Unsaturated Polyester Composites Research Articles

A comparison between the effects of hydrophobic and hydrophilic silica aerogel fillers on tensile and thermal properties of unsaturated polyester composites

A comparison between the effects of hydrophobic and hydrophilic silica aerogel fillers on tensile and thermal properties of unsaturated polyester composites

Nanomechanical behaviour of ZrO2 dispersed sisal-based polymeric composites

Alkali-treated sisal fibre-incorporated silanized ZrO2 dispersed unsaturated polyester composites were fabricated with a filler loading of 5, 15, 25, 35, 45 wt%, respectively. The mechanical characterization of the composites was suitably executed at the sub-micron scale using the nanoindentation technique. Various mechanical properties were derived from the standard nanoindentation measurements namely, nanohardness, reduced modulus, recovery index, residual depth, wear rate and indentation creep, respectively. A marked improvement in the mechanical properties of the unsaturated polyester matrix due to the incorporation of the fillers (sisal and/or ZrO2) was observed through indentation-derived parameters namely, nanohardness (∼186%), reduced modulus (∼175%), recovery index (∼62%), wear rate (∼63%) and indentation creep (∼33%), respectively. A simulated dynamic mechanical analysis was performed using the sinus mode of the nanoindentation technique. A similar enhancement in the dynamic mechanical properties of the matrix was further observed through dynamic mechanical analysis as storage modulus (∼71%), loss modulus (∼60%), loss factor (∼150%) and specific damping coefficient (∼200%), respectively.

The Influence of MMA Esterification on Interfacial Adhesion and Mechanical Properties of Hybrid Kenaf Bast/Glass Fiber Reinforced Unsaturated Polyester Composites.

The demand for natural fiber hybrid composites for various applications has increased, which is leading to more research being conducted on natural fiber hybrid composites due to their promising mechanical properties. However, the incompatibility of natural fiber with polymer matrix limits the performance of the natural fiber hybrid composite. In this research work, the mechanical properties and fiber-to-matrix interfacial adhesion were investigated. The efficiency of methyl methacrylate (MMA)-esterification treatments on composites’ final product performance was determined. The composite was prepared using the hand lay-up method with varying kenaf bast fiber (KBF) contents of 10, 15, 20, 25, 30, 35 (weight%) and hybridized with glass fiber (GF) at 5 and 10 (weight%). Unsaturated polyester (UPE) resin and methyl ethyl ketone peroxide (MEKP) were used as binders and catalysts, respectively. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) were used to examine the effects of MMA-esterification treatment on tensile strength and morphology (tensile fracture and characterization of MMA-esterification treatment) of the composite fabricated. The tensile strength of MMA-treated reinforced UPE and hybrid composites are higher than that of untreated composites. As for MMA treatment, 90 min of treatment showed the highest weight percent gain (WPG) and tensile strength of KBF-reinforced UPE composites. It can be concluded that the esterification of MMA on the KBF can lead to better mechanical properties and adhesion between the KFB and the UPE matrix. This research provides a clear reference for developing hybrid natural fibers, thus contributing to the current field of knowledge related to GF composites, specifically in transportation diligences due to their properties of being lightweight, superior, and involving low production cost.

The Effect of Alkali Treatment And Microcrystalline Cellulose Addition on Density Value of Cantala Fiber Reinforced Unsaturated Polyester Composites

<p>Natural fiber reinforced composites is one materials potentially developing in Indonesia. One of biggest problem with composites specimen is its void. One properties to find out void of composites is composites density value. The objective of research is to investigate the effect of fiber alkali (NaOH) treatment and microcrystalline cellulose (MCC) addition on density value of cantala fiber reinforced unsaturated polyester composites. Firstly, cantala fibers was submerged into alkali (NaOH) 6% solution for 0, 3, 6, 9, and 12 hours. Furthermore, the fiber was washed using acetid acid and then using clean water to reach pH 7. Thereafter, cantala fiber was dried in the oven for 10 hours at temperature 60<sup>0</sup>C. Composites was composed of cantala fiber, unsaturated polyester polymer matrix, and microcrystalline cellulose according to the composition with volume fraction 30%. Composites was casted using compression molding method with compressive strength of 10 MPa for 12 hours. All specimens of composites undertake post cure for 2 hours at 60<sup>0</sup>C. Density test was conducted using densimeter by calculating the density of composites in the air and the water. The result of research showed that the longer the alkali treatment time and the more addition of microcrystalline cellulose (MCC) filler, the higher is the composites density. The higher density value of cantala fiber reinforced unsaturated polyester is alkali treatment 6 hours, which was 1.223 gr/cm<sup>3</sup>.</p>

