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13 pages, 6254 KiB

Open AccessArticle

Structural and Optical Characterizations of Polymethyl Methacrylate Films with the Incorporation of Ultrafine SiO₂/TiO₂ Composites Utilized as Self-Cleaning Surfaces

by Maneerat Songpanit, Kanokthip Boonyarattanakalin, Saksorn Limwichean, Tossaporn Lertvanithphol, Mati Horprathum, Wisanu Pecharapa and Wanichaya Mekprasart

Polymers 2023, 15(15), 3162; https://doi.org/10.3390/polym15153162 - 25 Jul 2023

Cited by 1 | Viewed by 1137

Abstract

The structural and optical characterizations of nanocomposite films of polymethyl methacrylate (PMMA) and SiO₂/TiO₂ composites prepared via the spin-coating technique were investigated using different SiO₂:TiO₂ ratios. The SiO₂/TiO₂ nanocomposites were synthesized using the sonochemical [...] Read more.

The structural and optical characterizations of nanocomposite films of polymethyl methacrylate (PMMA) and SiO₂/TiO₂ composites prepared via the spin-coating technique were investigated using different SiO₂:TiO₂ ratios. The SiO₂/TiO₂ nanocomposites were synthesized using the sonochemical process with Si:Ti precursor ratios of 1:0.1, 1:0.5, 1:1, 1:2, 1:4, and 0:1. All characterizations of ultrafine SiO₂/TiO₂ particles were loaded at 1 wt.% in a PMMA matrix for the fabrication of transparent SiO₂/TiO₂/PMMA composite films. The phase structure and morphology of SiO₂/TiO₂/PMMA composite films were monitored using X-ray diffraction, optical microscopy, and field-emission scanning electron microscopy. A surface roughness analysis of SiO₂/TiO₂/PMMA nanocomposite films was conducted using atomic force microscopy. For optical characterization, transmission properties with different incident angles of SiO₂/TiO₂/PMMA composite films were analyzed with UV-vis spectrophotometry. The water contact angles of SiO₂/TiO₂/PMMA composite films were analyzed to identify hydrophilic properties on film surfaces. Photocatalytic reactions in SiO₂TiO₂ composite films under UV irradiation were evaluated using rhodamine B dye degradation. The optimal condition of SiO₂/TiO₂/PMMA nanocomposite films was obtained at a 1:1 SiO₂:TiO₂ ratio in self-cleaning applications, resulting from good particle dispersion and the presence of the TiO₂ phase in the composite. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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16 pages, 4194 KiB

Open AccessArticle

Fabrication, Structural Properties, and Electrical Characterization of Polymer Nanocomposite Materials for Dielectric Applications

by Ali Atta, Mohammed F. Alotiby, Nuha Al-Harbi, Mohamed R. El-Aassar, Mohamed A. M. Uosif and Mohamed Rabia

Polymers 2023, 15(14), 3067; https://doi.org/10.3390/polym15143067 - 17 Jul 2023

Viewed by 1059

Abstract

This research paper aims to fabricate flexible PVA/Cs/TiO₂ nanocomposite films consisting of polyvinyl alcohol (PVA), chitosan (Cs), and titanium oxide (TiO₂) for application in energy storage devices. The samples were analyzed using X-ray diffraction (XRD), atomic force microscope (AFM), scanning [...] Read more.

This research paper aims to fabricate flexible PVA/Cs/TiO₂ nanocomposite films consisting of polyvinyl alcohol (PVA), chitosan (Cs), and titanium oxide (TiO₂) for application in energy storage devices. The samples were analyzed using X-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and energy dispersive X-ray (EDX) techniques. The impact of TiO₂ on the electrical impedance, conductivity, permittivity, and energy efficiency of the PVA/Cs was determined in a frequency range of 100 Hz to 5 GHz. The XRD, FTIR, and EDX results showed the successful fabrications of the PVA/Cs/TiO₂. The SEM and AFM images illustrated that the TiO₂ was loaded and distributed homogenously in PVA/Cs chains. In addition, the electrical conductivity was enhanced from 0.04 × 10⁻⁷ S.cm⁻¹ of PVA/Cs to 0.25 × 10⁻⁷ S.cm⁻¹ and 5.75 × 10⁻⁷ S.cm⁻¹, respectively, for the composite PVA/Cs/0.01TiO₂ and PVA/Cs/0.1TiO₂, and the dielectric constant grew from 2.46 for PVA/Cs to 7.38 and 11.93, respectively. These results revealed that modifications were made to the produced films, paving the way for using the composite PVA/Cs/TiO₂ films in different energy applications, such as electronic circuits and supercapacitors. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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15 pages, 1861 KiB

Open AccessArticle

Preparation and Application of Active Bionanocomposite Films Based on Sago Starch Reinforced with a Combination of TiO₂ Nanoparticles and Penganum harmala Extract for Preserving Chicken Fillets

by Alireza Bagher Abiri, Homa Baghaei and Abdorreza Mohammadi Nafchi

Polymers 2023, 15(13), 2889; https://doi.org/10.3390/polym15132889 - 29 Jun 2023

Cited by 7 | Viewed by 990

Abstract

The aim of this study was to develop sago starch-based bionanocomposite films containing TiO₂ nanoparticles and Penganum harmala extract (PE) to increase the shelf life of chicken fillets. First, sago starch films containing different levels of TiO₂ nanoparticles (1, 3, and [...] Read more.

