Unsaturated Polyester Matrix Composites Research Articles

Morphological, chemical and mechanical properties of hybrid polyester composites reinforced with bamboo fibers and kaolin waste

This article presents a study on the use of natural fibers and kaolin waste as sustainable alternatives in the manufacture of polymer matrix composites. In the present research, isophthalic unsaturated polyester matrix composites were manufactured in association with bamboo fibers (Bambusa vulgaris) and kaolin waste. The kaolin waste was used with a particle size of 50–100 MESH and the fibers in lengths of 15 mm and 30 mm, randomly arranged within the matrix. Bamboo fibers were used fresh and treated with NaOH (5%/2 h). The chemical characterization of the fibers was obtained followed by the morphological characterization using Scanning Electron Microscopy (SEM). The composites were mechanically evaluated through flexural and tensile tests. The mechanical properties obtained were treated by analysis of variance (ANOVA) and Tukey test. The fracture surfaces of the composites were verified by SEM. Bamboo fibers had a chemical composition similar to other natural fibers already studied, with 7.55% extractives, 17.95% total lignin and 74.5% holocellulose. Composites with 30 mm long treated fibers and 30% kaolin showed better flexural strength (137.0 MPa), with deformation of (1.59 mm) and flexural modulus of (19.27 GPa). Through tensile tests, it was possible to identify that the addition of kaolin waste provided a significant improvement in tensile strength of 66% (15BTKW20) and 54% (30BTKW20) compared to neat polyester. SEM micrographs of bamboo fibers, surface roughness, starch granules, micropores and parenchyma cells were identified. ANOVA reinforced the reliability of the results, highlighting the feasibility of manufacturing kaolin waste/bamboo fiber hybrid composites.

The effect of containing Al2O3 microparticles in different matrix polymers on properties of pineapple fiber-reinforced composites

In this study, Al2O3 microparticle was used as a filler for pineapple fiber reinforced composites with different matrix polymers. The effect of Al2O3 microparticles in the epoxy and unsaturated polyester matrix on the mechanical, physical, and thermal properties of pineapple fiber reinforced composites was investigated. Pineapple fiber composite was manufactured by hand layup with various Al2O3 contents, 0, 5, 10, and 15 wt%, and a 30 wt% continuous pineapple fiber. The tensile, flexural strength, hardness, water absorption, and thermal stability were investigated according to ASTM. The results showed that flexural strength, hardness, density, and water resistance gradually increased, and the tensile strength rate gradually decreased with more the wt.% of Al2O3 microparticle. The TGA observation results indicated that the Al2O3 microparticles improved the composite's thermal stability. Composites with the epoxy matrix are superior in tensile strength and thermal stability compared to composites made of unsaturated polyester. In contrast, unsaturated polyester matrix composites had higher flexural strength, hardness, density, and water resistance than epoxy matrix composites. The effect of the content of 15 wt% Al2O3 microparticles in the composites resulted in the highest flexural strength, hardness, density, and water absorption resistance, while the tensile strength showed the lowest value.

Experimental study on bio fiber reinforced composites

Biofibers are an economical, environmentally friendly, and lightweight alternative to traditional materials. Different types of fibers have different properties, and each plays a key role in composites. Screw Pine (Pandanus Odoratissimus) is abundant and strong. This research made and tested NaOH- and Acetic Acid-treated random fiber composites. This research shows the mechanical properties of Pandanus Odoratissimus composite. The stem of the screw pine plant, Pandanus Odoratissimus, contained several interesting fibers (PO fibers). This research will investigate the effect of fibre concentration and alkali treatments on the mechanical properties of unsaturated polyester matrix composites. Similarly, soaking times will vary for alkali treatments. Individual PO fibres exhibit modifications in their cross-sectional area and water absorption prior to and after treatment with NaOH solution and acetic acid for varying durations of time. These modifications are observable prior to and after treatment. As a result of extended therapy, the cross-sectional area of PO fibres gradually decreases. Compared to other fibre types, PO fibres that were submerged in water for the longest period of time exhibited the most structural degradation. There is a considerable effect on the improvement of polyester composites' tensile strength and tensile modulus when PO fibre is soaked in different concentrations of NaOH and acetic acid for roughly 90 min. This influence is significant. This investigation will also shed light on how the composition of polyolefin (PO) fibres influences the mechanical properties of composite materials. Maximum tensile strength of a composite material is proportional to the fraction of fibres present in the material. After calculating tensile, compressive, shear, and other stresses, materials (components) are manufactured.

