Status and Progress of Soluble Polymers

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Chemistry".

Deadline for manuscript submissions: closed (5 March 2023) | Viewed by 21484

Special Issue Editors


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Guest Editor
Departamento de Ingeniería Química, Facultad de Ingeniería, Universidad de Concepción, Victor Lamas, Concepción 4030000, Chile
Interests: molecular dynamics; polymers; polyelectrolytes; adsorption; clays
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Guest Editor
Departamento de Ingeniería Química y Procesos de Minerales, Facultad de Ingeniería, Universidad de Antofagasta, Av. Angamos 601, Antofagasta 1240000, Chile
Interests: flocculation; rheology; froth flotation; colloids
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Polymers play an important role in various applied areas, including mining processing, the food industry, and paper. Its great importance lies mainly in its linear structure, and the ability to modify this structure under different operational conditions. Such characteristics allow polymers to be added at low doses and thus significantly change the properties of complex systems. This is due to their interaction with the medium or, in other words, their solubility. Therefore, it is necessary to study the chemical and electronic nature of polymers. First, the functional groups that constitute it can generate flexibility or rigidity of the main chain. If these functional groups also have an explicit electrical charge, they can respond to pH or salt. Knowing the structure and its behavior in the environment allows us to predict its effects at the macroscopic level and understand the phenomena that occur in real processes (at an industrial scale). For example, in flocculation processes, it is relevant that the polymers cover a large area and can also adhere to charged particles. It is necessary to generate a good electrostatic attraction between the polymers and the dispersed particles in the medium in wastewater treatment.

Due to these aspects, it is then relevant to determine the characteristics that ultimately influence macroscopic properties that are applicable to a process of interest from an atomic point of view. This Special Issue aims to contribute to the understanding of polymers on a molecular scale and the design and optimization of polymers dedicated to an application.

Dr. Gonzalo R. Quezada
Dr. Ricardo Ivan Jeldres
Guest Editors

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Keywords

  • linear and branched structure
  • polysaccharide and organic polymers
  • simulation (molecular, ab initio, and coarse grained)
  • pH-responsive polymers
  • ndustrial application

Published Papers (10 papers)

