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157 KiB

Open AccessEditorial

Special Issue: Water Soluble Polymers

by Alexander Penlidis

Processes 2017, 5(2), 31; https://doi.org/10.3390/pr5020031 - 17 Jun 2017

Cited by 5 | Viewed by 4909

Abstract

This Special Issue (SI) of Processes on water soluble polymers (WSP), and the associated Special Issue reprint, contain papers that deal with this extremely popular area of scientific investigation in polymer science and engineering, both in academic and industrial environments.[...] Full article

(This article belongs to the Special Issue Water Soluble Polymers)

Research

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8110 KiB

Open AccessArticle

Development of Molecularly Imprinted Polymers to Target Polyphenols Present in Plant Extracts

by Catarina Gomes, Gayane Sadoyan, Rolando C. S. Dias and Mário Rui P. F. N. Costa

Processes 2017, 5(4), 72; https://doi.org/10.3390/pr5040072 - 14 Nov 2017

Cited by 29 | Viewed by 7289

Abstract

The development of molecularly imprinted polymers (MIPs) to target polyphenols present in vegetable extracts was here addressed. Polydatin was selected as a template polyphenol due to its relatively high size and amphiphilic character. Different MIPs were synthesized to explore preferential interactions between the [...] Read more.

The development of molecularly imprinted polymers (MIPs) to target polyphenols present in vegetable extracts was here addressed. Polydatin was selected as a template polyphenol due to its relatively high size and amphiphilic character. Different MIPs were synthesized to explore preferential interactions between the functional monomers and the template molecule. The effect of solvent polarity on the molecular imprinting efficiency, namely owing to hydrophobic interactions, was also assessed. Precipitation and suspension polymerization were examined as a possible way to change MIPs morphology and performance. Solid phase extraction and batch/continuous sorption processes were used to evaluate the polyphenols uptake/release in individual/competitive assays. Among the prepared MIPs, a suspension polymerization synthesized material, with 4-vinylpyridine as the functional monomer and water/methanol as solvent, showed a superior performance. The underlying cause of such a significant outcome is the likely surface imprinting process caused by the amphiphilic properties of polydatin. The uptake and subsequent selective release of polyphenols present in natural extracts was successfully demonstrated, considering a red wine solution as a case study. However, hydrophilic/hydrophobic interactions are inevitable (especially with complex natural extracts) and the tuning of the polarity of the solvents is an important issue for the isolation of the different polyphenols. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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2776 KiB

Open AccessFeature PaperArticle

Organic Polymers as Porogenic Structure Matrices for Mesoporous Alumina and Magnesia

by Zimei Chen, Christian Weinberger, Michael Tiemann and Dirk Kuckling

Processes 2017, 5(4), 70; https://doi.org/10.3390/pr5040070 - 8 Nov 2017

Cited by 6 | Viewed by 6503

Abstract

Mesoporous alumina and magnesia were prepared using various polymers, poly(ethylene glycol) (PEG), poly(vinyl alcohol) (PVA), poly(N-(2-hydroxypropyl) methacrylamide) (PHPMA), and poly(dimethylacrylamide) (PDMAAm), as porogenic structure matrices. Mesoporous alumina exhibits large Brunauer–Emmett–Teller (BET) surface areas up to 365 m² g⁻¹, [...] Read more.

Mesoporous alumina and magnesia were prepared using various polymers, poly(ethylene glycol) (PEG), poly(vinyl alcohol) (PVA), poly(N-(2-hydroxypropyl) methacrylamide) (PHPMA), and poly(dimethylacrylamide) (PDMAAm), as porogenic structure matrices. Mesoporous alumina exhibits large Brunauer–Emmett–Teller (BET) surface areas up to 365 m² g⁻¹, while mesoporous magnesium oxide possesses BET surface areas around 111 m² g⁻¹. Variation of the polymers has little impact on the structural properties of the products. The calcination of the polymer/metal oxide composite materials benefits from the fact that the polymer decomposition is catalyzed by the freshly formed metal oxide. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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2482 KiB

