Improvement In Impact Strength Research Articles

Synergistic effect of microcrystalline cellulose from oil palm empty fruit bunch waste and tricresyl phosphate on the properties of polylactide composites

Microcrystalline cellulose (MCC) was extracted from oil palm empty fruit bunch (OPEFB) waste by integrated chemical treatments of delignification, bleaching, and acidic hydrolysis. The obtained MCC (OPMC) and tricresyl phosphate (TCP) were used as additives for polylactide (PLA) composites. The influences of OPMC and TCP contents, separately and in combination, were evaluated on the properties of the composites. Characterization studies confirmed the successful extraction of OPMC from OPEFB waste. With regard to the properties of the PLA composite, the appropriate content of OPMC should be 5 phr. The good distribution of OPMC in the polymer matrix changed the failure behavior of the composite from brittle to ductile. All the PLA composites with TCP and OPMC showed flame inhibition and retarded ignition. The synergistic effect of TCP and OPMC resulted in outstanding improvement of impact strength and flame retardancy of composites. The impact toughness of PT10M5 increased to about 218.4 % and 72.3 % that of neat PLA and PT0M5, respectively. Moreover, PT10M5 achieved V-0 rating with high LOI (38.5 %). All these characteristics promise extended applications for PLA composite in bio, circular, and green (BCG) economies and electronics industries.

Impact of nano-alumina on the mechanical characterization of PVA fibre-reinforced geopolymer composites

In this paper, four groups of polyvinyl alcohol fibre-reinforced geopolymer composites containing various content of nano-alumina particles were investigated. Results showed an improvement in geopolymer fracture toughness, compressive, impact and flexural strength with the added nano-alumina particles as compared to the control specimen. Flexural strength increases as the weight ratio of nano-alumina particles increases from 0.0 to 2.0 wt% and then decreases to 6.50 MPa at 3.0 wt%. Geopolymer reinforced by 2.0 wt% of nano-alumina (PVAGNC-2) displayed the highest flexural and compressive strength of 7.51 and 23.48, respectively. PVAGNC-2 exhibited the highest mechanical (compressive, flexural, impact and hardness) properties. Scanning Electron Microscopy examination showed that the PVAGNC-2 microstructure is compacted with fewer pores indicating the probability of PVAGNC-2 to display great compressive strength and excellent mechanical resistance to the external force needed for construction.

Study on the Impact and Water Absorption Performance of Prosopis juliflora & Glass Fibre Reinforced Epoxy Composite Laminates.

Current global trends demand the replacement of synthetic fibres with natural fibres in polymeric composites. The present work makes use of Prosopis juliflora, a plant that is a threat to the environment as a partial replacement in a hybrid composite. Individual Prosopis juliflora fibres are added to matrices at ratios of 12, 6, 9 and 8 wt % and glass fibres are added discretely at ratios of 28, 24, 21 and 32 wt % into matrices as well. The composites are prepared with four different combinations and tested in terms of the mechanical benefits and water absorption performance. This work exploits the mechanical advantage of impact energy in addition to producing Prosopis juliflora particles, fibre glass mats, and resin appropriate for structural uses. Water absorption tests are conducted for four different compositions. Among the four samples, sample 3 (9 wt % Prosopis juliflora fibres and 21 wt % glass fibres) has a higher rate of water absorption than the others, although sample 2 (6 wt % Prosopis juliflora fibres and 24 wt % glass fibres) has a lower rate. The difference in the quantity of water absorption between the hybrid composites can be attributed to the weight percentage of fibres. On the other hand, sample 1 (12 wt % Prosopis juliflora fibres and 28 wt % glass fibres) is reported to have absorbed 2.6 J of energy in the impact strength test. The increase in impact strength is attributed to the increase in the weight percentage of glass fibres. A scanning electron microscope is employed to study the fractured surfaces of the composites. This study shows that the developed hybrid composite could be employed in structural and automotive applications because of its improved impact strength and water resistance.

