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11 pages, 2663 KiB

Open AccessArticle

Closed-Loop Composite Welding and Bonding System Using Radio-Frequency Heating and Pressure

by Ian Enriquez, Colin Noronha, Katrina Teo, Anubhav Sarmah, Surabhit Gupta, Ankush Nandi, Blake Fishbeck, Micah J. Green and Aniruddh Vashisth

J. Compos. Sci. 2023, 7(3), 116; https://doi.org/10.3390/jcs7030116 - 13 Mar 2023

Cited by 3 | Viewed by 1672

Abstract

Polymer parts often replace traditional metallic parts in load-bearing applications due to their high strength-to-weight ratio, with thermoplastics at the forefront. Conventional manufacturing processes rely on using fasteners or adhesives to hold composite assemblies together, but thermoplastics can be welded together. Ultrasonic welding [...] Read more.

Polymer parts often replace traditional metallic parts in load-bearing applications due to their high strength-to-weight ratio, with thermoplastics at the forefront. Conventional manufacturing processes rely on using fasteners or adhesives to hold composite assemblies together, but thermoplastics can be welded together. Ultrasonic welding is widely used but becomes challenging for complex geometries, and new parameters need to be developed for different polymers and specimen geometries. In this work, we developed a closed-loop welding machine that employs the recent discovery of radio-frequency (RF) heating of carbonaceous materials. The machine is successfully able to weld polylactic acid (PLA) coupons with graphitic RF susceptors at the bondline in less than 2 min and using less than 50 W of input RF power. We found that a higher areal density of the graphitic paint lowers the mechanical properties of the weld because the carbonaceous materials hinder polymer chain diffusion. A significant change was not observed in weld properties for welding pressure ranges between 0 and 0.3 MPa. However, increasing out-of-plane welding displacement increased the modulus and strength of the weld. This work provides an interesting new automated system for welding polymer composites using RF fields, with potential applications in various manufacturing industries. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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16 pages, 5121 KiB

Open AccessArticle

Chitosan-Biopolymer-Entrapped Activated Charcoal for Adsorption of Reactive Orange Dye from Aqueous Phase and CO₂ from Gaseous Phase

by Pradip Nandanwar, Ravin Jugade, Vaishnavi Gomase, Anita Shekhawat, Apurva Bambal, Dhandayutham Saravanan and Sadanand Pandey

J. Compos. Sci. 2023, 7(3), 103; https://doi.org/10.3390/jcs7030103 - 07 Mar 2023

Cited by 14 | Viewed by 1727

Abstract

Polymers have been proven to be an interesting class of adsorbents applied in water treatment. Biopolymers are of special interest due to their unique properties such as biocompatibility, biodegradability, and reusability. This work reports a composite formed by a chitosan biopolymer and activated [...] Read more.

Polymers have been proven to be an interesting class of adsorbents applied in water treatment. Biopolymers are of special interest due to their unique properties such as biocompatibility, biodegradability, and reusability. This work reports a composite formed by a chitosan biopolymer and activated charcoal using sodium citrate as a crosslinking agent. The chitosan–citrate-activated charcoal composite (CCA) was characterized using FT–IR, SEM, EDAX, XRD, TGA–DTA and BET surface area analysis. The material was found to be microporous in nature with a surface area of 165.83 m²/g that led to high adsorption capacities toward both the targeted pollutants. In an aqueous phase, the dye adsorption studies were carried out with reactive orange 16 (R-16) dye, while in a gaseous phase, CO₂ adsorption capacity was evaluated. Under optimum solution conditions, maximum R-16 dye removal capacity was found to be 34.62 mg g⁻¹, while in the gas phase the CO₂ adsorption capacity was found to be 13.15 cm³g⁻¹. Intrinsic microporosity of CCA resulted in an enhanced capture capacity for R-16 dye and carbon dioxide in the respective phases. Material sustainability studies were carried out to evaluate various sustainability parameters. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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20 pages, 6990 KiB

Open AccessArticle

Impact Resistance Enhancement of Sustainable Geopolymer Composites Using High Volume Tile Ceramic Wastes

by Ghasan Fahim Huseien, Ziyad Kubba, Akram M. Mhaya, Noshaba Hassan Malik and Jahangir Mirza

J. Compos. Sci. 2023, 7(2), 73; https://doi.org/10.3390/jcs7020073 - 09 Feb 2023

Cited by 3 | Viewed by 1470

Abstract

The need for sustainable concrete with low carbon dioxide emissions and exceptional performance has recently increased in the building industry. Many distinct types of industrial byproducts and ecologically safe wastes have shown promise as ingredients for this kind of concrete. Meanwhile, as industrialization [...] Read more.

