Polyester Research Articles

Selection of a biocomposite material as an alternative for the manufacture of the rotor of a gravitational vortex turbine

In this research study, a polymeric matrix biocomposite reinforced with natural fibers was evaluated as an alternative for the manufacture of impeller blades for a gravitational vortex turbine. Laminates were manufactured using the manual impregnation method, combining unsaturated polyester resin with three layers of fique fiber. Density tests were conducted along with the mechanical properties of the biocomposite, and they were compared with conventional materials such as aluminum, stainless steel, and fiberglass, commonly used in the construction of impellers. As a result of the tests, it was determined that bio composites present advantages such as: low cost, environmental sustainability and lower density compared to traditional materials. Finally, a prototype rotor for a gravitational vortex turbine was manufactured with the material proposed in the present study. In conclusion, the findings suggest that the developed biocomposite has the potential as an alternative to replace conventional materials in the manufacture of hydraulic rotors.

Discrimination and Quantification of Cotton and Polyester Textile Samples Using Near-Infrared and Mid-Infrared Spectroscopies.

In the textile industry, cotton and polyester (PES) are among the most used fibres to produce clothes. The correct identification and accurate composition estimate of fibres are mandatory, and environmentally friendly and precise techniques are welcome. In this context, the use of near-infrared (NIR) and mid-infrared (MIR) spectroscopies to distinguish between cotton and PES samples and further estimate the cotton content of blended samples were evaluated. Infrared spectra were acquired and modelled through diverse chemometric models: principal component analysis; partial least squares discriminant analysis; and partial least squares (PLS) regression. Both techniques (NIR and MIR) presented good potential for cotton and PES sample discrimination, although the results obtained with NIR spectroscopy were slightly better. Regarding cotton content estimates, the calibration errors of the PLS models were 3.3% and 6.5% for NIR and MIR spectroscopy, respectively. The PLS models were validated with two different sets of samples: prediction set 1, containing blended cotton + PES samples (like those used in the calibration step), and prediction set 2, containing cotton + PES + distinct fibre samples. Prediction set 2 was included to address one of the biggest known drawbacks of such chemometric models, which is the prediction of sample types that are not used in the calibration. Despite the poorer results obtained for prediction set 2, all the errors were lower than 8%, proving the suitability of the techniques for cotton content estimation. It should be stressed that the textile samples used in this work came from different geographic origins (cotton) and were of distinct presentations (raw, yarn, knitted/woven fabric), which strengthens our findings.

Preparation and performance evaluation of bio-based wood-plastic composites from ricinoleic acid ring-openning epoxidized soybean oil

With the enhancement of sustainable development concepts and environmental protection awareness, replacing fossil resources with biomass to prepare unsaturated polyester resins is an essential approach to achieve green chemistry. In this study, a bio-based unsaturated polyester (ERM) was synthesized using epoxidized soybean oil and castor oil acid as raw materials. The reinforced modification of two fast-growing woods, Cunninghamia lanceolata (Chinese fir) and Pinus sylvestris var. mongolica (Pine), was investigated. The structure and molecular weight of the polyester at various stages were detected through infrared spectroscopy, proton nuclear magnetic resonance, and size exclusion chromatography. It was found that compared to the original wood, the density of the modified Cunninghamia lanceolata (Chinese fir) and Pinus sylvestris var. mongolica (Pine) increased from 0.36 g/cm3 and 0.45 g/cm3 to 0.9 g/cm3 and 0.78 g/cm3, respectively. Their compressive strength increased from 30.1 MPa and 32.1 MPa to 73.9 MPa and 73.8 MPa, respectively. The water absorption rate decreased from 167.3% and 103.8% to 16.86% and 16.59%, respectively, and thermal stability also showed a significant improvement.

Hazard assessment of microplastics and heavy metals contamination in Levant frogs (Pelophylax bedriagae): A bioindicator in Western Iran