The aim of this study was to develop sago starch-based bionanocomposite films containing TiO₂ nanoparticles and Penganum harmala extract (PE) to increase the shelf life of chicken fillets. First, sago starch films containing different levels of TiO₂ nanoparticles (1, 3, and 5%) and PE (5, 10, and 15%) were prepared. The barrier properties and antibacterial activity of the films against different bacteria strains were investigated. Then, the produced films were used for the chicken fillets packaging, and the physicochemical and antimicrobial properties of fillets were estimated during 12-day storage at 4 °C. The results showed that the addition of nano TiO₂ and PE in the films increased the antibacterial activity against gram-positive (S. aureus) higher than gram-negative (E. coli) bacteria. The water vapor permeability of the films decreased from 2.9 to 1.26 (×10⁻¹¹ g/m·s·Pa) by incorporating both PE and nano TiO₂. Synergistic effects of PE and nano TiO₂ significantly decreased the oxygen permeability of the sago starch films from 8.17 to 4.44 (cc.mil/m²·day). Application results of bionanocomposite films for chicken fillet storage at 4 °C for 12 days demonstrated that the films have great potential to increase the shelf life of fillets. The total volatile basic nitrogen (TVB-N) of chicken fillets increased from 7.34 to 35.28 after 12 days, whereas samples coated with bionanocomposite films increased from 7.34 to 16.4. For other physicochemical and microbiological properties of chicken fillets, similar improvement was observed during cold storage. It means that the bionanocomposite films could successfully improve the shelf life of the chicken fillets by at least eight days compared to the control sample. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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12 pages, 2846 KiB

Open AccessArticle

Enhancing Hydrophobicity and Oxygen Barrier of Xylan/PVOH Composite Film by 1,2,3,4-Butane Tetracarboxylic Acid Crosslinking

by Guoshuai Liu, Kang Shi, Hui Sun, Biao Yang and Yunxuan Weng

Polymers 2023, 15(13), 2811; https://doi.org/10.3390/polym15132811 - 25 Jun 2023

Cited by 2 | Viewed by 955

Abstract

Hemicellulose has potential advantages in food packaging because of its abundant reserves, degradability and regeneration. However, compared with fossil-derived plastic films, hemicellulose-based films show inferior hydrophobicity and barrier properties because of their low degree of polymerization and strong hydrophilicity. Focusing on such issues, [...] Read more.

Hemicellulose has potential advantages in food packaging because of its abundant reserves, degradability and regeneration. However, compared with fossil-derived plastic films, hemicellulose-based films show inferior hydrophobicity and barrier properties because of their low degree of polymerization and strong hydrophilicity. Focusing on such issues, this work covers the modification of a xylan/polyvinyl alcohol (PVOH) film using 1,2,3,4-butane tetracarboxylic acid (BTCA) as esterifying agent. The thus prepared composite film was more compact owing to the esterification reaction with xylan and PVOH forming a crosslinked network structure and reducing the distance between molecular chains. The results showed that BTCA had a positive effect on the oxygen barrier, hydrophobicity and mechanical properties of the composite film. The tensile strength of the xylan/PVOH composite film with 10% BTCA content increased from 11.19 MPa to 13.99 MPa. A 20% BTCA loading resulted in an increase in the contact angle of the composite film from 87.1° to 108.2°, and a decrease in the oxygen permeability from 2.11 to 0.43 (cm³·µm)/(m²·d·kPa), corresponding to increase in the contact angle by 24% and a decrease in oxygen permeability by 80%. The overall performance enhancement indicates the potential application of such composites as food packaging. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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18 pages, 16547 KiB

Open AccessArticle

Biodegradable Cellulose/Polycaprolactone/Keratin/Calcium Carbonate Mulch Films Prepared in Imidazolium-Based Ionic Liquid

by Dušica Stojanović, Aleksandra Ivanovska, Nemanja Barać, Katarina Dimić-Misić, Mirjana Kostić, Vesna Radojević, Djordje Janaćković, Petar Uskoković, Ernest Barceló and Patrick Gane

Polymers 2023, 15(12), 2729; https://doi.org/10.3390/polym15122729 - 18 Jun 2023

Cited by 1 | Viewed by 1983

Abstract

Ionic liquid 1-butyl-3-methylimidazolium chloride [BMIM][Cl] was used to prepare cellulose (CELL), cellulose/polycaprolactone (CELL/PCL), cellulose/polycaprolactone/keratin (CELL/PCL/KER), and cellulose/polycaprolactone/keratin/ground calcium carbonate (CELL/PCL/KER/GCC) biodegradable mulch films. Attenuated Total Reflectance Fourier-Transform Infrared (ATR-FTIR) spectroscopy, optical microscopy, and Field-Emission Scanning Electron Microscopy (FE-SEM) were used to verify the [...] Read more.

Ionic liquid 1-butyl-3-methylimidazolium chloride [BMIM][Cl] was used to prepare cellulose (CELL), cellulose/polycaprolactone (CELL/PCL), cellulose/polycaprolactone/keratin (CELL/PCL/KER), and cellulose/polycaprolactone/keratin/ground calcium carbonate (CELL/PCL/KER/GCC) biodegradable mulch films. Attenuated Total Reflectance Fourier-Transform Infrared (ATR-FTIR) spectroscopy, optical microscopy, and Field-Emission Scanning Electron Microscopy (FE-SEM) were used to verify the films’ surface chemistry and morphology. Mulch film made of only cellulose regenerated from ionic liquid solution exhibited the highest tensile strength (75.3 ± 2.1 MPa) and modulus of elasticity of 944.4 ± 2.0 MPa. Among samples containing PCL, CELL/PCL/KER/GCC is characterized by the highest tensile strength (15.8 ± 0.4 MPa) and modulus of elasticity (687.5 ± 16.6 MPa). The film’s breaking strain decreased for all samples containing PCL upon the addition of KER and KER/GCC. The melting temperature of pure PCL is 62.3 °C, whereas that of CELL/PCL film has a slight tendency for melting point depression (61.0 °C), which is a characteristic of partially miscible polymer blends. Furthermore, Differential Scanning Calorimetry (DSC) analysis revealed that the addition of KER or KER/GCC to CELL/PCL films resulted in an increment in melting temperature from 61.0 to 62.6 and 68.9 °C and an improvement in sample crystallinity by 2.2 and 3.0 times, respectively. The light transmittance of all studied samples was greater than 60%. The reported method for mulch film preparation is green and recyclable ([BMIM][Cl] can be recovered), and the inclusion of KER derived by extraction from waste chicken feathers enables conversion to organic biofertilizer. The findings of this study contribute to sustainable agriculture by providing nutrients that enhance the growth rate of plants, and hence food production, while reducing environmental pressure. The addition of GCC furthermore provides a source of Ca²⁺ for plant micronutrition and a supplementary control of soil pH. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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10 pages, 1091 KiB