The need for sustainable concrete with low carbon dioxide emissions and exceptional performance has recently increased in the building industry. Many distinct types of industrial byproducts and ecologically safe wastes have shown promise as ingredients for this kind of concrete. Meanwhile, as industrialization and lifestyle modernization continue to rise, ceramic waste becomes an increasingly serious threat to the natural environment. It is well known that free cement binder that incorporates tile ceramic wastes (TCWs) can significantly improve the material’s sustainability. We used this information to create a variety of geopolymer mortars by mixing TCWs with varied proportions of ground blast furnace slag (GBFS) and fly ash (FA). Analytical techniques were used to evaluate the mechanical properties and impact resistance (IR) of each designed mixture. TCWs were substituted for binders at percentages between 50 and 70 percent, and the resultant mixes were strong enough for real-world usage. Evidence suggests that the IR and ductility of the proposed mortars might be greatly improved by the addition of TCWs to a geopolymer matrix. It was found that there is a trend for both initial and failure impact energy to increase with increasing TCWs and FA content in the matrix. The results show that the raising of TCWs from 0% to 50, 60 and 70% significantly led to an increase in the failure impact energy from 397.3 J to 456.8, 496.6 and 595.9 J, respectively. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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19 pages, 2622 KiB

Open AccessArticle

The Effect of Metals of the 2nd and 12th Groups on the Productivity and Selectivity of Cumene Oxidation—The First Stage of the Technological Chain for the Production of Polymer Composites

by Nikolai V. Ulitin, Daria A. Shiyan, Yana L. Lyulinskaya, Nikolay A. Novikov, Konstantin A. Tereshchenko, Natalia M. Nurullina, Marina N. Denisova, Kharlampii E. Kharlampidi and Yaroslav O. Mezhuev

J. Compos. Sci. 2023, 7(2), 70; https://doi.org/10.3390/jcs7020070 - 08 Feb 2023

Viewed by 1362

Abstract

The effect of the process temperature and the initial concentration of Mg, Ca, Sr, Ba, Zn, Cd, and Hg 2-ethylhexanoates as catalysts on the productivity and selectivity of the oxidation stage of cumene is studied in the technological chain for the production of [...] Read more.

The effect of the process temperature and the initial concentration of Mg, Ca, Sr, Ba, Zn, Cd, and Hg 2-ethylhexanoates as catalysts on the productivity and selectivity of the oxidation stage of cumene is studied in the technological chain for the production of polymer composites from cumene; “production of phenol by cumene method (stage 1 is cumene oxidation to cumene hydroperoxide, stage 2 is decomposition of cumene hydroperoxide into phenol and acetone) → production of precursors from phenol → production of polymers from precursors → production of composites from polymers”. A criterion has been introduced that reflects the productivity of cumene oxidation at the moment of reaching the maximum concentration of cumene hydroperoxide, which takes into account the cumene conversion and selectivity achieved in this case in the shortest possible time using the selectivity comparable with the selectivity of a non-catalytic process. It has been shown that the achievement of the maximum value of this criterion, among all the considered catalysts, is ensured by Mg 2-ethylhexanoate at its relatively low initial concentration (1 mmol/L) under conditions of moderately-high process temperatures (393–413 K). Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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17 pages, 1700 KiB

Open AccessArticle

The Effect of Ca, Sr, and Ba Chloride Complexes with Dibenzo-18-Crown-6 Ether as Catalysts on the Process Criteria for the Efficiency of Cumene Oxidation (the First Stage in the Chain of Polymer Composite Production)

by Nikolai V. Ulitin, Nikolay A. Novikov, Yana L. Lyulinskaya, Daria A. Shiyan, Konstantin A. Tereshchenko, Natalia M. Nurullina, Marina N. Denisova, Yaroslav O. Mezhuev and Kharlampii E. Kharlampidi

J. Compos. Sci. 2023, 7(2), 60; https://doi.org/10.3390/jcs7020060 - 06 Feb 2023

Viewed by 1248

Abstract

A study was made on the effect of Ca, Sr, and Ba chloride complexes with dibenzo-18-crown-6 ether as catalysts on the process criteria of the efficiency of industrial cumene oxidation using kinetic modeling. It is the first stage in the process chain of [...] Read more.