The increasing pollution of aquatic ecosystems caused by microplastics (MPs) and heavy metal ions worldwide threatens the life of aquatic organisms, including amphibians. In this study, we investigated the presence and accumulation of MPs and heavy metal ions in the upper gastrointestinal tract (GIT) of the Levant frog (Pelophylax bedriagae) as a bioindicator in contaminated sites of Western Iran. A total of 192 adult frogs from 16 locations in the west and northwest of Iran were collected. We measured the accumulation of MPs and heavy metal ions in the collected frogs and determined the characteristics of MPs in the samples. Our findings revealed widespread MPs and heavy metal ions contamination in the frog GIT across all sampled stations. We found 742 MP particles in the digestive system of frogs, with the highest (7.09 MP/individual) and lowest (2.37 MP/individual) number observed in stations 10 and 9, respectively. Fibers were the most common MPs and polyester (PES) (42.5%) and polyethylene terephthalate (PET) (17.2%) were found to be the most common polymers in the GIT of frogs. The average accumulation of heavy metal ions showed significant differences (P < 0.05) among 16 sampling stations, and zinc (II) and mercury (II) showed the highest and lowest concentrations in frogs. We also found moderate to strong positive correlations between the detected MPs and heavy metal ions in the frog samples across all sampling stations. Our findings confirm the contamination of frogs by MPs and heavy metal ions and the potential capacity of MPs to increase the toxicity of heavy metals in P. bedriagae as a bioindicator in contaminated sites.

An Investigation on the Presence and Risk Assessment of Microplastics in Quilon Beach, South West Coast of India

Microplastics (MPs) are the most serious emerging pollutant around the globe. Anthropogenic activities are the major contributor of MPs in beach sediments. MPs are widely distributed along beaches and pose a serious threat to the marine food chain including human health. The present study aims to investigate, for the first time, the occurrence, quantification of abundance and risk assessment of MPs in Quilon beach, India and also identifies the potential sources along with the assessment of degree of MPs contamination using Pollution load index (PLI) and Pollution Hazard index (PHI) parameters. Sampling was conducted in dry season in the beach. A total of thirty-three samples were collected establishing a 20m grid pattern along the study area. MPs of size range 5mm - < 0.25mm were considered. The average abundance of MPs in the study area is 3145±2515 MPs/kg of sand. Polyester (PES), Acrylonitrile butadiene styrene (ABS) are the major polymer types in the study area. Fibre was the most dominant shapes. The frequent colours found were white and transparent. MPs of size <0.25mm were the most common of all the samples. Anthropogenic activities including sewage effluents, fishing and tourism activities might be the main sources of MPs pollution in this area.

Human inhalation exposure assessment of the airborne microplastics from indoor deposited dusts during winter in Dhaka, Bangladesh

Microplastic (MP) contamination has become a concern due to its ubiquitous presence. Recent studies have found MPs to be present in multiple human organs. This study was carried out to evaluate the presence and characterize MPs in indoor dust deposition. Deposited dust was collected from fifteen households in Dhaka city. The samples underwent quantification of MPs using stereomicroscopy. Fourier Transform Infrared (FTIR) spectroscopy was performed to understand the polymer composition. MPs of the size group ranging from 50 to 250 μm were the most dominant. The deposition rates varied from 7.52 × 10³ MPs/m2/day to 66.29 × 10³ MPs/m2/day, with the mean deposition rate being 34 × 10³ MPs/m2/day. Notably, the number of occupants and the height of the sampling location above the ground level were found to influence the deposition rates. Various polymers, including polyester (PET), polyethylene (PE), Nylon, and polypropylene (PP), were identified. The estimated mean inhalation exposure was 2986 ± 1035 MPs/kg-BW/day. This work highlights the need for additional research to explore indoor microplastic deposition and its potential effect on human health in the densely inhabited and severely polluted megapolis of Dhaka, Bangladesh.

Advancement in optical and dielectric properties of unsaturated polyester resin/zinc oxide nanocomposite: synthesis to application in electronics

Advancement in optical and dielectric properties of unsaturated polyester resin/zinc oxide nanocomposite: synthesis to application in electronics

Sustainable synthesis and characterization of cobalt-based biocatalysts from olive stone waste for enhanced curing of unsaturated polyester resins

The functionalization of native olive wood shell stone for the formation of new active heterogeneous cobalt-based biocatalysts has been conducted. The resulting biocatalysts have been fully characterized using various analytical techniques, including X-ray fluorescence (XRF), elemental analysis, granulometry, X-ray photoelectron spectroscopy (XPS), Fourier-Transform Infrared Spectroscopy (FTIR), thermogravimetry (TGA), moisture content, field-emission scanning electron microscopy (FESEM) and high-angle annular dark-field imaging (HAADF) with energy dispersive X-ray spectroscopy (EDX). The catalytic performance of these new functional heterogeneous materials has been verified by gelation time measurements on a multipurpose unsaturated polyester/styrene/tert-butyl peroxybenzoate system. The results are compared with those obtained using the current workhorse of the industry, which utilizes cobalt-based catalysts, particularly cobalt octoate dissolved in a solvent solution known to have adverse environmental and human health implications.