Open AccessArticle

Development of a Water Transmission Rate (WTR) Measurement System for Implantable Barrier Coatings

by Sébastien Buchwalder, Cléo Nicolier, Mario Hersberger, Florian Bourgeois, Andreas Hogg and Jürgen Burger

Polymers 2023, 15(11), 2557; https://doi.org/10.3390/polym15112557 - 01 Jun 2023

Cited by 1 | Viewed by 1420

Abstract

While water vapor transmission rate (WVTR) measurement is standardly used to assess material permeability, a system able to quantify liquid water transmission rate (WTR) measurement is highly desirable for implantable thin film barrier coatings. Indeed, since implantable devices are in contact or immersed [...] Read more.

While water vapor transmission rate (WVTR) measurement is standardly used to assess material permeability, a system able to quantify liquid water transmission rate (WTR) measurement is highly desirable for implantable thin film barrier coatings. Indeed, since implantable devices are in contact or immersed in body fluids, liquid WTR was carried out to obtain a more realistic measurement of the barrier performance. Parylene is a well-established polymer which is often the material of choice for biomedical encapsulation applications due to its flexibility, biocompatibility, and attractive barrier properties. Four grades of parylene coatings were tested with a newly developed permeation measurement system based on a quadrupole mass spectrometer (QMS) detection method. Successful measurements of gas and water vapor and the water transmission rates of thin parylene films were performed and validated, comparing the results with a standardized method. In addition, the WTR results allowed for the extraction of an acceleration transmission rate factor from the vapor-to-liquid water measurement mode, which varies from 4 to 4.8 between WVTR and WTR. With a WTR of 72.5 µm g m⁻² day⁻¹, parylene C displayed the most effective barrier performance. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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12 pages, 7719 KiB

Open AccessArticle

Excellent Energy Storage Performance in Epoxy Resin Dielectric Polymer Films by a Facile Hot−Pressing Method

by Zhe Pan, Minmin Mao, Bin Zhang, Zhongyu Li, Kaixin Song, Hai-Feng Li, Zhu Mao and Dawei Wang

Polymers 2023, 15(10), 2315; https://doi.org/10.3390/polym15102315 - 15 May 2023

Cited by 3 | Viewed by 1380

Abstract

Epoxy resin (EP), as a kind of dielectric polymer, exhibits the advantages of low-curing shrinkage, high-insulating properties, and good thermal/chemical stability, which is widely used in electronic and electrical industry. However, the complicated preparation process of EP has limited their practical applications for [...] Read more.

Epoxy resin (EP), as a kind of dielectric polymer, exhibits the advantages of low-curing shrinkage, high-insulating properties, and good thermal/chemical stability, which is widely used in electronic and electrical industry. However, the complicated preparation process of EP has limited their practical applications for energy storage. In this manuscript, bisphenol F epoxy resin (EPF) was successfully fabricated into polymer films with a thickness of 10~15 μm by a facile hot−pressing method. It was found that the curing degree of EPF was significantly affected by changing the ratio of EP monomer/curing agent, which led to the improvement in breakdown strength and energy storage performance. In particular, a high discharged energy density (U_d) of 6.5 J·cm⁻³ and efficiency (η) of 86% under an electric field of 600 MV·m⁻¹ were obtained for the EPF film with an EP monomer/curing agent ratio of 1:1.5 by hot pressing at 130 °C, which indicates that the hot−pressing method could be facilely employed to produce high−quality EP films with excellent energy storage performance for pulse power capacitors. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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19 pages, 2962 KiB

Open AccessArticle

Preparation and Evaluation of Caffeine Orodispersible Films: The Influence of Hydrotropic Substances and Film-Forming Agent Concentration on Film Properties

by Robert-Alexandru Vlad, Andrada Pintea, Mădălina Coaicea, Paula Antonoaea, Emőke Margit Rédai, Nicoleta Todoran and Adriana Ciurba

Polymers 2023, 15(9), 2034; https://doi.org/10.3390/polym15092034 - 25 Apr 2023

Cited by 1 | Viewed by 1848

Abstract

This study aimed to develop caffeine (CAF) orodispersible films (ODFs) and verify the effects of different percentages of film-forming agent and hydrotropic substances (citric acid—CA or sodium benzoate—SB) on various film properties. Hydroxypropyl methylcellulose E 5 (HPMC E 5) orodispersible films were prepared [...] Read more.

This study aimed to develop caffeine (CAF) orodispersible films (ODFs) and verify the effects of different percentages of film-forming agent and hydrotropic substances (citric acid—CA or sodium benzoate—SB) on various film properties. Hydroxypropyl methylcellulose E 5 (HPMC E 5) orodispersible films were prepared using the solvent casting method. Four CAF-ODF formulations were prepared and coded as CAF1 (8% HPMC E 5, CAF), CAF2 (8% HPMC E 5 and CAF:CA–1:1), CAF3 (9% HPMC E 5 and CAF:CA–1:1), and CAF4 (9% HPMC E 5 and CAF:SB–1:1). The CAF-ODFs were evaluated in terms of disintegration time, folding endurance, thickness, uniformity of mass, CAF content, thickness-normalized tensile strength, adhesiveness, dissolution, and pH. Thin, opaque, and slightly white CAF-ODFs were obtained. All the formulations developed exhibited disintegration times less than 3 min. The dissolution test revealed that CAF1, CAF2, and CAF3 exhibited concentrations of active pharmaceutical ingredients (APIs) released at 30 min that were close to 100%, whilst CAF4 showed a faster dissolution behaviour (100% of the CAF was released at 5 min). Thin polymeric films containing 10 mg of CAF/surface area (3.14 cm²) were prepared. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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12 pages, 2051 KiB

Open AccessArticle

Thermal Behavior of Poly(vinyl alcohol) in the Form of Physically Crosslinked Film

by Costas Tsioptsias, Dimitrios Fardis, Xanthi Ntampou, Ioannis Tsivintzelis and Costas Panayiotou

Polymers 2023, 15(8), 1843; https://doi.org/10.3390/polym15081843 - 11 Apr 2023

Cited by 4 | Viewed by 2707

Abstract

Evaluation and understanding of the thermal behavior of polymers is crucial for many applications, e.g., polymer processing at relatively high temperatures, and for evaluating polymer-polymer miscibility. In this study, the differences in the thermal behavior of poly(vinyl alcohol) (PVA) raw powder and physically [...] Read more.