Mechanical Behaviour of Jute/ZrO2 Based Polyester Composites at Microstructural Scale

Alkali treated jute fibre incorporated silanized ZrO2 based unsaturated polyester composites were synthesized using compression moulding technique. The filler loading was adopted with a progressive wt. %, of 5, 15, 25, 35 and 45 respectively. These samples were further subjected to structural investigation using scanning electron microscope and X-ray diffraction technique to observe the morphological features and crystalline nature of the matrix. The mechanical characterization was accomplished at the microstructural length scale from macro to submicron range. It was observed that the composite with 35 wt. % filler loading resulted in the best properties among the lot.

Effect of alkaline treatment on water absorption and thickness swelling of natural fibre reinforced unsaturated polyester composites

Environmental benefits and amazing performance can be obtained by utilizing palm oil fibres and kenaf fibres which illustrate colossal potential in fibre reinforced composites. An investigation has been made to determine the effects of alkaline treatment on water absorption and swelling behaviour of palm oil fibre composites as well as kenaf fibre composites. Untreated and treated natural fibres and were prepared in random orientation with different volume fraction of palm oil fibres and kenaf fibres; 30%, 40%, and 60. All the treated fibres were treated with 1 w/v% and 5 w/v% of sodium hydroxide concentration. Water absorption test was performed by immersing the sample in the distilled water periodically measuring the sample weight. Thickness swelling test was carried out by measuring the thickness of the specimens before and after soaking in the distilled water within certain period of time. All specimens were observed under Scanning Electron Microscope (SEM) to study the fibre morphology. TPOF_30_5SH achieved the least percentage of water absorption (1.44%) when it was compared with the UPOF_30 and TPOF_40_1SH. UPOF_60 shows the highest percentage of thickness swelling (8.96%). TPOF_30_5SH and TPOF_40_5SH show reduction of water absorption when they were compared with UPOF_30 and UPOF_40 respectively. All the treated kenaf fibre composites with 5 w/v% sodium hydroxide concentration such as TKF_30_5SH, TKF_40_5SH and TKF_60_5SH show improved result of thickness swelling. Materials covering the surface of palm oil fibres and kenaf fibres were more effectively removed with 5 w/v% sodium hydroxide than by treatment with 1 w/v% sodium hydroxide while observing under SEM.

Experimental Analysis of Heat-Affected Zone (HAZ) in Laser Cutting of Sugar Palm Fiber Reinforced Unsaturated Polyester Composites.

In this paper, the influence of processing input parameters on the heat-affected zone (HAZ) of three different material thicknesses of sugar palm fiber reinforced unsaturated polyester (SPF-UPE) composites cut with a CO2 laser was investigated. Laser power, traverse speed, and gas pressure were selected as the most influential input parameters on the HAZ to optimize the HAZ response with fixing all of the other input parameters. Taguchi’s method was used to determine the levels of parameters that give the best response to the HAZ. The significance of input parameters was also determined by calculating the max–min variance of the average of the signal-to-noise ratio (S/N) ratio for each parameter. Analysis of variation (ANOVA) was used to determine each input parameter’s contribution to the influence on HAZ depth. The general results show that the minimum levels of laser power and the highest levels of traverse speed and gas pressure gave the optimum response to the HAZ. Gas pressure had the most significant effect on the HAZ, with contribution decreases as the material thickness increased, followed by the traverse speed with contribution increases with the increase in material thickness. Laser power came third, with a minimal contribution to the effect on the HAZ, and it did not show a clear relationship with the change in material thickness. By applying the optimum parameters, the desired HAZ depth could be obtained at relatively low values.