Schiff base-coated ammonia polyphosphate for improving thermal and fire-retardant properties of unsaturated polyester

Schiff base-coated ammonia polyphosphate for improving thermal and fire-retardant properties of unsaturated polyester

Advancing reinforcement of sustainable gypsum composites: High-performance design by reusing waste materials

This study tends to optimize and develop an innovative gypsum material by incorporating hybrid waste compounds. Using a Doehlert design, this work explores the effects of introducing paper (X1), polystyrene (X2), and polyester fibers (X3), as well as their interactions, on gypsum's thermophysical and mechanical behavior. Bulk density, thermal conductivity, flexural strength, compressive strength, and the fire resistance test were performed on the developed formulations. Statistical analysis emphasizes the significant influence of all process variables on gypsum properties. Polyester fibers notably enhance flexural strength when combined with the cooperative effect of paper and polystyrene wastes, which strike a balance between physical and mechanical characteristics. The optimum formulation parameters lead to a significant 33% decrease in bulk density, a 43% reduction in thermal conductivity, a notable 42% increase in flexural strength, and a significant reduction in compressive strength of around 50%, but still meet the 2 MPa standard. The new samples show ductile behavior, highlighting gypsum's potential as a load-bearing material with excellent thermal insulation properties and impressive fire resistance. This research significantly improves our understanding of the effectiveness of a gypsum compound incorporating waste in a hybrid manner, bringing this approach into line with sustainable development objectives.

Transforming recycled polyester/cotton (Gossypium hirsutum L.) fibers into dye-free and eco-friendly denim fabrics: Preparation, properties evaluation, and feasibility analysis

Conventional denim production is plagued by the issue of wastewater pollution from warp dyeing. In this investigation, recycled cotton (R-CO), virgin cotton (V-CO), and dope-dyed recycled polyester (R-PET) fibers were spun into blue/white spaced warp yarns through a dual-feed-opening rotor spinning technique. These yarns were woven with V-CO weft yarns to produce fabrics featuring the classic denim color scheme of blue and white stripes, without the need for warp dyeing and complex finishing processes. The resulting fabrics fulfilled industry standards for tensile strength (>600 N), tearing resistance (>50 N), abrasion resistance (>25000 cycles), pH (≈6.5), and formaldehyde content (<10 mg/kg). The fabrics' air/moisture permeability and wearability (including crease-resistance, flexibility, drapability, and washing size stability) were outstanding. The fabrics' light and crocking colorfastness ratings all exceed grade 4, indicating excellent performance. A rise in R-CO content resulted in the degradation of several properties. The production of the denim covered by this study was more cost-effective and environment-friendly than that of conventional denim. This research provides a paradigm for the conversion of waste textiles into value-added and eco-friendly textile products.

Study on Basic Pavement Performance of High-Elasticity Asphalt Concrete.

In order to improve the basic pavement performance of high-elastic asphalt concrete filled in the expansion longitudinal joints of seamless bridges, rubber particles and polyester fibers were added to optimize the mix proportion of elastic asphalt concrete, and the optimal asphalt-aggregate ratio was determined. The influence of rubber particles and polyester fibers on the basic pavement performance of high-elastic asphalt concrete was studied. The results show that when the dosage of polyester fiber is not more than 0.6%, the optimal asphalt-aggregate ratio is 1:5, and when it exceeds 0.6%, the optimal asphalt-aggregate ratio is 1:4. The incorporation of rubber particles reduces the compressive strength of high-elastic asphalt concrete but enhances its high-temperature stability, fracture performance, and deformation recovery ability. The incorporation of polyester fibers improves its compressive strength, high-temperature stability, fracture performance, and deformation recovery ability. In addition, the incorporation of rubber granules and polyester fibers promotes the use of green building materials and provides strong support for sustainable building practices.