A study was made on the effect of Ca, Sr, and Ba chloride complexes with dibenzo-18-crown-6 ether as catalysts on the process criteria of the efficiency of industrial cumene oxidation using kinetic modeling. It is the first stage in the process chain of polymer composite production. The kinetic scheme of the process is made of classical reactions of the radical chain mechanism (reactions of initiation, chain propagation, and chain termination), molecular reactions, reactions of formation of intermediate adducts “component of the reaction mixture—catalyst” and their decomposition, as well as reactions that take into account the specifics of the catalyst used: (1) formation of planar catalyst complexes with various substances; (2) formation of acetophenone along the catalytic path; (3) hydration of the intermediate adduct “α-methylstyrene—catalyst” to the required alcohol. It is shown that the kinetic model fully reproduces the experimental time dependencies of the cumene hydroperoxide concentration in the cumene oxidation and cumene hydroperoxide decomposition. Using the kinetic model, computational experiments were carried out, as a result of which the following conclusions were made: (1) among the considered catalysts, the complex of Sr chloride with dibenzo-18-crown-6 ether should be recognized as the best, provided that it is used at temperatures of 393–413 K and an initial concentration < 2 mmol/L; (2) to ensure selectivity comparable to the selectivity of a non-catalytic process, it is necessary to conduct the catalytic process at a lowest possible initial concentration of any of the considered catalysts. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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11 pages, 3492 KiB

Open AccessArticle

Study of the Effects of Alkali Treatment and Fiber Orientation on Mechanical Properties of Enset/Sisal Polymer Hybrid Composite

by Abera E. Bekele, Hirpa G. Lemu and Moera G. Jiru

J. Compos. Sci. 2023, 7(1), 37; https://doi.org/10.3390/jcs7010037 - 12 Jan 2023

Cited by 20 | Viewed by 2300

Abstract

In the manufacturing process of innovative fiber-based composite materials, natural fibers are among the most commonly employed reinforcements. In this study, Enset/Sisal (E/S) fiber with a polyester matrix was used to develop the hybrid composites. Hand layup methods were employed for the sample [...] Read more.

In the manufacturing process of innovative fiber-based composite materials, natural fibers are among the most commonly employed reinforcements. In this study, Enset/Sisal (E/S) fiber with a polyester matrix was used to develop the hybrid composites. Hand layup methods were employed for the sample preparation from untreated, 5%, and 10% alkali-treated unidirectional and woven fiber orientations having 50:50 volume ratios. The mechanical properties and water absorption of natural fiber hybrid composites were influenced by fiber treatment and orientation. In the present investigation, the result shows that treated and woven fiber orientation hybrid composites exhibit better mechanical properties than untreated and unidirectional E/S hybrid composites. The 5% NaOH-treated samples have higher tensile and flexural strength properties than the untreated and 10% alkali-treated composites, while the 5% NaOH-treated fiber composites have lower water absorption properties. The tensile and flexural strengths and impacts of 5% NaOH-treated composites were improved by 5.21%, 9.25%, and 5.98%, respectively, over untreated E/S hybrid composites. The morphological properties of the fracture surface of the composite were observed using scanning electron microscopy (SEM). Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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18 pages, 3158 KiB

Open AccessArticle

Effect of Compatibilizer and Organoclay Reinforcement on Morphology and Properties of Styrene Copolymer Blends

by Marianna Triantou, Marios Gavriel and Petroula A. Tarantili

J. Compos. Sci. 2023, 7(1), 36; https://doi.org/10.3390/jcs7010036 - 11 Jan 2023

Viewed by 1170

Abstract

The blending of polymers leads to materials with the desired combined properties. These properties can further be improved by the incorporation of compatibilizer, organoclay, or both. In the present manuscript, the effects of compatibilizer and organoclay, as well as their combined use on [...] Read more.

