Addition Of Short Glass Fibers Research Articles

Effect of Short Glass Fiber Addition on Flexural and Impact Behavior of 3D Printed Polymer Composites.

Fused deposition modeling (FDM), one of the most widely used additive manufacturing (AM) processes, is used for fabrication of 3D models from computer-aided design data using various materials for a wide scope of applications. The principle of FDM or, in general, AM plays an important role in minimizing the ill effects of manufacturing on the environment. Among the various available reinforcements, short glass fiber (SGF), one of the strong reinforcement materials available, is used as a reinforcement in the acrylonitrile butadiene styrene (ABS) matrix. At the outset, very limited research has been carried out till date in the analysis of the impact and flexural strength of the SGF-reinforced ABS polymer composite developed by the FDM process. In this regard, the present research investigates the impact and flexural strength of SGF-ABS polymer composites by the addition of 15 and 30 wt % SGF to ABS. The tests were conducted as per ASTM standards. Increments in flexural and impact properties were observed with the addition of SGF to ABS. The increment of 42% in impact strength was noted for the addition of 15 wt % SGF and 54% increase with the addition of 30 wt % SGF. On similar lines, flexural properties also showed improved values of 44 and 59% for the addition of 15 and 30 wt % SGF to ABS. SGF addition greatly enhanced the properties of flexural and impact strength and has paved the path for the exploration of varied values of reinforcement into the matrix.

Polypropylene Random Copolymer Based Composite Used for Fused Filament Fabrication: Printability and Properties.

Fused filament fabrication (FFF) is one of the most commonly used additive manufacturing technologies. However, the applied material for commercial FFF is limited. Presently, though being one of the most used polymer materials, polypropylene (PP) is rarely used in FFF because of its serious warpage and shrinkage problems. This study investigated the impact of addition of short glass fibers (GF) and ethylene propylene diene monomer (EPDM) on the printability of polypropylene random copolymer (PPR) based FFF and mechanical properties of the printed samples, as well as other properties including rheology, thermal behaviors, and morphology. The results show that the modified PPR has excellent printability, as the printed samples are of good geometrical accuracy. The addition of GF can significantly improve the strength and modulus of the composite, but it also leads to serious decrease in toughness. EPDM addition can effectively improve the toughness of the composite, showing a complementary effect with GF. This work has important meaning in expanding the FFF applicable material and in broadening the application of PP.

Effect of fiber content and orientation on the scratch behavior of short glass fiber reinforced PBT composites

To investigate the scratch behavior of short glass fiber (SGF) reinforced polybutylene terephthalate (PBT) composites, the scratch tests with the progressively increasing normal load were conducted for PBT reinforced with 0 wt%, 10 wt%, 20 wt% and 30 wt% SGF. The effect of fiber content and orientation on the scratch behavior of PBT composites and underlying scratch damage mechanisms were investigated. The addition of SGF alters the critical normal loads of onset fish-scale deformation and material removal respectively. The glass fiber fracture was observed and its damage mechanism was analyzed. The results show that although the bulk mechanical properties of PBT are enhanced, the addition of glass fiber generally causes poor scratch resistance. The guidance for designing scratch-resistant SGF reinforced PBT is also discussed.

Mechanical and tribological properties of short glass fiber and short carbon fiber reinforced polyethersulfone composites: A comparative study

Abstract The polyethersulfone (PES) composites incorporated with short carbon fibers (SCFs) and short glass fibers (SGFs) were manufactured, and their mechanical and tribological properties were comparatively investigated. The tensile and flexural strengths of SCF/PES composites increase monotonically with increasing the SCF content while those of the SGF/PES composites initially increase dramatically but the strengths approaches a plateau when the SGF content is over 5 vol%. The Young’s and flexural moduli of both SGF/PES and SCF/PES composites exhibit a monotonic increase behavior with increasing the fiber content and achieve the maximum improvements of 128.7%, 227.2%, 165% and 234% with the introduction of 30 vol% short fibers. The addition of SGFs results in a monotonic increase of the friction coefficient and a maximum increase of 48.8% is achieved with 30 vol% SGFs. By contrary, the friction coefficient of SCF/PES composites decreases with the addition of SCFs and a maximum drop of 29.8% compared with that of pure PES is reached with the addition of 20 vol% SCFs. The wear resistance of PES composite is greatly improved by the incorporation of either SGFs or SCFs. The specific wear rates of the PES composites decrease significantly with the addition of short fibers, and the maximum reduction of 71.4% and 95.7% is achieved with the addition of 20 vol% short fibers. When cost is primary consideration while strength, modulus and tribological performance are secondary considerations for end users, SGFs are superior over SCFs; otherwise; SCFs are superior over SGFs.

