PP Fiber Research Articles

Synthesis of CH3I-quaternized polypropylene nonwoven fiber grafted with imidazole (PP-g-Vim) to adsorb vapor phase ammonia

Ammonia in gas phase has an unpleasant smell and is hazardous to human health. Though activated carbon has been widely used as a representative adsorbent, it is significantly vulnerable to humidity. In the study, a nonwoven fibrous polypropylene polymer was synthesized using a photo-graft reaction with imidazole followed by quaternization with CH3I. The time of each reaction was optimized for the maximum adsorption. The FT-IR confirmed that 1-vinyl imidazole (Vim) and methyl group (-CH3) were successfully introduced into PP fibers. The Langmuir isotherm characterized that the adsorption capacity was 44.84 mg NO3–N g−1. The adsorption intensity, 1/n, by Freundlich adsorption isotherm was 0.41 indicating that the adsorption of NO3–N onto PP-g-Vim-CH3I was favorable at the studied conditions. In the gas phase, maximum adsorption of was calculated to be 40 ± 0.69 mg NH3 g−1 by BET model. Though the adsorption amount decreased by 2.5 times as the temperature increased from 15 °C to 45 °C, the amounts and rates of adsorption were not influenced by humidity. In conclusion, the synthesized PP-g-Vim-CH3I was able to ammonia in the gas phase at a range of humidity.

Influence of flax/polypropylene distribution in twistless thermally bonded rovings on their composite properties

AbstractFlax has a short fiber length that makes the control of fiber orientation in the composite structure very difficult, which leads to composites with inferior mechanical properties. In order to overcome this difficulty, thermally bonded roving (TBR) with a novel structure where the flax fibers are in a twistfree state and are highly oriented to the roving axis have been developed. In this study, the influence of flax/polypropylene (PP) based TBR structures on their unidirectional (UD) composite properties has been explored. In total, five sets of TBR samples with varying the flax contents (40, 50, and 60 wt% levels) and with varying degrees of flax and PP fiber mixing by changing the number of drawing passages (two times, four times, and six times) have been produced in a specially designed machine. The produced TBR samples are consolidated in a compression molding machine and the resultant unidirectional composites are tested for tensile, flexural, and impact properties. It has been observed that the tensile, flexural, and impact properties of the composite samples improve with increasing flax content and with increasing flax and PP fiber mixing in the roving structure. The present composite samples exhibit better mechanical properties compared to those reported for flax/PP composites in literature. It is mainly due to better fiber orientation and fiber‐matrix distribution in the present composite samples.

Structure and Properties of a Metallocene Polypropylene Resin with Low Melting Temperature for Melt Spinning Fiber Application

An isotactic polypropylene (iPP-1) resin with low melting temperature (Tm) is synthesized by a metallocene catalyst and investigated for melt-spun fiber applications. The structure, thermal and mechanical properties, and feasibility of producing fibers of a commercial metallocene iPP (iPP-2) and a conventional Ziegler–Natta iPP (iPP-3) are carefully examined for comparison. Tm of iPP-1 is about 10 °C lower than the other two samples, which is well addressed both in the resin and the fiber products. Besides, the newly developed iPP-1 possesses higher isotacticity and crystallinity than the commercial ones, which assures the mechanical properties of the fiber products. Thanks to the addition of calcium stearate, its crystal grain size is smaller than those of the two other commercial iPPs. iPP-1 shows a similar rheological behavior as the commercial ones and good spinnability within a wide range of take-up speeds (1200–2750 m/min). The tensile property of fibers from iPP-1 is better than commercial ones, which can fulfill the application requirement. The formation of the mesomorphic phase in iPP-1 during melt spinning is confirmed by the orientation and crystallization investigation with wide angle X-ray diffraction (WAXD), which is responsible for its excellent processing capability and the mechanical properties of the resultant fibers. The work may provide not only a promising candidate for the high-performance PP fiber but also a deep understanding of the formation mechanism of the mesomorphic phase during fiber spinning.