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Research

17 pages, 4034 KiB  
Article
Methods and Characteristics of Drug Extraction from Ion-Exchange-Resin-Mediated Preparations: Influences, Thermodynamics, and Kinetics
by Junlin Yuan, Conghui Li, Shanshan Wang, Hui Zhang, Zengming Wang, Aiping Zheng and Xiuli Gao
Polymers 2023, 15(5), 1191; https://doi.org/10.3390/polym15051191 - 27 Feb 2023
Cited by 1 | Viewed by 2152
Abstract
Since the discovery of ion-exchange resins, they have been used in many fields, including pharmacy. Ion-exchange resin-mediated preparations can realize a series of functions, such as taste masking and regulating release. However, it is very difficult to extract the drug completely from the [...] Read more.
Since the discovery of ion-exchange resins, they have been used in many fields, including pharmacy. Ion-exchange resin-mediated preparations can realize a series of functions, such as taste masking and regulating release. However, it is very difficult to extract the drug completely from the drug–resin complex because of the specific combination of the drug and resin. In this study, methylphenidate hydrochloride extended-release chewable tablets compounded by methylphenidate hydrochloride and ion-exchange resin were selected for a drug extraction study. The efficiency of drug extraction by dissociating with the addition of counterions was found to be higher than other physical extraction methods. Then, the factors affecting the dissociation process were studied to completely extract the drug from the methylphenidate hydrochloride extended-release chewable tablets. Furthermore, the thermodynamic and kinetic study of the dissociation process showed that the dissociation process obeys the second-order kinetic process, and it is nonspontaneous, entropy-decreasing, and endothermic. Meanwhile, the reaction rate was confirmed by the Boyd model, and the film diffusion and matrix diffusion were both shown to be rate-limiting steps. In conclusion, this study aims to provide technological and theoretical support for establishing a quality assessment and control system of ion-exchange resin-mediated preparations, promoting the applications of ion-exchange resins in the field of drug preparation. Full article
(This article belongs to the Special Issue Status and Progress of Soluble Polymers)
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16 pages, 5475 KiB  
Article
Compressive Yield Stress of Flocculated Kaolin Suspensions in Seawater
by Steven Nieto, Eder Piceros, Pedro G. Toledo, Pedro Robles and Ricardo Jeldres
Polymers 2023, 15(3), 530; https://doi.org/10.3390/polym15030530 - 19 Jan 2023
Cited by 2 | Viewed by 1634
Abstract
The mining industry has resorted to using seawater while trying to find a solution to the water shortage, which is severe in some regions. Today, the industry looks to tailings dams to recover more water and, thus, increase recirculation. The migration of interstitial [...] Read more.
The mining industry has resorted to using seawater while trying to find a solution to the water shortage, which is severe in some regions. Today, the industry looks to tailings dams to recover more water and, thus, increase recirculation. The migration of interstitial water due to the consolidation of particle networks can give rise to large water mirrors in different dam areas. These pools can contain enough water to be recovered and recirculated if the external stress caused by the weight of the pulp exceeds the compressive yield stress. The density and rheological properties of the discarded pulps determine the feasibility of water expulsion during tailings consolidation. As these conditions are largely established in the thickening stage, it is necessary to revisit operations, looking at the dam as a water source. Thus, a thorough understanding of the compressive properties that determine the level of consolidation of typical pulps and their relationships to aggregate properties, such as size and fractal dimension, is crucial. Here, the effect of two types of water, industrial water and synthetic seawater, on kaolin flocculation, sedimentation rate, yield stress, and compressive yield stress were studied. In addition, the relationship of these properties with the flocculant dose and the resulting aggregate size and fractal dimension was examined. One promising finding to practitioners was that salt and small doses of high molecular weight flocculant improved the consolidation of kaolin slurries under compression. These conditions generated low compressive yield stress compared to fresh water and water with low salt content, favoring the consolidation of the pulps and the release of water. Full article
