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2 pages, 179 KiB

Open AccessEditorial

Special Issue on “Tailoring Polymeric Materials for Specific Applications”

by Katherine M. E. Stewart

Processes 2022, 10(8), 1508; https://doi.org/10.3390/pr10081508 - 1 Aug 2022

Viewed by 1269

Abstract

Polymers are a vast class of materials that are highly tailorable to a wide variety of applications and can be modified in numerous ways [...] Full article

(This article belongs to the Special Issue Tailoring Polymeric Materials for Specific Applications)

Research

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11 pages, 2910 KiB

Open AccessFeature PaperArticle

Innovative Polymer Microspheres with Chloride Groups Synthesis, Characterization and Application for Dye Removal

by Monika Wawrzkiewicz and Beata Podkościelna

Processes 2022, 10(8), 1568; https://doi.org/10.3390/pr10081568 - 10 Aug 2022

Cited by 7 | Viewed by 1435

Abstract

This article presents the synthesis and sorption characteristics of novel microspheres based on 4-vinylbenzene chloride (VBCl) with divinylbenzene (DVB) or ethylene glycol dimethylacrylate (EGDMA). To confirm the chemical structure of the homo- and co-polymers attenuated total reflectance, Fourier transform infrared spectroscopy (ATR-FTIR) was [...] Read more.

This article presents the synthesis and sorption characteristics of novel microspheres based on 4-vinylbenzene chloride (VBCl) with divinylbenzene (DVB) or ethylene glycol dimethylacrylate (EGDMA). To confirm the chemical structure of the homo- and co-polymers attenuated total reflectance, Fourier transform infrared spectroscopy (ATR-FTIR) was used. The presence of characteristic functional groups (−OH, −CH, −CH₂, C−O, C=O and C–O–C) in obtained microspheres was confirmed. Differential scanning calorimetry (DSC) analysis confirms the good thermal resistance of the polymers. The decomposition of microspheres is closely related to the chemical structure of the monomers used. DVB-derived materials decompose in one step, whereas the decomposition of EGDMA derivatives is multi-stage. Obtained polymeric microspheres were applied for auramine O (AO) basic dye removal form aqueous solutions. Equilibrium studies confirmed that the Freundlich model described the system better than Langmuir or Temkin equations and the adsorption capacities k_F ranged from 4.56 to 7.85 mg^1−1/n L^1/n/g. The sorption kinetic of AO from solutions of the 10 and 100 mg/L concentrations was very fast, and after 10 min, equilibrium was reached. Full article

(This article belongs to the Special Issue Tailoring Polymeric Materials for Specific Applications)

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13 pages, 40396 KiB

Open AccessArticle

Evaluation of the Thermal and Morphological Properties of γ-Irradiated Chitosan-Glycerol-Based Polymeric Films

by Waheed A. Al-Masry, Sajjad Haider, Asif Mahmood, Mujeeb Khan, Syed Farooq Adil and Mohammed Rafiq H. Siddiqui

Processes 2021, 9(10), 1783; https://doi.org/10.3390/pr9101783 - 7 Oct 2021

Cited by 11 | Viewed by 1997

Abstract

Industry-sponsored research has intensified to find suitable substitutes for synthetic polymers. For this purpose, biopolymers are promising materials that are extracted from renewable resources. However, there are areas of concern (biopolymers are mostly brittle in the dry state) that require further research before [...] Read more.

Industry-sponsored research has intensified to find suitable substitutes for synthetic polymers. For this purpose, biopolymers are promising materials that are extracted from renewable resources. However, there are areas of concern (biopolymers are mostly brittle in the dry state) that require further research before they are used in advanced applications. To overcome this, plasticizers are often added to biopolymers to enhance their physicochemical properties. In this study, chitosan (CH)-glycerol (GL)-based polymeric films were prepared by a simple drop-casting technique, and the influence of a plasticizer (GL) on the properties of chitosan films was analyzed. Additionally, the as-prepared samples were irradiated with γ-rays (⁶⁰Co γ rays with a dose of 10² kGy) to study the effect of γ-irradiation on the properties of polymeric composites. To achieve this, different samples were prepared by varying the amount of GL. FT-IR analysis revealed the interruption of hydrogen bonding in chitosan by the incorporation of GL. This led to the chain-spreading of CH, which ultimately increased the flexibility of the composite films (CH-GL). The DSC of the CH film showed two peaks: one endothermic peak below 100 °C (due to water vapor) and a second exothermic peak that appeared between 130 and 360 °C (degradation of the amino group). Plasticization of CH films with GL was confirmed by DSC, where the exothermic degradation was converted into an endothermic peak. Depending upon the amount of GL, γ-irradiation considerably affected the chemical structure of CH by breaking the carbohydrate and pyranose rings; this led to a decrease in the crystallinity of the composite films. The changes studied in the DSC and TGA analysis complemented each other. γ-irradiation also affected the morphology of the films, which changed from smooth and homogeneous to roasted structures, with random swelling on the surface of the films. This swelling reflected the degradation of the surfaces into thin layers. Considering the changes that occurred in the films post-γ-irradiation, it can be inferred that the irradiation dose of 10² kGy is sufficient to degrade as-prepared biopolymer composites. Full article