Open AccessEditor’s ChoiceArticle

Radical Copolymerization Kinetics of Bio-Renewable Butyrolactone Monomer in Aqueous Solution

by Sharmaine B. Luk and Robin A. Hutchinson

Processes 2017, 5(4), 55; https://doi.org/10.3390/pr5040055 - 1 Oct 2017

Cited by 2 | Viewed by 6061

Abstract

The radical copolymerization kinetics of acrylamide (AM) and the water-soluble monomer sodium 4-hydroxy-4-methyl-2-methylene butanoate (SHMeMB), formed by saponification of the bio-sourced monomer γ-methyl-α-methylene-γ-butyrolactone (MeMBL), are investigated to explain the previously reported slow rates of reaction during synthesis of superabsorbent hydrogels. Limiting conversions were [...] Read more.

The radical copolymerization kinetics of acrylamide (AM) and the water-soluble monomer sodium 4-hydroxy-4-methyl-2-methylene butanoate (SHMeMB), formed by saponification of the bio-sourced monomer γ-methyl-α-methylene-γ-butyrolactone (MeMBL), are investigated to explain the previously reported slow rates of reaction during synthesis of superabsorbent hydrogels. Limiting conversions were observed to decrease with increased temperature during SHMeMB homopolymerization, suggesting that polymerization rate is limited by depropagation. Comonomer composition drift also increased with temperature, with more AM incorporated into the copolymer due to SHMeMB depropagation. Using previous estimates for the SHMeMB propagation rate coefficient, the conversion profiles were used to estimate rate coefficients for depropagation and termination (k_t). The estimate for k_t,SHMeMB was found to be of the same order of magnitude as that recently reported for sodium methacrylate, with the averaged copolymerization termination rate coefficient dominated by the presence of SHMeMB in the system. In addition, it was found that depropagation still controlled the SHMeMB polymerization rate at elevated temperatures in the presence of added salt. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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14095 KiB

Open AccessFeature PaperArticle

Comparison of Polymer Networks Synthesized by Conventional Free Radical and RAFT Copolymerization Processes in Supercritical Carbon Dioxide

by Patricia Pérez-Salinas, Gabriel Jaramillo-Soto, Alberto Rosas-Aburto, Humberto Vázquez-Torres, María Josefa Bernad-Bernad, Ángel Licea-Claverie and Eduardo Vivaldo-Lima

Processes 2017, 5(2), 26; https://doi.org/10.3390/pr5020026 - 9 May 2017

Cited by 10 | Viewed by 6990

Abstract

There is a debate in the literature on whether or not polymer networks synthesized by reversible deactivation radical polymerization (RDRP) processes, such as reversible addition-fragmentation radical transfer (RAFT) copolymerization of vinyl/divinyl monomers, are less heterogeneous than those synthesized by conventional free radical copolymerization [...] Read more.

There is a debate in the literature on whether or not polymer networks synthesized by reversible deactivation radical polymerization (RDRP) processes, such as reversible addition-fragmentation radical transfer (RAFT) copolymerization of vinyl/divinyl monomers, are less heterogeneous than those synthesized by conventional free radical copolymerization (FRP). In this contribution, the syntheses by FRP and RAFT of hydrogels based on 2-hydroxyethylene methacrylate (HEMA) and ethylene glycol dimethacrylate (EGDMA) in supercritical carbon dioxide (scCO₂), using Krytox 157 FSL as the dispersing agent, and the properties of the materials produced, are compared. The materials were characterized by differential scanning calorimetry (DSC), swelling index (SI), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Studies on ciprofloxacin loading and release rate from hydrogels were also carried out. The combined results show that the hydrogels synthesized by FRP and RAFT are significantly different, with apparently less heterogeneity present in the materials synthesized by RAFT copolymerization. A ratio of experimental (Mc_exp) to theoretical (Mc_theo) molecular weight between crosslinks was established as a quantitative tool to assess the degree of heterogeneity of a polymer network. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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4049 KiB

