Fiber Reinforced Polypropylene Composites Research Articles

The synergy of the matrix modification and fiber geometry to enhance the thermo‐mechanical properties of basalt fiber‐polypropylene composites for automotive applications

AbstractBasalt fiber reinforced polypropylene composites with two initial fiber lengths (3.2 and 6.4 mm) were fabricated using twin‐screw extrusion compounding. In the case of composites with smaller initial fiber length, basalt fibers predominantly served as nucleating agents for polypropylene thereby resulting in an increase in the degree of crystallinity. The addition of polypropylene‐g‐maleic anhydride (PP‐g‐MA) caused the matrix to become amorphous, which was due to the establishment of a fiber–matrix interphase. This behavior was different for the composites with relatively larger initial fiber length especially at higher fiber content. The reduction in fiber length in the composites caused a decrease in crystallinity, as this hindered the ability of the polypropylene matrix to form crystals. Addition of PP‐g‐MA established a fiber–matrix interphase thereby synergistically contributing to the increased matrix amorphousness of the basalt fiber reinforced polypropylene composites with 6.4 mm initial fiber length. Reduced fiber length due to processing also accelerated the thermal degradation of the composites with an initial fiber length of 6.4 mm. However, the reduction in fiber length due to processing resulted in increased fiber orientation, which contributed to the improvement in tensile and flexural properties of the basalt fiber reinforced polypropylene composites with an initial fiber length of 6.4 mm. At 30% fiber content, the tensile strength and modulus of basalt fiber reinforced matrix modified polypropylene composites with 6.4 mm initial fiber length improved by 18% and 13% as compared with the composites with 3.2 mm initial fiber length.

Experimental investigation on effects of ultrasonic process parameters on the degree of impregnation of BF/PP composites

The properties of basalt fiber reinforced polypropylene composites (BF/PP) were improved by ultrasonic treatment of resin building pressure to assist melt impregnation. Combined with the study of ultrasonic pressure building theory, the mechanical properties of the modified composites were analyzed using the characterization of tensile, flexural and impact strengths in response to porosity and fracture rate. The effects of ultrasonic power, frequency and distance of action on resin building pressure and composite properties were investigated. The results showed that the best effect was achieved when the ultrasonic frequency was 25 kHz, the ultrasonic power was 300 W, and the action distance was 4 mm, at which time the porosity of the prepreg was reduced to 2.99%, the fracture rate was 3.36%, and the tensile, flexural, and impact strengths were 108.73 MPa, 116.81 MPa, and 51.59 KJ.m−2.

Performance analysis of fiber-reinforced polypropylene composite laminates under quasi-static and super-sonic shock loading conditions for impact application

In the present research, glass and basalt fiber-reinforced polypropylene composites’ behaviour in quasi-static and dynamic conditions is studied. Composites were fabricated by vacuum assisted Compression molding method. Composites failure under quasi-static tension and compressive conditions was studied along with its failure behaviour under low-velocity impact and super-sonic shock loading under dynamic conditions. The study results showed that basalt fiber-reinforced polypropylene (Basalt/PP) composite’s tensile and compressive strength is higher than glass fiber-reinforced polypropylene (Glass/PP). The Basalt/PP showed no penetration against low velocity impact (LVI) with negligible deformations till 50 J. However, the Glass/PP perforated at 50 J with various failure patterns occurring at back side. The fiber-matrix interface adhesion plays an important role in super-sonic shock loading by absorbing shock wave energy due to ductile nature of polypropylene and the two composites absorbed energy via matrix and fibers failure, no brittle failure of laminates occurred under shock loading.