(This article belongs to the Special Issue Tailoring Polymeric Materials for Specific Applications)

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11 pages, 1882 KiB

Open AccessArticle

Universal Chain-End Coupling Conditions for Brominated Polystyrenes, Polyacrylates, and Polymethacrylates

by Joseph J. Andry, Jaenic J. Lee, Jessica Wu, Katherine Xia and Eric S. Tillman

Processes 2021, 9(6), 1001; https://doi.org/10.3390/pr9061001 - 5 Jun 2021

Cited by 3 | Viewed by 3165

Abstract

Atom transfer radical coupling (ATRC), performed with or without radical traps, has allowed for high extents of coupling (X_c) for a variety of brominated polymers, yet structurally different polymeric chain ends require unique reagents and reaction conditions. Inspired by a similar [...] Read more.

Atom transfer radical coupling (ATRC), performed with or without radical traps, has allowed for high extents of coupling (X_c) for a variety of brominated polymers, yet structurally different polymeric chain ends require unique reagents and reaction conditions. Inspired by a similar study that focused on universal conditions for the controlled polymerization of different monomers using atom transfer radical polymerization (ATRP), this work focuses on developing a single set of conditions (or conditions with as little variation as possible) that will achieve extents of coupling greater than 80% or end-brominated chains of polystyrene (PSBr), poly(methyl methacrylate) (PMMABr), and poly(methyl acrylate) (PMABr). The radical traps α-phenyl-tert-butylnitrone (PBN), 2-methyl-2-nitrosopropane (MNP), and nitrosobenzene (NBz) were chosen in this study, along with copper catalysts, reducing agents, and nitrogen-based ligands. Ultimately, a single set of effective reaction conditions was identified with the only difference being the radical trap used: MNP was effective for coupling PSBr and PMABr while NBz was necessary to achieve similarly high extents of coupling for PMMABr. Full article

(This article belongs to the Special Issue Tailoring Polymeric Materials for Specific Applications)

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15 pages, 2878 KiB

Open AccessArticle

Partially Reduced Graphene Oxide Modified with Polyacrylonitrile for the Removal of Sm³⁺ from Water

by Khadijah Mohammedsaleh Katubi, Fatimah Mohammed Alzahrani, Norah Salem Alsaiari, Abdelfattah Amari, Faouzi Ben Rebah and Mohamed A Tahoon

Processes 2021, 9(5), 818; https://doi.org/10.3390/pr9050818 - 8 May 2021

Cited by 4 | Viewed by 2400

Abstract

An in situ emulsion polymerization method was used for the synthesis of polyacrylonitrile nanoparticles amino-functionalized partially reduced graphene oxide (PAN-PRGO). After that, hydrolyzed polyacrylonitrile nanoparticles amino-functionalized partially reduced graphene oxide (HPAN-PRGO) nanocomposite was achieved by the modification of nitrile groups of the composite [...] Read more.