The mechanical and thermal behaviour of unsaturated polyester matrix (UPM) composite filled with pistachio shell particles (PSP)

This investigation focuses to study the effect of the content of micro scale natural pistachio shell particles on the mechanical and thermal properties of unsaturated polyester matrix composites. The composite of polyester resin reinforced with 10, 20, 30 and 40 wt% PSP was made by hand mixing followed by compression molding. Several mechanical properties viz. tensile strength, flexural strength, impact strength are examined to understand the behaviour of composite material. The thermo-gravimetric analysis of the prepared composites is conducted. The field emission scanning electron microscope is used to investigate the surface morphology of the fabricated composite. The end result from the observation discovers that, the properties of the composites are improved. The maximum tensile, flexural and impact strength is resulted at 40, 40 and 10 wt% respectively.

The Comparative studies of mechanical and interfacial properties between jute and E-Glass fiber-reinforced unsaturated polyester resin based composites

Jute fiber (hessian cloth)-reinforced unsaturated polyester matrix composites (50 wt% fiber) were fabricated by hand lay-up technique. Tensile strength (TS), tensile modulus (TM), bending strength (BS), bending modulus (BM), elongation at break (Eb%), and impact strength (IS) of the composites were found to be 42 MPa, 2.7 GPa, 36 MPa, 2.1 GPa, 3%, and 21 kJ/m2, respectively. On the other hand, TS, TM, BS, BM, and Eb% of E-glass mat reinforced unsaturated polyester resin (UPR) composite were found to be 70 MPa, 3.8 GPa, 80 MPa, 2.5 GPa, and 5%, respectively. Then E-glass/UPR based composites (50 wt% fiber) were fabricated and the mechanical properties were compared with those of the Jute/UPR based composites. It was observed that E-glass fiber-based composites showed almost double mechanical properties as compared to jute composites. The interfacial shear strength of the jute and E-glass fiber-based systems was investigated and found to be 21 kJ/m2 and 21.56 kJ/m2, respectively, measured using the single-fiber fragmentation test. After flexural testing, fracture sides of both types of the composites were studied by scanning electron microscope (SEM) and the results showed that poor fiber-matrix adhesion for Jute/UPR based composites when it compared to that of the E-glass fiber composites. However, it was found that the E-glass fiber based composite has better strength as compared to jute fiber composite.

MECHANICAL PROPERTIES OF POLYESTER REINFORCED WITH POWDERED SHELLS OF THE SNAIL COMPOSITES

Composites of unsaturated polyester has been found to be useful virtually in all aspects of life. This project work was carried out to investigate the properties of particulate snail shell reinforced unsaturated polyester matrix composites. The snail shell particulate was calcinated, pulverized and sieved to -75 µm. The composites were developed using predetermined varying filler content. For each of the developed composites, the mixture was missed thoroughly until homogenous paste was obtained and poured into the mould and was allowed to cure before removing from the mould. The developed composites were then characterized by flexural and wear tests. The result showed that better results can be obtained within 5-20 wt% reinforcement addition since 25-30 wt% tends to give weak results in all. The result also proved that properties of the developed composites were highly enhanced compared to the unreinforced polyester material. The optimum properties were observed at 20% filler content.

Mechanical properties of recycled Kraft paper residue polyester composites

Construction industry has a significant grow in the past few years. Following that rate, the amount of residue produced from that growth also increases. The need to find alternatives apart from disposing that residue in landfills have led researchers to find new materials from disposal residues. In this paper, kraft paper from cement bags used in building constructions is utilized as reinforcement in unsaturated polyester matrix composites. The kraft paper residue (KPR) was used as shredded particles in different quantities, 30%, 40% and 50%, by weight, and also cutted in sheets to be used as laminas. Tensile and flexural tests were performed to characterize the KPR composites. The results showed that tensile strength and modulus of elasticity increase as shredded KPR content increase. Higher increase was observed when KPR laminas were used as reinforcement. In flexion, a decrease is reported when shredded KPR is used but an increase was observed due to KPR laminas. Flexural modulus was not altered by KPR.