Evaluation and understanding of the thermal behavior of polymers is crucial for many applications, e.g., polymer processing at relatively high temperatures, and for evaluating polymer-polymer miscibility. In this study, the differences in the thermal behavior of poly(vinyl alcohol) (PVA) raw powder and physically crosslinked films were investigated using various methods, such as thermogravimetric analysis (TGA) and derivative TGA (DTGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Various strategies were adopted, e.g., film casting from PVA solutions in H₂O and D₂O and heating of samples at carefully selected temperatures, in order to provide insights about the structure-properties relationship. It was found that the physically crosslinked PVA film presents an increased number of hydrogen bonds and increased thermal stability/slower decomposition rate compared to the PVA raw powder. This is also depicted in the estimated values of specific heat of thermochemical transition. The first thermochemical transition (glass transition) of PVA film, as for the raw powder, overlaps with mass loss from multiple origins. Evidence for minor decomposition that occurs along with impurities removal is presented. The overlapping of various effects (softening, decomposition, and evaporation of impurities) has led to confusion and apparent consistencies, e.g., from the XRD, it is derived that the film has decreased crystallinity, and apparently this is in agreement with the lower value of heat of fusion. However, the heat of fusion in this particular case has a questionable meaning. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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19 pages, 3445 KiB

Open AccessArticle

Understanding the Effect of Triazole on Crosslinked PPO–SEBS-Based Anion Exchange Membranes for Water Electrolysis

by Jiyong Choi, Kyungwhan Min, Yong-Hwan Mo, Sang-Beom Han and Tae-Hyun Kim

Polymers 2023, 15(7), 1736; https://doi.org/10.3390/polym15071736 - 31 Mar 2023

Cited by 5 | Viewed by 2089

Abstract

For anion exchange membrane water electrolysis (AEMWE), two types of anion exchange membranes (AEMs) containing crosslinked poly(phenylene oxide) (PPO) and poly(styrene ethylene butylene styrene) (SEBS) were prepared with and without triazole. The impact of triazole was carefully examined. In this work, the PPO [...] Read more.

For anion exchange membrane water electrolysis (AEMWE), two types of anion exchange membranes (AEMs) containing crosslinked poly(phenylene oxide) (PPO) and poly(styrene ethylene butylene styrene) (SEBS) were prepared with and without triazole. The impact of triazole was carefully examined. In this work, the PPO was crosslinked with the non-aryl ether-type SEBS to take advantage of its enhanced chemical stability and phase separation under alkaline conditions. Compared to their triazole-free counterpart, the crosslinked membranes made with triazole had better hydroxide-ion conductivity because of the increased phase separation, which was confirmed by X-ray diffraction (XRD) and atomic force microscopy (AFM). Moreover, they displayed improved mechanical and alkaline stability. Under water electrolysis (WE) conditions, a triazole-containing crosslinked PPO–SEBS membrane electrode assembly (MEA) was created using IrO₂ as the anode and a Pt/C catalyst as the cathode. This MEA displayed a current density of 0.7 A/cm² at 1.8 V, which was higher than that of the MEA created with the triazole-free counterpart. Our study indicated that the crosslinked PPO–SEBS membrane containing triazoles had improved chemo-physical and electrical capabilities for WE because of the strong hydrogen bonding between triazole and water/OH⁻. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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21 pages, 10594 KiB

Open AccessArticle

Effect of the Addition of Polyacrylic Acid of Different Molecular Weights to Coagulation Bath on the Structure and Performance of Polysulfone Ultrafiltration Membranes

by Tatiana Plisko, Katsiaryna Burts, Anastasia Penkova, Mariia Dmitrenko, Anna Kuzminova, Sergey Ermakov and Alexandr Bildyukevich

Polymers 2023, 15(7), 1664; https://doi.org/10.3390/polym15071664 - 27 Mar 2023

Cited by 1 | Viewed by 1577

Abstract

Membrane fouling is a serious issue in membrane technology which cannot be completely avoided but can be diminished. The perspective technique of membrane modification is the introduction of hydrophilic polymers or polyelectrolytes into the coagulation bath during membrane preparation via non-solvent-induced phase separation. [...] Read more.