Open AccessArticle

Design of Cross-Linked Starch Nanocapsules for Enzyme-Triggered Release of Hydrophilic Compounds

by Fernanda R. Steinmacher, Grit Baier, Anna Musyanovych, Katharina Landfester, Pedro H. H. Araújo and Claudia Sayer

Processes 2017, 5(2), 25; https://doi.org/10.3390/pr5020025 - 6 May 2017

Cited by 17 | Viewed by 7521

Abstract

Cross-linked starch nanocapsules (NCs) were synthesized by interfacial polymerization carried out using the inverse mini-emulsion technique. 2,4-toluene diisocyanate (TDI) was used as the cross-linker. The influence of TDI concentrations on the polymeric shell, particle size, and encapsulation efficiency of a hydrophilic dye, sulforhodamine [...] Read more.

Cross-linked starch nanocapsules (NCs) were synthesized by interfacial polymerization carried out using the inverse mini-emulsion technique. 2,4-toluene diisocyanate (TDI) was used as the cross-linker. The influence of TDI concentrations on the polymeric shell, particle size, and encapsulation efficiency of a hydrophilic dye, sulforhodamine 101 (SR 101), was investigated by Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS), and fluorescence measurements, respectively. The final NC morphology was confirmed by scanning electron microscopy. The leakage of SR 101 through the shell of NCs was monitored at 37 °C for seven days, and afterwards the NCs were redispersed in water. Depending on cross-linker content, permeable and impermeable NCs shell could be designed. Enzyme-triggered release of SR 101 through impermeable NC shells was investigated using UV spectroscopy with different α-amylase concentrations. Impermeable NCs shell were able to release their cargo upon addition of amylase, being suitable for a drug delivery system of hydrophilic compounds. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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2426 KiB

Open AccessFeature PaperArticle

Aqueous Free-Radical Polymerization of Non-Ionized and Fully Ionized Methacrylic Acid

by Eric Jean Fischer, Giuseppe Storti and Danilo Cuccato

Processes 2017, 5(2), 23; https://doi.org/10.3390/pr5020023 - 27 Apr 2017

Cited by 19 | Viewed by 8945

Abstract

Water-soluble, carboxylic acid monomers are known to exhibit peculiar kinetics when polymerized in aqueous solution. Namely, their free-radical polymerization rate is affected by several parameters such as monomer concentration, ionic strength, and pH. Focusing on methacrylic acid (MAA), even though this monomer has [...] Read more.

Water-soluble, carboxylic acid monomers are known to exhibit peculiar kinetics when polymerized in aqueous solution. Namely, their free-radical polymerization rate is affected by several parameters such as monomer concentration, ionic strength, and pH. Focusing on methacrylic acid (MAA), even though this monomer has been largely addressed, a systematic investigation of the effects of the above-mentioned parameters on its polymerization rate is missing, in particular in the fully ionized case. In this work, the kinetics of non-ionized and fully ionized MAA are characterized by in-situ nuclear magnetic resonance (NMR). Such accurate monitoring of the reaction rate enables the identification of relevant but substantially different effects of the monomer and electrolyte concentration on polymerization rate in the two ionization cases. For non-ionized MAA, the development of a kinetic model based on literature rate coefficients allows us to nicely simulate the experimental data of conversion versus time at a high monomer concentration. For fully ionized MAA, a novel propagation rate law accounting for the electrostatic interactions is proposed: the corresponding model is capable of predicting reasonably well the electrolyte concentration effect on polymerization rate. Nevertheless, further kinetic information in a wider range of monomer concentrations would be welcome to increase the reliability of the model predictions. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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3934 KiB

Open AccessArticle

Polymerization Kinetics of Poly(2-Hydroxyethyl Methacrylate) Hydrogels and Nanocomposite Materials

by Dimitris S. Achilias and Panoraia I. Siafaka

Processes 2017, 5(2), 21; https://doi.org/10.3390/pr5020021 - 24 Apr 2017

Cited by 40 | Viewed by 11680

Abstract

Hydrogels based on poly(2-hydroxyethyl methacrylate) (PHEMA) are a very important class of biomaterials with several applications mainly in tissue engineering and contacts lenses. Although the polymerization kinetics of HEMA have been investigated in the literature, the development of a model, accounting for both [...] Read more.