Fatigue behavior of pure polypropylene and recycled polypropylene reinforced with short glass fiber

In this study, the fatigue behavior of recycled polypropylene reinforced with short glass fiber with different weight fractions (5 wt%, 10 wt%, 20 wt%, and 30 wt%) was compared to pure polypropylene under dry and wet conditions. The specimens were manufactured using injection molding process. The results show that addition of short glass fiber to recycled polypropylene resulted in increasing water uptake compared to pure polypropylene. However, flexural fatigue strength of recycled polypropylene reinforced with short glass fiber with 10 wt%, 20 wt%, and 30 wt% exhibits higher relative fatigue strength than pure polypropylene under dry and wet conditions. Fatigue strength increases with the increase in fiber contents increased in recycled polypropylene matrix.

Tribological investigations of glass fiber reinforced epoxy composites under oil lubrication conditions

The tribological performance of short glass fibers (SGF), solid lubricants and silica nanoparticles filled epoxy (EP) composites was investigated under oil lubrication conditions. It is demonstrated that the addition of SGF greatly reduces the friction and wear of EP. However, further addition of solid lubricants and silica nanoparticles does not change obviously the friction and wear. It is identified that the high tribological performance of SGF reinforced EP is related to the high load carrying capacity and abrasion resistance of SGF. The nanostructure of the tribofilm was comprehensively characterized. It is deemed that the tribofilm plays an important role in the tribological performance by avoiding the direct rubbing of the sliding pairs exposed to boundary and mixed lubrication conditions.

Effect of Short Glass Fiber Loading on the Mechanical Behaviour of PA66/PTFE Blend Composites

The polymer blend of Polyamide66 and Polytetrafluroethylene (PA66/PTFE) (80/20 wt.%) were selected for the study. These blends were reinforced with 5, 10, 15, 20, 25 and 30 wt.% of silane treated short glass fibers (SGF) and were prepared by using melt mixing method with the help of twin screw extruder. The mechanical properties such as tensile strength, flexural strength, impact strength were studied in addition to hardness of the blend composites as per ASTM. The results revealed that the addition of SGF into PA66/PTFE blend greatly enhanced the mechanical properties of the polymer blend. The tensile strength and the flexural strength of the blend was almost double than that of the neat blend after reinforcing 30 wt.% of SGF. The addition of SGF into the blend greatly improved the flexural modulus and also the hardness of the blend. The impact strength of the blend decreased initially and then increased after the SGF addition into the blend. The density of PA66/PTFE blend increased after SGF addition. The strain at break almost remained constant but deflection due to bending decreased with the addition of SGF into the studied polyblend. However, the effect of higher loading of SGF on the mechanical behavior of PA66/PTFE blend was greatly appreciable. The fractured surfaces of the specimens were examined by using Scanning Electron Microscope photographs (SEM).

Post-consumer polyethylene terephthalate and polyamide 66 blends and corresponding short glass fiber reinforced composites

Blends of bottle-grade post-consumer polyethylene terephthalate (PET) and virgin polyamide 66 (PA66), over the complete composition range, and corresponding short glass fiber (SGF) reinforced composites were investigated. These materials were compounded in a twin-screw extruder and injection molded as standard specimens. Morphological investigation of the composites revealed that the short glass fibers have a good size distribution and are homogenously dispersed within a polymeric matrix. The PET/PA66/SGF composites showed good mechanical performance in flexural, tensile and impact tests demonstrating that the addition of SGFs to PET/PA66 blends is an interesting approach to obtaining new thermoplastic composites. In addition, this represents a potential application for post-consumer PET, an abundant and cheap material, in the well-established market of PA66/SGF composites, which are widely used in technical parts requiring high mechanical and thermal properties.