Novel thermally insulated ultra‐lightweight fireproof and high impact resistance advanced hybrid composite

AbstractThis work investigates the development of ultra‐lightweight, hybrid fireproof composite material. The composite panels are made of 2,5‐polybenizimidazole (ABPBI) a thermally stable high‐performance fiber and poly ether ketone (PEK) a high‐performance film. The surface of ABPBI fiber and PEK film were treated by nitrogen plasma to increase the adhesion characteristics. The composite was fabricated through the stacking method. The hybrid composite was developed by sandwiching silicone rubber foam between surface‐treated ABPBI/PEK composite. The entire sample was covered with surface‐treated ABPBI fiber using silicone adhesive. The hybrid composite was tested in exposure to dry ice, fire and compression tests. After exposure to fire for 10 min, negligible loss of material was noticed. The Scanning Electron Microscopy (SEM) analysis at the interface indicated strong interfacial adhesion between the PEK matrix and the ABPBI fiber. Limiting oxygen index (LOI) of ABPBI fiber and PEK film appear to be promising in terms of fire resistivity and hence the hybrid composite of PEK/ABPBI sandwiched by silicone foam results one of the best fireproof composite. This composite also shows significant improvement of impact and compressive strength. Analysis under Ansys Fluent software also shows similar results.

Biocomposite production from waste low-density polyethylene sachets and Prosopis africana pods biomass residue

Plastic litter has become a major concern in solid waste management in recent times due to the adverse effect on the environment. In most developing countries, low-density polyethylene (LDPE) waste bags and sachets constitute a significant portion of plastic wastes that are generated daily, leading to an unnecessary environmental burden that needs to be addressed. In this study, we report the use of Prosopis africana pod particles as fillers in LDPE matrix (obtained from waste plastic sachets) for biocomposite production. Biocomposites were produced from 150µm average filler size for 10, 20, 30 wt% filler contents, using hand lay-up method. The compression, flexural, impact, and tensile strengths; water absorption and the biodegradability characteristics of the prepared biocomposites were determined using ASTM standards. In comparison with the control sample, the prepared biocomposites samples exhibited 103% improved impact strength of 34.3 J and better resistance to deformation (flexural modulus of 348.9 N/mm2; Young’s modulus of 237.9 N/mm2) at 30 wt % filler content. Biocomposite sample with the 10 wt% gave the highest tensile strength of 8.3 N/mm2. Scanning Electron Microscopy (SEM) analysis of the fractured sample shows good adhesion in the matrix. Findings from this work indicate that valorization of LDPE waste sachet and prosopis pods agricultural residues can be a value-addition, affordable waste management method for producing biocomposites towards indoor applications.

Toughening polylactic acid by melt blending with polybutylene adipate‐co‐terephthalate and natural rubber, and the performance of the resulting ternary blends

AbstractPolylactic acid (PLA) is one of the most commercially potential bio‐based and biodegradable materials recently used to partially replace non‐biodegradable petroleum‐based plastics; however, PLA's innate brittleness limits its practical applications. The present work aims to reduce the brittleness and improve the toughness of PLA by blending it with polybutylene adipate‐co‐terephthalate (PBAT) and natural rubber (NR). PLA/PBAT/NR ternary blends were prepared by a melt blending process, using both an internal mixer and a twin‐screw extruder, and were converted into test specimens using an injection molding machine. The weight ratio of PBAT:NR was kept constant at 1:1, while the amounts of PBAT/NR blend were varied at 14, 26, and 38 wt%. SEM confirmed the incompatibility among PLA, PBAT, and NR, as island‐like NR phases and oval PBAT phases were dispersed in the PLA matrix. Compared with neat PLA, the PLA/PBAT/NR ternary blends exhibited increased elongation at break from 6.2% to 21.0% (up to 240%), improved impact strength from 36.6 to 85.0 J/m (up to 130%), decreased density from 1.254 to 1.159 g/cm3 (approximately 7.6%), enhanced thermal stability and water resistance, and reduced shear‐dependent behavior. The obtained PLA/PBAT/NR blends have potential for the production of injection‐molded articles such as biomedical devices, toys, agricultural supplies, office supplies.