Hydrogels based on poly(2-hydroxyethyl methacrylate) (PHEMA) are a very important class of biomaterials with several applications mainly in tissue engineering and contacts lenses. Although the polymerization kinetics of HEMA have been investigated in the literature, the development of a model, accounting for both the chemical reaction mechanism and diffusion-controlled phenomena and valid over the whole conversion range, has not appeared so far. Moreover, research on the synthesis of nanocomposite materials based on a polymer matrix has grown rapidly recently because of the improved mechanical, thermal and physical properties provided by the polymer. In this framework, the objective of this research is two-fold: to provide a kinetic model for the polymerization of HEMA with accurate estimations of the kinetic and diffusional parameters employed and to investigate the effect of adding various types and amounts of nano-additives to the polymerization rate. In the first part, experimental data are provided from Differential Scanning Calorimetry (DSC) measurements on the variation of the reaction rate with time at several polymerization temperatures. These data are used to accurately evaluate the kinetic rate constants and diffusion-controlled parameters. In the second part, nanocomposites of PHEMA are formed, and the in situ bulk radical polymerization kinetics is investigated with DSC. It was found that the inclusion of nano-montmorillonite results in a slight enhancement of the polymerization rate, while the inverse holds when adding nano-silica. These results are interpreted in terms of noncovalent interactions, such as hydrogen bonding between the monomer and polymer or the nano-additive. X-Ray Diffraction (XRD) and Fourier Transform Infra-Red (FTIR) measurements were carried out to verify the results. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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2768 KiB

Open AccessFeature PaperArticle

Kinetics of the Aqueous-Phase Copolymerization of MAA and PEGMA Macromonomer: Influence of Monomer Concentration and Side Chain Length of PEGMA

by Iñaki Emaldi, Shaghayegh Hamzehlou, Jorge Sanchez-Dolado and Jose R. Leiza

Processes 2017, 5(2), 19; https://doi.org/10.3390/pr5020019 - 20 Apr 2017

Cited by 20 | Viewed by 8880

Abstract

An in situ nuclear magnetic resonance spectroscopy (NMR) technique is used to monitor the aqueous-phase copolymerization kinetics of methacrylic acid (MAA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) macromonomers. In particular, the study analyses the effect of the number of ethylene glycol (EG) [...] Read more.

An in situ nuclear magnetic resonance spectroscopy (NMR) technique is used to monitor the aqueous-phase copolymerization kinetics of methacrylic acid (MAA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) macromonomers. In particular, the study analyses the effect of the number of ethylene glycol (EG) groups along the lateral chains of PEGMA and is carried out under fully ionized conditions of MAA at different initial monomer ratios and initial overall monomer concentrations (5–20 wt % in aqueous solution). The composition drift with conversion indicates that PEGMA macromonomer is more reactive than MAA. Individual monomer consumption rates show that the rates of consumption of both monomers are not first order with respect to overall concentration of the monomer. The reactivity ratios estimated from the copolymerization kinetics reveal, that for the short PEGMA, the reactivity ratios r_MAA and r_PEGMA increase with the solids content (SC). A totally different trend is obtained for the longer PEGMA, whose reactivity ratio (r_PEGMA₂₃) decreases with solids content, whereas the reactivity ratio of MAA remains roughly constant. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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1143 KiB

