Water-soluble Monomers Research Articles

Microwave Assisted Selective Hydrolysis of Polyamides from Multicomponent Carpet Waste.

Selective hydrolysis of polyamide‐6 (PA‐6) and polyamide‐66 (PA‐66) from commercial multicomponent PA‐6/PA‐66/polypropylene (PP) carpet is demonstrated by a microwave‐assisted acid catalyzed hydrothermal process, yielding monomeric products and solid polypropylene residue. First, an effective method is established to chemically recycle neat PA‐6 and PA‐66 granules using microwave irradiation. The optimized, hydrochloric acid (HCl) catalyzed process leads to selective production of monomers, 6‐aminocaproic acid or adipic acid and hexamethylenediamine, after only 30 min. A piece of commercial carpet is then recycled using the same reaction conditions, but with the alteration of the reaction time from 1 to 6 h. The produced water‐soluble products and the remaining solid residue are carefully characterized, proving that the polyamide‐part of the carpet is selectively hydrolyzed into water‐soluble monomers and the polypropylene‐part remains as an unconverted solid that can be further used to produce recycled filaments containing the carpet residue and virgin polypropylene. The developed process opens the possibility to recycle multicomponent materials, such as carpets, through selective hydrolysis. It can also contribute to a circular economy, producing original monomers and materials ready for a new life‐cycle.

New Aldehyde-Functional Methacrylic Water-Soluble Polymers.

Aldehyde groups enable facile conjugation to proteins, enzymes, oligonucleotides or fluorescent dyes, yet there are no literature examples of water‐soluble aldehyde‐functional vinyl monomers. We report the synthesis of a new hydrophilic cis‐diol‐based methacrylic monomer (GEO5MA) by transesterification of isopropylideneglycerol penta(ethylene glycol) using methyl methacrylate followed by acetone deprotection via acid hydrolysis. The corresponding water‐soluble aldehyde monomer, AGEO5MA, is prepared by aqueous periodate oxidation of GEO5MA at 22 °C. RAFT polymerization of GEO5MA yields the water‐soluble homopolymer, PGEO5MA. Aqueous periodate oxidation of the terminal cis‐diol units on PGEO5MA at 22 °C affords a water‐soluble aldehyde‐functional homopolymer (PAGEO5MA). Moreover, a library of hydrophilic statistical copolymers bearing cis‐diol and aldehyde groups was prepared using sub‐stoichiometric periodate/cis‐diol molar ratios. The aldehyde groups on PAGEO5MA homopolymer were reacted in turn with three amino acids to demonstrate synthetic utility.

Intrinsic water-soluble benzoxazine-functionalized cyclodextrin and its formation of inclusion complex with polymer

In this study a new water-soluble benzoxazine-functionalized cyclodextrin monomer (β-CD-BZ) was synthesized through monoazido-functionalized β-cyclodextrin (N 3 -CD) with 3,4-dihydro-3-(prop-2-ynyl)-2H-benzoxazine (Ppa) by Huisgen [2 + 3] cycloadditions (click reaction) based on 1 H NMR and FTIR spectroscopy. Its thermal curing polymerization and thermal stability were monitored by DSC and TGA displaying the ring-opening polymerization of benzoxazine units. Incorporation of β-CD into the benzoxazine monomer could improve the thermal stability and water-solubility because of the highly hydroxyl contents of the cyclodextrin unit. Furthermore, the presence of the β-CD cavity could allow the benzoxazine monomer to form inclusion complex (IC) with poly(propylene glycol) (PPG) based on XRD, 1 H NMR, FTIR and TGA. From the XRD results, the PPG were confined into the β-CD-BZ channels and then form the columnar crystalline structures where the stoichiometries of repeat unit of PPG: β-CD-BZ = 2 : 1 were determined by 1 H NMR analysis. More importantly, the benzoxazine units in β-CD-BZ/PPG inclusion complex could further provide the thermal curing polymerization behavior to improve their thermal properties that could not be observed in typical inclusion complex system. • A new water-soluble benzoxazine-functionalized cyclodextrin monomer (β-CD-BZ) was successfully synthesized. • Incorporation of β-CD into the benzoxazine monomer could improve the thermal stability and water-solubility of BZ monomer. • Formation inclusion complex (IC) between β-CD-BZ) and poly(propylene glycol) (PPG). • The thermal properties of β-CD-BZ/PPG inclusion complex significantly improved.