Development and characterisation of sugarcane bagasse nanocellulose/ PLA composites

ABSTRACT Nanocellulose from sugarcane bagasse fibres was isolated via chemo-mechanical method subjected to preparation of its PLA-based bionanocomposites using an Injection moulding process with varying weight percentages of nanocellulose. The mechanical properties (i.e. tensile, flexural, fracture toughness, and impact), thermal property (TGA analysis) and dynamic mechanical properties (i.e. storage modulus, loss modulus, and damping) of the prepared bionanocomposites were studied. In addition, water absorption behaviour in terms of maximum water uptake and sorption, diffusion and permeability coefficients of the bionanocomposites were also investigated. Anoticeable improvement in thermal stability, water resistance, and mechanical performance was seen in bionanocomposites with 2 wt. % of nanocellulose. There were 41.44%, 26.21%, 89.79%, and 16.38% improvements in tensile strength, flexural strength, fracture toughness and impact strength, respectively, for 2 wt. % of nanocellulose reinforcement composite over neat PLA matrix. ANOVA analysis was also performed and found that contents of nanocellulose have asignificant impact on the mechanical properties of the bionanocomposites.

Hybridization effect of functionalized microcrystalline cellulose and liquid acrylonitrile butadiene rubber on epoxy

Toughening epoxy resins by adding different agents has been employed as a way to reduce brittleness in composites. Some hybridization strategies combining liquid rubbers and rigid fillers can be found in the literature, but the pair cellulose-based reinforcement, such as microcrystalline cellulose (MCC), and liquid acrylonitrile butadiene rubber (NBR) is hardly studied. The aim of this work is to investigate the effect of hybridizing MCC and amino-functionalized MCC (MCCSi) with NBR on the thermal, mechanical, and dynamic-mechanical behavior of epoxy. X-ray microtomography showed a good dispersion of MCCSi fillers in epoxy/NBR compared to the non-treated MCC filler. NBR with MCCSi was found to slightly increase the thermal stability of epoxy. The addition of MCC, regardless of the functionalization, decreased tensile strength and elastic modulus, but improved impact strength and toughness properties (KIC). Also, MCCSi composites displayed better dynamic-mechanical behavior, attributed to the enhanced chemical interaction, with a small effect on glass transition temperature.

Effect of carbon nanotubes on mechanical properties of polyamide 12 parts by fused filament fabrication

Polymer parts fabricated by fused filament fabrication (FFF) technique usually exhibit weak and anisotropic mechanical properties, compared with their injection-molded (IM) counterparts. Thus, the evolution of FFF from rapid prototyping into manufacture tool requires three-dimensional enhancement ways for FFF-printed parts. To this end, we develop a series of carbon nanotubes (CNTs)-embedded polyamide 12 (PA12) filaments and investigate the effect of CNTs on the mechanical properties of the FFF-printed PA12 parts. In the direction parallel to the deposited strands, PA12/CNT parts show considerable mechanical reinforcement compared with neat PA12 specimens, including the increase of tensile and impact strength by 18% and 125%, respectively. The marked improvement in impact strength arises from the oriented structures induced by the shear field during FFF process as well as the layer-by-layer microstructure, which provide multiple ways to dissipate impact energy. However, these oriented CNTs and inter-filament voids tend to act as stress concentration points under the tensile stress, thus accounting for a slight increase in tensile strength. In the direction perpendicular to the deposited strands, the FFF-printed PA12/CNT parts also exhibit improved tensile strength, i.e. interfacial weld strength, as CNTs allow the rapid transfer of the thermal energy from the newly-deposited filament to the weld interface and thus provide longer time for molecular interdiffusion. Altogether, the anisotropy in tensile strength of the FFF-printed parts is reduced from 0.36 for neat PA12 parts to 0.28 for PA12/CNT specimens. This work is believed to provide a facile route to overcome mechanical limitations in FFF technique.

Pineapple Leaf Fiber Reinforced Polyester Composite Modified with Particles from Horse Dung Waste: Characterization of Mechanical Properties and Morphology

Abstract. The modification of the characteristics of natural fiber composites with components derived from abundant and environmentally beneficial horse dung waste has piqued interest. The purpose of this investigation was to see how adding horse dung particles (DN) to pineapple leaf fiber (DN)/polyester composites affected the results. To create new samples, different percentages of HF (5–30%) are utilized. Hand-layup method was used to create the DN/HF composite. The results revealed that adding 30% (vol. percent) HF to the composite improved elongation, flexural strength, and flexural modulus, while adding 5% (vol. percent) HF improved impact strength, tensile strength, and tensile modulus of elasticity. At 30% HF concentration, maximum flexural strength values of 63.91 5.1 MPa were recorded. The composite's fracture morphology revealed weak interfacial interactions between DN-polyester-HF, and particle accumulation.