(This article belongs to the Special Issue Status and Progress of Soluble Polymers)
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10 pages, 2466 KiB  
Article
Tumor-Targeting Polymer–Drug Conjugate for Liver Cancer Treatment In Vitro
by Jiankun Xu, Shanmeng Lin, Hao Hu, Qi Xing and Jin Geng
Polymers 2022, 14(21), 4515; https://doi.org/10.3390/polym14214515 - 25 Oct 2022
Cited by 1 | Viewed by 1676
Abstract
Bufalin (buf) has poor solubility in aqueous solution, poor tumor targeting, and many non-specific toxic and side effects. The advantages of high-molecular-weight polymer conjugates are that they can improve the water solubility of buf, prolong plasma half-life, and reduce non-specific toxicity. A novel [...] Read more.
Bufalin (buf) has poor solubility in aqueous solution, poor tumor targeting, and many non-specific toxic and side effects. The advantages of high-molecular-weight polymer conjugates are that they can improve the water solubility of buf, prolong plasma half-life, and reduce non-specific toxicity. A novel water-soluble polymer–drug conjugate with buf and fluorescein pendants was prepared by the combination of reversible addition-fragmentation transfer (RAFT) polymerization and click chemistry. Its anticancer performance and cellular uptake behavior against liver cancer were investigated in vitro. The polymer–buf conjugates exhibit controlled release and tumor-targeting capabilities, showing promise for clinical applications. Full article
(This article belongs to the Special Issue Status and Progress of Soluble Polymers)
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9 pages, 2259 KiB  
Article
A Facile Synthesis of Cellulose Nanofibers from Corn Cob and Rice Straw by Acid Hydrolysis Method
by Madhuri Rajanna, Latha Muglihalli Shivashankar, Onkarappa Honnebagi Shivamurthy, Shwetha Uramundina Ramachandrappa, Virupaxappa Shekarappa Betageri, Chandan Shivamallu, Raghavendra Hallur Lakshmana Shetty, Saurabh Kumar, Raghavendra G. Amachawadi and Shiva Prasad Kollur
Polymers 2022, 14(20), 4383; https://doi.org/10.3390/polym14204383 - 17 Oct 2022
Cited by 2 | Viewed by 2271
Abstract
Agricultural residues are suitable to make useful products that can potentially replace the non-biodegradable polymeric materials. In the present work, corn cob and rice S=straw is quantitatively transformed to cellulose by alkali treatment preceded by bleaching. The obtained cellulose is changed into nanocellulose [...] Read more.
Agricultural residues are suitable to make useful products that can potentially replace the non-biodegradable polymeric materials. In the present work, corn cob and rice S=straw is quantitatively transformed to cellulose by alkali treatment preceded by bleaching. The obtained cellulose is changed into nanocellulose (NC) by the acid hydrolysis method followed by ultrasonication. Further NC was characterized by FTIR to study its functional regions and XRD for crystallinity. Thermal properties have been studied using TGA/DTA. The surface morphology of nanocellulose was done using SEM and TEM. The obtained results revealed remarkable thermal stability, semi-crystalline and fibrous nature of both corn cob and rice straw. The size of the cellulose is in the nanoscale dimension. This work provides the way to utilize corn cob and rice straw as a more useful raw material for many applications. Full article
(This article belongs to the Special Issue Status and Progress of Soluble Polymers)
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14 pages, 1238 KiB  
Article
A Molecular Dynamics Simulation of Polymers’ Interactions with Kaolinite (010) Surfaces in Saline Solutions
by Gonzalo R. Quezada, Williams Leiva, Jorge H. Saavedra, Pedro Robles, Edelmira Gálvez and Ricardo I. Jeldres
Polymers 2022, 14(18), 3851; https://doi.org/10.3390/polym14183851 - 15 Sep 2022
Cited by 4 | Viewed by 1835
Abstract
The search for polymers that meet the demands of the water recovery process in mining is a contingent challenge. Both the presence of clays and saline waters can impair water recovery from tailings when conventional flocculants are used. In this work, the adsorption [...] Read more.