Micelle Purification in Continuous Flow via Inline Dialysis

Micelle dispersions purification is made available via inline flow dialysis in which micelles are separated from the organic solvent used to dissolve the block copolymers in the micelle formation step. Purification was performed using simple and cost-effective dialysis units employing cellulose membranes. The proposed setup allows us to remove THF from a micelle dispersion within a few hours almost entirely in a looped flow system, without significantly changing the micelle size. Purification is found to be independent of the exact flow rates and only on the circulation time through the dialysis units. The system is not only able to reduce the concentration of the organic solvent, but also water-soluble monomers can be removed. Further, the integration of the method into a full synthesis line to produce encapsulated micelles directly from block copolymer solutions is demonstrated with a throughput of 1.2 g of micelles per hour.

Cosolvent-Driven Interfacial Polymerization for Superior Separation Performance of Polyurea-Based Pervaporation Membrane.

A thin-film composite (TFC) polyurea membrane was fabricated for the dehydration of an aqueous tetrahydrofuran (THF) solution through interfacial polymerization, wherein polyethyleneimine (a water-soluble amine monomer) and m-xylene diisocyanate (an oil-soluble diisocyanate monomer) were reacted on the surface of a modified polyacrylonitrile (mPAN) substrate. Cosolvents were used to tailor the membrane properties and increase the membrane permeation flux. Four types of alcohols that differed in the number of carbon (methanol, ethanol, isopropanol, and tert-butanol) were added as cosolvents, serving as swelling agents, to the aqueous-phase monomer solution, and their effect on the membrane properties and pervaporation separation was discussed. Attenuated total reflection Fourier transform infrared spectroscopy confirmed the formation of a polyurea layer on mPAN. Field emission scanning electron microscopy and surface water contact angle analysis indicated no change in the membrane morphology and hydrophilicity, respectively, despite the addition of cosolvents for interfacial polymerization. The TFC membrane produced when ethanol was the cosolvent exhibited the highest separation performance (permeation flux = 1006 ± 103 g·m−2·h−1; water concentration in permeate = 98.8 ± 0.3 wt.%) for an aqueous feed solution containing 90 wt.% THF at 25 °C. During the membrane formation, ethanol caused the polyurea layer to loosen and to acquire a certain degree of cross-linking. The optimal fabrication conditions were as follows: 10 wt.% ethanol as cosolvent; membrane curing temperature = 50 °C; membrane curing time = 30 min.

Aqueous Synthesis of Upper Critical Solution Temperature and Lower Critical Solution Temperature Copolymers through Combination of Hydrogen-Donors and Hydrogen-Acceptors.

The synthesis of thermo-responsive polymers from non-responsive and water-soluble monomers has great practical advantages but significant challenges. Herein, the authors report a novel aqueous copolymerization strategy to prepare polymers with tunable upper critical solution temperature (UCST) or lower critical solution temperature (LCST) from non-responsive monomers. Acrylic acid (AAc), N-vinylpyrrolidone (NVP), and acrylamide (AAm) are copolymerized in water, yielding copolymers with UCST behavior. Interestingly, by simply replacing AAm with its methylated homologue, dimethyl acrylamide (DMA), the thermo-responsiveness of the copolymers is converted into LCST-type. The cloud points of the copolymers can be tuned rationally with their monomer ratios and the condition of the solvent. The UCST property of the poly(AAc-NVP-AAm) comes from the AAc-AAm and AAc-NVP hydrogen-bonds, while the LCST property of poly(AAc-NVP-DMA) originates from the hydrophobic aggregation of AAc-NVP complex and DMA, as indicated by temperature-dependent 1 H NMR and dynamic light scattering.

Hetero-network hydrogels crosslinked with silica nanoparticles for strategic control of thermal responsive property.