Influence of selected submicron inorganic particles on mechanical and thermo-mechanical properties of unsaturated polyester/glass composites

In this paper, the influence of different submicron-scaled particles (zinc oxide, titanium dioxide, or silica) on mechanical and thermo-mechanical properties of unsaturated polyester matrix composites reinforced with glass fabric was investigated. Surface morphology of obtained composites was also examined. At first inorganic particles were mechanically dispersed into unsaturated polyester resin system as per the calculated weight ratio (2 or 4 wt% of polymer matrix). For prepared liquid dispersions viscosity was measured. Composites were produced by using hand lay-up method and contained 39–41 wt% of glass fibers. The flexural and dynamic mechanical analyses were carried out for each group of fabricated polyester/glass composites. All results were compared with the control samples (without submicron particles). It was found that addition of 2 wt% ZnO or TiO2 to unsaturated polyester resin enhanced the flexural strength and flexural modulus of composites. Dynamic mechanical analysis showed the increase of storage and loss modulus. Similar effect of submicron-scaled inorganic particles on Tg value of composites was observed. The scanning electron microscopic analysis of prepared composites showed good dispersion of submicron particles in polymer matrix and generally absence of voids was also observed.

Thermal and mechanical properties of functionalized mullite reinforced unsaturated polyester composites

This work studies the development of varying weight percentages (0.5, 1.0, and 1.5 wt%) of surface functionalized mullite reinforced unsaturated polyester (UP) composites and their thermal, dielectric, water absorption, and mechanical properties. The synthesized mullite was functionalized with vinyltriethoxysilane (VTES). The introduction of vinyl groups on the surface of mullite was confirmed by FT‐IR, TGA, and X‐ray diffraction (XRD) analyses. Varying weight percentages (0.5, 1.0 and 1.5 wt%) of vinyl functionalized mullite (VFM) were incorporated into UP resin with a benzoyl peroxide initiator to obtain composites. The resultant data obtained from thermal, mechanical, dielectric, and water absorption studies, indicate that incorporation of VFM, leads to a significant improvement in the thermo mechanical, dielectric, and moisture resistant properties of the UP composites, compared with those of neat UP matrices. The molecular dispersion of VFM fiber in reinforced UP matrix composites was confirmed by SEM analysis. POLYM. COMPOS., 35:1663–1670, 2014. © 2013 Society of Plastics Engineers

Fracture toughness and notch sensitivity of jute fiber mats reinforced unsaturated polyester matrix composites based on the characteristic distance

Recycled needle punched natural jute fiber mats were used to reinforce unsaturated polyester matrix composites via modifying the hand lay-up technique with resin pre-impregnation into the jute fiber mats in vacuum. The notch sensitivity of these composites was investigated by using the characteristic distance do calculated by Finite Element Method (FEM) according to Whitney and Nuismer model definition. In this work, the concept of the characteristic distance was discussed from the point view of fracture mechanics, therefore the aim of this study is to investigate and reconfirm the physical meaning of do by investigation the fracture toughness (KIc) of jute mat composites (JMC) based on do calculated by Finite Element Method (FEM) with width, W, to the hole diameter (D = 10 mm) ratio (W/D = 3) with 25 wt% fiber weight content. The results showed that JMC composites in terms of residual tensile strength (σn/σo) (the ratio of notched to unnotched strength) that there is only 16 % loss in the tensile strength due to the presence of the hole. Moreover, the experimental maximum load during tension test with hole is almost near to the maximum load calculated using KIc and do which validates the physical meaning of do which represents the distance from the hole boundary at which the brittle fracture starts to occur.

Effect of Alkalization on Mechanical Properties of Water Hyacinth Fibers-Unsaturated Polyester Composites

Characteristic of local water hyacinth (WH) fibers and composites that consist of mixing WH fibers and unsaturated polyester (UPR) were studied. Composites mixed with the WH fibers treated in different alkali concentration for 1 h soaking time were tested by tensile and flexure machine and their fracture surface was observed by using scanning electron microscope (SEM). The results show that 7% NaOH, 1 h, treated WH fibers provided better mechanical properties on UPR matrix composites in comparison with other alkali concentrations. From SEM observation, some untreated WH fibers pulled out from their matrix were observed clearly in fracture surface of composites. The high alkali concentration created damage of cellulosic structure, thus decreasing of mechanical properties of the composites.