Open AccessArticle

Biodegradable and Biocompatible P_DLLA-PEG_1k-P_DLLA Diacrylate Macromers: Synthesis, Characterisation and Preparation of Soluble Hyperbranched Polymers and Crosslinked Hydrogels

by Alan Hughes, Hongyun Tai, Anna Tochwin and Wenxin Wang

Processes 2017, 5(2), 18; https://doi.org/10.3390/pr5020018 - 20 Apr 2017

Cited by 7 | Viewed by 7327

Abstract

A series of P_DLLA-PEG_1k-P_DLLA tri-block co-polymers with various compositions, i.e., containing 2–10 lactoyl units, were prepared via ring opening polymerisation of d,l-lactide in the presence of poly (ethylene glycol) (PEG) (M_n = [...] Read more.

A series of P_DLLA-PEG_1k-P_DLLA tri-block co-polymers with various compositions, i.e., containing 2–10 lactoyl units, were prepared via ring opening polymerisation of d,l-lactide in the presence of poly (ethylene glycol) (PEG) (M_n = 1000 g·mol⁻¹) as the initiator and stannous 2-ethylhexanoate as the catalyst at different feed ratios. P_DLLA-PEG_1k-P_DLLA co-polymers were then functionalised with acrylate groups using acryloyl chloride under various reaction conditions. The diacrylated P_DLLA-PEG_1k-P_DLLA (diacryl-P_DLLA-PEG_1k-P_DLLA) were further polymerised to synthesize soluble hyperbranched polymers by either homo-polymerisation or co-polymerisation with poly(ethylene glycol) methyl ether methylacrylate (PEGMEMA) via free radical polymerisation. The polymer samples obtained were characterised by ¹H NMR (proton Nuclear Magnetic Resonance), FTIR (Fourier Transform Infra-red spectroscopy), and GPC (Gel Permeation Chromatography). Moreover, the diacryl-P_DLLA-PEG_1k-P_DLLA macromers were used for the preparation of biodegradable crosslinked hydrogels through the Michael addition reaction and radical photo-polymerisation with or without poly(ethylene glycol) methyl ether methylacrylate (PEGMEMA, M_n = 475 g·mol⁻¹) as the co-monomer. It was found that fine tuning of the diacryl-P_DLLA-PEG_1k-P_DLLA constituents and its combination with co-monomers resulted in hydrogels with tailored swelling properties. It is envisioned that soluble hyperbranched polymers and crosslinked hydrogels prepared from diacryl-P_DLLA-PEG_1k-P_DLLA macromers can have promising applications in the fields of nano-medicines and regenerative medicines. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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2426 KiB

Open AccessArticle

Simultaneous Monitoring of the Effects of Multiple Ionic Strengths on Properties of Copolymeric Polyelectrolytes during Their Synthesis

by Aide Wu, Zifu Zhu, Michael F. Drenski and Wayne F. Reed

Processes 2017, 5(2), 17; https://doi.org/10.3390/pr5020017 - 11 Apr 2017

Cited by 2 | Viewed by 5016

Abstract

A new Automatic Continuous Online Monitoring of Polymerization reactions (ACOMP) system has been developed with multiple light scattering and viscosity detection stages in serial flow, where solution conditions are different at each stage. Solution conditions can include ionic strength (IS), pH, surfactants, concentration, [...] Read more.