EFFECT OF CHEMICAL TREATMENT WITH OXIDANTS ON THE MECHANICAL PROPERTIES OF LUFFA SPONGE/UNSATURATED POLYESTER COMPOSITES

This study investigates a synergistic treatment comprising alkali, permanganate, dichromate, silane and bleaching pretreatment on Luffa sponge (LF) fibers intended to be used as reinforcement in an unsaturated polyester (UP) matrix to improve the mechanical properties of Luffa sponge fibers reinforced unsaturated polyester composites. Treatment effects by NaOH (5 wt%), K2Cr2O7 (0.2 wt%), KMnO4 (0.0125 wt%), NaClO (13°) and silane (0.5 wt%) on the performance of the prepared composites were evaluated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), SEM and mechanical tests (flexural strength and modulus). The results of the analyses indicated that composites reinforced with treated fibers have higher flexural strength than composites reinforced with untreated fibers.

Water absorption, tensile, flexural and impact properties of aged bamboo fibre/nano CaCO3-modified unsaturated polyester composites

ABSTRACT This paper presents the investigation on the effects of nano CaCO3 on the durability of bamboo fibres/unsaturated polyester composites aged in distilled water up to 112 days. The nano CaCO3 contents in the unsaturated polyester matrix were 0, 1, 3 and 5 wt%, while the bamboo fibre content in the bamboo fibre/nano CaCO3-modified unsaturated polyester composites was fixed by 25 vol%. It was found that the equilibrium water uptake and diffusion rate decreased up to 16.2 and 15.6 %, respectively, by adding nano CaCO3 up to 3 wt%; however, at the content of 5 wt%, they were higher than those of the unfilled composites. For the unaged composites, the tensile and flexural strengths were improved by adding nano CaCO3 up to 1 and 3 wt%, respectively, whereas adding 5 wt% could not give positive effects. On the other hand, the increase of nano CaCO3 up to 5 wt% increased the elastic modulus almost linearly for both loadings. For the aged composites, adding 1-5 wt% nano CaCO3 reduced the degradation of composites both in tensile and flexural loadings, but the best enhancement was obtained at the content range of 1-3 wt%. Under impact loading, adding 1-5 wt% nano CaCO3 enhanced the impact strength of composites, regardless of the ageing condition.

Investigation of abrasive water jet machining parameters on turkey fibre reinforced polyester composites

Polymer based composites are finding wide variety of application in industries due to the excellent strength to weight ratio and better mechanical properties. In this wok an effort is made to fabricate unsaturated polyester composites using 20% turkey fibre as reinforcement materials. Methyl Ethyl Ketone Peroxide (MEKP) and Cobalt Naphthalene (CN) is castoff as catalyst and accelerator. The composite is fabricated using compression molding machine and curing is done within the machine itself. Machinability study of the fabricated composites is studied using Abrasive Water Jet Machine (AWJM). Corollary of three parameters namely pressure (P), standoff distance (SoD) and feed rate (ƒr) on surface roughness (Ra) and taper angle (Ta) of the composite is studied and reported. It is observed from the results of experiments, working with higher pressure increases the Ra of the composites irrespective of ƒr and SoD. But in case of taper angle reverse trend is observed increase in pressure decrease the taper angle irrespective of SoD and ƒr. Multi-objective Optimization by Ratio Analysis (MOORA) is employed to optimize the machining parameter and to improve the process capability. It is observed that the optimal machining parameters are A3, B2 and C2.