Enhancement of interfacial performance of carbon fiber reinforced polypropylene composites by dual action of polyetherimide nanoparticles and coatings

In order to enhance the interfacial bonding between carbon fibers (CFs) and polypropylene (PP) resin, a multiscale modification system of composite interfacial physical embedding-chemical bonding was established by the dual action of polyetherimide (PEI) nanoparticles and coatings prepared on the surface of CFs. Hemispherical PEI nanoparticles were prepared by evaporation-induced treatment to improve the mechanical interlocking ability of the composite interface. Based on PEI nanoparticles, coatings with different concentrations were introduced on the CF surface to exert chemical bonds and enhance compatibility with the PP resin. The surface properties of CFs, including chemical composition, morphology, wettability, and interfacial adhesion were systematically investigated. Compared with unmodified CFs, modified CFs showed increased surface roughness, enhanced surface activity, and improved surface wettability. Due to the dual action of PEI nanoparticles and coatings, the tensile strength and interlaminar shear strength (ILSS) of the composite were both enhanced. Specifically, the ILSS of PCF-0.10/PP composite increased by 119.35%, indicating that the dual modification significantly improved the mechanical reinforcement and interfacial adhesion of the composite. On this basis, the interfacial strengthening mechanism in the composite was proposed, and an effective and feasible method was proposed to improve the interfacial performance of composites. The method has the limitation of a long preparation time, but it is simple, easy, and cost-effective, which provides a promising prospect for the application of composites.

Dyeability and mechanical properties of banana fiber reinforced polypropylene composite

AbstractBanana fibers being highly strong and biodegradable, have always been an interesting aspect of polymer science. The research examines the pretreatment process to enhance the dyeability of banana fibers with synthetic dyes, followed by the preparation of polypropylene (PP) composites with dyed fibers to explore their mechanical properties. Raw banana fibers were extracted from the pseudo stems of banana plants for pretreating with sodium hydroxide and hydrogen peroxide and further dyed in the exhaust method using direct, basic, reactive, and vat dyes. Despite a decrease in fiber strength, the scoured‐bleached fibers appeared whiter and lustrous compared to untreated fibers. Direct dye exhibited a higher color strength (K/S) value of 20.7 and better wash fastness on average of 4‐3 rating compared to basic dye. Later polypropylene sheets were prepared using a Hot Plate Molding Machine, and composite specimens were fabricated by sandwiching the fibers between PP sheets and hot pressing. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed minor bond formations between the dyed fibers and polypropylene matrix in composites showing significant bonding at NH, CH, and OH regions. The composites containing dyed fibers showed slight improvements in tensile strength and modulus which is at best 2% than that of untreated fiber.Highlights Direct and basic dyes were determined as the most suitable synthetic dyes. FTIR analysis revealed minimal bond formation between the fiber and PP matrix. Composites having dyed banana fiber showed little better mechanical features.

Mechanical, Thermal, and Electrical Properties on 3D Printed Short Carbon Fiber Reinforced Polypropylene Composites

Mechanical, Thermal, and Electrical Properties on 3D Printed Short Carbon Fiber Reinforced Polypropylene Composites

Long coir and glass fiber reinforced polypropylene hybrid composites prepared via wet-laid technique

Natural fiber composites offer an advantage in terms of weight saving for many automotive applications; however, many natural fiber composites lack properties to justify substitution for synthetic composites. Hybridizing the natural fiber composites by adding a fraction of synthetic fibers is an innovative approach to provide a balance between composite's performance and weight savings. In this study, coir fiber (40 wt%)-reinforced polypropylene (PP) composites were hybridized by substituting a fraction of coir fiber with glass fiber (0–30 wt%). The composites were prepared using a novel wet-laid technique followed by compression molding, where the fiber length is preserved. The composites prepared by hybridizing PP/coir fibers with glass fibers were light in weight (6–20% lighter compared to 40 wt% glass fiber reinforced PP) with significantly enhanced tensile (strength – 49–182%, modulus – 54–130%), flexural (strength – 41–104%, modulus – 64–193%), and impact properties (157 - 474%) compared to 40 wt% coir fiber reinforced PP composites. Furthermore, the addition of glass fiber (10–30 wt%) to coir fiber reduced the water-absorbing tendency (by 18–74%) of PP/coir fiber composites. All in all, this work has potential applications in automotive, mass transit, and truck applications where natural fiber composites are being investigated as alternatives to metal and/or fully synthetic composites.

