Rule Of Hybrid Mixtures Research Articles

Development and Assessment of Polyester Reinforced with Sansevieria Cylindrica/Zawa Flour Composites

This paper zero in on preparation of hybrid composites in which Polyester matrix filled with Sanseveria cylindrica fiber(SCF) and Zawa flour. SCF fiber was taken 10% volume constantly in all the samples. Camera ready samples were prepared using hand layup technique in which filler constituent proportions were taken by using rule of hybrid mixture (RoHM). The mail aim of the composites is to increase the tensile flexural, and impact strengths, TGA, DSC results by incorporating the filler. It was observed that, tensile strength was linearly increased up to 4wt.% zawa after that sudden falling was observed. On other hand, tensile modulus was increased linearly up to 5wt.% was the clear indication of addition of zawa imparts more stiffness to the composites. Flexural strength was increased up 3wt.% zawa flour after than it starts depreciating suddenly. Flexural modulus was increased linearly up to 3wt.% zawa four composites after that decreases. Impact strength was optimised at 4wt.% zawa flour after that it starts going down. In DSC analysis, for 3wt.% zawa flour composite registered good performance than the 2wt.%,whereas in TGA analysis 3wt.% composite was having good performance than 2wt.% zawa flour composites. Reasons attributed for increased glass transition temperature was due to the less moisture content or due to the deprived of void due to the good bonding strength

Preparation of GF/Wollastonite Reinforced Epoxy Hybrid Composite: Mechanical Properties

Performance of injection moulded short wollastonite fibre and chopped glass fibre reinforced hybrid epoxy composites was studied. The results showed that hybridisation of glass fibre and wollastonitewas in congruence to epoxy glass fibre composite system. Effect of fibre length, fibre orientation in matrix and analysis and fracture surface was undertaken. The mechanical properties of injection moulded, chopped glass fibre/wollastonite/epoxy hybrid composites were investigated by considering the effect of hybridisation by these two fillers. It was observed that the tensile, flexural, and impact properties of the filled epoxy were higher than those of unfilled epoxy. The effect of filler on epoxy matrix subjected to the tensile strength and modulus was studied and compared with the rule of mixture. The actual results are marginally low as compared with the values obtained by the rule of hybrid mixtures (RoHM).

Effect of coupling agent content and water absorption on the mechanical properties of coir‐agave fibers reinforced polyethylene hybrid composites

In this study, high‐density polyethylene/agave‐coir composites with two fiber contents (20 and 30 wt%) and different coir‐agave fiber ratios (1–0, 0.8–0.2, 0.6–0.4, 0.4–0.6, 0.2–0.8, and 0–1) were produced in a two‐step process using twin‐screw extrusion followed by injection molding. The effect of mixing two different natural fibers and the addition of coupling agent on water absorption, mechanical properties, and morphology is reported. The rule of hybrid mixture was used to predict the properties of the composites, showing a good agreement with the experimental data. The results obtained showed that the combination of different fibers produces composites with unique characteristics as coir fibers absorb less water than agave fibers, while at the same time increase more tensile and flexural strengths. On the other hand, agave fibers were found to improve the impact strength of coir composites. Also, the effect of water absorption on the mechanical properties was studied. Finally, the use of a coupling agent had a positive effect on mechanical properties, while lowering water uptake. POLYM. COMPOS., 37:3015–3024, 2016. © 2015 Society of Plastics Engineers

The effect of hybridization on moisture absorption and mechanical degradation of natural fiber composites: An analytical approach

Abstract The method of hybridization by adding synthetic hydrophobic fibers into the natural fiber reinforced composites is used to reduce moisture absorption and mechanical degradation of the composites. A linear constitutive model for this hybrid fiber composite is proposed to study the effect of hybridization on the mechanical properties of the composites. The natural fibers absorb large amounts of water when exposed to the humid environment, which causes remarkable modulus loss and interface damage between natural fiber and matrix. Based on the Rule of Hybrid Mixture (RoHM), the overall mechanical properties of the hybrid short fiber reinforced composites are obtained, in which one internal variable is introduced to reflect both the modulus loss of natural fibers and the interface damage. From the thermodynamics modeling, the evolutions of moisture absorption and mechanical degradation are derived. Compared with the experimental results of hemp and glass fiber reinforced composites, a good agreement is obtained.

