Analysis of polymeric materials properties changes after addition of reinforcing fibers

2019 ◽  
Vol 30 (6) ◽  
pp. 2833-2843 ◽  
Author(s):  
Adam Gnatowski ◽  
Agnieszka Kijo-Kleczkowska ◽  
Rafał Gołębski ◽  
Kamil Mirek

Purpose The issues concerning the prediction of changes in properties of polymer materials as a result of adding reinforcing fibers are currently widely discussed in the field of polymer material processing. This paper aims to present strengths and weaknesses of composites based on polymer materials strengthened with fibers. It touches upon composite cracking at the junction of a matrix and its reinforcement. It also discusses the analysis of changes in properties of chosen materials as a result of adding reinforcing fibers. The paper shows improvement in the strength of polymer materials with fiber addition, which is extremely important, because these types of composites are used in the aerospace, automotive and electrical engineering industries. Design/methodology/approach Comparing the properties of matrix strength with fiber properties is practically impossible. Thus, fiber tensile strength and composite tensile strength shall be compared (González et al., 2011): tensile (glass fiber GF) = 900 [MPa], elongation ΔL≈ 0; yield point (polyamide 66) = 70−90 [MPa], elongation Δ[%] = 3,5-18; tensile (polyamide 66 + 15% GF) = 80-125 [MPa], elongation Δ[%] ≈ 0; tensile (polyamide 66 + 30% GF) = 190 [MPa], elongation Δ[%] ≈ 0; yield point (polyamide 6) = 45-85 [MPa], elongation Δ[%] = 4-15; tensile (polyamide 6 + 15% GF) = 80-125 [MPa], elongation Δ[%] ≈ 0; tensile (polyamide 6 + 30% GF) = 95-130 [MPa] elongation Δ[%] ≈ 0. Comparison of properties of selected polymers and composites is presented in Tables 1−10 and Figures 1 and 2. The measurement methodology is presented in detail in the paper Kula et al. (2018). The increase in fiber content (to the extent discussed) leads to the increase in yield strength stresses and hardness. The value of yield strength for polyamide with the addition of fiberglass grows gradually with the increase in fiber content. The hardness of the composite of polyamide with glass balls increases together with the increase in reinforcement content. The changes of these values do not occur linearly. The increase in fiber content has a slight impact on density change (the increase of about 1 g/mm3 per 10 per cent). Findings The use of polymers as a matrix allows to give composites features such as: lightness, corrosion resistance, damping ability, good electrical insulation and thermal and easy shaping. Polymers used as a matrix perform the following functions in composites: give the desired shape to the products, allow transferring loads to fibers, shape thermal, chemical and flammable properties of composites and increase the possibilities of making composites. Fiber-reinforced polymer composites are the effect of searching for new construction materials. Glass fibers show tensile strength, stiffness and brittleness, while the polymer matrix has viscoelastic properties. Glass fibers have a uniform shape and dimensions. Fiber-reinforced composites are therefore used to increase strength and stiffness of materials. Polymers have low tensile strength, exhibit high deformability. Polymers reinforced by glass fiber have a high modulus of elasticity and therefore provide better the mechanical properties of the material. Composites with glass fibers do not exhibit deformations in front of cracking. An increase in the content of glass fiber in composites increases the tensile strength of the material. Polymers reinforced by glass fiber are currently one of the most important construction materials and are widely used in the aerospace, automotive and electro-technical industries. Originality/value The paper presents the test results for polyethylene composites with 25 per cent and 50 per cent filler coming from recycled car carpets of various car makes. The tests included using differential scanning calorimetry, testing material hardness, material tensile strength and their dynamic mechanical properties.

2018 ◽  
Vol 15 (2) ◽  
pp. 312-320 ◽  
Author(s):  
Shanti Kiran Zade ◽  
Suresh Babu V. ◽  
Sai Srinadh K.V.

Purpose The purpose of this study is to manufacture test boards for re-enacting plant or field situations where vacuum chamber for expelling gas bubbles and autoclave equipment would not be accessible. This research focuses on the examination and enhancement of tensile strength for the nanocomposites consisting of uniaxial glass fiber mats, nanoclay (NC) and epoxy. Design/methodology/approach The parameters considered are the weight content of Cloisite 15A NC, the volume of glass fiber (Vgf) and the direction of glass fibers (θ). The composites are made by hand lay-up technique and tested according to ASTM D 638 standard. Taguchi L9 orthogonal array is used to design the experiments. Findings The results imply that the orientation of fibers exhibited high significance with a p-value of 0.001 for the upgrade of strength. NC percentage and the volume of fiber have a low effect as the p-values obtained were 0.375 and 0.294. Confirmation tests were performed at the optimal levels of parameters and the outcomes were in the permissible range of the anticipated values of S/N ratio and mean tensile strength. The negligible effect of nanoclay is due to the lack of infusion of resin into the d-spacing of clay layers due to the low configuration settings of mixing conditions which was confirmed by XRD studies. The negligible effect of glass fiber volume is due to the void content and lack of stress transfer between fibers uniformly due to the void content and improper mixing of nanoclay. Research limitations/implications The limitation of this study is that a low-speed mechanical stirrer was used to mix NC in the epoxy and the mixture was not subjected to vacuum and ultrasonication for degassing and deagglomeration. Practical implications These composites can be used as substitute materials in place of metallic parts in the aerospace and automobile sector. These composites can be used in civil structures instead of steel and concrete, which have low strength-to-weight ratio and where the requirement of strength is in the range of 60 to 390 MPa. Social implications The composites can be used in a variety of applications, for example, structural works, automotive panels and low-cost housing. Originality/value This research gives an idea about the combined contribution of NC, Vgf and “θ” to the improvement of tensile strength of the glass-epoxy composite.