Study on the Characterization of Physical, Mechanical, and Mildew Resistance Properties of Enzymatically Treated Bamboo Fiber-Reinforced Polypropylene Composites

The enhancement of the physical and mechanical properties and the anti-mildew performance of wood–plastic composites are of great significance for broadening their application field. In this research, bamboo fibers underwent treatments with safe, environmentally friendly bio-enzymes. Subsequently, a bamboo–plastic composite (BPC) was developed using the modified bamboo fibers and polyethylene. The effects of biological enzymatic treatments on the surface free energy, the chemical composition of the bamboo fibers, water resistance, thermal stability, bending performance, impact performance, and anti-mildew performance of the BPC samples were analyzed. This study revealed that treating bamboo powder with bio-enzymes (xylanase, lipase, laccase, pectinase, hemicellulase, or amylase) decreased the surface free energy and the polar components of the bamboo fibers while improving the surface O/C atomic ratio of the bamboo fibers. These enzyme treatments enhanced the water resistance, bending performance, and anti-mildew performance of the BPC samples. However, on the whole, the thermal stability of the composites decreased. Particularly, after hemicellulase treatment, the composites had the lowest water absorption, reflecting a decrease of 68.25% compared to the control group. With xylanase modification, the 24 h water absorption thickness swelling rate of the composites was the lowest, reflecting a decrease of 71.27% compared to the control group. After pectinase modification, the static bending strength and elastic modulus of the prepared composites were the highest, with an increase of 15.45% and 13.31%, respectively, compared to the unmodified group. After xylanase modification, the composites exhibited the best anti-mildew effect, with an anti-mold effectiveness of 74.67%. In conclusion, bio-enzyme treatments can enhance the physical and mechanical properties and anti-mildew performance of BPCs. This research provides a theoretical foundation for the preparation of high-performance wood–plastic composites.

Effects of different types of functionalized polypropylenes on the tensile strength of short carbon fiber-reinforced polypropylene composites

In this study, the effects of various functionalized polypropylenes (PPs) with different types and contents of functional groups and crystallinities on the tensile strength of short carbon fiber (SCF)-reinforced plastics (SCFRPs) prepared by injection molding were evaluated. The tensile strengths of SCFRPs were significantly influenced by interfacial adhesion. The types and contents of functional groups introduced into functionalized PP were the dominant factors impacting the development of interfacial adhesion. In particular, near the surface where SCF and PP were highly oriented in parallel, functionalized PP with more functional groups added to side chains exhibited higher interfacial adhesion than that with fewer functional groups. These results suggested that PP molecular chain orientations resulting from the shear flow of injection molding were among the key factors affecting the interfacial adhesion of the PP matrix.

Numerical simulation analysis of forming of continuous fiber reinforced polypropylene composites: Relaxation, creep, and hot stamping

Numerical simulation analysis of forming of continuous fiber reinforced polypropylene composites: Relaxation, creep, and hot stamping

Nanomechanical properties of sized and de-sized carbon fiber reinforced polypropylene composites

Most of the research to date has focused on tailoring the interphase adhesion by controlling the degree of chemical bonding between fiber and resin. However, recent studies suggest that apart from chemical bonding, mechanical interlocking plays a crucial role to enhance the interphase thickness and hence the interfacial shear strength. In this study, the effect of textured carbon fiber surface on the interphase thickness, and interfacial shear strength has been studied and analyzed. The hot water was used to remove the epoxy-based sizing agent from the carbon fiber (sized CF) surface and thereby to create a textured surface morphology in de-sized one (De-sized CF). To study the distinctions of the interphase between sized and de-sized CF/PP composites, the Derjaguin-Muller-Toporov (DMT) modulus by Peak Force Quantitative Nano-Mechanics (PF-QNM) was applied to determine the interphase thickness and its nanomechanical properties. It was found that no chemical changes occurred after hot water treatment albeit the surface morphology of de-sized carbon fiber became textured. The average interphase thickness in de-sized CF/PP composites was found to be 84.17% higher (212.9 ± 21 nm) as compared to 115.6 ± 21 nm in sized CF/PP composites. This study shows the potential for using mechanical interlocking effects without significantly affecting the chemical bonding, to improve the interphase thickness in fiber reinforced composites.