Fiber‐reinforced lightweight self‐compacting concrete incorporating scoria aggregates at elevated temperatures

Self‐compacting concrete (SCC) has developed rapidly in modern concrete structures to accommodate the need of high deformability and considerable resistance to segregation. The lightweight aggregate called scoria is also utilized to manufacture lightweight self‐compacting concrete (LWSCC) to improve the strength‐to‐weight ratio with considerable cost beneficial. Meanwhile, the LWSCC employs fibers (polypropylene [PP] and steel) equipping different replacement ratios of traditional aggregates, the SCC will be invented to reveal balanced fresh property, spalling behavior, mechanical performance especially at elevated temperatures. In this study, eight LWSCC mix designs were explored with varying fiber ratios by volume of PP fiber (0.1, 0.15, 0.20, and 0.25%) and steel fiber (0.25, 0.5, 0.75, and 1.0%). The effects of different fiber types and ratios are tested with fresh properties (slump flow and J‐ring), hardened mechanical performance (compressive and tensile strength at 20°C) and high temperature resistance (compressive and tensile strength, mass loss and spalling) after 28‐day curing at 100, 300, 600, and 900°C. The 0.25% optimum fiber ratio for PP fiber mix and 0.75% for steel fiber mix are determined with balanced fresh properties as well as high‐temperature resistance for the hardened properties.

A Review: Performance of Polypropylene Fiber Reinforced Concrete

Plain concrete has low strain capacity due to which crack occur on the outer layer of the concrete structures. The fibers are incorporated in concrete to prevent the crack formation and enhance the tensile strength of the mix. Polypropylene fiber reinforced concrete (PPFRC) is a composite material that contains short discrete randomly distributed fibers. PP fibers in concrete shows promising results while enhancing the mechanical properties, stiffness and durability. This paper presents a review of properties of PPFRC based on various research works.

Flexural performance of hybrid polypropylene–polyolefin FRC composites

The objectives of the present study are to conduct experimental studies and determine the flexural strength and ductility of fiber-reinforced concrete (FRC) by adding two types of fibers, namely the polypropylene (PO) and polyolefin (PP) fibers in mono and hybrid forms, and assess the flexural toughness of fiber-reinforced concrete (FRC). The reinforced concrete (RC) beams of size 150 mm × 200 mm × 1000 mm were cast by adding discontinuous fibers of volume fraction (Vf) of 1% of PP (100%), PO (100%) and PP–PO (50–50%) in concrete. The flexural toughness of FRC beams with PP-1%, PO-1% and hybrid-1% (PP–PO) was evaluated from the area under the load–deflection curve and compared with control specimens (CS) (without fibers). The flexural strength and ductility were higher for FRC beam specimens reinforced with hybrid fibers (PP-Vf = 0.5% + PO-Vf = 0.5%) than beam specimens cast with mono PP fibers of Vf = 1% and PO fibers of Vf = 1%, and CS. The flexural toughness (FT) at beam deflection, L/150 (L = span length) and flexural toughness ratio (FTR) were found to be higher for FRC-hybrid PP–PO beam specimens than the specimens reinforced with PP and PO and control specimens (CS). The first-crack width and ultimate crack width of beam specimens were comparatively lesser for hybrid PP–PO than PP, PO fibers and CS.

Influence of different fibers on properties of thermal insulation composites based on geopolymer blended with glazed hollow bead

In this work, fly ash and slag were used as aluminosilicate raw materials to prepare geopolymer paste, and different fibers and glazed hollow beads (GHB) were incorporated into the paste to produce various series of fiber reinforced geopolymer composites. The preparation process of geopolymer composites was explored and the optimum preparation conditions was obtained. Compressive strength, flexural strength, water absorption, porosity, thermal conductivity, linear shrinkage rate, microstructure and morphology have been characterized and assessed. Polypropylene fiber, alkali resistant glass fiber and lignin fibers were added to improve the cracking resistance and to enhance the strength. The results show that the optimal strength of fiber reinforced GHB blended geopolymer is obtained with 15% GHB addition, 0.75% fiber addition and liquid-solid ratio of 1.1. The improving effect of fibers on enhancing and anti-shrinkage follows the following sequence: PP fiber, alkali resistant glass fiber and lignin fiber. It is also observed that the fiber not only prevents the separation of the GHB and geopolymer matrix, but also inhibits the generation and expansion of the cracks, and finally improves the strength regardless of hybrid fibers or single fiber.