Experimental analysis and theoretical modeling of the mechanical behavior of short glass fiber and short carbon fiber reinforced polycarbonate hybrid composites

In this research, polycarbonate (PC) composites with short glass fiber (SGF) and short carbon fiber (SCF) hybrid fiber reinforcements were compounded by single screw extruder and specimens were prepared by injection molding machine. This article aims to investigate the mechanical properties of PC hybrid composites, by means of the experimental and the theoretical methods. The composites were subjected to tensile test. Experimental results showed the improvements in tensile strength and modulus by increasing the SCF content of the hybrid composite. The theoretical tensile strength was predicted based on Kelly–Tyson model and rule of hybrid mixture. Kelly–Tyson model showed to be a good approximation to predict the tensile strength of composite. When the SCF was replaced by milled carbon fiber (MCF) to form a PC/SGF/MCF hybrid system, poorer mechanical properties are reported due to the weaker interfacial adhesion between MCF and PC, as proven by the scanning electron microscopy. POLYM. COMPOS., 37:1238–1248, 2016. © 2014 Society of Plastics Engineers

Utilization of Wallostonite/Quasi Isotropic S2 Glass Fiber Doped in to Epoxy on Mechanical and Thermal Properties

Study focused on the performance of injection moulded short Wallostonite filler and chopped glass fiber reinforced hybrid epoxy composites. Results showed that hybridization of glass fiber and Wallostonite was found to be comparable to that of epoxy glass fiber composites. Analysis of fiber length distribution in the composite and fracture surface was performed to study fiber breakage fracture mechanism. The simultaneous compounding of epoxy with two fillers was done to obtain a hybrid composite. The mechanical properties of hybrid, injection molded, chopped glass fiber/ Wallostonite/epoxy composites have been investigated by considering the effect of hybridization by these two fillers. This system is expected to have considerable mechanical properties. It has been found that the tensile, flexural, and impact properties of the filled epoxy were higher than those of unfilled epoxy. The hybrid effects of the tensile strength and modulus were studied by the rule of hybrid mixtures (RoHM) using the values of single fiber composites.

Utilization of Wallostonite/Quasi Isotropic S2 Glass Fiber Doped in to Epoxy on Mechanical and Thermal Properties

Study focused on the performance of injection moulded short Wallostonite filler and chopped glass fiber reinforced hybrid epoxy composites. Results showed that hybridization of glass fiber and Wallostonite was found to be comparable to that of epoxy glass fiber composites. Analysis of fiber length distribution in the composite and fracture surface was performed to study fiber breakage fracture mechanism. The simultaneous compounding of epoxy with two fillers was done to obtain a hybrid composite. The mechanical properties of hybrid, injection molded, chopped glass fiber/ Wallostonite/epoxy composites have been investigated by considering the effect of hybridization by these two fillers. This system is expected to have considerable mechanical properties. It has been found that the tensile, flexural, and impact properties of the filled epoxy were higher than those of unfilled epoxy. The hybrid effects of the tensile strength and modulus were studied by the rule of hybrid mixtures (RoHM) using the values of single fiber composites.

Electrical and mechanical properties of carbon/glass hybridized long fiber reinforced polypropylene composites

The electrical percolation and hybrid effect that forms from long carbon fiber (LCF) and long glass fiber (LGF) hybridized composite in a polypropylene matrix were studied by investigating electrical and mechanical properties. As a process, the electrical and mechanical properties were investigated in terms of LCF loading at constant volume percentage in the total. The electrical resistivities of volume and surface were measured in order to learn the percolation threshold points, which were 8–9 and 10–12 volume percents of LCF loading individually. The mechanical properties, such as, were tensile and flexural modulus of the hybridized composite were obtained and compared with the prediction results using the rule of hybrid mixtures (RoHM) equation. The hybrid effect was observed in the result of the tensile modulus in the range of 6–10 volume percent of LCF loading whereas there was no hybrid effect in flexural modulus. The tensile and flexural strengths of LCF/LGF hybridized composite are 100 and 140MPa at 20 vol% of LCF loading. The tensile and flexural modulus are approximately 22 and 14 GPa at 20 vol% of LCF. The interaction between reinforced fiber and the matrix was reported and analyzed by scanning electron microscopy (SEM) and heat depletion temperature (HDT). Through the process, the mechanical strength was more related to the interaction between fiber and the polypropylene matrix than the mechanical modulus. Open image in new window