Kenaf fibers reinforced unsaturated polyester composites: A review

Recently development of high-performance polymer composites made from natural resources in the various sectors is increasing tremendously due to the environmental issues and health hazard possessed by the synthetic fibers during disposal and manufacturing. Among the many different types of natural resources, kenaf fibers have been extensively investigated as an alternative reinforcement for polymer composites over the past few years due to their low cost, good mechanical properties, high specific strength, nonabrasive, eco-friendly, and biodegradability characteristics. Kenaf is regarded as an industrial crop in Malaysia and grown commercially in other parts of the world for different applications. It is certainly one of the important plants cultivated for natural fibers globally which has great potential to use as automotive and construction materials. In many research studies, kenaf fibers have been used as reinforcement in unsaturated polyester (UPE) which perfectly improved the features of the polyester resin. The tensile properties of kenaf fiber reinforced UPE are mainly influenced by the interfacial adhesion between the fibers and the polyester resin. Several chemical modifications are employed to improve the interfacial bonding between kenaf fibers and polyester, resulting in the enhancement of mechanical properties of the composites. Therefore, this paper explores and highlights of the previous studies around kenaf fiber reinforced UPE composites, in terms of processing methods, mechanical, water absorption, and morphological properties to provide a perfect source of literature for doing further research in this topic.

Filler Type and Particle Distribution Effect on Compact Properties of Polymer Composites

This study reports the effects of silica (S), quartz (Q), and basalt (B) fillers on the chemical, thermal, and mechanical properties of unsaturated polyester (PE) composites. In the study, fillers were selected as same class grain distribution and mixed with orthophtalic based PE resin to produce composites. The thermal characterization of the composites was determined with thermogravimetric and thermal conductivity. Chemical characterization was carried out with FT-IR. Compressive strength was investigated with Universal Testing Machine. SEM device was used to investigate the morphological alterations of the composites. Also, statistical analysis was carried out for thermal conductivity and mechanical results. At the end of the present study, some minor chemical alterations were seen in FT-IR after the interaction of the fillers and PE resin. Thermal stability decreased after adding fillers. The thermal conductivity and thermogravimetric analysis were not agreed with each other that higher thermal conductivity was seen in the PE-Q composites. The compressive strength of filler-based composites was higher than that of the neat PE composite whereas the higher compressive strength was obtained in the PE-Q. This study confirms the applicability of various fillers as a reinforcing agent in the polymer.

Multi-Response Optimization of Bamboo Fiber Reinforced Unsaturated Polyester Composites using Hybrid Taguchi – Grey Relational Analysis Method

ABSTRACT This study involves application of industrial engineering principles in Bamboo fiber composite production, which include finding the best parameter settings for processing bamboo fiber polyester composites using experimental design and optimization techniques. Multi response optimization of properties of bamboo fiber polyester composites using hybrid Taguchi-Grey relational analysis was carried out. The test samples consist of untreated, mercerized, acetylated, and mercerized-acetylated bamboo fiber composites at fiber contents of 10, 20, 30, 40 and 50 wt %. All composite samples were fabricated using conventional hand lay-up process on randomly oriented long bamboo fibers. Multi response optimization shows that the optimal design parameter is Mercerized-acetylated fibers and 50 wt% fiber content; as that was the factor combination that gave desirable values for all the considered performance characteristics. The application of optimization techniques was used to improve the process of bamboo fiber polyester composite production in order to achieve high performance composites.

Modification of Mineral Powder by Various Organic Materials: Their Potential as Reinforcement for Unsaturated Polyester Composites

Industrial by product dumped from iron making industry (slag) has been modified by various chemical agents, particularly, paraffin wax, liquid nitrile butadiene rubber (NBR) and silane coating agent. The modified slag powder samples were characterized by differential scanning calorimeter (DSC), thermogravimetric analysis (TGA) and the corresponding differential thermal gravimetric (DTG). As further evidence on the effectiveness of the modification process, the modified slag samples were subjected to attenuated total reflectance infrared spectroscopy (ATR-IR). The potential of the modified slag as reinforcement for unsaturated polyester (UPE) composites were studied. The mechanical and dynamic mechanical properties of the fabricated composites were inspected as a function of modification type.