Mechanical and morphological properties of coextruded wood plastic composites with glass fiber‐filled shell

Coextrusion technology makes various properties of wood plastic composites (WPCs) highly tunable. However, structural and material optimization of core‐shell shaped WPCs is needed to balance manufacturing cost, processing efficiency, and product performance. In this study, various systems of coextruded WPCs were designed and analyzed using short glass fiber (SGF)‐filled shells in combination with three core systems (i.e., weak, moderate, and strong). A comparison of the composite flexural property of the manufactured WPCs (i.e., modulus and strength) shows that SGF reinforcements in the shell layer were optimized at high SGF loading levels regardless of core qualities. Also, SGF alignments in the shell layer played an important role in determining the flexural property of the WPCs. When the shell modulus and strength were lower than these of the core, the increase of shell thickness led to reduced composite properties. On the other hand, when the shell properties were higher than the core properties, the opposite was true. Composite impact strength increased with shell thickness increase for all three core systems. However, at a given shell thickness, the impact strength decreased with the addition of SGFs in the shell. Further increase of SGFs in the shell led to somewhat increased impact strength. The structure–property relationship plots provide a design guide for optimizing performance of coextruded WPCs with various combinations of core‐shell qualities. POLYM. COMPOS., 37:824–834, 2016. © 2014 Society of Plastics Engineers

Impact-Resistant Polypropylene/Short Glass Fiber Composites with Far-Infrared Emission: Manufacturing Technique and Property Evaluation

This study produces the far-infrared emitting composites by using impact-resistant polypropylene, short glass fibers, and far-infrared masterbatches. The addition of short glass fiber and far-infrared masterbatches is then evaluated to determine their influence on the mechanical properties and far-infrared emissivity of the resulting composites. The experimental results show that with an increase in the content of short glass fibers, the tensile strength increases from 34 MPa to 56 MPa, the far-infrared emissivity increases from 0.85 to 0.93, but the impact strength decreases from 1037 J/m to 197 J/m, proving that the resulting composites have desired mechanical properties and far-infrared emission.

Effect of processing variables and fiber reinforcement on the mechanical properties of wood plastic composites

Wood plastic composite (WPC) specimens were fabricated in shapes relevant to flute (musical instrument) production using African blackwood powder and phenolic resin in a hot compression molding setup. The roles of composition and processing parameters on the mechanical properties (flexural strength, elastic modulus, and impact failure energy) were systematically investigated. Cracks were observed in composites with more than 70% wood particles due to the formation of gas in the system during manufacturing, and lack of fluidity in the system to flush out entrapped air and the produced gases. Based on these results, the optimum temperature, pressure, and wood volume fraction for manufacturing WPC in the form of a flute is developed. A further series of experimental procedures were performed to improve the mechanical properties of WPC samples by studying the addition of short glass fibers to the molding compound prior to hot pressing. The results showed that the addition of short fiber did not improve the strength of WPC but rather reduced its strength compared to unreinforced composite. This was attributed to lack of bonding between the short fibers and composite matrix.

The Effect of Injection Molding Process Parameters on the Buckling Properties of PBT/Short Glass Fiber Composites

This study investigates the effect of various injection molding process parameters and fiber amount on buckling properties of Polybutylene Terephthalate (PBT)/short glass fiber composite. The buckling specimens were prepared under injection molding process. These forming parameters about filling time, melt temperature and mold temperature that govern injection molding process are discussed. The buckling properties of neat PBT, 15 wt%, and 30 wt% are obtained using two ends fixed fixture and computerized closed-loop server-hydraulic material testing system. The fracture surfaces are observed by scanning electron microscopy (SEM). The global buckling forces are raised when increased the fiber weight percentage of PBT. Also, the fracture mechanisms in PBT and short glass fiber matrix are fiber pullout in skin area and fiber broken at core area. It is found that the addition of short glass fiber can significantly strengthen neat PBT.