Assessment of Glass/Drumstick Fruit Fiber (Moringa oleifera) Reinforced Epoxy Hybrid Composites

Glass fibers/drumstick fruit fibers (GF/DFF) reinforced with epoxy hybrid composites were fabricated using the rule of hybrid mixtures. Properties like impact strength, frictional coefficient, dielectric strength, and chemical resistance were studied. Treated and untreated DFF were reinforced along with GF to assess two different epoxy hybrid composites. The effect of alkali treatment on the above-mentioned properties was also studied. It is observed that the impact strength and frictional coefficient properties of the hybrid composites increased with increase in glass fiber content. Performance was elevated for alkali-treated DFF hybrid composites when compared with untreated DFF. Chemical resistance was significantly increased for all chemicals except carbon tetrachloride due to attack of chloride hydrocarbons on the cross-linking of the epoxy. Elimination of amorphous hemi-cellulose by alkali treatment improved the properties. Fiber-polymer interactions were studied by scanning electron microscopy on the cross-sections of fractured surfaces.

Prediction of tensile properties of hybrid-natural fiber composites

The tensile strength and modulus of short, randomly oriented hybrid-natural fiber composite was found out experimentally and also predicted using Rule of Hybrid Mixture (RoHM). Hybrid composites were prepared using banana/sisal fibers of 40:0, 30:10, 20:20, 10:30, and 0:40 ratios, while overall fiber volume fraction was fixed as 0.4Vf. The comparison between experimental and RoHM showed that they are in good agreement.

Effect of temperature on weldline integrity of injection moulded short glass fibre and glass bead filled ABS hybrids

The present study investigated the effect of temperature on weldline strength of injection moulded ABS polymer reinforced with both short glass fibres (GF) and spherical glass beads (GB) over the temperature range 25 to 100 °C. It was noted that weld and non-weld tensile strength of ABS/GF/GB hybrids increased as the concentration of total glass in the hybrids increased. A linear increase in both weld and non-weld tensile strength was found with increasing the hybrid ratio of the glass fibre, χ. Results indicated that weld and non-weld tensile strength for the hybrid at a given temperature can be estimated from the rule of hybrid mixtures. Weld and non-weld tensile strength of the hybrid system decreased with increasing temperature in a linear manner. The rate at which weld and non-weld tensile strengths decreased with temperature was dependent upon the hybrid ratio of the glass fibre, χ, and the total concentration of glass in the hybrids. Weldline integrity factor for the hybrids decreased non-linearly with increasing χ, but increased linearly with increasing temperature.

Development of glass fiber, wollastonite reinforced polypropylene hybrid composite: Mechanical properties and morphology

Hybridization with small amounts of mineral fibers makes these glass fiber composites more suitable for technical applications. This study focused on the performance of injection molded short wollastonite fiber and chopped glass fiber reinforced hybrid polypropylene composites. Results showed that hybridization of glass fiber and wollastonite was found to be comparable to that of polypropylene glass fiber composites. Analysis of fiber length distribution in the composite and fracture surface was performed to study fiber breakage fracture mechanism. The simultaneous compounding of polypropylene with two fillers was done to obtain a hybrid composite. The mechanical properties of hybrid, injection molded, chopped glass fiber/wollastonite/polypropylene composites have been investigated taking into account the effect of hybridization by these two types of fillers. This system is expected to have considerable mechanical properties, good surface finish and low cost. It has been found that the tensile, flexural, and impact properties of the filled polypropylene were higher than those of unfilled polypropylene. The hybrid effects of the tensile strength and modulus were studied by the rule of hybrid mixtures (RoHM) using the values of single fiber composites.

Elastic properties, notched strength and fracture criterion in untreated woven jute–glass fabric reinforced polyester hybrid composites

The elastic properties and notch sensitivity of untreated woven jute and jute–glass fabric reinforced polyester hybrid composites has been investigated analytically and experimentally. Elastic properties were predicted by using the rule of hybrid mixture and classical lamination theory (CLT). Analytical investigation on notch sensitivity was carried out by using well known point stress criterion (PSC) and modified PSC criterion. Experimentally, elastic properties and notch sensitivity were determined by conducting tension test on specimens. The objective of the investigation is to determine the extent of applicability of stress fracture criteria that were developed for synthetic fibre composites, to natural fibre and hybrid composites. The characteristic dimension of PSC criteria was found to increase slightly with the increase in the hole size for all the types of laminates considered. However, modified PSC model has resulted in excellent agreement between the experimental and predicted values. The effect of hybridization of glass fibre with jute fibre as well the effect of hole size on the notch sensitivity of the composites under consideration is discussed.