A new Automatic Continuous Online Monitoring of Polymerization reactions (ACOMP) system has been developed with multiple light scattering and viscosity detection stages in serial flow, where solution conditions are different at each stage. Solution conditions can include ionic strength (IS), pH, surfactants, concentration, and other factors. This allows behavior of a polymer under simultaneous, varying solution conditions to be monitored at each instant of its synthesis. The system can potentially be used for realtime formulation, where a solution formulation is built up additively in successive stages. It can also monitor the effect of solution conditions on stimuli responsive polymers, as their responsiveness changes during synthesis. In this first work, the new ACOMP system monitored light scattering and reduced viscosity properties of copolymeric polyelectrolytes under various IS during synthesis. Aqueous copolymerization of acrylamide (Am) and styrene sulfonate (SS) was used. Polyelectrolytes in solution expand as IS decreases, leading to increased intrinsic viscosity (η) and suppression of light scattering intensity due to electrostatically enhanced second and third virial coefficients, A₂ and A₃. At a fixed IS, the same effects occur if polyelectrolyte linear charge density (ξ) increases. This work presents polyelectrolyte response to a series of IS and changing ξ during chemical synthesis. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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2240 KiB

Open AccessFeature PaperArticle

Kinetic control of aqueous polymerization using radicals generated in different spin states

by Ignacio Rintoul

Processes 2017, 5(2), 15; https://doi.org/10.3390/pr5020015 - 24 Mar 2017

Cited by 13 | Viewed by 5461

Abstract

Background: Magnetic fields can interact with liquid matter in a homogeneous and instantaneous way, without physical contact, independently of its temperature, pressure, and agitation degree, and without modifying recipes nor heat and mass transfer conditions. In addition, magnetic fields may affect the mechanisms [...] Read more.

Background: Magnetic fields can interact with liquid matter in a homogeneous and instantaneous way, without physical contact, independently of its temperature, pressure, and agitation degree, and without modifying recipes nor heat and mass transfer conditions. In addition, magnetic fields may affect the mechanisms of generation and termination of free radicals. This paper is devoted to the elucidation of the appropriate conditions needed to develop magnetic field effects for controlling the kinetics of polymerization of water soluble monomers. Methods: Thermal- and photochemically-initiated polymerizations were investigated at different initiator and monomer concentrations, temperatures, viscosities, and magnetic field intensities. Results: Significant magnetic field impact on the polymerization kinetics was only observed in photochemically-initiated polymerizations carried out in viscous media and performed at relatively low magnetic field intensity. Magnetic field effects were absent in polymerizations in low viscosity media and thermally-initiated polymerizations performed at low and high magnetic field intensities. The effects were explained in terms of the radical pair mechanism for intersystem crossing of spin states. Conclusion: Polymerization kinetics of water soluble monomers can be potentially controlled using magnetic fields only under very specific reaction conditions. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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2868 KiB

Open AccessArticle

Poly(Poly(Ethylene Glycol) Methyl Ether Methacrylate) Grafted Chitosan for Dye Removal from Water

by Bryan Tsai, Omar Garcia-Valdez, Pascale Champagne and Michael F. Cunningham

Processes 2017, 5(1), 12; https://doi.org/10.3390/pr5010012 - 14 Mar 2017

Cited by 23 | Viewed by 9011

Abstract

As the demand for textile products and synthetic dyes increases with the growing global population, textile dye wastewater is becoming one of the most significant water pollution contributors. Azo dyes represent 70% of dyes used worldwide, and are hence a significant contributor to [...] Read more.

As the demand for textile products and synthetic dyes increases with the growing global population, textile dye wastewater is becoming one of the most significant water pollution contributors. Azo dyes represent 70% of dyes used worldwide, and are hence a significant contributor to textile waste. In this work, the removal of a reactive azo dye (Reactive Orange 16) from water by adsorption with chitosan grafted poly(poly(ethylene glycol) methyl ether methacrylate) (CTS-GMA-g-PPEGMA) was investigated. The chitosan (CTS) was first functionalized with glycidyl methacrylate and then grafted with poly(poly(ethylene glycol) methyl ether methacrylate) using a nitroxide-mediated polymerization grafting to approach. Equilibrium adsorption experiments were carried out at different initial dye concentrations and were successfully fitted to the Langmuir and Freundlich adsorption isotherm models. Adsorption isotherms showed maximum adsorption capacities of CTS-g-GMA-PPEGMA and chitosan of 200 mg/g and 150 mg/g, respectively, while the Langmuir equations estimated 232 mg/g and 194 mg/g, respectively. The fundamental assumptions underlying the Langmuir model may not be applicable for azo dye adsorption, which could explain the difference. The Freundlich isotherm parameters, n and K, were determined to be 2.18 and 17.7 for CTS-g-GMA-PPEGMA and 0.14 and 2.11 for chitosan, respectively. An “n” value between one and ten generally indicates favorable adsorption. The adsorption capacities of a chitosan-PPEGMA 50/50 physical mixture and pure PPEGMA were also investigated, and both exhibited significantly lower adsorption capacities than pure chitosan. In this work, CTS-g-GMA-PPEGMA proved to be more effective than its parent chitosan, with a 33% increase in adsorption capacity. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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1370 KiB