Dynamic mechanical analysis of thermotropic copolyester—short glass fiber composites

AbstractThe influence of short glass fibers (SGF) on the dynamic mechanical properties and microstructure of thermotropic copolyesters based on 1,4‐hydroxybenzoic acid and 2,6‐hydroxynaphthoic acid (denoted B‐N) has been investigated. The mechanical relaxations of the reinforced B‐N/SGF composites were studied under torsion mode and the results were correlated with the degree of molecular alignment and degree of crystallinity as revealed by wide‐angle X‐ray scattering (WAXS). Addition of SGFs to B‐N liquid crystalline polymer (LCP) produced an increase in the solid‐to‐nematic transition temperature as well as an increase in the decomposition temperatures. Dynamic mechanical analysis (DMA) showed that the local motions associated with the β‐transition (∼61°C) are enhanced as the frequency of oscillation increases, i.e. the tan δ maximum increases at higher frequencies. On the other hand, the cooperative motions associated with the α‐transition (∼100°C) are decreased at higher frequencies. The addition of SGF reduced significantly the strength of the α‐transition. Thus, the cooperative molecular motions involving segments of the molecular chains associated with the α‐transition were compromised by the presence of SGFs resulting in an increase of the storage modulus, melting, and degradation temperatures. X‐ray scattering showed that the SGFs disrupted the degree of molecular alignment (as quantified by the order parameter $\bar P_2 $), $\bar P_2 $, and the degree of crystallinity in the composites decreased as the concentration of SGFs increased. Thus, it is suggested that the increase in storage modulus in the composites is attributed to the contribution of the SGFs. Copyright © 2008 John Wiley & Sons, Ltd.

Reinforcement of conventional glass-ionomer restorative material with short glass fibers

This study investigated the strengthening effect of glass fibers when added to conventional glass-ionomer restorative material. Glass fibers were incorporated into glass-ionomer powder in 3 wt% and 5 wt%. The fibers used had 1 mm length and 10 μm thickness. These criteria of fiber length, diameter, and concentration represent a new approach for reinforcing conventional glass-ionomer [Medifill, conventional restorative glass-ionomer]. The mechanical properties tested were diametral tensile strength, hardness, flexural strength, flexural modulus and fracture toughness after 24-h and 7-days of storage in deionized water. Glass short fibers were mixed thoroughly into the glass-ionomer powder before mixing with the cement liquid. Samples of specific dimensions were prepared for each time interval and fiber loading according to the manufacturer’s instructions and international standards. Hardness was measured using a micro-hardness tester at 100 gram applied load for 15 s. The other mechanical properties were measured using a Lloyd universal testing machine. The results showed increased diametral tensile strength, flexural strength, flexural modulus, and fracture toughness by the addition of glass fibers. There was an appreciable increase of the tested mechanical properties of glass-ionomer restorative material as a result of increasing fiber loading and water storage for 1 week. It was concluded that conventional glass-ionomer can be reinforced by the addition of short glass fibers.

Fracture Toughness of Injection-Molded Poly(Butylene Terephthalate) Composites

: The influences of various fiber amounts and injection molding process conditions on the fracture toughness of injection-molded short fiber-reinforced poly(butylene terephthalate) (PBT) composites were investigated. Three materials of various fiber amounts, neat PBT, 15 wt.%, and 30 wt.% short fiber-reinforced PBT composites, were used in this study. The compact tension (CT) specimens were prepared by various injection molding process conditions, wherein filling time, melt temperature, mold temperature, and packing pressure were design parameters used to measure fracture toughness. The morphology of the specimens, which consisted of frozen, intermediate, and core layers, was evaluated by scanning electron microscopy (SEM) and related to the fracture toughness. The fracture surfaces were also observed by SEM to understand the difference between the fracture mechanisms of neat PBT and fiber-reinforced PBT. It was found that the fracture toughness of neat PBT was significantly increased by the addition of short glass fibers. However, the variation of the injection molding design parameter had little effect on the fracture toughness. The fracture toughness depended on the thickness of the layers where fibers oriented perpendicular to the crack direction. The layer thickness was strongly affected by the fiber amounts.

