Methyl Methacrylate Units Research Articles

Peculiar Behavior of Methyl Methacrylate Emulsion Polymerization-Induced Self-Assembly Mediated by RAFT Using Poly(Methacrylic Acid) Macromolecular Chain Transfer Agent.

Reversible addition-fragmentation chain transfer (RAFT) emulsion polymerization of methyl methacrylate (MMA) is successfully performed in water in the presence of a poly(methacrylic acid) (PMAA) macromolecular chain transfer agent (macroCTA) leading to the formation of self-stabilized PMAA-b-PMMA amphiphilic block copolymer particles. At pH3.7, the reactions are well-controlled with narrow molar mass distributions. Increasing the initial pH, particularly above 5.6, results in a partial loss of reactivity of the PMAA macroCTA. The effect of the degree of polymerization (DPn) of the PMMA block, the solids content, the nature of the hydrophobic segment, and the pH on the morphology of the obtained diblock copolymer particles is then investigated. Worm-like micelles are formed for a DPn of PMMA of 20 (PMMA20), while "onion-like" particles and spherical vesicles are obtained for PMMA30 and PMMA50, respectively. In contrast, spherical particles are obtained for the DPns higher than 150. This unusual evolution of particle morphologies upon increasing the DPn of the PMMA block seems to be related to hydrogen bonds between hydrophilic MAA and hydrophobic MMA units.

Unraveling the role of counter anions on optical and microwave absorption characteristics of flexible copolymers

Engineering the structural architecture of materials is critical for the transmittance of visible light and absorb microwave radiation in various stealth and electronic applications. Transparent copolymers comprising of methyl methacrylate (MMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) were synthesized at different compositions using reversible addition-fragmentation chain transfer (RAFT) polymerization. The copolymers exhibited a high percentage of light transmittance (>90%) within the visible range owing to the majority fraction of MMA units. The amine functionalities in the synthesized copolymers were ionized at room temperature by treating with dilute acids such as hydrochloric acid (HCl), trifluoroacetic acid (TFA), nitric acid (HNO3), tetrafluoroboric acid (HBF4), and hexafluorophosphoric acid (HPF6). The quaternization of the side-chain amine groups have resulted in a series of copolymer salts with an ion-pair complex. The investigation of the counter anion effect on the conductivity of the materials has been carried out to produce the highly transparent and conductive MMA-based copolymers. The presence of partially mobile Cl⁻ counter anions in the copolymers can result in conductance as high as 0.939 mS cm−1. Moreover, the optically transparent MMA-based copolymer salts have witnessed a high microwave absorption due to multiple reflections from structural and physical anisotropies.

Formulation of polymeric particles with controlled charges by alkaline tempering

The control of surface charge of polymeric microparticles is a major challenge because electrostatic interactions stabilize their aqueous suspensions. In this study, anionic PMMA particles were prepared with 5 wt% of methacrylic acid as a comonomer. This comonomer was expected to give a negative charge to the particles, but none was observed from zeta potential measurements. The evolution of the zeta potential in alkaline medium was investigated to better understand this observation. It was demonstrated that the acid groups were present almost only in the core of the particles and that their deprotonation was possible using an alkaline tempering. Two phenomena occurred simultaneously leading to the charge appearance at the particle surface: i) the diffusion of hydroxide ions into the particles, allowing the migration of the negative charges to the particle surface with an appearance rate per mol of particles of 2.0 10−3m3 mol−1 s−1 (multiplied by the hydroxyl ion concentration), and ii) the hydrolysis of ester groups of methyl methacrylate units characterized by a pseudo first order kinetics with k = 3.0 10−9 m3 mol−1 s−1. By carefully choosing the parameters of the tempering process, hydrolysis is minimized and anionic particles can be prepared with stable and controlled charges coming from the anionic comonomer. Doing so, anionic PMMA-like particles exhibited a stable zeta potential of −11.5 mV.