Two thermoresponsive copolymers with different lower critical solution temperatures (LCSTs) were crosslinked using silica nanoparticles to afford hybrid hydrogels exhibiting two distinct thermo-responsivities. The thermo-responsive copolymers were synthesised by free radical polymerisation from a monomer with a reactive side chain (3-methacryloxypropyl trimethoxysilane (S)) and water-soluble monomers with different thermo-responsivities (N-isopropyl acrylamide (N) or N-(3-methoxy propyl)acrylamide (M)). The obtained reactive copolymers, poly(N-isopropyl acrylamide-co-3-methacryloxypropyl trimethoxysilane) (pNS) and poly(N-(3-methoxy propyl acrylamide-co-3-methacryloxypropyl trimethoxysilane)) (pMS), were characterized by multiple techniques including 1H NMR and FTIR spectroscopy. The hetero-network hybrid hydrogels were easily prepared by mixing aqueous solutions of the copolymer with an aqueous colloidal silica suspension; their gelation properties could be tuned by varying the amounts of pNS, pMS, and Si. Differential scanning calorimetric analysis showed that the hetero-network hydrogel exhibited a critical two-step phase transition at temperatures around the LCST of each copolymer (33 °C for pNS, 73 °C for pMS), indicating that each polymer does not disturb the phase transitions of the other. The deswelling of the hetero-network hydrogel could be controlled with respect to temperature and time.

AFM imaging of pore forming proteins.

Pore forming proteins are released as water-soluble monomers that form-mostly oligomeric-pores in target membranes. Our understanding of such pore formation relies in part on the direct visualization of their assemblies on and in the membrane. Here, we discuss the application of atomic force microscopy (AFM) to visualize and understand membrane pore formation, illustrated specifically by studies of proteins of the MACPF/CDC superfamily on supported lipid bilayers. Besides detailed protocols, we also point out common imaging artefacts and strategies to avoid them, and briefly outline how AFM can be effectively used in conjunction with other methods.

Elucidating preparation-structure relationships for the morphology evolution during the RAFT dispersion polymerization of N-acryloyl thiomorpholine

Depending on the conditions, nearly monodisperse spherical micelles or complex morphologies are formed during a polymerization induced self-assembly (PISA) process based on the water-soluble monomer N-acryloylthiomorpholine.

Emulsion-templated macroporous ammonium based polymers: Synthesis and dye adsorption study

Emulsion templating was used to prepare new hydrophilic macroporous polymers via o/w high internal phase emulsion (known as polyHIPEs) to be studied as adsorbents for anionic dye removal. A water soluble monomer, 2-(Methacryloyloxy)ethyl]trimethylammonium chloride (METAC) and a cross-linker comonomer (N,N’-methylenebisacrylamide) were polymerized in the continuous aqueous phase yielding in ammonium based monoliths with 10 and 15 % cross-linking density by varying the cross linker content. The prepared monoliths were characterized in terms of their structure, morphology and their ability to adsorb water. Macroporous structures with high ion exchange capacities were obtained. PolyHIPE-METAC-90 with the lower cross-linker percentage (10 %) reached very fast, within 30 min, a higher water uptake (corresponding to 18 times its weight) compared to the sample with the higher cross-linking degree (15 %). Moreover, a detailed study regarding PolyHIPE-METAC-90 adsorption behavior towards two anionic dyes, OII and RB-19 has been performed. The Pseudo-second order model for OII and the Elovich and the Langmuir models for both dyes agreed very well with the experimental data suggesting that chemisorption is the dominant adsorption mechanism. However, the Weber–Morris model indicated that three regimes are involved in the diffusion of anionic dyes, including film diffusion and intra-particle diffusion which is mainly the rate-controlling step. Thus, the synergistic effect of chemisorption and diffusion for the dye adsorption on polyHIPE structures was confirmed. The maximum adsorption capacity of RB-19 (1675.22 mg g−1) is the highest among other adsorbents reported in the literature, while the corresponding one for OII (1632.03 mg g−1) is also one of the highest, suggesting that these materials due to their superior performance, simple synthesis and easy regeneration can be used as highly efficient adsorbents for dyes.