1997 ◽  
Vol 12 (4) ◽  
pp. 1091-1101 ◽  
Author(s):  
Seunggu Kang ◽  
Hongy Lin ◽  
Delbert E. Day ◽  
James O. Stoffer

The dependence of the optical and mechanical properties of optically transparent polymethyl methacrylate (PMMA) composites on the annealing temperature of BK10 glass fibers was investigated. Annealing was used to modify the refractive index (R.I.) of the glass fiber so that it would more closely match that of PMMA. Annealing increased the refractive index of the fibers and narrowed the distribution of refractive index of the fibers, but lowered their mechanical strength so the mechanical properties of composites reinforced with annealed fibers were not as good as for composites containing as-pulled (chilled) glass fibers. The refractive index of as-pulled 17.1 μm diameter fibers (R.I. = 1.4907) increased to 1.4918 and 1.4948 after annealing at 350 °C to 500 °C for 1 h or 0.5 h, respectively. The refractive index of glass fibers annealed at 400 °C/1 h best matched that of PMMA at 589.3 nm and 25 °C, so the composite reinforced with those fibers had the highest optical transmission. Because annealed glass fibers had a more uniform refractive index than unannealed fibers, the composites made with annealed fibers had a higher optical transmission. The mechanical strength of annealed fiber/PMMA composites decreased as the fiber annealing temperature increased. A composite containing fibers annealed at 450 °C/1 h had a tensile strength 26% lower than that of a composite made with as-pulled fibers, but 73% higher than that for unreinforced PMMA. This decrease was avoided by treating annealed fibers with HF. Composites made with annealed and HF (10 vol. %)-treated (for 30 s) glass fibers had a tensile strength (∼200 MPa) equivalent to that of the composites made with as-pulled fibers. However, as the treatment time in HF increased, the tensile strength of the composites decreased because of a significant reduction in diameter of the glass fiber which reduced the volume percent fiber in the composite.


Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3929 ◽  
Author(s):  
Amirmohammad Rahimizadeh ◽  
Jordan Kalman ◽  
Rodolphe Henri ◽  
Kazem Fayazbakhsh ◽  
Larry Lessard

This research validates the viability of a recycling and reusing process for end-of-life glass fiber reinforced wind turbine blades. Short glass fibers from scrap turbine blades are reclaimed and mixed with polylactic acid (PLA) through a double extrusion process to produce composite feedstock with recycled glass fibers for fused filament fabrication (FFF) 3D printing. Reinforced filaments with different fiber contents, as high as 25% by weight, are extruded and used to 3D print tensile specimens per ASTM D638-14. For 25 wt% reinforcement, the samples showed up to 74% increase in specific stiffness compared to pure PLA samples, while there was a reduction of 42% and 65% in specific tensile strength and failure strain, respectively. To capture the level of impregnation of the non-pyrolyzed recycled fibers and PLA, samples made from reinforced filaments with virgin and recycled fibers are fabricated and assessed in terms of mechanical properties and interface. For the composite specimens out of reinforced PLA with recycled glass fibers, it was found that the specific modulus and tensile strength are respectively 18% and 19% higher than those of samples reinforced with virgin glass fibers. The cause for this observation is mainly attributed to the fact that the surface of recycled fibers is partially covered with epoxy particles, a phenomenon that allows for favorable interactions between the molecules of PLA and epoxy, thus improving the interface bonding between the fibers and PLA.


2017 ◽  
Vol 50 (6) ◽  
pp. 491-500 ◽  
Author(s):  
Sajjad Daneshpayeh ◽  
Amir Tarighat ◽  
Faramarz Ashenai Ghasemi ◽  
Mohammad Sadegh Bagheri

The object of this work is to study and predict the tensile properties (tensile strength, elastic modulus, and elongation at break) of ternary nanocomposites based on epoxy/glass fiber/nanosilica using the fuzzy logic (FL). Two factors in three levels including glass fiber at 0, 5, and 10 wt% and nanosilica at 0, 0.5, and 1 wt% were chosen for adding to an epoxy matrix. From FL surfaces, it was found that the glass fiber content had a main role in the tensile properties of nanocomposites. The high levels of glass fiber content led to a significant increase in the elastic modulus and generally, the presence of glass fiber decreased the tensile strength and elongation at break. Also, addition of the nanosilica content resulted in an increased elastic modulus but decreased the elongation at break of nanocomposites. Finally, an FL model was obtained for each tensile property.