Processes of Cracking and Crushing in Hybrid Fibre Reinforced High-Performance Concrete Slabs

This paper presents the experimental results obtained with the non-contact three-dimensional deformation measuring system–ARAMIS and finite element analysis performed using ANSYS of three slabs made of high-performance concrete (HPC) and hybrid (steel/ST and polypropylene/PP) fibre reinforced high-performance concrete (FRHPC). The research was performed on reinforced concrete (RC) slabs with a web mesh of ϕ8 mm bars. All the slabs had an identical amount of steel bars and differed by the fibre volume content. The main objective of the research was to determine the impact of adding polypropylene and steel fibres on the carrying capacity and ductility of HPC slabs. Analysis of the results was conducted based on load–deflection curves, crack distribution, vertical displacements and strains. The research findings indicate that fibres may improve peak strength. The presence of PP and ST hybrid fibres in HPC restricted the propagation of cracks. The energy absorption capacity as well as the ductility index of HPC can be raised by adding hybrid fibres. A comparison of the experimental test results with the nonlinear finite element analysis is made. The numerical results concurred well with the experimental data. The research results indicate that non-contact measurement of deformation is an effective tool for monitoring crushing in FRHPC slabs.

Laboratory Investigation on Mechanical Properties of Cementitious Composites with a Low Brittleness

In this study, laboratory tests were conducted to investigate the mechanical behaviors of cement mortars incorporated with different admixtures, such as polypropylene fiber (PP), slag, silica fume and fly ash. Orthogonal tests were designed to evaluate the effects of the admixtures on the brittleness. The flexural strengths and the compressive-flexural ratios were selected to evaluate the brittleness. The optimal proportion can be obtained when PP content was 1.6 kg/m3, and the content of fly ash, slag and silica fume was 10%, 20% and 3% of the cement content respectively. Using the optimal proportion, the 3d flexural strength of cement mortar was 5.65 MPa, which was 19% larger than the specimens without the addition of admixtures; the compressive-flexural ratio was 4.1, which was reduced by 19% in contrast to the control group. The flexural strength at 28d was 9.04 MPa, which was 13% higher than the control group; and the compressive-flexural ratio was 4.21, decreasing 24% compared to the control group. SEM technology was utilized to characterize the evolution of the microstructure induced by the addition of mineral admixtures and PP fiber. Results showed that mineral admixtures made the mortars denser, and the PP fiber formed a cross-linking structure, improving the brittle-resistance. The test results provided some guidance for the mixture design of pavement concrete with a high flexural strength and a low brittleness.

Research on seismic properties of steel reinforced PP ECC column

The mechanical property of steel reinforced PP ECC columns under reverse cyclic load is investigated and results are presented in this paper. The influence of reinforcement ratio, curing age and volume fraction of PP fiber on load bearing capacity, energy dissipation and stiffness degradation is investigated. The results highlighted the positive contribution of PP ECC to enhance strength and energy dissipation capacity which is important to evaluate the performance of structures subjected to reverse cyclic loads. According to the experimental study on mechanical behavior of steel reinforced PP ECC columns under reverse cyclic loading, the formula of model parameters related to reinforcement ratio are proposed，it is founded that the restoring force model established is of a certain degree of adaptability.

Developing a Polypropylene Fabric, Silica Fume, and Redispersible Emulsion Powder Cementitious Composite for Dynamic Water Environment.