Effect of imbibed moisture on monotonic and low‐velocity impact behavior of injection over‐molded short/continuous fiber reinforced polypropylene composites

AbstractDesign of automotive components with over‐molded short/continuous fiber reinforced thermoplastic composites necessitates understanding of their behavior under extreme outdoor conditions. The short, quasi‐isotropic and over‐molded short/continuous glass fiber reinforced polypropylene (PP) composite specimens were prepared as per standard and immersed in water until equilibration to study their relative moisture absorption characteristics and consequent mechanical behavior. As the absorbed moisture mostly occupied the interface between fiber and matrix in laminated composite inserts and moisture absorption of short fiber composite core is insignificant, the moisture absorption of over‐molded composites is just above 50% of that of laminated composites. The flexural, interlaminar shear and impact behavior of equilibrated composites is primarily governed by the quantum of imbibed moisture of composite materials. Optical analysis of failed moisture equilibrated over‐molded specimens showed a marginal delamination between plies of the inserts without any perceptible damage within the short fiber composite similar to dry as molded specimens.

Effect of interface temperature on low‐velocity impact response of injection over‐molded short/continuous fiber reinforced polypropylene composites

AbstractInjection over‐molded short/continuous fiber reinforced composites are a unique class of materials for fabricating lightweight components having complex geometries in automotive manufacturing due to their higher specific mechanical properties, lower assembly cost, and short production cycle time. The influence of interface temperature on the low‐velocity impact response of short/continuous fiber‐reinforced polypropylene was experimentally investigated by varying the melt temperature. The over‐molded specimens fabricated at an interface temperature considerably higher than the melting point of polypropylene exhibited a 12% enhanced peak load with less impact damage compared with specimens over‐molded at a lower interface temperature. Optical analysis of impacted specimens over‐molded at lower interface temperature revealed interface debonding and insert delamination. Whereas insert delamination alone was observed for the specimens fabricated at higher interface temperature. The specimens over‐molded at high interface temperature exhibited less impact energy absorption and high compression strength after impact because of their strong interfacial adhesion.Highlights Impact energy absorption is less if melt temperature is high in injection over‐molding. Higher melt temperature enhances interface bonding by raising interface temperature. Interface debonding and insert delamination are the dominant impact failure modes. The compression strength after impact has increased with higher melt temperature. Impact and compression strength after impact is governed by the interfacial strength.

Quasi-Static and Low-Velocity Impact Behavior of Injection Over-Molded Short/Continuous Fiber Reinforced Polypropylene Composites

Quasi-Static and Low-Velocity Impact Behavior of Injection Over-Molded Short/Continuous Fiber Reinforced Polypropylene Composites

Jute and E-glass fiber-reinforced polypropylene composites: Comparative study

As a matrix, polypropylene is a very adaptable material, and PP can be combined with a variety of reinforcing fibres to improve its mechanical and physical characteristics. In this review work, we have explored how two fibers—glass fibre reinforced with PP, a synthetic fibre, and jute fibre reinforced with PP, a natural fiber—are used to reinforce polypropylene (PP). Tensile strength, flexural strength, and impact strength were compared as three mechanical characteristics. The glass - reinforced PP was found to have better mechanical qualities than the jute reinforced PP. But jute fibre reinforced PP showed biodegradability, whilst glass fibre reinforced PP did not.

Non-isothermal crystallization kinetics of halloysite nanotube/short glass fibre-reinforced polypropylene composites

Non-isothermal crystallization kinetics of halloysite nanotube/short glass fibre-reinforced polypropylene composites

Material and mechanical characterization of recycled polypropylene reinforced with different weight percentages of short glass fiber developed by injection molding