2012 ◽  
Vol 430-432 ◽  
pp. 909-912
Author(s):  
Zhao Wang ◽  
De Hong Lu ◽  
Hui Gong ◽  
Xiao Gang He

Aiming to improve the crack-resistance of the mould of ceramic mould casting, glass fibers whose average diameter was approximately 16 µm, length 1mm were dispersed, and the effect of the glass fibers on the tensile strength and shrinkage rate of the ceramic mould was investigated in this study. In the ceramic green body, quartz sand was selected as refractory, silica sol was binder. The results show that, with increasing glass fiber, the tensile strength of the ceramic mould increased linearly from 0.175 MPa to 0.221 MPa at the same sintering temperature, and the shrinkage rate fell from 1.37% to 1.33% at room temperature. With the sintering temperature rising, the tensile strength increased and the shrinkage decreased by the glass fiber dispersion, but their variation rule were not changed. The investigation proposed a new method to improve the crack-resistance of the ceramic mould, i.e., glass fiber dispersion into the ceramic mould.


2020 ◽  
Vol 8 (5) ◽  
pp. 3916-3919

Conventional concrete i.e. the concrete generally has low tensile strength with limited ductility and low resistance towards cracking. The micro cracks that are developed internally are inherent among concrete and can be explained with the help of propagation of that micro cracks due to its inferior tensile strength. Different fibers, added at a certain percentage of concrete known to improve the deformation properties of concrete along with the plasticity against crack resistance, such as flexural strength. Mainly concrete & ferroconcrete research has been moved to steel fibers, and glass fibers have recently become more available, with no corrosion problems associated with glass fibers. This article describes an experimental study of the usage of glass fibers in the structural concrete. High-dispersion CEM-FILL fiberglass of 14 μm diameter with an aspect ratio of 857 was used at a dosage of 0.33% to 1% by weight in concrete and its mechanical properties such as compressive strength, flexural strength and modulus of elasticity.


2018 ◽  
Vol 89 (16) ◽  
pp. 3280-3290 ◽  
Author(s):  
Chenkai Zhu ◽  
Ifty Ahmed ◽  
Andrew Parsons ◽  
Jinsong Liu ◽  
Xiaoling Liu

Phosphate glass fibers have been widely considered as potential biomedical materials for orthopedical application due to their full degradability and excellent cytocompatibility. In this study, phosphate-based glass fibers were drawn from the glass system 48P2O5-12B2O3-14CaO-20MgO-1Na2O-5Fe2O3, via a melt-drawn spinning process and then woven into textile fabric using a small lab-scale inkle-loom. The annealing treatment was applied to both fibers and textiles with 1-hour heat treatment at 540℃, which was 10℃ above the glass transition temperature. An increase in Young's modulus was observed for the single filament fibers and a decrease in tensile strength with annealing treatment. During the degradation period, the tensile strength of non-annealed fibers presented a decrease by day 28, whilst annealed fibers had increased by day 7, then decreased by day 28, which was suggested to be due to the peeling effect observed on the surface of the fibers. The cytocompatibility of the textile fabric with annealing treatment (A-textile) and the non-annealed fabric (N-textile) was characterized via seeding of MG63 cells. Higher metabolic activity and DNA concentration were obtained for the A-textile samples when compared to the N-textile, which was suggested to be due to the lower dissolution rate of the A-textile resulting in fewer ions leaching into the solution. The phosphate glass fiber textiles investigated in this study have shown potential application as bioresorbable composites reinforcement for orthopedic treatment.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Abhishek Vyas ◽  
Kawaljit Singh Randhawa

Purpose The purpose of this study is to improve the mechanical and tribological performance of polypropylene (PP) material. The influence of hexagonal boron nitride (h-BN) microparticles on mechanical and tribological properties of PP/polyamide 6 (nylon 6) (PA6) blend has been investigated in this paper. Design/methodology/approach Tensile strength, elongation, elastic modulus and Rockwell hardness were measured to identify the mechanical properties of materials. Coefficient of friction (COF) and wear rates of materials were measured with the help of a pin-on-disc tribometer to check the tribological behavior of blend and composite materials. Findings As a result, a small decrease in tensile strength and elongation and improvement in elastic modulus were found for PP/PA6 and PP/PA6/h-BN composite compared to pure PP. The wear rate of PP/PA6 blend and PP/PA6/h-BN composite was found low compared to pure PP matrix, while the COF of PP/PA6 blend was found slightly higher owing to the presence of harder PA6 matrix which was then improved by the h-BN filler reinforcement in PP/PA6/h-BN composite. The addition of PA6 in PP improved the wear rate of PP by 8–24%, whereas the addition of h-BN microparticles improved the wear rate by 22–50% and 24–44% compared to pure PP and PP/PA6 blend, respectively, in different parameters. Originality/value Modulus of elasticity and hardness of pure PP was enhanced by blending with PA6 and was further improved by h-BN fillers. The addition of PA6 in PP improved the wear rate, while h-BN fillers were found effective in reducing the COF by generating smooth thin lubricating film.


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