An in situ emulsion polymerization method was used for the synthesis of polyacrylonitrile nanoparticles amino-functionalized partially reduced graphene oxide (PAN-PRGO). After that, hydrolyzed polyacrylonitrile nanoparticles amino-functionalized partially reduced graphene oxide (HPAN-PRGO) nanocomposite was achieved by the modification of nitrile groups of the composite polymer chains to carboxylic groups, aminoethylene diamine, and amidoxime functional groups through partial hydrolysis using a basic solution of sodium hydroxide for 20 min. Different synthesized materials were characterized and compared using well-known techniques including transmission electron microscope (TEM), scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FT-IR), Raman spectra, and X-ray diffraction (XRD). The nanocomposite was structured through the interaction between acrylonitrile’s (AN) nitrile groups and amino-functionalized graphene oxide nanosheets’ amino groups to successfully graft polyacrylonitrile over the surface of functionalized nanosheets as approved by characterization techniques. The synthesized composite was examined for the removal of samarium ions (Sm³⁺) from water. Different experimental conditions including pH, contact time, initial concentration, and adsorbent dose were investigated to determine the optimum conditions for the metal capture from water. The optimum conditions were found to be a contact time of 15 min, pH 6, and 0.01 g of adsorbent dosage. The experimental results found, in a good agreement with the Langmuir isotherm model, the maximum adsorption capacity of Sm³⁺ uptake was equal to 357 mg/g. A regeneration and reusability study of synthesized composite up to six cycles indicated the ability to use HPAN-PRGO nanocomposite several times for Sm³⁺ uptake. The obtained results prove that this polymer-based composite is a promising adsorbent for water treatment that must be studied for additional pollutants removal in the future. Full article

(This article belongs to the Special Issue Tailoring Polymeric Materials for Specific Applications)

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10 pages, 2899 KiB

Open AccessArticle

Study of Surface Mechanical Characteristics of ABS/PC Blends Using Nanoindentation

by Saira Bano, Tanveer Iqbal, Naveed Ramzan and Ujala Farooq

Processes 2021, 9(4), 637; https://doi.org/10.3390/pr9040637 - 6 Apr 2021

Cited by 29 | Viewed by 6619

Abstract

Acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) are considered a well-known class of engineering thermoplastics due to their efficient use in automotive, 3D printing, and electronics. However, improvement in toughness, processability, and thermal stability is achieved by mixing together ABS and PC. The [...] Read more.

Acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) are considered a well-known class of engineering thermoplastics due to their efficient use in automotive, 3D printing, and electronics. However, improvement in toughness, processability, and thermal stability is achieved by mixing together ABS and PC. The present study focuses on the understanding of surface mechanical characterization of acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) blends using nano-indentation. Polymer blends sheets with three different proportions of ABS/PC (75:25, 50:50, and 25:75) were fabricated via melt-processing and thermal press. Fourier transform infrared (FTIR) spectroscopy was performed to analyze the intermolecular interactions between the blends’ components. To understand the surface mechanical properties of ABS and PC blends, a sufficient number of nano-indentation tests were performed at a constant loading rate to a maximum load of 100 mN. Creeping effects were observed at the end of loading and start of unloading section. Elastic modulus, indentation hardness, and creep values were measured as a function of penetration displacement in the quasi-continuous stiffness mode (QCSM) indentation. Load-displacement curves indicated an increase in the displacement with the increase in ABS contents while a decreasing trend was observed in the hardness and elastic modulus values as the ABS content was increased. We believe this study would provide an effective pathway for developing new polymer blends with enhanced mechanical performance. Full article

(This article belongs to the Special Issue Tailoring Polymeric Materials for Specific Applications)

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12 pages, 2595 KiB

Open AccessArticle

Study of the Physical and Mechanical Properties of Thermoplastic Starch/Poly(Lactic Acid) Blends Modified with Acid Agents

by Carolina Caicedo and Heidy Lorena Calambás Pulgarin

Processes 2021, 9(4), 578; https://doi.org/10.3390/pr9040578 - 26 Mar 2021

Cited by 15 | Viewed by 3971

Abstract

In this work, we present a functionalization strategy of starch-poly(lactic acid) (PLA) blends with organic acids. Lactic and acetic acid were used as acid agents, and oleic acid was also included in the previous acids, with the aim of finding a synergy that [...] Read more.

In this work, we present a functionalization strategy of starch-poly(lactic acid) (PLA) blends with organic acids. Lactic and acetic acid were used as acid agents, and oleic acid was also included in the previous acids, with the aim of finding a synergy that thermodynamically benefits the products and provides hydrophobicity. The ratio of starch and sorbitol was 70:30, and the added acid agent replaced 6% of the plasticizer; meanwhile, the thermoplastic starch (TPS)–PLA blend proportion was 70:30 considering the modified TPS. The mixtures were obtained in a torque rheometer at 50 rpm for 10 min at 150 °C. The organic acids facilitated interactions between TPS and PLA. Although TPS and PLA are not miscible, PLA uniformly dispersed into the starch matrix. Furthermore, a reduction in the surface polarity was achieved, which enabled the wettability to reach values close to those of neat PLA (TPS–L-PLA increased by 55% compared to TPS–PLA). The rheological results showed a modulus similar to that of TPS. In general, there were transitions from elastic to viscous, in which the viscous phase predominated. The first and second-order thermal transitions did not show significant changes. The structural affinity of lactic acid with biopolymers (TPS–L-PLA) allowed a greater interaction and was corroborated with the mechanical properties, resulting in a greater resistance with respect to pure TPS and blended TPS–PLA (28.9%). These results are particularly relevant for the packaging industry. Full article