The blending of polymers leads to materials with the desired combined properties. These properties can further be improved by the incorporation of compatibilizer, organoclay, or both. In the present manuscript, the effects of compatibilizer and organoclay, as well as their combined use on the rheological, thermal, and mechanical properties of styrene copolymer blends, is examined. Styrene-containing copolymers blends were prepared by melt-mixing in a twin screw extruder. The addition of SAN into ABS decreases its thermal stability, whereas it increases its tensile strength and modulus. The incorporation of organoclay in ABS/SAN blends increases their viscosity and slightly improves their thermal stability and significantly improves the tensile and storage moduli. In PC/SAN blends, the SAN copolymer increases the flow rate, as well as the tensile strength and modulus of PC, whereas it decreases the thermal stability. The addition of ABS-g-MAH compatibilizer in PC/SAN blends increases the melt viscosity and maximum decomposition rate temperature of SAN phase, while it leads to the earlier decomposition of the PC phase. The incorporation of organoclay reinforcement enhances the thermal decomposition resistance of thes SAN phase. The opposite effect was recorded for the PC phase. The addition of organoclay enhances the elastic modulus of PC/SAN hybrids. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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14 pages, 2938 KiB

Open AccessArticle

Effect of Modification with a Biocide Containing Metal Nanoparticles on Selected LDPE Properties

by Katarzyna Janczak, Daria Lisewska, Alicja Mazuryk and Rafał Malinowski

J. Compos. Sci. 2023, 7(1), 13; https://doi.org/10.3390/jcs7010013 - 05 Jan 2023

Viewed by 1212

Abstract

In this work, the physicomechanical, chemical and thermal properties of low-density polyethylene (LDPE) modified with a biocide containing metal nanoparticles: nanoAg, nanoCu, and nanoFe₂O₃ were examined. The presented studies, apart from the previously proven antimicrobial effectiveness, have shown that the [...] Read more.

In this work, the physicomechanical, chemical and thermal properties of low-density polyethylene (LDPE) modified with a biocide containing metal nanoparticles: nanoAg, nanoCu, and nanoFe₂O₃ were examined. The presented studies, apart from the previously proven antimicrobial effectiveness, have shown that the application of the biocide in concentrations of 0.5% and 1% has the least influence on the remaining properties. In the remaining concentrations (2–5%), despite the lack of significant influence on the chemical structure, the biocide primarily influenced the strength properties and melt flow rate (MFR). Previous research showed almost 100% antimicrobiological properties against bacteria and fungi of samples with the addition of 4% biocide. For such samples, the presented studies showed a decrease in MFR by approx. 17%, tensile strength at break by approx. 45%, an increase in elongation at breaking by approx. 25%, a decrease in density >2%, no increase in water absorption, and no significant changes in the chemical structure and in thermal properties in relation to LDPE without biocide. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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23 pages, 2943 KiB

Open AccessArticle

Effect of Sequential Thermal Aging and Water Immersion on Moisture Kinetics and SBS Strength of Wet Layup Carbon/Epoxy Composites

by Vistasp M. Karbhari and SoonKook Hong

J. Compos. Sci. 2022, 6(10), 306; https://doi.org/10.3390/jcs6100306 - 11 Oct 2022

Cited by 2 | Viewed by 1525

Abstract

This paper presents results of specific cases of sequential exposure of wet layup ambient cured carbon/epoxy composites to thermal aging and immersion in deionized water. Thermal aging is conducted at temperatures between 66 °C and 260 °C for periods of time up to [...] Read more.

This paper presents results of specific cases of sequential exposure of wet layup ambient cured carbon/epoxy composites to thermal aging and immersion in deionized water. Thermal aging is conducted at temperatures between 66 °C and 260 °C for periods of time up to 72 h whereas immersion is up to 72 weeks. Effects are characterized in terms of moisture kinetics using a two-stage diffusion model, and through short beam shear (SBS) strength. The response is characterized by a competition between the mechanisms of postcure, which results in increased polymerization and increases in SBS strength and glass transition temperature; and thermally induced microcracking and polymer degradation as well as moisture-induced plasticization and hydrolysis accompanied by fiber-matrix debonding, which results in deterioration. Thermal aging by itself is not seen to negatively impact SBS strength until the highest temperatures of exposure are considered in the investigation. However, the subsequent immersion in deionized water is seen to have a greater deteriorative effect with the period of post-thermal aging immersion being the dominant deteriorative factor. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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9 pages, 4423 KiB

Open AccessArticle

Damage Analysis of Thermoplastic Composites with Embedded Metal Inserts Using In Situ Computed Tomography

by Juliane Troschitz, René Füßel, Robert Kupfer and Maik Gude

J. Compos. Sci. 2022, 6(10), 287; https://doi.org/10.3390/jcs6100287 - 29 Sep 2022

Cited by 4 | Viewed by 1519

Abstract

Thermoplastic composites (TPCs) are predestined for use in lightweight structures, for example, in automotive engineering, due to their good specific mechanical properties. In many areas of lightweight design, the use of metal inserts for load introduction into composite structures has become established. The [...] Read more.