Porous thin-film molecularly imprinted polymer device for simultaneous determination of phenol, alkylphenol and chlorophenol compounds in water

A porous water-compatible molecularly imprinted polymer (MIP) coating using catechol as a pseudo-template and a water-soluble functional monomer (4-vinyl benzoic acid) with ethylene glycol dimethacrylate as the crosslinker was developed for extraction of phenols from environmental water samples. The MIP devices were combined with ultra high performance liquid chromatography with a photodiode array detector (UHPLC-PDA) suitable for the simultaneous determination of trace levels of phenolic compounds with a wide range of polarities —phenol, alkylphenols and chlorophenols— in seawater and produced water. Parameters that influence extraction efficiency (salinity, pH, polymer mass, desorption solvent, and desorption time) were optimized to give method detection limits (LOD) ranging from 0.1 to 2 μg L−1 and linearity (R2>0.99) over at least three orders of magnitude for the hydrophobic phenols (e.g., 0.5–1000 μg L−1 for 2,4,6-trichlorophenol) and ~2 orders of magnitude for the light phenols (e.g., 10–120 μg L−1 for phenol, 5–120 μg L−1 for methylphenols and 2-chlorophenol, 0.5–120 μg L−1 3-methyl-4-chlorophenol and 2,4-dichlorophenol). The recoveries from authentic spiked samples ranged from 85 to 100% with %RSDs of 0.2–14% for seawater and 81–107% with %RSD of 0.1–11% for produced water. The resulting MIP-based extraction requires no pre-conditioning of the sorbent, and because the required sample size is small and sample manipulation is limited, the method is easy to multiplex for high throughput sample processing.

Composite materialis based on propylene and modified Na +-montmorillonite N, N-diallylacrilamide

The monomer N, N-diallylacrylamide was synthesized by alkylation of acrylamide. The IR spectra of acrylamide and N, N-diallylacrylamide are analyzed. The possibility of obtaining alkyl acrylamide is shown. Modified organoclay is obtained on the basis of montmorillonite of the Na + - form and acrylamide, a water-soluble monomer. The structures and properties of the synthesized compounds were investigated. Composites based on polypropylene modified montmorillonite prepared by mixing in a twin screw melt extruder of the company “JiangsuXindaScience & Technology”. The structure of the composites was investigated using X-ray diffraction and scanning electron microscopy. It is shown that, compared with the unfilled polypropylene, modulus, toughness, melt flow index composites increases, and the time of combustion and the flame propagation velocity is decreased. Shown, that with the introduction of 3-5 wt.% Of the modified Na + - montmorillonite + N, N-diallylacrylamide into the PP, a decrease in the flame propagation rate by 74-79% is observed. The slowing down of the burning rate of the composite is associated with a limitation of the diffusion of atmospheric oxygen into the material due to the presence of a barrier layer created by plane of montmorillonite particles. The presented data are consistent with the results previously obtained in.

Self-Peristaltic Gel-Microspheres Based on Carboxymethyl Cellulose and Polyacrylic Acid Prepared via Inverse Suspension for Recovery Rare Earth Ions from Aqueous Solution

In this study, cross-linked microspheres formed by interpenetrating networks of carboxymethyl cellulose and polyacrylic acid were prepared via inverse-suspension polymerization. The resultant has high adsorption capacity for rare earth ions, can reach 313 mg/g for Ce3+ under the condition of pH 6 at normal temperature. Unique self-creep characteristic gives it a fast-speed adsorption performance, which makes it to reach adsorption equilibrium within 70 min. It also has good reuse performance; its adsorption capacity decrease rate is only 21% after six adsorption–desorption cycles. Adsorption kinetics and thermodynamic studies and adsorption isothermal analysis were researched as well. The research conclusion suggested that this adsorbent is a promising adsorbent for recovering the rare earth ions from wastewater containing rare earth. And all related experiments show that ISP method is effective for making spherical macromolecular adsorbents via water-soluble monomers.

Moldable Strong Cation Exchange Polymer and Microchannel Fabrication.