In the dynamic water environment, grouting requires a material with higher strength and anti-washout performance to prevent groundwater inrush. This study aims to develop a dynamic water slurry by mixing polypropylene fiber (PP fiber), silica fume (SF) and the polymer material of redispersible emulsion powder (REP) to the Portland cement. Towards this aim, a series of tests, including strength, gel time, bleeding rate, fluidity, and anti-washout, were conducted to evaluate the effects of SF, PP fiber, and REP on the slurry properties. The test results show that: (1) SF displays significant effects on strength, gel time, fluidity, and bleeding rate of cement slurry. Differently, PP fiber mainly affects the stress–strain behavior of the slurry and can improve the ductility significantly. (2) By mixing SF and fiber simultaneously, the slurry strength can increase by about 30%, and its strain can extend by more than 70%. Meanwhile, the composite slurry possesses great anti-washout properties at a low flow velocity (v ≤ 0.4 m/s), and the grouting retention rate (GRR) can reach up to 98.7%. However, the GRR decreases to a maximum value of 31.3% when v = 0.6 m/s. (3) By mixing the REP into the fiber-SF composite slurry, the GRR can further increase, reaching more than 60% even when v = 0.6 m/s. As a result, the developed fiber-SF cementitious composite slurry, which when mixed with REP, presents a favorable performance in the dynamic water environment.

Graphene oxide-functionalized dual-scale channels architecture for high-throughput removal of organic pollutants from water

Amino-functionalized polypropylene nonwoven/graphene oxide (GO) hybrid material (PP-g-DMAEMA/GO) with dual-scale channels structure was fabricated via irradiation polymerization and self-assembly method for rapid removal of 7 kinds of organic pollutants from water. The GO sheets tethered to grafted branches of dimethylaminoethyl methacrylate (DMAEMA) on PP fiber surface could form nanochannels between GO and fiber. Meanwhile, polypropylene nonwoven could provide the backbone for building micron-channels. The overlapped and intertwined structure of PP-g-DMAEMA/GO with many channels assures water permeating fluently, and the GO could capture quickly the organic pollutants carried by water both in batch and filtration process. The obtained PP-g-DMAEMA/GO could keep 74.3% of the adsorption performance of GO, which demonstrated two sides of GO could afford accessible binding sites. While the flow rate reach 40 mL/min, the PP-g-DMAEMA/GO was able to effectively remove Bisphenol A (BPA) with the contact time of 3.4 s. Moreover, the PP-g-DMAEMA/GO could simply be recovered by washing with ethanol solution. We conclude the paper that the facile synthesis of PP-g-DMAEMA/GO exploiting inexpensive PP nonwoven offer high water permeability, solving the separation problem of GO, and promising potential for applications of GO for water applications.

폴리프로필렌섬유를 혼입한 콘크리트와 화강토콘크리트의 역학적 특성†

The study conducted an experiment in which residual aggregate and polypropylene fibers are mixed in concrete, and an experiment in which granite and polypropylene fibers are mixed. Two types of experiments, in particular, changed the amount of polypropylene fibers, and examined the mechanical properties of slump, compressive strength, tensile strength and the like. To establish a light and easy-to-use material for landscape construction and packaging material development by comparing two kinds of experimental results, comparing and analyzing residual aggregate as experimental materials and materials using granite soil to prevent partial destruction due to cracks in drying shrinkage. The more the amount of the PP fibers increases in concrete, the more the volume of the PP fibers increases, the less the slump is determined. As a result of the compressive strength, the cast-down earth concrete is measured to be about 59% to 71% of the concrete strength. As the amount of PP fibers mixed in increased, the compression strength showed a relative decrease. As a result of tensile strength, it is found that the granite concrete is about 68-67% of concrete tensile strength. It was found that the compression strength decreased as the amount of PP fibers mixed in concrete or fire-gant concrete was increased. Then, when polypropylene fibers are mixed in the concrete and the concrete, it is found that tensile strength is increased. By analyzing these results, a fixed amount of PP fiber is mixed in the concrete mixed with the granite soil and utilized for various structures in the field of landscape construction or materials related to packaging, the prevention and improvement effect of the structure is determined.

Effect of Accelerated Curing on the Furnace Slag Based Polypropylene Fiber Reinforced Concrete

The study aims to explore the effects of crimped polypropylene fiber (PP) inclusions in slag (GGBS) based concrete, which was used as cement replacement. The mode of accelerated curing on mechanical properties of the GGBS based concrete for various mixes of concrete was investigated systematically. The addition of PP fiber in the concrete increases the strain hardening properties of the concrete due to matrix reinforcing efficiency offered by discrete fibers present in the matrix. The experimental test results showed an increase in bending stress in concrete with an increase in percentage of PP fibers from 0.1% to 0.3% Vfof concrete. In the case of slag concrete, the optimum addition of slag up to 25% proved to be effective in improving the concrete strength properties. Further replacement of OPC in GGBS up to 50% concrete mixes showed a reduction in the compressive strength in normal curing. Indeed, an apparent increase in the compressive and flexural strength of slag based concrete was noticed in accelerated curing for various mixes of structural concrete.