Thermoplastic composites (TPCs) are predestined for use in lightweight structures, for example, in automotive engineering, due to their good specific mechanical properties. In many areas of lightweight design, the use of metal inserts for load introduction into composite structures has become established. The inserts can be embedded during composite manufacturing without fibre damage. The technology is based on the concept of moulding holes with a pin tool and simultaneously placing the insert in the moulded hole. The embedding process results in a complex material structure in the joining zone with inhomogeneous three-dimensional fibre orientation and locally varying fibre content. The local material structure has a significant influence on the mechanical behaviour of the joining zone. For this reason, in situ computed tomography (CT) analyses are conducted in this work for a better understanding of the damage behaviour in the joining zone. In situ CT push-out tests were carried in the two thickness directions of along and opposed to the direction of the embedding process. The characteristic local material structure in the joining zone led to direction-dependent damage behaviour based on different failure modes. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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12 pages, 2329 KiB

Open AccessArticle

Nitrogen Doped Carbon-Dot Embedded Poly(lactic acid-co-glycolic acid) Composite Films for Potential Use in Food Packing Industry and Wound Dressing

by Mehtap Sahiner, Betul Ari, Manoj K. Ram and Nurettin Sahiner

J. Compos. Sci. 2022, 6(9), 260; https://doi.org/10.3390/jcs6090260 - 08 Sep 2022

Viewed by 1495

Abstract

Here, nitrogen-doped carbon dots (N-doped CDs) were synthesized by the hydrothermal method embedded within poly(lactic acid-co-glycolic acid) ((PLGA)) films at different amounts. The N-doped CDs (or CD) that possess fluorescence properties also have antimicrobial properties against S. aureus and E. coli microorganisms, determined [...] Read more.

Here, nitrogen-doped carbon dots (N-doped CDs) were synthesized by the hydrothermal method embedded within poly(lactic acid-co-glycolic acid) ((PLGA)) films at different amounts. The N-doped CDs (or CD) that possess fluorescence properties also have antimicrobial properties against S. aureus and E. coli microorganisms, determined by the disc diffusion method with 19 ± 2 and 18 ± 1 mm zone diameters, respectively. The CD embedded PLGA films (CD@PLGA) with different CD contents revealed an increased fluorescence intensity with the increased amount of CD. Moreover, the antibacterial potency of 50% CD containing PLGA (50-CD@PLGA) films (by weight) against S. aureus and E. coli microorganisms was examined and the zone diameters were found to be 14 ± 1 and 13 ± 1 mm, respectively. In addition, CD release studies from different amounts of CD (2.5–50 by weight) containing composite films showed that 50-CD@PLGA film released 127 ± 16 mg/g CD dots, which is 38 ± 5% of the embedded CDs in about 12 days, suggesting their potential application in food packing and wound dressing. Moreover, all CD@PLGA films were found to be blood compatible via hemolysis and blood clotting index tests with <5% hemolysis and >90% blood clotting indices regardless of their CD content. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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15 pages, 5781 KiB

Open AccessArticle

Impact of Dialysis Clinical Operating Conditions on Human Serum Protein-Mediated Inflammatory Biomarkers Released in Patients Using Polyarylethersulfone Membranes

by Heloisa Westphalen, Shaghayegh Saadati, Jumanah Bahig, Huu Doan, Ahmed Shoker and Amira Abdelrasoul

J. Compos. Sci. 2022, 6(8), 226; https://doi.org/10.3390/jcs6080226 - 04 Aug 2022

Cited by 2 | Viewed by 1655

Abstract

Hemodialysis (HD) is a life-sustaining treatment of crucial importance in managing end-stage renal disease (ESRD). However, this membrane-based therapy is associated with acute side-effects due to bioincompatibility issues and limitations on the removal of uremic toxins. The present study assessed the influence of [...] Read more.