Membrane fouling is a serious issue in membrane technology which cannot be completely avoided but can be diminished. The perspective technique of membrane modification is the introduction of hydrophilic polymers or polyelectrolytes into the coagulation bath during membrane preparation via non-solvent-induced phase separation. The influence of polyacrylic acid (PAA) molecular weight (100,000, 250,000 and 450,000 g·mol⁻¹) added to the aqueous coagulation bath (0.4–2.0 wt.%) on the polysulfone membrane structure, surface roughness, water contact angle and zeta potential of the selective layer, as well as the separation and antifouling performance, was systematically studied. It was found that membranes obtained via the addition of PAA with higher molecular weight feature smaller pore size and porosity, extremely high hydrophilicity and higher values of negative charge of membrane surface. It was shown that the increase in PAA concentration from 0.4 wt.% to 2.0 wt.% for all studied PAA molecular weights yielded a substantial decrease in water contact angle compared with the reference membrane (65 ± 2°) (from 27 ± 2° to 17 ± 2° for PAA with M_n = 100,000 g·mol⁻¹; from 25 ± 2° to 16 ± 2° for PAA with M_n = 250,000 g·mol⁻¹; and from 19 ± 2° to 10 ± 2° for PAA with M_n = 450,000 g·mol⁻¹). An increase in PAA molecular weight from 100,000 to 450,000 g·mol⁻¹ led to a decrease in membrane permeability, an increase in rejection and tailoring excellent antifouling performance in the ultrafiltration of humic acid solutions. The fouling recovery ratio increased from 73% for the reference membrane up to 91%, 100% and 136% for membranes modified with the addition to the coagulation bath of 1.5 wt.% of PAA with molecular weights of 100,000 g·mol⁻¹, 250,000 g·mol⁻¹ and 450,000 g·mol⁻¹, respectively. Overall, the addition of PAA of different molecular weights to the coagulation bath is an efficient tool to adjust membrane separation and antifouling properties for different separation tasks. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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18 pages, 12793 KiB

Open AccessArticle

Characterization of Composite Film of Gelatin and Squid Pen Chitosan Obtained by High Hydrostatic Pressure

by Ya-Ling Huang and Da-Ming Wang

Polymers 2023, 15(7), 1608; https://doi.org/10.3390/polym15071608 - 23 Mar 2023

Cited by 2 | Viewed by 1339

Abstract

In the present study, gelatin-based films incorporating squid pen chitosan obtained by high hydrostatic pressure (HHP chitosan) at varying proportions were prepared and their properties were compared with films containing untreated chitosan. The resulting films were characterized by analyzing the physical, morphological, mechanical [...] Read more.

In the present study, gelatin-based films incorporating squid pen chitosan obtained by high hydrostatic pressure (HHP chitosan) at varying proportions were prepared and their properties were compared with films containing untreated chitosan. The resulting films were characterized by analyzing the physical, morphological, mechanical and barrier properties. The addition of different ratios of HHP chitosan to the gelatin-based film yielded significant improvements in mechanical and moisture barrier properties. The reason for this might be that HHP chitosan contributed to a regular and dense microstructure of the composite films due to forming a three-dimensional network structure in gelatin-based films with enhanced intermolecular interactions. The FTIR spectra showed no new chemical bond formed by incorporating HHP chitosan into gelatin-based film. The SEM micrographs showed that the gelatin-based film fabricated with three types of chitosan had a homogeneous surface morphology, indicating good compatibility of the materials. Compared to the gelatin-based films containing untreated chitosan, films containing HHP chitosan significantly delayed oxidative deterioration in oil during storage. Therefore, the chitosan obtained by HHP treatment could have a potential application in edible gelatin-based films as packaging materials. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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12 pages, 2440 KiB

Open AccessArticle

Salt Transport in Crosslinked Hydrogel Membranes Containing Zwitterionic Sulfobetaine Methacrylate and Hydrophobic Phenyl Acrylate

by Yi-hung Lin, Jung Min Kim and Bryan S. Beckingham

Polymers 2023, 15(6), 1387; https://doi.org/10.3390/polym15061387 - 10 Mar 2023

Cited by 2 | Viewed by 3088

Abstract

Produced water is a by-product of industrial operations, such as hydraulic fracturing for increased oil recovery, that causes environmental issues since it includes different metal ions (e.g., Li⁺, K⁺, Ni²⁺, Mg²⁺, etc.) that need to [...] Read more.

Produced water is a by-product of industrial operations, such as hydraulic fracturing for increased oil recovery, that causes environmental issues since it includes different metal ions (e.g., Li⁺, K⁺, Ni²⁺, Mg²⁺, etc.) that need to be extracted or collected before disposal. To remove these substances using either selective transport behavior or absorption-swing processes employing membrane-bound ligands, membrane separation procedures are promising unit operations. This study investigates the transport of a series of salts in crosslinked polymer membranes synthesized using a hydrophobic monomer (phenyl acrylate, PA), a zwitterionic hydrophilic monomer (sulfobetaine methacrylate, SBMA), and a crosslinker (methylenebisacrylamide, MBAA). Membranes are characterized according to their thermomechanical properties, where an increased SBMA content leads to decreased water uptake due to structural differences within the films and to more ionic interactions between the ammonium and sulfonate moieties, resulting in a decreased water volume fraction, and Young’s modulus increases with increasing MBAA or PA content. Permeabilities, solubilities, and diffusivities of membranes to LiCl, NaCl, KCl, CaCl₂, MgCl₂, and NiCl₂ are determined by diffusion cell experiments, sorption-desorption experiments, and the solution-diffusion relationship, respectively. Permeability to these metal ions generally decreases with an increasing SBMA content or MBAA content due to the corresponding decreasing water volume fraction, and the permeabilities are in the order of K⁺ > Na⁺ > Li⁺ > Ni²⁺ > Ca²⁺ > Mg²⁺ presumably due to the differences in the hydration diameter. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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25 pages, 3002 KiB

Open AccessArticle

Nanofiltration Mixed Matrix Membranes from Cellulose Modified with Zn-Based Metal–Organic Frameworks for the Enhanced Water Treatment from Heavy Metal Ions

by Mariia Dmitrenko, Anna Kuzminova, Andrey Zolotarev, Artem Selyutin, Sergey Ermakov and Anastasia Penkova

Polymers 2023, 15(6), 1341; https://doi.org/10.3390/polym15061341 - 07 Mar 2023

Cited by 6 | Viewed by 2162

Abstract

Nowadays, nanofiltration is actively used for water softening and disinfection, pre-treatment, nitrate, and color removal, in particular, for heavy metal ions removal from wastewater. In this regard, new, effective materials are required. In the present work, novel sustainable porous membranes from cellulose acetate [...] Read more.