Revisiting the structure of copolymer via anionic hybrid copolymerization of methyl methacrylate and ε-caprolactone

Anionic hybrid copolymerization of vinyl and cyclic monomers provides a powerful strategy to synthesize heteropolymers. Yet, there are some open questions regarding its mechanism and the structure of the resulted polymer. We reported that the copolymer (Poly(MMA- co -CL)) of methyl methacrylate (MMA) and ε-caprolactone (CL) via such copolymerization was random. However, a recent study proposed that the copolymer might be simple graft one with poly(methyl methacrylate) (PMMA) as the main chain and poly(ε-caprolactone) (PCL) as the graft chain. In this study, we synthesized a model graft copolymer (PMMA- g -PCL) by using a combination of reversible complexation-mediated polymerization and ring-opening polymerization, and made comparison with Poly(MMA- co -CL) in their properties and hydrolysis. Differential scanning calorimeter (DSC) measurements show that the graft copolymer PMMA- g -PCL possesses two glass transitions and a melt peak. In contrast, Poly(MMA- co -CL) exhibits only one glass transition without a melt peak because it is amorphous, clearly indicating that it is random. Proton nuclear magnetic resonance ( 1 H NMR) measurements reveal that the hydrolysis of PMMA- g -PCL yields only PMMA oligomers. However, the hydrolyzed products of Poly(MMA- co -CL) consist of MMA and CL units. The facts further indicate that the copolymer Poly(MMA- co -CL) is random. Considering that the transesterification reactions are unavoidable in the anionic hybrid copolymerization, the copolymer should consist of random main chain and random branches. • The present study demonstrates that anionic hybrid copolymerization of MMA and CL generally yields random copolymer but not graft copolymer. • Transesterification is not the essential step in the anionic hybrid copolymerization, but it can cause branching of the copolymer. • The hybrid copolymer of MMA and CL consists random main chain and random branches.

Diselenide as a Dual Functional Mechanophore Capable of Stress Self-Reporting and Self-Strengthening in Polyurethane Elastomers

Diselenide as a Dual Functional Mechanophore Capable of Stress Self-Reporting and Self-Strengthening in Polyurethane Elastomers

Unity Makes Strength: Constructing Polymeric Catalyst for Selective Synthesis of CO 2 /Epoxide Copolymer

Unity Makes Strength: Constructing Polymeric Catalyst for Selective Synthesis of CO ₂ /Epoxide Copolymer

Preparation of Durable Superhydrophobic Cotton Fabric for Self-cleaning and Oil-water Separation

Improving the surface roughness and reducing the surface energy are the main strategies for constructing cotton fabrics with superhydrophobic surface. However, the complex finishing process and poor durability still impede the production and application of superhydrophobic cotton fabrics. Therefore, it is critical to produce superhydrophobic fabrics with excellent durability via a noncomplicated method. In this work, monomers of methyl methacrylate (MMA) and trifluoroethyl methacrylate (TFMA) were polymerized via free radical polymerization to produce a fluoropolymer. Then, the fabric was coated with the fluoropolymer to construct a superhydrophobic surface via the pad-dry-cure technology. The TFMA unit in the fluoropolymer had lower surface energy than the MMA unit. Under the high-temperature curing condition, the MMA unit in the fluoropolymer was grafted onto the cotton fabric via transesterification, and the TFMA was exposed on the fabric surface. The finished fabric showed durable superhydrophobic properties, outstanding oil-water separation properties, and excellent self-cleaning properties. Given the results, the finished fabric has great potential application in clothing and industrial fields.

Effect of Substituted Styrene‐Butadiene Rubber Binders on the Stability of 4.5 V‐Charged LiCoO2 Electrode

AbstractThe combination of synthetically modified styrene‐butadiene rubber (SBR) and sodium carboxymethyl cellulose (CMC) was studied as an aqueous binder for LiCoO2 composite electrodes under high‐voltage operation. Methyl methacrylate (MMA) and 2‐vinylpyridine (VP) substituted SBR copolymers were synthesized and examined as functional polymer binders. The electrolyte‐solvent uptake of the binder‐polymer film was increased by the introduction of the MMA units, but the solubility of the polymer in the solvent remained negligibly low. Hard‐X‐ray photoelectron spectroscopy revealed the formation of a relatively thick passivation layer on the LiCoO2 surface with MMA‐substituted SBR and CMC binder, which suppressed the self‐discharge of 4.5 V‐charged LiCoO2. The capacity retention during battery cycling experiments was similar for the LiCoO2 electrodes with MMA‐modified and unmodified SBR binders. While the effect of VP‐substitution was not significant, incorporation of the MMA unit enhanced the stability of the charged LiCoO2 electrode and provided improved self‐discharge performance.