On the elastic modulus of hybrid particle/short-fiber/polymer composites

In this investigation, the elastic modulus of hybrid particle/short-fiber/polymer composites was studied using the rule of hybrid mixtures (RoHM) equation and the laminate analogy approach (LAA). In the RoHM, such a hybrid composite was treated as a hybrid system consisting of two separate single systems, namely particle/polymer system and short-fiber/polymer system. Thus, no interaction between particles and short-fibers could be considered. Then, the elastic modulus of the hybrid composite was evaluated from that of the two single systems using the RoHM. In the LAA, particle-filled polymer was regarded as an effective-matrix. The interaction between particles and short-fibers was incarnated in a manner that short-fibers were incorporated into the effective-matrix containing particles. The modulus of the short-fiber reinforced effective-matrix composite was then estimated using the LAA. In addition, the two approaches were applied to previous experimental results. It was interestingly observed that the predicted values by the LAA and the experimental results for the elastic modulus of hybrid particle/short-fiber/polymer composites were consistently higher than those predicted by the RoHM, suggesting that the modulus of hybrid particle/short-fiber/polymer composites shows a positive hybrid effect.

Synergistic effect on the fracture toughness of hybrid short glass fiber and short carbon fiber reinforced polypropylene composites

The fracture behavior of injection-molded polypropylene (PP) composites reinforced with hybrid short glass fibers (SGF) and short carbon fibers (SCF) was studied. The fracture toughness ( K c) of the composites was measured using compact tension specimens made from the manufactured plaques. It was of interest to note that the fracture toughness of hybrid SGF/SCF/PP composites was higher than that predicted by the rule of hybrid mixtures (RoHM), showing a positive hybrid (synergistic) effect. Also, the fracture toughness of the hybrid composites was higher than that of both single SGF/PP and SCF/PP composites, thus showing that the synergistic effect was remarkable. SEM observations on the fracture surfaces of the materials were performed. A three-layer structure, that is, a skin–core–skin layer structure, of the composites was observed for all the investigated composites. For the single short-fiber composites, the three-layer structure was the same as that reported previously. In the skin layers, the fibers lay parallel to the mold flow direction (MFD); in the core layer, the fibers were perpendicular to the MFD. However, for the hybrid short-fiber composites, the three-layer structure was different. In the skin layers, the fibers were aligned parallel to the MFD, but in the core layer, the fibers were aligned oblique to the MFD. The oblique fibers would result in a higher pullout toughness contribution to the hybrid composites. Moreover, for the single SCF/PP composite, the matrix in the core layer fractured in a brittle fashion. In contrast, for the hybrid SGF/SCF/PP composites, the matrix in the core layer fractured in a ductile manner, imparting an additional contribution to the total toughness of the hybrid composites. Consequently, the positive hybrid (synergistic) effect on the fracture toughness of hybrid SGF/SCF/PP composites could be explained.

Hybrid effects on tensile properties of hybrid short-glass-fiber-and short-carbon-fiber-reinforced polypropylene composites

Hybrid composites of polypropylene reinforced with short glass fibers and short carbon fibers were prepared using extrusion compounding and injection molding techniques. The tensile properties of these composites were investigated taking into account the effect of the hybridization by these two types of short fibers. It was noted that the tensile strength and modulus of the hybrid composites increase while the failure strain of the hybrid composites decreases with increasing the relative carbon fiber volume fraction in the mixture. The hybrid effects for the tensile strength and modulus were studied by the rule of hybrid mixtures (RoHM) using the tensile strength and modulus of single-fiber composites, respectively. It was observed that the strength shows a positive deviation from that predicted by the RoHM and hence exhibits a positive hybrid effect. However, the values of the tensile modulus are close to those predicted by the RoHM and thus the modulus shows no existence of a hybrid effect. Moreover, the failure strains of the hybrid composites were found to be higher than the failure strain of the single carbon fiber-reinforced composite, indicating that a positive hybrid effect exists. Explanations for the hybrid effects on the tensile strength and failure strain were finally presented.