Hemodialysis (HD) is a life-sustaining treatment of crucial importance in managing end-stage renal disease (ESRD). However, this membrane-based therapy is associated with acute side-effects due to bioincompatibility issues and limitations on the removal of uremic toxins. The present study assessed the influence of hydrodynamic conditions applied during HD treatment on protein-mediated inflammatory and thrombotic responses. The membrane modules considered are commonly used in Canadian hospitals and are comprised of a polymer blend of polyarylether sulfone-polyvinylpyrrolidone (PAES). The membranes morphology and hydrophilicity were assessed using SEM, AFM, BET, and zeta potential. An in vitro study evaluated the adsorptive behavior of fibrinogen (FB) to the membrane under different flow conditions. Lower rates of 200 mL/min promoted slower and significant FB adsorption, leading to more severe inflammatory and thrombotic responses. Hydrodynamic conditions also affected the concentration of all inflammatory biomarkers. Lower flow rates triggered more complement activation as well as coagulation, clotting, and inflammatory responses compared to higher flow rates. At the end of the dialysis session, patients treated with a Qb of 200 mL/min presented a significant increase in the concentration of C5a (232%), properdin (114%), serpin (545%), IL-1α (50%), IL-6 (450%), and vWF (212%). IL-1β and TNF-α concentrations declined by 12.5 and 35.5%, respectively. Male patients experienced more severe inflammatory responses than female patients at the operating conditions considered. Comparing the pre- and post-dialysis levels of female and male patients, female patients experienced significantly higher levels of IL-6 and properdin, while male patients presented higher levels of C5a, IL-1α, and IL-6. The results of this study will help clinical doctors evaluate the impact of HD operating conditions on blood activations before prescribing treatment and inform expectations for outcomes in female and male patients. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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14 pages, 2513 KiB

Open AccessArticle

Study of Machinability in Drilling Operation of Enset–Sisal Hybrid Polyester Composite

by Abera E. Bekele, Hirpa G. Lemu and Moera G. Jiru

J. Compos. Sci. 2022, 6(7), 205; https://doi.org/10.3390/jcs6070205 - 14 Jul 2022

Cited by 4 | Viewed by 1469

Abstract

Due to their light weight, low density, high-specificity strength, and ease of fiber surface treatment, natural-fiber-reinforced composites are recognized as the most suitable materials for interior part applications. Moreover, natural fibers are widely accessible and environmentally friendly. The fabricated parts are assembled predominantly [...] Read more.

Due to their light weight, low density, high-specificity strength, and ease of fiber surface treatment, natural-fiber-reinforced composites are recognized as the most suitable materials for interior part applications. Moreover, natural fibers are widely accessible and environmentally friendly. The fabricated parts are assembled predominantly by fastening using drilled holes, which makes drilling operations common machining processes for the composite parts. Damage occurs at the entry and exit surfaces of drilled holes. In this study, hand layup procedures are used to create unidirectional and woven forms of 1:1 ratio enset (false banana)/sisal hybrid polyester composites that have been treated with 5% NaOH. The drill operation was performed using a computer numerical control (CNC) drill machine with high-speed steel twist drill. A Taguchi design tool was used to complete the analysis. The experiments were conducted at different levels of drilling speeds: 600, 1200, and 1800 rpm. Feed rates of 0.1, 0.2, and 0.3 mm/rev and drill bit diameters of 6, 9, and 12 mm were used. These were determined to be the study parameters that influenced the delamination factors (F_d) and surface roughness (SR) of the hybrid composite drilled parts. Delamination occurred at the entry and exit surfaces of the drilled holes, and surface roughness occurred at the inner surface of the sectioned drilled hole. The quality of the drilled holes was compared based on the delamination factor and the surface roughness, as analyzed by the 3D optical surface profiles. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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15 pages, 3998 KiB

Open AccessArticle

Investigation of Mechanical Properties and Microstructure of Construction- and Demolition-Waste-Based Geopolymers

by Beata Figiela, Karolina Brudny, Wei-Ting Lin and Kinga Korniejenko

J. Compos. Sci. 2022, 6(7), 191; https://doi.org/10.3390/jcs6070191 - 01 Jul 2022

Cited by 14 | Viewed by 2233

Abstract

Construction and demolition waste (CDW) is the third-most abundant waste generated annually in the countries of the European Union. One of the alternatives to the use of these wastes is geopolymeric materials. Partial replacement of commonly used raw materials for the production of [...] Read more.