The objective of this study was to develop short glass fiber-reinforced recycled polypropylene composites using injection molding technique with varying fiber percentages (0–50 wt%). The study aimed to evaluate the mechanical and material properties of the composites and their potential applications. To achieve this, polypropylene composite pellets were prepared using a low-cost and simple manufacturing method that involved plastic recycling using a crushing method and pelletizing with different weight percentages of short glass fiber using twin-screw extruder. The study conducted various analyses, such as melt flow index, capillary rhinometry, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. Results showed that the recycled polypropylene/short glass fiber composites exhibited improved heat resistance, crystallization rate, and thermal stability compared to the pure polymer. The best impact mechanical (about 3.65 ± 0.09 J/m) properties were obtained at 50 wt% of short glass fiber in the fabricated composites. Scanning electron microscope analysis indicated a uniform dispersion of short glass fiber in the polypropylene matrix. The potential applications of these composites were found in household appliances, industrial plastic products, and other areas. Overall, this study demonstrates the potential of short glass fiber-reinforced polypropylene composites as a cost-effective, environmentally friendly and sustainable alternative for various applications.

Thermo-visco mechanical behavior of glass fiber reinforced thermoplastic composite

Thermoplastic composite materials are being increasingly used in many domains, such as automotive, marine and aeronautics. This growing interest is due to the relatively good mechanical properties and the recycle-ability of these materials. In various heat assisted forming technologies, thermoplastic composites may be subjected to severe conditions such as high temperatures, complex strain paths and potentially significant strain rates. This is expected to highly influence the overall behavior of these materials and make the characterization of their mechanical behavior more complicated. In this paper, the mechanical behavior of discontinuous glass fiber reinforced polypropylene composite is investigated at temperatures going from room temperature (RT) to 120°C and strain rates ranging from quasi-static conditions to 10 s−1 by means of uniaxial tensile tests. The effect of material orientation is also investigated at RT and quasi-static strain rate of 0.001 s−1 pointing out a clear anisotropic behavior. The tensile properties including Young’s modulus E, ultimate tensile strength σ ult and strain at failure ɛ f are determined based on the Standard ISO-527 reporting an obvious sensitivity of the material to temperature and strain rate. Based on literature review, the phenomenological isotropic constitutive model of G’Sell and Jonas, originally designed for unreinforced semi-crystalline polymers, is selected to describe the mechanical behavior of the studied material. A modification of the original constitutive equation is proposed for a better representation of the overall behavior of the material at different temperature and strain rate conditions. Finally, the validity of this phenomenological law calibrated by means of the uniaxial tests, is evaluated for an equi-biaxial loading state close to that encountered by the material during heat assisted sheet forming process. The significant disagreement highlighted between numerical and experimental results proved that the uniaxial tensile tests are not sufficient to characterize the behavior of the material when a complex loading condition is imposed.

Effect of Strain Rate and Temperature on the Tensile Properties of Long Glass Fiber-Reinforced Polypropylene Composites.

Strain rate and temperature are influential factors that significantly impact the mechanical properties of long glass fiber-reinforced polypropylene composites. This study aims to investigate the tensile properties of these composites, analyzing the effects of temperature, strain rate, and their interplay on variables such as tensile stress, tensile strength, fracture stress, and fracture morphology through a series of comprehensive tensile experiments. The experimental results demonstrate a notable increase in both tensile strength and tensile fracture stress when the temperature is set at 25 °C, accompanied by strain rates of 10-4, 10-3, 10-2, and 10-1 s-1. Conversely, a significant decrease is observed in the aforementioned properties when the strain rate is fixed at 10-4, while varying temperatures of -25 °C, 0 °C, 25 °C, 50 °C, and 75 °C are applied. At lower temperatures, cracks manifest on the fracture surface, while matrix softening occurs at higher temperatures. Additionally, in the context of strain rate-temperature coupling, the decreasing trend of both tensile strength and tensile fracture stress decelerates as the temperature ranges from -25 °C to 75 °C at a strain rate of 10-1, compared to 10-4 s-1. These findings highlight the significant influence of both strain rate and temperature on high fiber content long glass fiber-reinforced polypropylene composites.

Dynamic mechanical and drilling behavior of Alstonia macrophylla fiber-reinforced polypropylene (PP) composites

Dynamic mechanical and drilling behavior of Alstonia macrophylla fiber-reinforced polypropylene (PP) composites