We characterize a high-capacity cation exchange membrane (CEM) synthesized from an aqueous poly(vinyl alcohol) (PVA) solution and varying amounts of a water-soluble ionic monomer, sodium styrenesulfonate. Highly hydrophilic but water-insoluble transparent polymers with a range of ion exchange capacities (IECs) can be made; at the high end, the ion exchange capacities (IEC) is >2× that of the benchmark CEM, Nafion. The water uptake of the polymer (as moles of water/mole H+) is 5-10× greater than that of Nafion. Except at the highest IECs (where steeply increasing water sorption and resultant swelling outpaces IEC increase), the specific conductance increases with increasing IEC while the conductance anisotropy decreases. The material withstands repeated regeneration cycles and hour-long boiling in water or alcohols. The aqueous prepolymer mixture can be cast around a fine wire acting as a mandrel. Fabrication of an ion exchanger microchannel, capable of withstanding at least 300 psi, is demonstrated. We also discuss entirely novel considerations on ab initio limits of conductance of ion exchange membranes.

Dark polymerization of acrylamide induced by tyrosine-containing peptide

We proposed a novel photoinitiation system composed of photosensitizer and tyrosine-containing peptide, which could initiate radical photopolymerization of acrylamide in water in air. And, when the irradiation was extinguished, the formula with purged nitrogen kept polymerizing in the dark for a long time. The highlight of this system stems from the fact that after low-intensity irradiation as brief as 2 or 5 min, the generated radicals have long lifetime, allowing polymerization propagation in the dark to result in high molecular weight and high conversion. The dark polymerization might be ascribed to the protonation and the steric hindrance of polyacrylamide macroradicals, endowed by the tyrosine-containing peptide, preventing the biradical termination. And these behaviors of the investigated peptides were related to the location of the tyrosine residue on polypeptide chain. In addition, this novel photoinitiator can’t initiate dark polymerization of other water-soluble monomers, but can initiate dark copolymerization of acrylamide with these monomers, further indicating that the hydrogen bonding between acrylamide and polypeptide might be the key factor for dark polymerization. This novel system has potential applications in the preparation of biohydrogels.

Supramolecular Polymeric Radicals: Highly Promoted Formation and Stabilization of Naphthalenediimide Radical Anions.

The supramolecular polymeric radicals are developed to promote the generation efficiency and stability of naphthalenediimide (NDI) radical anions. To this end, a water-soluble bifunctional monomer bearing two naphthalene-viologen end groups and a NDI center is designed and synthesized. The supramolecular polymeric NDI radical anions are fabricated on the basis of host-guest complexation between the NDI-containing bifunctional monomer and cucurbit[8]uril (CB[8]) and followed by the photoinduced electron transfer process under UV light irradiation. The electrostatic effect of CB[8] and the bulky and rigid structure of supramolecular polymer are combined to stabilize the excited state of NDIs and NDI radical anions, contributing to the high enhancement of the formation of NDI radical anions with excellent stability. It is found that the highest occupied molecular orbital energy and lowest unoccupied molecular orbital energy of NDI are also lowered by the formation of supramolecular polymer. In addition, the supramolecular polymeric NDI radical anions could be utilized as a supramolecular photoreducing agent to reduce cytochrome C with a higher efficiency. It is anticipated that other radicals can also be stabilized through this strategy, and this line of research may lead to the development of novel polymeric radical materials.

SYNTHESIS OF N, N-DIALLILBENZOTRIAZOLBROMIDA

This article presents the results of a study of a water-soluble diallyl monomer N, N- diallylbenzotriazolium bromide containing quaternary nitrogen atoms using an alkylation reaction. Synthesis of said monomer was carried out by reacting benzotriazole with allyl bromide at 50-60 °C in an organic solvent medium. Acetone, ethanol, and toluene are used as organic solvents. The structure of the synthesized salt of N, N-diallyl benzo triazolyl bromide, was confirmed by UV-, NMR-spectroscopy. The thermal behavior of the monomers was evaluated by thermoanalytical analysis.