Peng-Robinson Cubic Equation of State Based on Key Group Contribution and Calculation of Nitrogen Gas Solubility in MMA Dimer

Previously authors have reported facts that nitrogen (N2) and oxygen solubilities in styrene is the same as those in benzene and divinylbenzene at 303 K. Though the three compounds have an atomic composition, (CH)n (n=6, 8 and 10), the gas solubilities are thought to depend on the number of aromatic carbons in the solution. Then, authors named it ‘a key group in solubility’. In this research, the key group was investigated for N2 solubility in methyl methacrylate (MMA) and its dimer, ethylene glycol dimethacrylate (EGDMA). Therefore, the calculations were carried out by Peng-Robinson (PR) equation of state based on group contribution methods. The experimental data employed were those of Lai et al., where N2 solubility are reported in MMA at 303 K. The N2 solubility in EGDMA was assumed to be double of that in MMA at 303 K, because EGDMA has two MMA units in the molecule. Two types of group contribution methods were proposed to calculate N2 solubility in EGDMA. One was for the critical temperature and pressure proposed by Joback and Reid. Using these properties, the attractive and excluded volume parameters in PR equation were evaluated for EGDMA. Other was similar to a method proposed by Orbey and Sandler. The excluded volume parameter in PR equation can be evaluated from those of MMA by multiplying the number of repeating units, and the attractive by multiplying the squared number. Instead of the method, the powers were proposed to be 3/4 and 3/2 for the excluded volume and attractive perimeters, respectively. The powers were come from a scaling theory by de Gennes. The binary parameter for N2 – EGDMA was also set to k12 = 0.224, which was the same as that for N2 –MMA. The calculated N2 solubility in EGDMA was far smaller than the hypothetical N2 solubility in EGDMA at 303 K. Otherwise, to reproduce the hypothetical N2 solubility, a quite different value, k12 = -0.044, was necessary for the method by Joback and Reid. The results suggested that a key group for gas solubility will not be accepted in MMA.

Backbone-Degradable Polymers via Radical Copolymerizations of Pentafluorophenyl Methacrylate with Cyclic Ketene Acetal: Pendant Modification and Efficient Degradation by Alternating-Rich Sequence.

This work deals with syntheses of backbone-degradable polymers via the radical copolymerization of pentafluorophenyl methacrylate (PFMA) with 5,6-benzo-2-methylene-1,3-dioxepane (BMDO), which undergoes ring-opening propagation to afford an ester-bonded backbone. The combination of the electron-deficient methacrylate with the electron-rich cyclic monomer allowed high crossover copolymerization, and the electronic effect was clarified by the comparison with the copolymerization of methyl methacrylate (MMA) and BMDO. The PFMA units of the resultant copolymer underwent quantitative alcoholysis or aminolysis transformation into methacrylate or methacrylamide units along with the pendant functionalization. The alternating-rich sequence was achieved by feeding an excess ratio of BMDO, which was supported by MALDI-TOF-MS of the copolymer obtained by the RAFT copolymerization. The methanolysis-transformed copolymer carrying MMA units was decomposed under basic condition, and the degradation efficiency was superior to that of the copolymer obtained via radical copolymerization of MMA with BMDO because of the alternating-rich sequence.

CO2-triggered hydrophobic/hydrophilic switchable waterborne polyurethane–acrylate with simultaneously improved water resistance and mechanical properties

Traditional waterborne polyurethane (WPU) has poor water resistance because of the incorporation of permanent hydrophilic groups, such as carboxyl group or ammonium salt, into polymer chains. Therefore, developing WPU with excellent water resistance and mechanical properties is highly desirable for industrial applications. In this study, CO2-triggered hydrophobic/hydrophilic switchable waterborne polyurethane–acrylate (WPUA) containing methyl methacrylate (MMA) units were designed and synthesized. The molecular structure, hydrophobic/hydrophilic switchable behavior, water resistance, and mechanical properties were systematically investigated and characterized. The WPUA with 10 wt% MMA exhibited a low water uptake (2.15 wt%) and linear swelling ratio (0.17 L%), as well as a high tensile strength (16.7 MPa) and modulus (85.9 MPa), which were much higher than those of the pristine WPU. This study indicated that the CO2-triggered WPUA dispersed stably as latex particles in water and possessed excellent water resistance and mechanical properties after the film formation.

Performance of Cotton, Cotton-Polyester, and Polyester-Elastane Fabrics Impregnated with Ultrafine Polymeric Nanoparticles Loaded with Lavender Oil

Lavender oil- (LO-) loaded ultrafine nanoparticles (NP) ( diameter < 50 nm ) of a copolymer were used for impregnating fabrics of cotton, cotton polyester, and polyester-elastane. The copolymer was composed mainly of methyl methacrylate (MMA) units with a low proportion of methacrylic acid (MAA). Moreover, two kinds of NP were used: one containing uncrosslinked copolymer and another one composed of crosslinked material. All the fabrics impregnated with NP of uncrosslinked copolymer keep the aroma up to 25 washes. Under storage at ambient conditions, the fabrics impregnated with NP of either uncrosslinked or crosslinked copolymer emitted aroma for up to almost 60 days. The long duration of aroma emission from fabrics is attributed to ease of the small nanoparticles used in this study of penetrating and staying inside the pores of the fabric fibers.