Highly toughened poly (lactic acid) blends plasticized by cardanol in presence of dicumyl peroxide

Grafting reaction between poly (lactic acid) (PLA) and cardanol was initiated by dicumyl peroxide at different compositions, and the mechanical, thermal properties were characterized. In absence of dicumyl peroxide (DCP), the PLA/cardanol blends showed a typical plastic behavior with increasing cardanol content, i.e. decrement of tensile strength, accompanied by increment of elongation at break, while the notched Izod impact strength kept low level until the cardanol content reached 20 wt%. When DCP was introduced into the blends, only 15 wt% cardanol content was needed to improve the notched Izod impact strength significantly. According to the thermal behavior testing results, the grafting of cardanol onto PLA chains might take responsibility for the further improvement of impact strength with less cardanol content.

Improvement of impact strength of epoxy matrix composites reinforced with E-glass fiber and novel calophyllum inophyllum filler in comparison with plain GFRP composite

The aim of the study was to evaluate Izod impact strength on epoxy matrix composite reinforced with E-Glass fiber and calophyllum inophyllum powder novel Hybrid composite in comparison with plain GFRP epoxy composite. The E-glass fiber was used as the reinforcement material and Epoxy (LY556), hardener (HY951), were used as the matrix materials.Calophyllum inophyllum powder with 5 % and 10 % volume fraction was used as the filler material. Composites were prepared by hand lay up method. Impact test was conducted as per ASTM-D256 standards. The sample size per group was 20. The pre test power for testing was 80 %, Alpha = 0.05 % and CL was 95 %, G power test was used to fix the number of samples for each group. Calophyllum inophyllum filler with 10 % volume fraction added with epoxy matrix reinforced by glass fiber laminate exhibits more Izod impact value when compared to 5 % volume fraction of calophyllum inophyllum filler added with epoxy laminate and plain GFRP laminate. The Significance value (p) obtained by the experimental and control groups was 0.000 (p < 0.05). A hybrid composite made by epoxy matrix with addition of 10 % volume fraction of novel calophyllum inophyllum filler reinforced by glass fiber hybrid composite enhances improved impact strength than plain and 5 % filler added composite.

Improvement of impact strength of novel intra-ply basalt/kevlar composite by addition of silica nanoparticles in comparison with basalt/kevlar composite using resin transfer mould process

The objective of this work was to enhance the impact strength of hybrid basalt/kevlar composite by the addition of 8% of silica nanoparticles. In this research work, a novel composite laminate was developed using hybrid composite fibers i.e basalt and kevlar with addition to silica nanoparticles. The influence of silica nanoparticles as filler material on the mechanical properties is studied. The two groups of materials are taken; they are the control group and the experimental group. In both groups, the basalt and kevlar fibers are used. The composite materials basalt/kevlar without addition of silica nanoparticles was considered as a control group. The composite materials basalt/kevlar with the addition of 8% silica nanoparticles was considered as an experimental group. From each group, twenty samples are taken for the study. The impact testing machine was used to conduct the impact test. The SPSS tools are used for statistical analysis. It was clearly shown that basalt and Kevlar fiber with filler exhibits an improvement of 20% increase in the impact strength when compared with basalt and Kevlar fiber without filler. The significance value of 0.029 which was less than 0.05. Within the scope of the study, the laminates with the addition of silica nanoparticles exhibit better impact strength compared with plain hybrid basalt and Kevlar composites that can be used as a replacement for automobile components and also aircraft fuselage.