Construction and demolition waste (CDW) is the third-most abundant waste generated annually in the countries of the European Union. One of the alternatives to the use of these wastes is geopolymeric materials. Partial replacement of commonly used raw materials for the production of these materials can help reduce the number of landfills and the consumption of natural resources. In this study, the authors partially replaced metakaolin and fly ash with clay bricks and concrete debris. The research method in article is connected with analysis of microstructures and the mechanical and physical properties of the geopolymers. The results obtained show the possibility of manufacturing useful construction materials based on industrial byproducts (fly ash) and CDW. Compressive strength and flexural strength were, for samples containing metakaolin, 20.1 MPa and 5.3 MPa, respectively. Geopolymers containing fly ash displayed 19.7 MPa of compressive strength and 3.0 MPa of flexural strength. The results for both synthesized materials give them perspectives for future applications in the construction industry. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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9 pages, 3594 KiB

Open AccessCommunication

Synthesis and Characterization of Novel Fe₃O₄/PVA/Eggshell Hybrid Nanocomposite for Photodegradation and Antibacterial Activity

by Piyush Kumar Gupta, Senthilkumar Palanisamy, Tamilarasi Gopal, Ranjithkumar Rajamani, Soumya Pandit, Somya Sinha and Vijay Kumar Thakur

J. Compos. Sci. 2021, 5(10), 267; https://doi.org/10.3390/jcs5100267 - 12 Oct 2021

Cited by 9 | Viewed by 2449

Abstract

In the 21st century, hybrid nanocomposites were widely used in bioelectronic, biosensing, photocatalytic, and biomedical applications. In the present study, we fabricated a novel Fe₃O₄/PVA/Eggshell hybrid nanocomposite and physicochemically characterized it using powder XRD, EDS, FTIR, VSM, and HR-TEM [...] Read more.

In the 21st century, hybrid nanocomposites were widely used in bioelectronic, biosensing, photocatalytic, and biomedical applications. In the present study, we fabricated a novel Fe₃O₄/PVA/Eggshell hybrid nanocomposite and physicochemically characterized it using powder XRD, EDS, FTIR, VSM, and HR-TEM analysis. The XRD spectrum revealed the crystalline and FCC configuration of Fe₃O₄ NPs with average crystal size of 16.28 nm, and the HRTEM image indicates the prepared hybrid nanocomposite is of spherical shape with less agglomeration. This hybrid nanocomposite showed a significant photodegradation property in degrading organic pollutants such as congo red and crystal violet dyes under the sunlight irradiation. In addition, the hybrid nanocomposite also displayed a potent antibacterial property against different Gram +ve and Gram −ve bacterial pathogens. This study provides a significant example in the overview of fabrication of cost effectively, eco-friendly, and multiple-application hybrid nanocomposites through eggshell membrane fibers. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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Review

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19 pages, 3352 KiB

Open AccessReview

Shape Memory Polymeric Materials for Biomedical Applications: An Update

by Dinesh Rokaya, Hans Erling Skallevold, Viritpon Srimaneepong, Anand Marya, Pravin Kumar Shah, Zohaib Khurshid, Muhammad Sohail Zafar and Janak Sapkota

J. Compos. Sci. 2023, 7(1), 24; https://doi.org/10.3390/jcs7010024 - 10 Jan 2023

Cited by 12 | Viewed by 4919

Abstract

Shape memory polymers (SMPs) are emerging smart materials that have the ability to change to a shape and revert to their permanent shape on application of external stimulus. SMPs can be divided into four types based on their permanent shape, elasticity origin, and [...] Read more.

Shape memory polymers (SMPs) are emerging smart materials that have the ability to change to a shape and revert to their permanent shape on application of external stimulus. SMPs can be divided into four types based on their permanent shape, elasticity origin, and temporary shape fixing mechanism: chemically cross-linked glassy thermosets, chemically cross-linked semi-crystalline, physically cross-linked glassy copolymers, and physically cross-linked block copolymers. The broad overview of recent developments on SMPs for biomedical applications proves their wide applicability in the field of general medicine, drug delivery, regenerative medicine, dentistry, neuromedicine, cancer therapy, orthopedics, and corrosion protection. Herein, a comprehensive analysis of SMPs and their composites with focus on their types, mechanism, functionality and biomedical applications is presented. Relevant biomedical technologies based on SMPs and their future advancement towards biomedical applications are also discussed. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume II)

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