Influence of Fibre Length on the Behaviour of Polypropylene Fibre Reinforced Cement Concrete

Concrete being a mixture of cement, aggregates (fine and coarse) and water, can be used in vast range of applications. It has excellent durability and availability which are its main advantages. Though, concrete is strong in compression it is comparatively weak in tensile loading. Over the years various materials have been used to reinforce concrete to withstand the tensile stresses. Polypropylene fibre is one such fibre which comes in varied sizes, is nowadays being utilized to reinforce concrete. In this study, three PP fibres were used at 0.20%, 0.25% and 0.30% content by weight. The flexural and compressive strengths were determined. Based on the results, it was observed with increase in size of fibre the compressive strength decreased significantly though it was still higher than the controlled sample. The length of PP fibres had significant effect on the compressive strength and flexural strength of concrete. Short PP fibres showed relatively higher compressive strength but lower flexural strength when higher fibre content is used, while long PP fibres achieved lower compressive strength but higher flexural strength than shorter PP fibres. The optimum dosage for both PP fibre sizes was 0.25% at which it achieved increased strength as compared to control sample.

Experimental Analysis on Tensile Behavior of Engineered Cementitious Composite (ECC) using Polypropylene Fiber

The high demand of tensile strength in concrete is always a critical issue for engineers, as 10% of the compressive strength is not sufficient to withstand higher loadings. Lesser ductility and strain capacity is another major issue of normal concrete. In the queue of modern researches, this paper is an attempt to study Engineered Cementitious Composite (ECC) from research of Professor Victor Li, the University of Michigan. ECC is an ultra-ductile cementitious composite which is highly crack resistant, with a high tensile strain capacity over that of normal concrete. The composite replaces coarse aggregates and fine aggregates by sand and fly ash respectively. ECC is made up of OPC, sand (passing from 250 µm and retained on 150µm), Fly Ash (Class F) with addition of Polypropylene fiber on different percentages i.e. 0%, 0.25%, 0.5%, 0.75%, 1.0% were studied. Tensile Strength of ECC was measured by casting & testing cylinders of 4”x 8” in Universal Testing Machine (UTM). The experimental results revealed that 111.40% increment in tensile strength was found at 0.5% PP fiber at ECC 1:1:1 and an increment of 74.74% was observed at ECC 1:0.8:1.2 at 1% PP fiber. The study concludes that this composite could substitute the normal concrete where high tension is the ultimate requirement with higher strain capacity.

On the mechanical behavior of polypropylene, steel and hybrid fiber reinforced self-consolidating concrete

This article presents the results of an experimental investigation on the mechanical behavior of a self-consolidating concrete reinforced with steel, polypropylene and hybrid fibers. Hooked end steel fibers with different lengths and diameters were used as reinforcement in fiber volume fractions of 0.50%, 1.00% and 2.00%. Polypropylene fibers were used as reinforcement in volume fractions of 0.33%, 0.66% and 1.10%. Hybrid composites (HyFRC) were also developed to study the synergy effects of both fibers. The hybrid fiber self-consolidating concrete was produced with the addition of 0.50% of hooked-end steel fibers and 0.66% of polypropylene fibers.Pre-notched SCC prims where tested under monotonic and cyclic three-point bending. The tests where controlled by the crack mouth opening displacement in order to have a better analysis of the post cracking regime. The addition of polypropylene, hooked-end and hybrid fibers was effective in improving the post-peak strength of the composites, even though the use of steel fibers promoted higher values of flexural residual stress due to its geometrical and material properties. The same behavior was observed for the fracture parameters results with an improvement of the crack growth resistance for the analyzed composites.Finally, the effect of the fiber reinforcement on the flexural behavior was studied through structural tests on fiber reinforced self-consolidating concrete beams. Both hooked-end steel fiber and hybrid composites enhanced the resistance at yielding and promoted a lower rate of stiffness degradation, while the polypropylene fiber reinforcement presented an improvement in the ductile behavior of the structural composite. The present work gives an important contribution on the structural and cyclic behavior of steel, PP and hybrid fiber reinforced concrete. The paper makes a comparison on the mechanics of the different composite systems aiming its application in structural elements.