(This article belongs to the Special Issue Tailoring Polymeric Materials for Specific Applications)

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15 pages, 1935 KiB

Open AccessArticle

Innovative Magnetite Based Polymeric Nanocomposite for Simultaneous Removal of Methyl Orange and Hexavalent Chromium from Water

by Norah Salem Alsaiari, Abdelfattah Amari, Khadijah Mohammedsaleh Katubi, Fatimah Mohammed Alzahrani, Faouzi Ben Rebah and Mohamed A. Tahoon

Processes 2021, 9(4), 576; https://doi.org/10.3390/pr9040576 - 26 Mar 2021

Cited by 37 | Viewed by 3070

Abstract

One of the most important directions for environmental remediation is the effective removal of dyes and toxic heavy metals from water using newly fabricated nanoadsorbents. Here, magnetic Fe₃O₄ nanoparticles were combined with nitrogen-containing functional group polymers chitosan (CS) and polypyrrole [...] Read more.

One of the most important directions for environmental remediation is the effective removal of dyes and toxic heavy metals from water using newly fabricated nanoadsorbents. Here, magnetic Fe₃O₄ nanoparticles were combined with nitrogen-containing functional group polymers chitosan (CS) and polypyrrole (ppy) to synthesize a nanocomposite (polypyrrole@magnetic chitosan) useful for removing methyl orange (MO) and hexavalent chromium (Cr (VI)) from water. The physicochemical properties of the nanocomposite were determined using SEM, TEM, XRD, FT–IR, and TGA techniques. The effect of different factors on the adsorption system was studied including the contact time, pH, and the effect of co-existed ions. The kinetic study illustrated that the adsorption fit well with Langmuir isotherm. The maximum adsorption capacity of MO and Cr (VI) was found to be 95 and 105 mg/g, respectively. The reusability of the nanocomposite was studied for up to five cycles using 0.1 M NaOH as eluent with a slight decrease of adsorbent efficiency. Furthermore, the removal mechanism studied suggested the removal of MO via adsorption and Cr (VI) via chemical reduction and adsorption. This study suggests that a ppy@magnetic chitosan nanocomposite is a promising nanoadsorbent for removing MO and Cr (VI) from water. Full article

(This article belongs to the Special Issue Tailoring Polymeric Materials for Specific Applications)

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22 pages, 10836 KiB

Open AccessFeature PaperArticle

Theoretical Evaluation of the Melting Efficiency for the Single-Screw Micro-Extrusion Process: The Case of 3D Printing of ABS

by Andrea La Gala, Rudinei Fiorio, Mustafa Erkoç, Ludwig Cardon and Dagmar R. D’hooge

Processes 2020, 8(11), 1522; https://doi.org/10.3390/pr8111522 - 23 Nov 2020

Cited by 31 | Viewed by 5009

Abstract

One of the challenges for single-screw micro-extrusion or additive manufacturing (AM), thus 3D printing, of polymers is controlling the melting efficiency so that energy and equipment costs can be minimized. Here, a numerical model is presented for AM process design, selecting acrylonitrile–butadiene–styrene (ABS) [...] Read more.

One of the challenges for single-screw micro-extrusion or additive manufacturing (AM), thus 3D printing, of polymers is controlling the melting efficiency so that energy and equipment costs can be minimized. Here, a numerical model is presented for AM process design, selecting acrylonitrile–butadiene–styrene (ABS) as viscoelastic reference polymer. It is demonstrated that AM melting is different compared to conventional melting due to variation in extrusion dimensions, leading to a different balance in heating by conduction and viscous heat dissipation as caused by the shearing between the melt layers in the associated film layer near the barrel. The thickness of this melt film layer is variable along the screw length, and it is shown that simplified models assuming an overall average value are too approximate. It is highlighted that the screw frequency, pitch angle and compression ratio are important process parameters to control the point of melt finalization. In addition, the power-law index reflecting the shear thinning nature of the polymer melt is showcased as a key parameter. Moreover, AM process results assuming constant and temperature dependent specific heat capacities and thermal conductivities are compared. The current work opens the door for on-line AM process control, addressing all relevant operating and material parameters. Full article