Mechanical Properties of Screw Pine (Pandanus Odoratissimus) Fibers—Unsaturated Polyester Composites

Interesting fibers researched was taken from leaves of screw pine plant of species Pandanus Odoratissimus (PO fibers). In this research, effect of alkali treatments for various soaking time and effect of fiber content on mechanical properties of unsaturated polyester matrix composites was studied. Both cross-section area and moisture absorption of individual PO fibers before and after treatment with 5% NaOH solution for various soaking times show changing. The cross section area decreases continuously, since PO fibers were treated for long time. Untreated PO fibers has the highest moisture absorption and PO fibers treated by the longest soaking times has the lowest one. PO fibers treated by longest soaking time displays the largest damage of the fiber structure. PO fiber treated by various soaking time in 5% NaOH for 90 minutes gives effect significantly on increasing tensile strength and tensile modulus of polyester composite. Effect of various PO fiber content on mechanical properties of composite was also shown in this research. Fibers content of 40% displayed maximum tensile strength of composite. From observation with scanning electron microscope (SEM), some conditions of fracture surface of the composite was obtained.

Mechanical Properties of Natural Jute Fabric/Jute Mat Fiber Reinforced Polymer Matrix Hybrid Composites

Recycled needle punched jute fiber mats as a first natural fiber reinforcement system and these jute mats used as a core needle punched with recycled jute fabric cloths as skin layers as a second natural fiber reinforcement system were used for unsaturated polyester matrix composites via modifying the hand lay-up technique with resin preimpregnation into the jute fiber in vacuum. The effect of skin jute fabric on the tensile and bending properties of jute mat composites was investigated for different fiber weight contents. Moreover, the notch sensitivity of these composites was also compared by using the characteristic distance d o calculated by Finite Element Method (FEM). The results showed that the tensile and flexural properties of jute mat composites increased by increasing the fiber weight content and by adding the jute fabric as skin layers. On the other hand, by adding the skins, the characteristic distance decreased and, therefore, the notch sensitivity of the composites increased. The fracture behavior investigated by SEM showed that extensive fiber pull-out mechanism was revealed at the tension side of jute mat composites under the bending load and by adding the jute cloth, the failure mode of jute mat was changed to fiber bridge mechanism.

Improvement of resin impregnation into glass cloth by silane treatment in resin transfer molding

An evaluation method was proposed for resin impregnation using resin transfer molding of unsaturated polyester matrix composites with silane-treated glass cloth. The determination of whitening of the composite was carried out as a parameter of incompleteness of resin impregnation. The change of whitening with silane concentration was compared with the bending modulus as a parameter of chemical reinforcement. The materials used were unsaturated polyester resin as a matrix and methacryloxypropyltrimethoxysilane as a silane coupling agent for glass cloth. Resin transfer molding was used to produce four plies of glass cloth laminates by impregnating the resin. The silane-treated glass cloth repressed whitening above 0.026 w/w% of silane in aqueous solution, while the chemical reinforcement due to silane gave no appearance below 0.2 w/w% based on the bending test of the laminates. The large difference between the concentrations suggested that silane has a couple of functions, that is, chemical reinforcement and physico-chemical resin wettability.

Mathematical model for the pultrusion of blocked PU–UP matrix composites

AbstractThe thermokinetic behavior of blocked polyurethane (PU)–unsaturated polyester (UP)–based composites during the pultrusion of glass‐fiber‐reinforced composites was investigated utilizing a mathematical model that accounted for the heat transfer and heat generation during curing. The equations of continuity and energy balance, coupled with a kinetic expression for the curing system, were solved using a finite difference method to calculate the temperature profiles and conversion profiles in the thickness direction in a rectangular pultrusion die. A kinetic model, dP/dt = A exp(−E/RT)Pm(1 − P)n, was proposed to describe the curing behavior of a blocked PU–UP resin. Kinetic parameters for the model were obtained from dynamic differential scanning calorimetry scans using a multiple regression technique, which was able to predict the effects of processing parameters on the pultrusion. The effects of processing parameters including pulling speed, die wall temperature, and die thickness on the performance of the pultrusion also were evaluated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1996–2002, 2003