Asymmetrical surface-modified polyester/cotton fabrics for temperature-adaptive moisture and thermal management of human body

Personal moisture and thermal management fabrics that can regulate skin temperature are highly desired for improving human comfort and performance. Here, a symmetric surface modified polyester/cotton fabric (Janus T/C fabric) exhibiting exceptional temperature-adaptive personal moisture and thermal managements was developed. This was achieved by integrating two distinct temperature-sensitive hydrophobic/hydrophilic transition materials through single-sided spray coating technique and in-situ ultraviolet-induced free radical polymerization in 60/40 polyester/cotton blend fabric (T/C fabric, composed of 60 % cotton and 40 % polyester fibers). 2-(2-methoxyethoxy) ethoxyethyl-methacrylate (MEO2MA) was utilized to create lower critical solution temperature (LCST) polymer, while N, N-dimethyl (methacryloylethyl) ammonium propane sulfonate (DMAPS) formed an upper critical solution temperature (UCST) polymer on T/C fabric surface. Fabric’s surface demonstrated a reversible transition in hydrophobicity/hydrophilicity in response to environmental temperature changes. The distinct hydrophobic and hydrophilic surfaces configuration resulted in a remarkable wettability gradient, significantly increased moisture permeability to 6792.5 g/m2·24 h—an increase of 1132.1 g/m2·24 h compared to the 60/40 T/C fabric at 40 °C. Moreover, the Janus T/C fabric provided practical temperature adaptation benefits, offering a cooling effect of approximately 1.2 °C in hot environments and a warming effect of approximately 1.0 °C in cold conditions. These thermal responsive properties make the asymmetric surface-modified polyester/cotton fabric an ideal choice for personalized moisture and thermal management, ensuring optimal comfort across varying temperatures.

Characterizing the Sensing Response of Carbon Nanocomposite-Based Wearable Sensors on Elbow Joint Using an End Point Robot and Virtual Reality.

Physical therapy is often essential for complete recovery after injury. However, a significant population of patients fail to adhere to prescribed exercise regimens. Lack of motivation and inconsistent in-person visits to physical therapy are major contributing factors to suboptimal exercise adherence, slowing the recovery process. With the advancement of virtual reality (VR), researchers have developed remote virtual rehabilitation systems with sensors such as inertial measurement units. A functional garment with an integrated wearable sensor can also be used for real-time sensory feedback in VR-based therapeutic exercise and offers affordable remote rehabilitation to patients. Sensors integrated into wearable garments offer the potential for a quantitative range of motion measurements during VR rehabilitation. In this research, we developed and validated a carbon nanocomposite-coated knit fabric-based sensor worn on a compression sleeve that can be integrated with upper-extremity virtual rehabilitation systems. The sensor was created by coating a commercially available weft knitted fabric consisting of polyester, nylon, and elastane fibers. A thin carbon nanotube composite coating applied to the fibers makes the fabric electrically conductive and functions as a piezoresistive sensor. The nanocomposite sensor, which is soft to the touch and breathable, demonstrated high sensitivity to stretching deformations, with an average gauge factor of ~35 in the warp direction of the fabric sensor. Multiple tests are performed with a Kinarm end point robot to validate the sensor for repeatable response with a change in elbow joint angle. A task was also created in a VR environment and replicated by the Kinarm. The wearable sensor can measure the change in elbow angle with more than 90% accuracy while performing these tasks, and the sensor shows a proportional resistance change with varying joint angles while performing different exercises. The potential use of wearable sensors in at-home virtual therapy/exercise was demonstrated using a Meta Quest 2 VR system with a virtual exercise program to show the potential for at-home measurements.

Polyester Composite and Waste of Natural Materials Recyclable: Fracture Aspect After Tensile Test

Objective: This study aims to analyze the fractography of polymeric composites reinforced by recyclable materials, verifying the main types of defects present in the manufactured materials. Theoretical Framework: Composites can be understood as mutltiphasic materials that present a significant portion of the properties of their constintuintes. There are two phases, matrz and reinforcement. From the fractofrgographic analysis of the fracture surface of the material, one can evaluate the mechanisms of failure and interaction between the interfaces of the phases. Method: Specimens were manufactured using silicone molds according to ASTM D638. The matrix was unsaturated and pre-accelerated terephthalic polyester resin, while the reinforcement materials were: Jatoba wood residues, the hybridization of Jute and Sisal fibers, the hybrid of sisal and coffee grounds, and açaí leaves. Results and Discussion: For the composite with reinforcement of wood waste, there was a predominance of voids. For hybrids, the presence of the fibers culminated in the pull-out defect, therefore, using sisal fibers and coffee grounds, the presence of voids was also observed. The composite with acai leaves presented delamination between the reinforcement layers and the matrix. Research Implications: The analysis of the predominant defects, evaluates the possibility of improvement of the manufacturing process in order to certify the presence of this and promote and improve the efficiency of handling the material. Originality/Value: The use of natural and recyclable materials is of great importance from a sustainable analysis. In addition, it aims to generate added value to raw materials with little or no functionality.