(This article belongs to the Special Issue Tailoring Polymeric Materials for Specific Applications)

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Review

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16 pages, 694 KiB

Open AccessReview

Aloe vera as Promising Material for Water Treatment: A Review

by Khadijah Mohammedsaleh Katubi, Abdelfattah Amari, Hamed N. Harharah, Moutaz M. Eldirderi, Mohamed A. Tahoon and Faouzi Ben Rebah

Processes 2021, 9(5), 782; https://doi.org/10.3390/pr9050782 - 29 Apr 2021

Cited by 29 | Viewed by 15755

Abstract

Aloe vera plant offers a sustainable solution for the removal of various pollutants from water. Due to its chemical composition, Aloe vera has been explored as coagulant/flocculant and biosorbent for water treatment. Most of the used materials displayed significant pollutants removals depending on [...] Read more.

Aloe vera plant offers a sustainable solution for the removal of various pollutants from water. Due to its chemical composition, Aloe vera has been explored as coagulant/flocculant and biosorbent for water treatment. Most of the used materials displayed significant pollutants removals depending on the used preparation methods. AV-based materials have been investigated and successfully used as coagulant/flocculant for water treatment at laboratory scale. Selected AV-based materials could reduce the solids (total suspended solids (TSS), suspended solids (SS), total dissolved solids (TDS), and dissolved solids (DS)), turbidity, chemical oxygen demand (COD), biochemical oxygen demand (BOD), heavy metals, and color, with removal percentages varied depending on the coagulant/flocculant materials and on the wastewater characteristics. In the same context, AV materials can be used as biological flocculant for wastewater sludge treatment, allowing good solid–liquid separation and promoting sludge settling. Moreover, using different methods, AV material-based biosorbents were prepared and successfully used for pollutants (heavy metal dyes and phenol) elimination from water. Related results showed significant pollutant removal efficiency associated with an interesting adsorption capacity comparable to other biosorbents derived from natural products. Interestingly, the enzymatic system of Aloe vera (carboxypeptidase, glutathione peroxidase, and superoxide dismutase) has been exploited to degrade textile dyes. The obtained results showed high promise for removal efficiencies of various kinds of pollutants. However, results varied depending on the methodology used to prepare the Aloe vera based materials. Because of its valuable properties (composition, abundance, ecofriendly and biodegradable), Aloe vera may be useful for water treatment. Full article

(This article belongs to the Special Issue Tailoring Polymeric Materials for Specific Applications)

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17 pages, 1064 KiB

Open AccessReview

A Succinct Review on the PVDF/Imidazolium-Based Ionic Liquid Blends and Composites: Preparations, Properties, and Applications

by Ahmad Adlie Shamsuri, Rusli Daik and Siti Nurul Ain Md. Jamil

Processes 2021, 9(5), 761; https://doi.org/10.3390/pr9050761 - 27 Apr 2021

Cited by 25 | Viewed by 4952

Abstract

Poly(vinylidene fluoride) (PVDF) is a versatile thermoplastic fluoropolymer with intriguing characteristics, which is receiving considerable attention from researchers in many areas. Recently, PVDF and its copolymer, such as poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) have been blended with ionic liquids to produce blend and composite materials [...] Read more.

Poly(vinylidene fluoride) (PVDF) is a versatile thermoplastic fluoropolymer with intriguing characteristics, which is receiving considerable attention from researchers in many areas. Recently, PVDF and its copolymer, such as poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) have been blended with ionic liquids to produce blend and composite materials for target applications. In this succinct review, two types of ionic liquids that are utilized for the preparation of PVDF and PVDF-HFP blends and composites, namely, hydrophilic and hydrophobic imidazolium-based ionic liquids, are reviewed. In addition, the effect of the ionic liquids on the physicochemical properties of the PVDF and PVDF-HFP blends and composites, is described as well. On top of that, a multitude of applications of the blends and composites are also succinctly reviewed. This review may give inspirations to the polymer blend and composite researchers in diversifying the applications of thermoplastic fluoropolymers through the utilization of ionic liquids. Full article

(This article belongs to the Special Issue Tailoring Polymeric Materials for Specific Applications)

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