Carbon Nanotube‐Based Reinforced Polymers for Medical Applications: Improving Impact Strength of Polymer‐Polymer Composites

There is a continuous need for innovative biomaterials with advanced properties to meet the biomechanical requirements of orthopedic implants and interventional devices. Recent research findings show that using material composites leads to significantly improved properties, which are beneficial for medical applications. Therefore, this work aims at studying polymer‐polymer composites of high‐density polyethylene (HDPE) and ultrahigh molecular weight polyethylene (UHMWPE), which were mixed with and without reinforcement of multiwall carbon nanotubes (MWCNTs) in two steps. An extensive characterization workflow including mechanical tensile tests, tribological performance, and surface characteristics was used to analyze the reinforced polymer‐polymer composite samples. The results of the mechanical tests showed that the developed MWCNT‐reinforced samples achieved better performance, due to a higher yield point that is the highest in the sample with 48.5% HDPE‐50% UHMWPE‐0.5% MWCNTs, a higher value in the hardness test peaking in the sample with 49.5% HDPE‐50% UHMWPE‐0.5% MWCNTs, and a lower friction coefficient in HDPE‐UHMWPE‐MWCNTs samples. Overall, the reinforcement of polymer‐polymer composites with MWCNTs led to a significant improvement of the material characteristics required for the designated use in orthopedic implants and interventional biopsy needles, which will lead to improved clinical results.

Impact modification of hybrid polypropylene composites with poly(vinyl alcohol) fibers

Polypropylene (PP) hybrid composites were prepared by the combination of three reinforcing (carbon, glass, and wood) and a synthetic (PVA) fiber. Tensile and impact testing, acoustic emission measurements, and scanning electron microscopy (SEM) were used for the characterization of the composites as well as to follow deformation and failure processes. The results obtained prove that the novel concept of using synthetic fibers for impact modification can be applied successfully also with PVA fibers. The extent of improvement in impact strength depends on fiber type and content, but also on interfacial adhesion which strongly influences the local deformation processes occurring around the fibers during fracture. Both the reinforcing and the synthetic fibers take part in these processes and contribute to energy consumption. Debonding and the subsequent plastic deformation of the matrix consumes energy the most efficiently, but the fracture of the PVA fibers also requires energy; thus, PVA fibers improve impact resistance both at poor and good adhesion. This approach allows the design of materials for structural applications; the combination of a stiffness of 4–6 GPa and an impact resistance of 20–25 kJ/m2 exceeds the properties of most PP composites available on the market.

3D printing of fibre-reinforced ceramic composites with hierarchical structure

ABSTRACT This paper reports the 3D printing of fibre-reinforced ceramic composite with hierarchical structures. Through printing precursor formulation, short SiC fibres have been successfully incorporated into silicate materials and gradient porous hierarchical structure has been achieved for the printed parts. The mechanical testing shows a 27% improvement in impact strength, 22% improvement in flexural modulus, and 7.5% in flexural strength compared with parts without fibre reinforcement. High-resolution tomography analysis using x-ray microscopy shows that the inner structure has a porosity of 27%, while the outer layer shows a dense structure with little pores formation. This 3D printed ceramic composite with fibre-reinforcement shows high similarity to the gradient porous structures of human bone and tooth. The results indicate that 3D printing of nano/microfibre reinforced ceramic composite with hierarchical structure is a promising method to enhance the fracture toughness of ceramics and allow accurate patient-specific customisation for their implants.

Effect of erosive parameters on solid particle erosion of cotton fiber–based nonwoven mat/wooden dust reinforced hybrid polymer composites

Abrasive particle-induced erosive wear of polymeric engineering components is a major industrial issue. The research of solid particle erosion characteristics of polymeric composites becomes essential due to operational needs in dusty conditions. Nonwovens are now employed in industrial applications for polymeric composites. Nonwoven products are made from a wide range of raw materials, ranging from synthetic to natural fibers. This work finding the effect of nonwoven cotton fiber (5, 10, and 15 wt.%) loading on the physical, mechanical, and erosion wear of fixed wooden dust (4 wt.%) filled hybrid epoxy composites. Experimental results reveal improved impact strength, hardness, and compressive and tensile strength with an increment of fiber loading from 5–15 wt.%. The density of the composites was found to increase, whereas void content decreases with an increase in cotton fiber. The erosion wear of the composites has been studied using an L27 orthogonal array to assess the effects of various parameters such as fiber loading, erodent size, impact velocity, impingement angle, and stand-off distance. The erosion wear increased with impact velocity and remained highest for 60° of impingement angle. The most significant parameter affecting the erosion wear was determined as impact velocity followed by impingement angle. Surface morphologies of eroded samples reveal the fiber pull-out, and fiber breakage was the prominent phenomenon for the erosion wear of the evaluated composites.