The search for polymers that meet the demands of the water recovery process in mining is a contingent challenge. Both the presence of clays and saline waters can impair water recovery from tailings when conventional flocculants are used. In this work, the adsorption of polyacrylamide (PAM), hydrolyzed polyacrylamide (HPAM), poly(2-acrylamido-2-methyl-1-propane sulfonic acid) (PAMPS), polyacrylic acid (PAA), polyethylene oxide (PEO), and guar gum (GUAR) on a kaolinite surface (010) was investigated using classical molecular dynamics. The results show that the presence of sodium chloride modifies the affinities of the polymers with kaolinite (010). At low salt concentrations, the PAM and GUAR polymers generally show higher adsorption due to the formation of hydrogen bridges. However, the highest adsorptions occur in salt solutions in the presence of HPAM by cationic bridging with sodium ions as a mediator. This high affinity of HPAM is not efficient for flocculation because it re-disperses the particles, but it is promising for the design of new additives produced by grafting HPAM groups onto advanced polymers. Full article
(This article belongs to the Special Issue Status and Progress of Soluble Polymers)
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26 pages, 53790 KiB  
Article
Intracranial In Situ Thermosensitive Hydrogel Delivery of Temozolomide Accomplished by PLGA–PEG–PLGA Triblock Copolymer Blending for GBM Treatment
by Weinan Gu, Ranran Fan, Jingnan Quan, Yi Cheng, Shanshan Wang, Hui Zhang, Aiping Zheng and Shenghan Song
Polymers 2022, 14(16), 3368; https://doi.org/10.3390/polym14163368 - 18 Aug 2022
Cited by 7 | Viewed by 2685
Abstract
Glioblastoma (GBM) recurrence after surgical excision has grown to be a formidable obstacle to conquer. In this research, biodegradable thermosensitive triblock copolymer, poly(D, L–lactic acid–co–glycolic acid)–b–poly(ethylene glycol)–b–poly(D, L–lactic acid–co–glycolic acid (PLGA–PEG–PLGA) was utilized as the drug delivery system, loading with micronized temozolomide(micro-TMZ) to [...] Read more.
Glioblastoma (GBM) recurrence after surgical excision has grown to be a formidable obstacle to conquer. In this research, biodegradable thermosensitive triblock copolymer, poly(D, L–lactic acid–co–glycolic acid)–b–poly(ethylene glycol)–b–poly(D, L–lactic acid–co–glycolic acid (PLGA–PEG–PLGA) was utilized as the drug delivery system, loading with micronized temozolomide(micro-TMZ) to form an in situ drug–gel depot inside the resection cavity. The rheology studies revealed the viscoelastic profile of hydrogel under various conditions. To examine the molecular characteristics that affect gelation temperature, 1H–NMR, inverse gated decoupling 13C–NMR, and GPC were utilized. Cryo-SEM and XRD were intended to disclose the appearance of the hydrogel and the micro-TMZ existence state. We worked out how to blend polymers to modify the gelation point (Tgel) and fit the correlation between Tgel and other dependent variables using linear regression. To simulate hydrogel dissolution in cerebrospinal fluid, a membraneless dissolution approach was used. In vitro, micro-TMZ@PLGA–PEG–PLGA hydrogel exhibited Korsmeyer–Peppas and zero–order release kinetics in response to varying drug loading, and in vivo, it suppressed GBM recurrence at an astoundingly high rate. Micro-TMZ@PLGA–PEG–PLGA demonstrates a safer and more effective form of chemotherapy than intraperitoneal TMZ injection, resulting in a spectacular survival rate (40%, n = 10) that is much more than intraperitoneal TMZ injection (22%, n = 9). By proving the viability and efficacy of micro-TMZ@PLGA–PEG–PLGA hydrogel, our research established a novel chemotherapeutic strategy for treating GBM recurrence. Full article
(This article belongs to the Special Issue Status and Progress of Soluble Polymers)
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16 pages, 4748 KiB  
Article
Electrocrystallization of Calcium Oxalate on Electrospun PCL Fibers Loaded with Phytic Acid as a Template
by Tatiana Zegers Arce, Mehrdad Yazdani-Pedram and Andrónico Neira-Carrillo
Polymers 2022, 14(15), 3190; https://doi.org/10.3390/polym14153190 - 5 Aug 2022
Cited by 1 | Viewed by 1578
Abstract
Crystallization occurs widely in living organisms where different organs could associate with the calcification process, such as the formation of calcium oxalate (CaOx) calculi in the urinary tract. However, the pathogenesis and the role of an inhibitor in the pathological processes involved in [...] Read more.