Open AccessArticle

AMPS/AAm/AAc Terpolymerization: Experimental Verification of the EVM Framework for Ternary Reactivity Ratio Estimation

by Alison J. Scott, Niousha Kazemi and Alexander Penlidis

Processes 2017, 5(1), 9; https://doi.org/10.3390/pr5010009 - 25 Feb 2017

Cited by 18 | Viewed by 6403

Abstract

The complete error-in-variables-model (EVM) framework, consisting of both design of experiments and parameter estimation stages, is applied to the terpolymerization of 2-acrylamido-2-methylpropane sulfonic acid (AMPS, M₁), acrylamide (AAm, M₂) and acrylic acid (AAc, M₃). This water-soluble terpolymer [...] Read more.

The complete error-in-variables-model (EVM) framework, consisting of both design of experiments and parameter estimation stages, is applied to the terpolymerization of 2-acrylamido-2-methylpropane sulfonic acid (AMPS, M₁), acrylamide (AAm, M₂) and acrylic acid (AAc, M₃). This water-soluble terpolymer has potential for applications in enhanced oil recovery, but the associated terpolymerization kinetic characteristics are largely unstudied. In the current paper, EVM is used to design optimal experiments (for the first time in the literature), and reactivity ratios are subsequently estimated based on both low and medium-high conversion data. The results from the medium-high conversion data are more precise than those from the low conversion data, and are therefore used next to predict the terpolymer composition trajectory over the full course of conversion. Good agreement is seen between experimental data and model predictions, which confirms the accuracy of the newly determined ternary reactivity ratios: r₁₂ = 0.66, r₂₁ = 0.82, r₁₃ = 0.82, r₃₁ = 0.61, r₂₃ = 1.61, r₃₂ = 0.25. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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1857 KiB

Open AccessFeature PaperArticle

Poly(methacrylic acid-ran-2-vinylpyridine) Statistical Copolymer and Derived Dual pH-Temperature Responsive Block Copolymers by Nitroxide-Mediated Polymerization

by Milan Marić, Chi Zhang and Daniel Gromadzki

Processes 2017, 5(1), 7; https://doi.org/10.3390/pr5010007 - 21 Feb 2017

Cited by 10 | Viewed by 8644

Abstract

Nitroxide-mediated polymerization using the succinimidyl ester functional unimolecular alkoxyamine initiator (NHS-BlocBuilder) was used to first copolymerize tert-butyl methacrylate/2-vinylpyridine (tBMA/2VP) with low dispersity (Đ = 1.30–1.41) and controlled growth (linear number average molecular M_n versus conversion, M_n = [...] Read more.