Novel epoxy‐based glass fiber reinforced composites containing compatibilized para‐aramid fibers and silanized nanoclay for improved impact strength

AbstractThis research developed epoxy‐based glass fiber reinforced composite (GFRPs) containing multi‐scale fiber reinforcement comprising of silanized nanoclay (nano‐reinforcement) and compatibilized para‐aramid (PA) fibers (micro‐reinforcement) for enhanced impact strength and tensile‐flexural properties. VARIM technique was used for fabrication of GFRPs. Surface modification (silanization) of nanoclay was confirmed by FTIR and that of PA fibers was confirmed by SEM‐EDS and FTIR. Dispersion/morphology of nanoclay in the processed nanocomposites was determined by XRD and TEM analysis. Three different methods were used for the compatibilization of PA fibers. All methods exhibited a substantial increase in impact strength without a decrease in flexural/tensile strength. Nanocomposite containing 1.0 phr MAH treated PA fibers and 2 phr silanized nanoclay showed the highest improvement in impact strength (34% higher than the reference composite) along with minor improvements in tensile strength (6%), and flexural modulus (13%). SEM micrographs of the fractured surface of impact test samples were used to identify the mechanisms/reasons for the improved mechanical performance of the newly developed GFRPs.

A local green composite study: the effect of edible oil on the morphological and mechanical properties of PBS/bentonite composite

Abstract Composites of a biodegradable thermoplastic aliphatic polyester, polybutylene succinate (PBS), with bentonite were investigated for morphological and mechanical properties. The bentonite was modified with soybean oil (SBO) and lard oil (LO) (2:98 clay:oil % by weight) by mechanical stirring and ultrasonication. The PBS/modified bentonite composite was prepared by using an internal mixer and processed by compression molding. Under bentonite modification conditions, XRD and SEM showed that the bentonite layers were broken into small layers, and the d-spacing between the layers was increased by edible oil molecules. A small plate like structure of modified bentonite composite was observed by SEM micrograph, which revealed short and long layer silicate structure non-directionally throughout the matrix phase. The mechanical properties of PBS were reinforced by this structure. The tensile modulus and elongation at break seem to depend on its directional bentonite. Interestingly, considerable improvement in impact strength was observed at over 2 wt% of clay. The impact strengths of PBS, PBS/modified BTN with SBO composite, and PBS/modified BTN with LO composite were increased from 1 to 1.5 and 2 kJ/m2, respectively. Comparatively, using LO modified bentonite had a better performance for increased interlayer and resulted in higher impact strength of the composite than that of SBO composite. The results demonstrated that PBS/modified bentonite using edible oil could be a potential alternative low cost, eco-friendly material with superior impact properties useful for further applications.

Property Correlations of Polypropylene based Composites Filled with Mimusop elengi Seed Shell Powder

The saturation point of Mimusop elengi seed shell powder (MESSP) and the effect of MESSP addition on the mechanical, thermal, water absorption and morphological properties of polypropylene (PP) composites were studied. Tensile fracture, physio-mechanical properties and thermal behavior of composites were characterized using tensile and impact testing, thermogravimetric analysis, scanning electron micrograph, and differential scanning calorimetry. Processability of composites were feasible up to 20 wt. % MESSP by which agglomeration of MESSP and poor dispersion of MESSP in PP was observed above 20 wt% MESSP loading. Increasing MESSP loading showed tremendous improvement in tensile modulus and impact strength, whereas tensile strength and elongation at break were reduced. Water absorption and thermal decomposition of composites remain comparable with addition of MESSP up to 20 wt. %. Reduction of tensile strength was attributed by weak adhesion between MESSP and PP. However, morphological analysis revealed the presence of physical interaction via PP chain interlocking on MESSP surface.