Crystallization occurs widely in living organisms where different organs could associate with the calcification process, such as the formation of calcium oxalate (CaOx) calculi in the urinary tract. However, the pathogenesis and the role of an inhibitor in the pathological processes involved in urolithiasis is poorly understood. Therefore, the use of phytic acid (PA) as an inhibitor for the organic fibrillar matrix is a novel approach to inhibit the formation of pathological CaOx crystals. Herein, electrospun polymer fiber meshes of polycaprolactone (PCL) with random (R) and aligned (A) fiber orientations containing PA were prepared by electrospinning, and their role as a 3D organic template in in vitro CaOx crystallization was investigated. CaOx crystals were generated on conductive tin indium oxide (ITO)-modified glass with R-PCL and A-PCL fibers in the presence of PA through an electrocrystallization (EC) procedure. This study provides a simple electrochemical approach to evaluate the role of PA as an inhibitor in the nucleation of pathological CaOx crystals. The resulting CaOx crystals were analyzed by chrono-potentiometry, optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). We found that PA and the fiber orientations are key factors in the nucleation and crystal growth of CaOx, achieving the stabilization of healthy CaOx crystal and the inhibition of the pathological crystal form. Full article
(This article belongs to the Special Issue Status and Progress of Soluble Polymers)
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13 pages, 1940 KiB  
Article
Effects of Neutral, Anionic and Cationic Polymer Brushes Grafted from Poly(para-phenylene vinylene) and Poly(para-phenylene ethynylene) on the Polymer’s Photoluminescent Properties
by Thomas Kerr-Phillips, Mona Damavandi, Lisa I. Pilkington, Kathryn A. Whitehead, Jadranka Travas-Sejdic and David Barker
Polymers 2022, 14(14), 2767; https://doi.org/10.3390/polym14142767 - 6 Jul 2022
Cited by 2 | Viewed by 1892
Abstract
The conformation of a fluorescent polymer, in the solid state or in solution, plays a critical role in the polymer’s fluorescent properties. Thus, grafted side chains on a fluorescent polymer can directly influence its optical properties. In this study, the effect of grafted [...] Read more.
The conformation of a fluorescent polymer, in the solid state or in solution, plays a critical role in the polymer’s fluorescent properties. Thus, grafted side chains on a fluorescent polymer can directly influence its optical properties. In this study, the effect of grafted polymeric side chains on the photoluminescent properties of poly(para-phenylene vinylene) (PPV) and poly(para-phenylene ethynylene) (PPE) were investigated. Low- and high-molecular-weight grafts of neutral poly(n-butyl acrylate), cationic poly(trimethylaminoethyl methacrylate) and anionic poly(sulfopropyl acrylate) were grafted onto PPVs and PPEs, and the effect of the grafting on the graft copolymer’s absorption and emission wavelengths, the fluorescence intensity and the quantum yield were studied. The results indicate that in the case of the ionic grafts, contrary to the expectations, the polymers have a reduced quantum yield. This contrasts with the copolymers with uncharged side chains (PnBA), where a major increase in the quantum yield is seen for the self-quenching conjugated pristine polymers. These results reinforce that the molecular conformation of the polymer in a solid or solution plays a critical role in fluorescent polymers photoluminescent properties. Full article
(This article belongs to the Special Issue Status and Progress of Soluble Polymers)
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25 pages, 4627 KiB  
Article
Formulation of Polymers-Based Methotrexate Patches and Investigation of the Effect of Various Penetration Enhancers: In Vitro, Ex Vivo and In Vivo Characterization
by Muhammad Shahid Latif, Asif Nawaz, Sheikh Abdur Rashid, Muhammad Akhlaq, Asif Iqbal, Muhammad Jamil Khan, Muhammad Shuaib Khan, Vuanghao Lim and Mulham Alfatama
Polymers 2022, 14(11), 2211; https://doi.org/10.3390/polym14112211 - 30 May 2022
Cited by 4 | Viewed by 2632
Abstract
The present study aimed to prepare methotrexate-loaded transdermal patches with different blends of hydrophobic and hydrophilic polymers (Eudragit S-100 and hydroxypropyl methylcellulose) at different concentrations. The polymers employed in transdermal patches formulations served as controlled agent. Transdermal patches were prepared using the solvent [...] Read more.
The present study aimed to prepare methotrexate-loaded transdermal patches with different blends of hydrophobic and hydrophilic polymers (Eudragit S-100 and hydroxypropyl methylcellulose) at different concentrations. The polymers employed in transdermal patches formulations served as controlled agent. Transdermal patches were prepared using the solvent casting technique. The suitable physicochemical properties were obtained from the formulation F5 (HPMC and Eudragit S-100 (5:1). Various penetration enhancers were employed in different concentrations to investigate their potential for enhancing the drug permeation profile from optimized formulations. A preformulation study was conducted to investigate drug–excipient compatibilities (ATR-FTIR) and the study showed greater compatibility