Non-destructive characterisation of all-polypropylene composites using small angle X-ray scattering and polarized Raman spectroscopy

Small angle X-ray scattering (SAXS) and polarized Raman spectroscopy were used to examine the structure of unidirectional all-polypropylene composites prepared at different consolidation temperatures. Analysis of the anisotropy of the X-ray scattering pattern provided a way to quantify the disorientation of the crystallites and a direct correlation has been found between a measure of overall orientation and the Young’s modulus of the composites. In the case of the Raman spectroscopic measurements, the molecular orientation state of the reinforcing PP fibres were evaluated by classical least squares (CLS) modelling with real reference spectra. Strong correlation was evinced between the estimated relative degree of orientation of the reinforcing fibres and the Young’s modulus of the multi-layered all-polypropylene composites. Based on these results, both SAXS and Raman spectroscopy are suitable methods to predict the mechanical performance of all-polymer composites, being especially sensitive to manufacturing and application conditions, in a non-destructive way.

Effect of fiber type on the behavior of cementitious composite beam-column joints under reversed cyclic loading

This paper investigates the effect of using different types of fiber on the behavior of engineered cementitious composite (ECC) beam-column joints under reversed cyclic loading. The tested ECC beam-column joints were cast with different types of fiber, including 8 mm and 12 mm polyvinyl alcohol fibers (PVA8 and PVA12), 13 mm polypropylene fibers (PP13), and 13 mm steel fibers (SF13). The investigation also tested a conventional normal concrete (NC) beam-column joint made with 10 mm coarse aggregate for comparison. The performance of the tested specimens was evaluated based on hysteresis behavior, ductility, energy dissipation capacity, and cracking behavior. The results indicated that compared to NC, ECC with either PVA or PP fibers can be a promising construction material to develop beam-column joints with improved ductile behavior under reversed cyclic loading. Using shorter PVA fibers (PVA8 vs. PVA12) appeared to have a stronger influence on improving the cyclic behavior of ECC joints. The highest improvements in terms of first crack load, ultimate load, ductility, and energy dissipation capacity were observed when SF13 was used. The results also indicated that the failure pattern of all ECC joints showed better cracking behavior and higher shear strength compared to the NC joint.

Effect of hybrid fibers on flexural performance of reinforced SCC symmetric inclination beams

In order to evaluate the effect of hybrid fibers on the flexural performance of tunnel segment at room temperature, twelve reinforced self-consolidating concrete (SCC) symmetric inclination beams containing steel fiber, macro polypropylene fiber, micro polypropylene fiber, and their hybridizations were studied under combined loading of flexure and axial compression. The results indicate that the addition of mono steel fiber and hybrid fibers can enhance the ultimate bearing capacity and cracking behavior of tested beams. These improvements can be further enhanced along with increasing the content of steel fiber and macro PP fiber, but reduced with the increase of the reinforcement ratio of beams. The hybrid effect of steel fiber and macro PP fiber was the most obvious. However, the addition of micro PP fibers led to a degradation to the flexural performance of reinforced beams at room temperature. Meanwhile, the hybrid use of steel fiber and micro polypropylene fiber didn\'t present an obvious improvement to SCC beams. Compared to micro polypropylene fiber, the macro polypropylene fiber plays a more prominent role on affecting the structural behavior of SCC beams. A calculation method for ultimate bearing capacity of flexural SCC symmetric inclination beams at room temperature by taking appropriate effect of hybrid fibers into consideration was proposed. The prediction results using the proposed model are compared with the experimental data in this study and other literature. The results indicate that the proposed model can estimate the ultimate bearing capacity of SCC symmetric inclination beams containing hybrid fibers subjected to combined action of flexure and axial compression at room temperature.