Characterization of aloe vera gel incorporated unsaturated polyester resin jute-cotton fabric composites for enhanced biodegradability, flexibility, and insulation properties

In this research, Aloe Vera Gel (AVG) was incorporated into Unsaturated Polyester Resin (UPR) with jute-cotton union fabric to fabricate partially biodegradable composites. These composites were fabricated using a hand lay-up technique and characterized using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry Analysis (TGA), thermal conductivity measurements, water absorption tests, degradation assessments, cracking tests, and Universal Testing Machine (UTM) analysis. The study found that increasing the percentage of AVG in the composites led to a decrease in thermal conductivity, indicating improved insulation properties. Samples reinforced with AVG showed enhanced resistance to damage from iron nails, with reduced scratching and fiber displacement observed. However, the addition of AVG resulted in decreased thermal, mechanical, and water resistance properties compared to composites without AVG. FTIR analysis demonstrated interactions between AVG and the matrix materials. In degradation tests, composites subjected to an alkali environment (PH = 11.96) showed the highest weight reduction (2.22 %) compared to those without AVG. Similarly, composites buried in soil exhibited greater weight loss (2.38 %) than their counterparts lacking AVG. Overall, the developed composite's reduced heat transfer rate suggests its potential application as an insulating material in environments such as rural poultry housing and the automotive industry.

Performance assessment of polyester fiber modified stone matrix asphalt mixtures with statistical analysis

Performance assessment of polyester fiber modified stone matrix asphalt mixtures with statistical analysis

Decreasing the electrostatic discharge generated from friction of polyester and polyamide sing carbon fiber

AbstractThe present work discusses the voltage difference as a measure for electrostatic charge generated from the contact‐separation and sliding of polymeric textiles on polyamide textile. It is proposed to blend polyester by carbon fiber to decrease the electrostatic charge generated on the contact surfaces. Because polyester acquires a negative charge and polyamide gains a positive one, carbon fiber is proposed to conduct the negative electrostatic charge from polyester to polyamide and conducts the positive one from polyamide to polyester, so that the resultant electrostatic charge decreased. The effect of carbon fiber to decrease the electrostatic charge depends on its area of contact, interaction, and distribution with polyester. Polyester double weaved by carbon fiber showed the lowest voltage. Based on those observations, it can be recommended to use double weaves of carbon fiber with polyester. The reduction in voltage was relatively lower for braided polyester by carbon fiber than that detected for double‐weaved polyester by carbon fiber.

Obtaining unsaturated polyester resins using products of recycled polyethylene terephthalate solvolysis

A technique for obtaining an unsaturated polyester resin based on recycled polyethylene terephthalate has been developed. The process of curing an unsaturated polyester resin under the action of styrene, a peroxide compound (Butanox 50M) and an accelerator (cobalt ortoate) has been studied. The physical and mechanical properties of polymeric materials based on the developed resin have been studied, it was found that their strength depends on the mass fraction of recycled polyethylene terephthalate in the oligoether polyol used in the synthesis.

Recycling of Blended Fabrics for a Circular Economy of Textiles: Separation of Cotton, Polyester, and Elastane Fibers

The growing textile industry is polluting the environment and producing waste at an alarming rate. The wasteful consumption of fast fashion has made the problem worse. The waste management of textiles has been ineffective. Spurred by the urgency of reducing the environmental footprint of textiles, this review examines advances and challenges to separate important textile constituents such as cotton (which is mostly cellulose), polyester (polyethylene terephthalate), and elastane, also known as spandex (polyurethane), from blended textiles. Once separated, the individual fiber types can meet the demand for sustainable strategies in textile recycling. The concepts of mechanical, chemical, and biological recycling of textiles are introduced first. Blended or mixed textiles pose challenges for mechanical recycling which cannot separate fibers from the blend. However, the separation of fiber blends can be achieved by molecular recycling, i.e., selectively dissolving or depolymerizing specific polymers in the blend. Specifically, the separation of cotton and polyester through dissolution, acidic hydrolysis, acid-catalyzed hydrothermal treatment, and enzymatic hydrolysis is discussed here, followed by the separation of elastane from other fibers by selective degradation or dissolution of elastane. The information synthesized and analyzed in this review can assist stakeholders in the textile and waste management sectors in mapping out strategies for achieving sustainable practices and promoting the shift towards a circular economy.