between drug, polymers and excipients. The prepared patches containing different penetration enhancers at different concentrations were subjected for evaluating different physicochemical parameters and in vitro drug release studies. The obtained data were added to various kinetic models, then formulated patch formulations were investigated for ex vivo permeation studies, in vivo studies and skin drug retention studies. The prepared patches showed elastic, smooth and clear nature with good thickness, drug content, % moisture uptake and weight uniformity. The prepared transdermal patches showed % drug content ranging from 91.43 ± 2.90 to 98.37 ± 0.56, % swelling index from 36.98 ± 0.19 to 75.32 ± 1.21, folding endurance from 61 ± 3.14 to 78 ± 1.54 and tensile strength from 8.54 ± 0.18 to 12.87 ± 0.50. The formulation F5, containing a greater amount of hydrophilic polymers (HPMC), showed increased drug release and permeation and drug retention when compared to other formulated transdermal patch formulations (F1-F9). No significant change was observed during a stability study for a period of 60 days. The rabbit skin samples were subjected to ATR-FTIR studies, which revealed that polymers and penetration enhancers have affected skin proteins (ceramides and keratins). The pharmacokinetic profiling of optimized formulation (F5) as well as formulations with optimized concentrations of penetration enhancers revealed Cmax ranged 167.80 ng/mL to 178.07 ± 2.75 ng/mL, Tmax was 8 h to 10 h, and t1/2 was 15.9 ± 2.11 to 21.49 ± 1.16. From the in vivo studies, it was revealed that the formulation F5-OA-10% exhibited greater skin drug retention as compared to other formulations. These results depicted that prepared methotrexate transdermal patches containing different blends of hydrophobic and hydrophilic polymers along with different penetration enhancers could be safely used for the management of psoriasis. The formulated transdermal patches exhibited sustained release of drug with good permeations and retention profile. Hence, these formulated transdermal patches can effectively be used for the management of psoriasis. Full article
(This article belongs to the Special Issue Status and Progress of Soluble Polymers)
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12 pages, 2685 KiB  
Article
Species Surface Distribution and Surface Tension of Aqueous Solutions of MIBC and NaCl Using Molecular Dynamics Simulations
by Omar Alvarado, Gonzalo R. Quezada, Jorge H. Saavedra, Roberto E. Rozas and Pedro G. Toledo
Polymers 2022, 14(10), 1967; https://doi.org/10.3390/polym14101967 - 12 May 2022
Cited by 2 | Viewed by 1874
Abstract
Methyl isobutyl carbinol (MIBC) is a high-performance surfactant with unusual interfacial properties much appreciated in industrial applications, particularly in mineral flotation. In this study, the structure of air–liquid interfaces of aqueous solutions of MIBC-NaCl is determined by using molecular dynamics simulations employing polarizable [...] Read more.
Methyl isobutyl carbinol (MIBC) is a high-performance surfactant with unusual interfacial properties much appreciated in industrial applications, particularly in mineral flotation. In this study, the structure of air–liquid interfaces of aqueous solutions of MIBC-NaCl is determined by using molecular dynamics simulations employing polarizable and nonpolarizable force fields. Density profiles at the interfaces and surface tension for a wide range of MIBC concentrations reveal the key role of polarizability in determining the surface solvation of Cl ions and the expulsion of non-polarizable Na+ ions from the interface to the liquid bulk, in agreement with spectroscopic experiments. The orientation of MIBC molecules at the water liquid–vapor interface changes as the concentration of MIBC increases, from parallel to the interface to perpendicular, leading to a well-packed monolayer. Surface tension curves of fresh water and aqueous NaCl solutions in the presence of MIBC intersect at a reproducible surfactant concentration for a wide range of salt concentrations. The simulation results for a 1 M NaCl aqueous solution with polarizable water and ions closely capture the MIBC concentration at the intercept. The increase in surface tension of the aqueous MIBC/NaCl mixture below the concentration of MIBC at the intersection seems to originate in a disturbance of the interfacial hydrogen bonding structure of the surface liquid water caused by Na+ ions acting at a distance and not by its presence on the interface. Full article
(This article belongs to the Special Issue Status and Progress of Soluble Polymers)
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