Nitroxide-mediated polymerization using the succinimidyl ester functional unimolecular alkoxyamine initiator (NHS-BlocBuilder) was used to first copolymerize tert-butyl methacrylate/2-vinylpyridine (tBMA/2VP) with low dispersity (Đ = 1.30–1.41) and controlled growth (linear number average molecular M_n versus conversion, M_n = 3.8–10.4 kg·mol⁻¹) across a wide composition of ranges (initial mol fraction 2VP, f_2VP,0 = 0.10–0.90). The resulting statistical copolymers were first de-protected to give statistical polyampholytic copolymers comprised of methacrylic acid/2VP (MAA/2VP) units. These copolymers exhibited tunable water-solubility due to the different pKas of the acidic MAA and basic 2VP units; being soluble at very low pH < 3 and high pH > 8. One of the tBMA/2VP copolymers was used as a macroinitiator for a 4-acryloylmorpholine/4-acryloylpiperidine (4AM/4AP) mixture, to provide a second block with thermo-responsive behavior with tunable cloud point temperature (CPT), depending on the ratio of 4AM:4AP. Dynamic light scattering of the block copolymer at various pHs (3, 7 and 10) as a function of temperature indicated a rapid increase in particle size >2000 nm at 22–27 °C, corresponding to the 4AM/4AP segment’s thermos-responsiveness followed by a leveling in particle size to about 500 nm at higher temperatures. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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858 KiB

Open AccessFeature PaperReview

Synthesis of Water-Soluble Group 4 Metallocene and Organotin Polyethers and Their Ability to Inhibit Cancer

by Charles E. Carraher, Michael R. Roner, Jessica Frank, Alica Moric-Johnson, Lindsey C. Miller, Kendra Black, Paul Slawek, Francesca Mosca, Jeffrey D. Einkauf and Floyd Russell

Processes 2017, 5(3), 50; https://doi.org/10.3390/pr5030050 - 1 Sep 2017

Cited by 2 | Viewed by 6216

Abstract

Water-soluble metallocene and organotin-containing polyethers were synthesized employing interfacial polycondensation. The reaction involved various chain lengths of poly(ethylene glycol), and produced water-soluble polymers in decent yield. Commercially available reactants were used to allow for easy scale up. The polymers exhibited a decent ability [...] Read more.

Water-soluble metallocene and organotin-containing polyethers were synthesized employing interfacial polycondensation. The reaction involved various chain lengths of poly(ethylene glycol), and produced water-soluble polymers in decent yield. Commercially available reactants were used to allow for easy scale up. The polymers exhibited a decent ability to inhibit a range of cancer cell lines, including two pancreatic cancer cell lines. This approach should allow the synthesis of a wide variety of other water-soluble polymers. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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8563 KiB

Open AccessReview

Applications of Water-Soluble Polymers in Turbulent Drag Reduction

by Wen Jiao Han, Yu Zhen Dong and Hyoung Jin Choi

Processes 2017, 5(2), 24; https://doi.org/10.3390/pr5020024 - 4 May 2017

Cited by 52 | Viewed by 12513

Abstract

Water-soluble polymers with high molecular weights are known to decrease the frictional drag in turbulent flow very effectively at concentrations of tens or hundreds of ppm. This drag reduction efficiency of water-soluble polymers is well known to be closely associated with the flow [...] Read more.

Water-soluble polymers with high molecular weights are known to decrease the frictional drag in turbulent flow very effectively at concentrations of tens or hundreds of ppm. This drag reduction efficiency of water-soluble polymers is well known to be closely associated with the flow conditions and rheological, physical, and/or chemical characteristics of the polymers added. Among the many promising polymers introduced in the past several decades, this review focuses on recent progress in the drag reduction capability of various water-soluble macromolecules in turbulent flow including both synthetic and natural polymers such as poly(ethylene oxide), poly(acrylic acid), polyacrylamide, poly(N-vinyl formamide), gums, and DNA. The polymeric species, experimental parameters, and numerical analysis of these water-soluble polymers in turbulent drag reduction are highlighted, along with several existing and potential applications. The proposed drag reduction mechanisms are also discussed based on recent experimental and numerical researches. This article will be helpful to the readers to understand better the complex behaviors of a turbulent flow with various water-soluble polymeric additives regarding experimental conditions, drag reduction mechanisms, and related applications. Full article

(This article belongs to the Special Issue Water Soluble Polymers)

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