Optimization on the Dry Sliding Wear Behaviour of Mercerized Coconut Inflorescence Fibril Fortified Unsaturated Polyester Composites

The contemporary work emphasizes the importance of using coconut inflorescence fibril as a viable alternate to manmade fibril in polymer matrix composites for application components undergoing wear. The extracted inflorescence fibril from coconut tree is exposed to mercerization treatment with 5% wt/vol of aqueous solution. The composite samples were fabricated by varying the fibril content (10, 20, 30 and 40 wt %) of fibril/polyester matrix. The composite specimens were subjected to wear test employing a pin on disc tribometric setup under dry sliding state. Design of experiments inspired taguchi analysis is employed for wear analysis. The experiments were performed for 16 trial runs for the load (5, 10, 15, 20 N), sliding distance of (250, 500, 750 and 100 m) and sliding velocity of (6.3, 12.5, 19 and 25.3 m/s) as the operating parameters. The parametric analysis revealed fibril content is the more inducing parameter which have a notable impact on the wear behaviour of the composites ensued by sliding distance. Artificial Neural Networks (ANN) is adopted to forecast the dry sliding wear behaviour of the composites over a broad scope of test conditions. The extensive experimentation leads to the conclusion that fortification of inflorescence fibril to the polyester resin resulted in improvement of wear resistance up to optimum fibril content and then decrease in wear resistance was observed when the fibril content increases. Finally SEM analysis was performed on the wornout surfaces to study the governing mechanism such as ploughing, wedge formation and fibril pullouts.

Effect of water and mechanical retting process on mechanical and physical properties of kenaf bast fiber reinforced unsaturated polyester composites

The properties of polymer composite filled or reinforced with kenaf fiber have been extensively studied in recent decades as an alternative for replacing synthetic fiber in composite structures. Although many studies have been conducted on natural fiber filled or reinforced composite, lack of researches have been done on the processing factors that contributed to the overall fiber strength. Thus, this study aims to determine the efficiency of retting process which significantly influences the characteristics and performance of the final composite products. In this study, the kenaf bast fibers composites were prepared using hand lay-up method at different fiber loadings (weight%) of 10, 15, 20, 25, 30 and 35 through two retting methods namely water and mechanical retting process. Unsaturated polyester (UPE) resin and methyl ethyl ketone peroxide (MEKP) were used as binder and catalyst, respectively. This current research aims to examine the effects of different retting processes and fiber loadings on tensile strength, water absorption and morphology which consists of tensile fracture and fiber surface, using Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The tensile strength of water retted kenaf bast fibers reinforced UPE composites exhibited higher value than mechanical retted kenaf bast fibers reinforced UPE composites. In terms of water absorption, it was found that mechanical retted kenaf bast fiber reinforced UPE composites absorb more moisture than water retted kenaf bast fibers reinforced UPE composites. From the results, it can be concluded that the water retting process yielded higher mechanical and water absorption properties compared to mechanical retting process at all different fiber loadings (weight%). This current study contributes to the current field of knowledge by providing a clear reference for future development of high-performance polymer composites based on kenaf bast fibers as reinforcements, specifically in structural applications such as floor decking, door and window frames.

Recycling of carbon fibers from unsaturated polyester composites via a hydrolysis-oxidation synergistic catalytic strategy

Unsaturated polyester resins (UPRs) composites have many industrial applications, such as fan blades in wind energy. However, the stable cross-linked polymer networks of resin matrix lead to large numbers of composite wastes that are difficult to recycle. Developing an efficient approach to explore the recovery of high-value fiber from composites is thus imperative. In this paper, an efficient and mild hydrolysis-oxidation synergistic catalytic strategy was proposed to efficiently recycle carbon fibers from UPRs composites by selectively cleaving chemical bonds of UPRs. Ester bonds in UPRs were cleaved by using hydrolysis of 80% hydrazine hydrate along with NaOH. Afterwards, the cleavage of carbon-carbon bonds was accomplished via the Fenton reaction for the purpose of complete degrading UPRs. The result figured that UPRs could be efficiently degraded at 100 °C below via this hydrolysis-oxidation strategy. Interestingly, applying the strategy, the recovery of carbon fibers from UPRs composites was investigated. The reclaimed carbon fibers kept their original surface microscopic morphology, chemical structure and tensile strength almost close to the virgin carbon fibers. This strategy opens up a new way for efficient and mild degradation of thermosets.