Pore Assembly of Bacterial Alpha Pore-Forming Toxin (αPFT), Cytolysin a on Lipid Membranes

Due to its significance as the primary barrier to cellular entry, cell membrane integrity is key to its sustenance. To overcome this barrier, pathogens have devised diverse cell membrane disruption strategies. Once such mechanism is the formation of nanopores by pore forming toxins (PFTs) released by several bacteria. PFTs, a major class of bacterial toxins are released as water soluble monomers. Upon binding the target bilayer membrane, they undergo structural rearrangements and oligomerize to form a stable transmembrane pore. The molecular mechanisms that result in efficient pore formation on eukaryotic membranes have been unclear. We dissect the assembly pathway of Cytolysin A (ClyA), a representative αPFT by devising single-molecule fluorescence assays that decouple pore formation stages and report on membrane binding, membrane insertion and oligomerization on artificial membrane bilayers. By evaluating the kinetics of intermediates along assembly pathway in membranes of different compositions, testing putative membrane binding domains with mutations, and combining them with mathematical modeling of erythrocyte lysis kinetics, we present a comprehensive mechanistic framework for ClyA pore formation. Our results show that cellular receptors are not essential for ClyA activity but cholesterol, a key component of mammalian membranes, is critical for cell lysis. Interestingly, initial binding of ClyA to membranes is not cholesterol dependent. However, cholesterol enhances the pore formation dynamics by driving the transmembrane domain insertion and oligomerization. Newly discovered cholesterol binding motifs within the N-terminus and β-tongue regions of the protein impart this selective enhancement of ClyA activity on cholesterol membranes. Finally, a cell lysis kinetics model which incorporates the cholesterol dependence of various pathway intermediates is developed to capture ClyA mediated erythrocyte lysis across different mutants.

A study of digital image analysis on the acrylamide derivative monomers induced apoptosis in rat cerebrum.

Nowadays, apoptosis is mostly evaluated visually in histological studies. By using the quantitative digital image analysis, this study aimed to investigate the effect of acrylamide-based monomers (acrylamide [AAm], methacrylamide [MAAm], N-isopropylacrylamide [NIPAm]) on the cerebrum tissues in rats, which are the most common water-soluble monomers in the production of polymeric hydrogels used as biomaterials. The Wistar albino rats weighing ~220-240 g were divided into control and three test groups. The control group received 1 mL of saline, and the test groups received 1 mL of aqueous 50 mg/kg/day intramuscular injection of AAm, MAAm, and NIPAm, respectively. At the end of the experiments, brain tissues of all rats euthanized by intramuscular injection of sodium pentobarbital were removed. Terminal deoxynucleotide transferase dUTP nick and labeling (TUNEL) method was applied to brain tissue sections. The monomers have been shown to cause apoptosis due to oxidative stress in cerebrum tissue. Based on apoptosis by tunneling method, quantitative digital image analysis of cell fragments was performed with Olympus cellSens Dimension 1.15 software, and the number, total count area, selected area, average area, and ROI% values of the fragments were found. In addition, the total area and ROI% values of the fragments increased linearly with increasing the molar mass of monomers from the digital image analysis data. Quantitative digital image analysis can facilitate the monitoring of apoptosis caused by the oxidative stress of monomers used in the production of the biomaterials.

Optimization of Ring-Opening Metathesis Polymerization (ROMP) under Physiologically Relevant Conditions.

Ring opening metathesis polymerization (ROMP) is widely considered an excellent living polymerization technique that proceeds rapidly under ambient conditions and is highly functional group tolerant when performed in organic solvents. However, achieving the same level of success in aqueous media has proved to be challenging, often requiring an organic co-solvent or a very low pH to obtain fast initiation and high monomer conversion. The ability to efficiently conduct ROMP under neutral pH aqueous conditions would mark an important step towards utilizing aqueous ROMP with acid-sensitive functional groups or within a biological setting. Herein we describe our efforts to optimize ROMP in an aqueous environment under neutral pH conditions. Specifically, we found that the presence of excess chloride in solution as well as relatively small changes in pH near physiological conditions have a profound effect on molecular weight control, polymerization rate and overall monomer conversion. Additionally, we have applied our optimized conditions to polymerize a broad scope of water-soluble monomers and used this methodology to produce nanostructures via ring opening metathesis polymerization induced self-assembly (ROMPISA) under neutral pH aqueous conditions.