Nowadays, nanofiltration is actively used for water softening and disinfection, pre-treatment, nitrate, and color removal, in particular, for heavy metal ions removal from wastewater. In this regard, new, effective materials are required. In the present work, novel sustainable porous membranes from cellulose acetate (CA) and supported membranes consisting of CA porous substrate with a thin dense selective layer from carboxymethyl cellulose (CMC) modified with first-time synthesized Zn-based metal–organic frameworks (Zn(SEB), Zn(BDC)Si, Zn(BIM)) were developed to increase the efficiency of nanofiltration for the removal of heavy metal ions. Zn-based MOFs were characterized by sorption measurements, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The obtained membranes were studied by the spectroscopic (FTIR), standard porosimetry and microscopic (SEM and AFM) methods, and contact angle measurement. The CA porous support was compared with other, prepared in the present work, porous substrates from poly(m-phenylene isophthalamide) and polyacrylonitrile. Membrane performance was tested in the nanofiltration of the model and real mixtures containing heavy metal ions. The improvement of the transport properties of the developed membranes was achieved through Zn-based MOF modification due to their porous structure, hydrophilic properties, and different particle shapes. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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11 pages, 2243 KiB

Open AccessArticle

Copolymerization of Parylene C and Parylene F to Enhance Adhesion and Thermal Stability without Coating Performance Degradation

by Han Xu, Zhou Yang, Yechang Guo, Qingmei Xu, Songtao Dou, Pan Zhang, Yufeng Jin, Jiajie Kang and Wei Wang

Polymers 2023, 15(5), 1249; https://doi.org/10.3390/polym15051249 - 28 Feb 2023

Cited by 1 | Viewed by 1946

Abstract

Parylene C has been widely used in the fields of microelectromechanical systems (MEMS) and electronic device encapsulation because of its unique properties, such as biocompatibility and conformal coverage. However, its poor adhesion and low thermal stability limit its use in a wider range [...] Read more.

Parylene C has been widely used in the fields of microelectromechanical systems (MEMS) and electronic device encapsulation because of its unique properties, such as biocompatibility and conformal coverage. However, its poor adhesion and low thermal stability limit its use in a wider range of applications. This study proposes a novel method for improving the thermal stability and enhancing the adhesion between Parylene and Si by copolymerizing Parylene C with Parylene F. The successful preparation of Parylene copolymer films containing different ratios of Parylene C and Parylene F was confirmed using Fourier-transform infrared spectroscopy and surface energy calculations. The proposed method resulted in the copolymer film having an adhesion 10.4 times stronger than that of the Parylene C homopolymer film. Furthermore, the friction coefficients and cell culture capability of the Parylene copolymer films were tested. The results indicated no degradation compared with the Parylene C homopolymer film. This copolymerization method significantly expands the applications of Parylene materials. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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15 pages, 3000 KiB

Open AccessArticle

An Imidazolium-Based Ionic Liquid as a Model to Study Plasticization Effects on Cationic Polymethacrylate Films

by Thashree Marimuthu, Zainul Sidat, Pradeep Kumar and Yahya E. Choonara

Polymers 2023, 15(5), 1239; https://doi.org/10.3390/polym15051239 - 28 Feb 2023

Cited by 2 | Viewed by 1249

Abstract

Ionic liquids (ILs) have been touted as effective and environmentally friendly agents, which has driven their application in the biomedical field. The study compares the effectiveness of an IL agent, 1-hexyl-3-methyl imidazolium chloride ([HMIM]Cl), to current industry standards for plasticizing a methacrylate polymer. [...] Read more.

Ionic liquids (ILs) have been touted as effective and environmentally friendly agents, which has driven their application in the biomedical field. The study compares the effectiveness of an IL agent, 1-hexyl-3-methyl imidazolium chloride ([HMIM]Cl), to current industry standards for plasticizing a methacrylate polymer. Industrial standards glycerol, dioctyl phthalate (DOP) and the combination of [HMIM]Cl with a standard plasticizer was also evaluated. Plasticized samples were evaluated for stress–strain, long-term degradation, thermophysical characterizations, and molecular vibrational changes within the structure, and molecular mechanics simulations were performed. Physico-mechanical studies showed that [HMIM]Cl was a comparatively good plasticizer than current standards reaching effectiveness at 20–30% w/w, whereas plasticizing of standards such as glycerol was still inferior to [HMIM]Cl even at concentrations up to 50% w/w. Degradation studies show HMIM-polymer combinations remained plasticized for longer than other test samples, >14 days, compared to glycerol <5 days, while remaining more pliable. The combination of [HMIM]Cl-DOP was effective at concentrations >30% w/w, demonstrating remarkable plasticizing capability and long-term stability. ILs used as singular agents or in tandem with other standards provided equivalent or better plasticizing activity than the comparative free standards. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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14 pages, 3797 KiB

Open AccessArticle

Dopamine-Assisted Modification of Polypropylene Film to Attain Hydrophilic Mineral-Rich Surfaces

by Alenka Ojstršek, Angela Chemelli, Azra Osmić and Selestina Gorgieva

Polymers 2023, 15(4), 902; https://doi.org/10.3390/polym15040902 - 11 Feb 2023

Viewed by 1639

Abstract

The presented study focuses on the modification of polypropylene (PP) film with tetraethyl orthosilicate (TEOS) under heterogeneous conditions via polydopamine/polyethylene imine (PDA/PEI) chemistry using a facile dip-coating procedure to attain hydrophilic mineral-rich surfaces. Thus, the resulting PP-based films were further immersed in ion-rich [...] Read more.