Physico-mechanical Properties of Unsaturated Polyester Resin Reinforced Maize Cob and Jute Fiber Composites

ABSTRACT In this research, the composites of maize cob (MC)/unsaturated polyester resin (UPR) and composites of jute fiber (JF)/unsaturated polyester resin (UPR) were prepared using the hand lay-up technique. The study employed 5%, 10%, 15%, and 20% filler loadings for the preparation of the MC/UPR and JF/UPR composites. The composites were subsequently characterized to examine their mechanical and physical properties. The results reveal that the increase in percentage filler loading decreases the tensile strength, impact strength, flexural strength, hardness, and density, whereas the water absorption increases at higher filler loading. This observation could be ascribed to clumping, voids, and agglomeration formed during composites preparation for both fillers. The MC/UPR composite exhibited better flexural resistance of 31.41 Mpa to 28.88 Mpa compared to 25.72 Mpa to 22.14 Mpa for JF/UPR due to the excellent dispersion of MC, larger surface area, and intermolecular interactions between the particulate MC filler/matrix. The MC/UPR composites also exhibited higher density compared to the JF/UPR due to the larger surface area and reduced voids in the structure. Overall, the study demonstrated that the valorization of maize cob and jute fibers into composite materials is a sustainable and environmental approach to waste disposal and management.

Tensile, Flexural and Water Absorption Properties of Bamboo Fiber/Unsaturated Polyester Composites: Effect of Calcium Carbonate Content

The paper presents the effect of CaCO3 content on the tensile, flexural and water absorption properties of bamboo fiber/polystyrene-modified unsaturated polyester composites. Two volume fractions of bamboo fibers had been used with the CaCO3 content varied from 2.5 to 10 (wt%). The tensile and flexural properties were used to characterize the composites. In addition, the water absorption and its effect of the flexural properties had also been conducted. The results showed that at the bamboo content of 30%, adding CaCO3 up to 10wt% tended to decrease the tensile strength and elastic modulus of bamboo fiber/modified unsaturated polyester composites up to 27% and 4%, respectively; however, at the bamboo content of 20%, its effect was not significant for both the tensile strength and the elastic modulus. Adding CaCO3 seemed not to have a significant effect for both the flexural strength and modulus. Having exposed in distilled water, CaCO3 did not significantly affect the water uptakes and the flexural properties of bamboo fiber/modified unsaturated polyester composites; however, the flexural strength and modulus significantly decreased in the ranges of 24 - 45% and 36 - 43%, respectively, compared to those in dry condition.

The influence of fibre orientation and chemical treatment on the performance of unsaturated polyester/chrysanthemum stem fibre composites

Chrysanthemum flowers are usually used for cultural and religious ceremonies however, the chrysanthemum stems are left for open burning or landfilling on many farmlands. These stems are one of the sources of agricultural waste in Malaysia that cause environmental impacts. In order to reduce the impact of chrysanthemum stems, this research study has utilised these valuable chrysanthemum stems in producing a new polymer composite. Hence, the present research study focuses on the preparation of non-woven and woven chrysanthemum stem fibre (CSF) reinforced unsaturated polyester (UPs) composites via simple hand lay-up method. The results showed the tensile properties (tensile strength and modulus of elasticity) of woven fibre filled UPs was higher than non-woven fibre filled UPs composites. However, non-woven fibre filled UPs presented higher water absorption and elongation at break as compared to woven fibre filled UPs composites. Furthermore, bleaching treatment with hydrogen peroxide is carried out in order to improve the tensile properties and water resistance of UPs/CSF composites. The functional groups of unbleached and bleached fibres were analysed using Fourier Transform Infrared (FTIR) analysis. Some lignin, hemicellulose and impurities of CSF have been removed after the bleaching treatment on CSF, as proven by FTIR results.