Design of a Slot-Coater-Based Layered-Composites Manufacturing System

This paper addresses the reinforcement of photopolymers, through the addition of short glass fibers, for Rapid Layered Composite parts Manufacturing (RLCM). Novel designs for an (external) fiber-resin-mixing subsystem and a (slot-coating-based) liquid-layer-formation subsystem are presented. These subsystems, when used as integral parts of a lithography-based RLCM system, successfully cope with typical difficulties encountered in the formation of thin layers from a highly viscous fiber-photopolymer composite liquid. Axiomatic Design theory was utilized for the analysis of both subsystem designs. Verification experiments run on an RLCM system confirmed (i) the ability of the fiber-resin-mixing subsystem to supply liquid composite with specified fiber content and to avoid fiber degradation through breakage, as well as (ii) the ability of the liquid-layer-formation subsystem to form solid layers with high fiber content and of uniform thickness.

The Effect of Injection Molding Process Parameters on the Tensile Properties of Short Glass Fiber-Reinforced PBT

This study investigates the influence of various injection molding process parameters and fiber amount on the tensile properties of short fiber-reinforced polybutylene terephthalate (PBT). The parameters that govern injection molding process are filling time, melt temperature, mold temperature, and packing pressure. The tensile properties of neat PBT, 15 wt%, and 30 wt% short fiber-reinforced PBT are obtained using a computerized closed-loop servohydraulic testing system. The frozen core morphology is observed by scanning electron microscopy (SEM), which can define the layer thickness. The observation can explain the influence of fiber orientation on the tensile properties. The fracture surfaces are also observed by SEM to understand the fracture mechanisms of different fiber orientations. It is found that the addition of short glass fibers can significantly strengthen neat PBT. The strength depends on the thickness of the layer where fibers are oriented in the loading direction. The layer thickness is strongly affected by the injection molding parameters and pin gate locations. Also, the fracture mechanisms of fiber pullout and across-matrix crack dominate the failure process in the layer where fibers are parallel to the direction of applied load. However, the failure of fiber–matrix interface dominates the fracture mechanism of the layer where fibers are mostly perpendicular to the applied load.

Mechanical characteristics of fiber‐filled photo‐polymer used in stereolithography

The effects of the addition of short glass fibers into an acrylic‐based photo‐polymer (De Solite SCR310) used in the laser solidification process have been studied. Comparisons of the mechanical properties between pure‐polymer specimens and their fiber‐filled counterparts were made by subjecting the parts to tensile tests. It was observed that the fiber‐reinforced specimens yielded higher measured values of elastic modulus and ultimate tensile strength. The amount of shrinkage encountered by the reinforced prototypes during post‐curing was also found to be less than their non‐reinforced counterparts. It was also found that the mechanical properties of the post‐cured fiber‐reinforced specimens were functions of the layer pitch and laser exposure density used during fabrication. By increasing the laser exposure density and decreasing the layer pitch, the mechanical properties of the post‐cured fiber‐reinforced prototype can be improved, leading to the realization of end products with higher mechanical strengths and better dimensional accuracy.

Reinforcement of denture base resin with glass fillers.

This study evaluated the effect of short glass fibers on the transverse strength of a heat-polymerized acrylic resin denture base material. Four groups of specimens (n = 10) were fabricated according to the ISO standard for the transverse strength test. E-glass fibers were triturated to produce short fibers of different lengths. Specimens for Group 1 (control) were made of unfilled polymethylmethacrylate (PMMA). For group 2, the PMMA powder was modified with 0.1 g of dry glass fibers. For group 3, the PMMA powder was modified with 0.1 g of silanized glass fibers. For group 4, the PMMA powder was modified with 0.2 g of silanized glass fibers. A three-point loading test was used to determine the transverse strength of the tested specimens. The fracture surface of each specimen was evaluated using SEM. The addition of untreated glass fibers increased the transverse strength by 11% but produced some porosity in the polymeric matrix. The addition of silane-treated glass fibers increased the transverse strength of PMMA by 28% for group 3 and by 26% for group 4, and produced a dense structure for the polymer-fiber composite. The transverse strength of PMMA can be slightly increased by the addition of short glass fibers.