The presented study focuses on the modification of polypropylene (PP) film with tetraethyl orthosilicate (TEOS) under heterogeneous conditions via polydopamine/polyethylene imine (PDA/PEI) chemistry using a facile dip-coating procedure to attain hydrophilic mineral-rich surfaces. Thus, the resulting PP-based films were further immersed in ion-rich simulated body fluid (SBF) to deposit Ca-based minerals onto the film’s surfaces efficiently. In addition, the chemical reaction mechanism on PP film was proposed, and mineralisation potential inspected by determination of functional groups of deposits, zeta potential, hydrophilicity and surface morphology/topography using Fourier transform infrared (FTIR) spectroscopy, streaming potential, water contact angle (WCA), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The obtained results show the improved wettability of samples on account of PDA inclusion (WCA was reduced from 103° for pure PP film to 28° for PDA-modified film), as well as the presence of functional groups, due to the PDA/PEI/TEOS surface functionalisation, increased the ability of minerals to nucleate on the PP film’s surface when it was exposed to an SBF medium. Moreover, the higher surface roughness due to the silica coatings influenced the enhanced anchoring and attachment of calcium phosphate (CaP), revealing the potential of such a facile approach to modify the chemically inert PP films, being of particular interest in different fields, including regenerative medicine. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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15 pages, 9559 KiB

Open AccessArticle

Functional Properties of Nonwovens as an Insulating Layer for Protective Gloves

by Dunja Šajn Gorjanc

Polymers 2023, 15(3), 785; https://doi.org/10.3390/polym15030785 - 03 Feb 2023

Viewed by 1344

Abstract

The basic intention of the present work is to analyze the influence of the incorporated microporous membrane and the technology of the needling process on the functional properties of nonwovens designed as an insulating layer for protective gloves for protection against high temperatures. [...] Read more.

The basic intention of the present work is to analyze the influence of the incorporated microporous membrane and the technology of the needling process on the functional properties of nonwovens designed as an insulating layer for protective gloves for protection against high temperatures. The investigated nonwovens are produced in carded nonwoven formation and mechanically bonded with needle bonding. The studied nonwovens contain a microporous membrane of polyester (PES) with a thickness of 20 µm (samples marked as ST and STL). In the theoretical part of the research work, the nonwovens and some technology stages are presented. The experimental part of the present work deals with the mechanical properties: breaking stress and strain, viscoelastic properties (yield strength, elastic modulus) and elastic recovery after cyclic loading and thermal conduction. In the experimental part, permeability properties (water vapor permeability, air permeability) are also analyzed. The results of the investigation show that the samples marked as ST and STL, which contain a microporous PES membrane, have a higher breaking stress than the samples marked as T and TL without the microporous PES membrane. Samples marked as ST and STL also exhibit higher values of elongation at break and limit of recoverable deformation (stress and strain at yield) and a lower modulus of elasticity than samples marked as T and TL. The samples marked as ST and STL are mechanically bonded to the lamellar plate using forked needles and therefore have a textured (ribbed) shape that affects the improved mechanical properties. The TL and STL samples, which contain a microporous PES membrane, have higher elastic recovery and lower air permeability than the T and TL samples, while water vapor permeability is lower only for the ST sample. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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21 pages, 5448 KiB

Open AccessArticle

Potential Applications of Thermoresponsive Poly(N-Isoproplacrylamide)-Grafted Nylon Membranes: Effect of Grafting Yield and Architecture on Gating Performance

by Todsapol Kajornprai, Putita Katesripongsa, Sang Yong Nam, Zuratul Ain Abdul Hamid, Yupaporn Ruksakulpiwat, Nitinat Suppakarn and Tatiya Trongsatitkul

Polymers 2023, 15(3), 497; https://doi.org/10.3390/polym15030497 - 18 Jan 2023

Cited by 4 | Viewed by 1381

Abstract

This study illustrated the potential applications of thermoresponsive poly(N-isopropylacrylamide) (PNIPAm) grafted nylon membranes with different grafting yields and grafting architecture. The thermoresponsive gating performance at temperatures below and above the lower critical solution temperature (LCST) of PNIPAm (32 °C) were demonstrated. [...] Read more.

This study illustrated the potential applications of thermoresponsive poly(N-isopropylacrylamide) (PNIPAm) grafted nylon membranes with different grafting yields and grafting architecture. The thermoresponsive gating performance at temperatures below and above the lower critical solution temperature (LCST) of PNIPAm (32 °C) were demonstrated. The linear PNIPAm-grafted nylon membrane exhibited a sharp response over the temperature range 20–40 °C. The grafting yield of 25.5% and 21.9%, for linear and crosslinked PNIPAm respectively, exhibited highest thermoresponsive gating function for water flux and had a stable and repeatable “open-closed” switching function over 5 cycle operations. An excellent oil/water separation was obtained at T < 32 °C, at which the hydrophilic behavior was observed. The linear PNIPAm-grafted nylon membrane with 35% grafting yield had the highest separation efficiency of 99.7%, while PNIPAm structures were found to be independent of the separation efficiency. In addition, the membranes with thermoresponsive gas permeability were successfully achieved. The O₂ and CO₂ transmission rates through the PNIPAm-grafted nylon membranes decreased when the grafting yield increased, showing the better gas barrier property. The permeability ratio of CO₂ to O₂ transmission rates of both PNIPAm architectures at 25 °C and 35 °C were around 0.85 for low grafting yields, and approximately 1 for high grafting yields. Ultimately, this study demonstrated the possibility of using these thermoresponsive smart membranes in various applications. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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14 pages, 2703 KiB

Open AccessArticle

The Effect of Thermal Annealing on the Structure and Gas Transport Properties of Poly(1-Trimethylsilyl-1-Propyne) Films with the Addition of Phenolic Antioxidants

by Anton Kossov, Vladimir Makrushin, Ivan Levin and Samira Matson

Polymers 2023, 15(2), 286; https://doi.org/10.3390/polym15020286 - 05 Jan 2023

Cited by 2 | Viewed by 1301

Abstract

The thermally activated relaxation of poly(1-trimethylsilyl-1-propyne) (PTMSP) samples of various cis-/trans-compositions (50–80% units of cis-configuration) in the presence of phenolic antioxidants of various structures was investigated. It was pointed out that polymers with a high content of cis-units [...] Read more.

