slab specimens and steel ring restrained specimens, indicated that the surface oxyfluorinated fibres possess a higher shrinkage cracking resistance than do unmodified fibres. The effect of surface oxyfluorination on the fibre/concrete matrix interfacial bondings was investigated using a fibre pull-out test. A mechanism for this interfacial bonding improvement is proposed. Oxyfluorinated polypropylene fibre surfaces and their interfaces with concrete matrix, compared with that of unmodified fibre, were observed using scanning electronic microscopy. Some field application tests were conducted and the good results that were achieved are presented.

Characterizing Spin Finish Layers on Polypropylene Fiber Surfaces by Means of Scanning Force Microscopy Techniques

For a better understanding of the structure, distribution, and composition of spin finish layers on fiber surfaces, scanning force microscopy techniques are used to image spin finish layers on polypropylene fiber surfaces with submicrometer resolution. The polypropylene staple fibers are made into nonwovens, and common antistatic, wetting, and hydrophobizing agents are the spin finishes. Distribution and thickness profiles of the wax-like antistatic and hydrophobizing agents are successfully measured with con tact mode atomic force microscopy and lateral force microscopy. Nanometer scale measurements of local adhesion forces and elastic moduli of the spin finish layer sur faces by force modulation techniques (pulsed force mode) provide further information on the distribution and composition of the spin finish layers. In addition, the oil-like wetting agent layer, which is too soft and sticky for contact mode measurements, can be imaged with the pulsed force mode technique.

A microstructural study of fibre/mortar interfaces during fibre debonding and pull-out

Attempts were made to connect the change in interfacial properties during fibre pull-out in cementitious material to the microstructural features of the interface. The microstructural features of fibre (steel, nylon and polypropylene)/mortar interfaces were examined during the fibre debonding and pull-out process. Because fibre pull-out was found to be sensitive to lateral compression, microscopic studies were carried out on fibres pulled out with and without lateral compression. SEM and energy-dispersive X-ray (EDX) analyses were performed at four different stages: (a) before debonding; (b) immediately after debonding; (c) at small sliding distance; and (d) at large sliding distance. For the steel fibre/mortar interface, it was found that the mortar surface (interfacial transition zone) was subjected to abrasion, while the steel surface was subjected to plastic deformation. EDX analysis on the mortar interface showed that the ratio of calcium/silicon count first increases within a short sliding distance and decreases thereafter, indicating a process of CH layer abrasion and C-S-H layer exposure. The rapid post-peak drop of the pull-out force at the beginning of sliding is due to the “grinding” effect, which leads to crushing and abrasion of the CH crystals and a reduction of asperity on the mortar surface. The grinding and abrasion effect becomes more significant with the application of lateral compression, which results in more rapid drop of the pullout force. For the nylon and polypropylene fibre/mortar interfaces, the fibre surface peels and the mortar surface experiences very little damage. Nylon fibre surface swells and is peeled with short whiskers on the surface, leading to significant increase in interfacial friction causing the post-debonding pull-out force to increase. The polypropylene fibre surface is peeled and plowed with long whiskers and long scratch lines which also leads to an increase in interfacial friction. On applying lateral compression to the mortar during fibre pull-out, the abrasion and peeling effects are more severe. With lateral compression, holes may form on the polypropylene surface over a longer sliding distance. The ratio of calcium/silicon count on the mortar surface by EDX does not show obvious trends with sliding distance indicating that the mortar surface experiences very little damage.

Surface modification by continuous graft copolymerization. IV. Photoinitiated graft copolymerization onto polypropylene fiber surface

AbstractPhotochemically induced graft copolymerization (with UV light) of acrylamide (AM) and acrylic acid (AA) on polypropylene (PP) fiber surface by the presoaking method under nitrogen atmosphere in a continuous process has been developed. The results are measured by means of ESCA spectra. In grafting AM and AA, the relative intensity N1s/C1s and O1s/C1s of the fiber increase from 3–5 and 20% (background) to 8–13 and 23–39% in 9–10 s irradiation time, respectively. Titration results show that 1.75 3.58 mg/m2 poly(acrylic acid) has been grafted on the surface of PP fiber at various monomer concentrations of the presoaking solution. Commercial additives, such as antioxidant and UV stabilizer, affect the grafting yield of the fiber. As solvent in the presoaking solution, acetone is better than MEK and MPK. Various monomer and initiator concentrations in the presoaking solution have been studied. In the process developed 0.5–0.8 M acrylamide or 1.5–2.0 M acrylic acid and 0.2 M benzophenone (BP) in the presoaking solution are approapriate.