The thermally activated relaxation of poly(1-trimethylsilyl-1-propyne) (PTMSP) samples of various cis-/trans-compositions (50–80% units of cis-configuration) in the presence of phenolic antioxidants of various structures was investigated. It was pointed out that polymers with a high content of cis-units exhibited greater thermal-oxidative stability due to the greater flexibility of the cis-enriched macrochains. The use of hindered phenols as antioxidants made it possible to prevent the process of thermally initiated oxidative degradation. At the same time, the most effective stabilizing agents were antioxidants with larger molecules such as Vulkanox BKF, Irganox 1010, and Irganox 1076. It was shown that the permeability coefficients of stabilized PTMSP during thermal treatment initially slightly decreased (by 20–30%), which, according to the X-ray diffraction data, was associated with an increase in the density of the macrochain packing, and during further heating remained practically unchanged. Note that for the cis-enriched samples, no signs of oxidation or decrease in the transport characteristics were observed during polymer heating for 240 h at 140 °C. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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28 pages, 6816 KiB

Open AccessReview

The Difference in Performance and Compatibility between Crystalline and Amorphous Fillers in Mixed Matrix Membranes for Gas Separation (MMMs)

by Mariolino Carta, Ariana R. Antonangelo, Johannes Carolus Jansen and Mariagiulia Longo

Polymers 2023, 15(13), 2951; https://doi.org/10.3390/polym15132951 - 05 Jul 2023

Cited by 5 | Viewed by 1544

Abstract

An increasing number of high-performing gas separation membranes is reported almost on a daily basis, yet only a few of them have reached commercialisation while the rest are still considered pure research outcomes. This is often attributable to a rapid change in the [...] Read more.

An increasing number of high-performing gas separation membranes is reported almost on a daily basis, yet only a few of them have reached commercialisation while the rest are still considered pure research outcomes. This is often attributable to a rapid change in the performance of these separation systems over a relatively short time. A common approach to address this issue is the development of mixed matrix membranes (MMMs). These hybrid systems typically utilise either crystalline or amorphous additives, so-called fillers, which are incorporated into polymeric membranes at different loadings, with the aim to improve and stabilise the final gas separation performance. After a general introduction to the most relevant models to describe the transport properties in MMMs, this review intends to investigate and discuss the main advantages and disadvantages derived from the inclusion of fillers of different morphologies. Particular emphasis will be given to the study of the compatibility at the interface between the filler and the matrix created by the two different classes of additives, the inorganic and crystalline fillers vs. their organic and amorphous counterparts. It will conclude with a brief summary of the main findings. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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19 pages, 1986 KiB

Open AccessReview

Research Progress in Hemicellulose-Based Nanocomposite Film as Food Packaging

by Guoshuai Liu, Kang Shi and Hui Sun

Polymers 2023, 15(4), 979; https://doi.org/10.3390/polym15040979 - 16 Feb 2023

Cited by 7 | Viewed by 2639

Abstract

As the main component of agricultural and forestry biomass, hemicellulose has the advantages of having an abundant source, biodegradability, nontoxicity and good biocompatibility. Its application in food packaging has thus become the focus of efficient utilization of biomass resources. However, due to its [...] Read more.

As the main component of agricultural and forestry biomass, hemicellulose has the advantages of having an abundant source, biodegradability, nontoxicity and good biocompatibility. Its application in food packaging has thus become the focus of efficient utilization of biomass resources. However, due to its special molecular structure and physical and chemical characteristics, the mechanical properties and barrier properties of hemicellulose films are not sufficient, and modification for performance enhancement is still a challenge. In the field of food packaging materials preparation, modification of hemicellulose through blending with nanofibers or nanoparticles, both inorganic and organic, has attracted research attention because this approach offers the advantages of efficient improvement in the expected properties and better cost efficiency. In this paper, the composition of hemicellulose, the classification of nanofillers and the research status of hemicellulose-based nanocomposite films are reviewed. The research progress in modification of hemicellulose by using layered silicate, inorganic nanoparticles and organic nanoparticles in food packaging is described. Challenges and outlook of research in hemicellulose-based nanocomposite film in food packaging is discussed. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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49 pages, 7884 KiB

Open AccessReview

Advanced Polymeric Nanocomposite Membranes for Water and Wastewater Treatment: A Comprehensive Review

by Abhispa Sahu, Raghav Dosi, Carly Kwiatkowski, Stephen Schmal and Jordan C. Poler

Polymers 2023, 15(3), 540; https://doi.org/10.3390/polym15030540 - 20 Jan 2023

Cited by 23 | Viewed by 4397

Abstract

Nanomaterials have been extensively used in polymer nanocomposite membranes due to the inclusion of unique features that enhance water and wastewater treatment performance. Compared to the pristine membranes, the incorporation of nanomodifiers not only improves membrane performance (water permeability, salt rejection, contaminant removal, [...] Read more.

Nanomaterials have been extensively used in polymer nanocomposite membranes due to the inclusion of unique features that enhance water and wastewater treatment performance. Compared to the pristine membranes, the incorporation of nanomodifiers not only improves membrane performance (water permeability, salt rejection, contaminant removal, selectivity), but also the intrinsic properties (hydrophilicity, porosity, antifouling properties, antimicrobial properties, mechanical, thermal, and chemical stability) of these membranes. This review focuses on applications of different types of nanomaterials: zero-dimensional (metal/metal oxide nanoparticles), one-dimensional (carbon nanotubes), two-dimensional (graphene and associated structures), and three-dimensional (zeolites and associated frameworks) nanomaterials combined with polymers towards novel polymeric nanocomposites for water and wastewater treatment applications. This review will show that combinations of nanomaterials and polymers impart enhanced features into the pristine membrane; however, the underlying issues associated with the modification processes and environmental impact of these membranes are less obvious. This review also highlights the utility of computational methods toward understanding the structural and functional properties of the membranes. Here, we highlight the fabrication methods, advantages, challenges, environmental impact, and future scope of these advanced polymeric nanocomposite membrane based systems for water and wastewater treatment applications. Full article

(This article belongs to the Special Issue Feature Papers in Polymer Membranes and Films II)

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