Development of polymethacrylate thickener for low pour point transmission oil

The influence of the molecular weight and composition of polyalkyl (meth) acrylate thickeners on the properties NS-3 ultralow pour point naphthenic base oil (Nynas, Sweden) was determined. Using standard experimental techniques, it has been shown that copolymers of higher alkyl methacrylates with C12- C15 alkyl groups, containing 5- 15% methyl methacrylate or butyl methacrylate units and having an average molecular weight М n = 18000- 20000, have good thickening properties and high resistance to mechanical destruction (which are not inferior to the indicators of the used foreign additive Viscoplex 0-220). The results made it possible to develop a thickening additive K-64-03 for low pour point transmission oil, which can be used in highly loaded machinery in the winter conditions of the Far North. Additive K-64-03 exhibits the required thickening properties at elevated and negative temperatures, does not worsen the ultra-low pour point of the base oil (below minus 70°C) and has a high resistance to mechanical destruction.

Determination of monomer reactivity ratios and thermal properties of poly(GMA-co-MMA) copolymers

In this study, the free radical copolymerization of glycidyl methacrylate (GMA) and methyl methacrylate (MMA) was investigated for the first time by solution free radical copolymerization in toluene at 80 °C using azobisisobutyronitrile as an initiator. The 1H-NMR spectroscopy has been used for determining the copolymer composition. Monomer reactivity ratios (r values) were calculated by various linear least-square methods. According to the results, using the Kelen–Tudos (KT) and extended Kelen–Tudos (Ex KT) methods the r values were obtained as $$ r_{\text{G}} = 1.528 \pm 0.168 $$ , $$ r_{\text{M}} = 0.789 \pm 0.121 $$ , and $$ r_{\text{G}} = 1.577 \pm 0.186 $$ , $$ r_{\text{M}} = 0.783 \pm 0.129 $$ , respectively. The calculated monomer reactivity ratios showed the higher reactivity for GMA (rG) compared to MMA (rM). Furthermore, the findings demonstrated random or ideal behavior ( $$ r_{\text{G}} \cdot r_{\text{M}} \simeq 1 $$ ) for these copolymers. The monomers sequence distribution as probability of finding the multiple sequence distribution of the GMA and MMA units in copolymers was calculated and showed higher probabilities for GMA sequences. Thermogravimetric analysis of the copolymers had three degradation stages, and the main degradation occurred at third stage (340–456 °C) with 56% weight loss. Also, with regard to initial temperature of degradation and T50, the thermal stability was improved 62% and 2.3%, respectively, by increasing MMA content in copolymer. These studies could uncover the underlying GMA–MMA composition in copolymer, shedding light on the future design of top-performing applications such as UV printing ink and resin industry.

Composition‐dependent crystallization behavior of copolyperoxides from methyl methacrylate and 4‐vinylbenzyl stearate

AbstractTo study the composition‐dependent crystallization behavior of copolyperoxides, herein a series of copolymers were prepared by varying the ratios of methyl methacrylate (MMA) and 4‐vinylbenzyl stearate (VBS) under 100 psi oxygen pressure using AIBN as an initiator at 50°C in toluene. Both 13C NMR and electron impact mass spectroscopy (EI‐MS) approved an alternative placement of either of the monomer and peroxy (–O–O–) links throughout the polymer chain. Thermal stability of the resulting copolyperoxides was investigated by thermogravimetric analysis (TGA) and the degradation fragments have been recognized from EI‐MS study. In addition, differential scanning calorimetry (DSC) displayed an endothermic peak as well as an exotherm associated with the melting of the side chain crystalline domains and degradation of –O–O– links in the polymer main chain, respectively. Furthermore, DSC thermograms unveiled a systematic decrease of the crystalline melting temperature (Tm) with the enhancement of MMA content in the copolymers. Small angle X‐ray scattering (SAXS) revealed the existence of lamellar morphology (depends on VBS content in the copolyperoxide) in the synthesized polyperoxide materials, further supported by atomic force microscopy (AFM) analysis showing a layered fibrillar assembly with multiple heights of the lamella. The significant crystalline nature of the polyperoxides was further evidenced from the appearance of lattice fringes in the transmission electron microscope (TEM) micrographs. The crystalline morphology with birefringent texture was further evidenced from the polarized optical microscopy (POM) study. Thus, the present study reported the effective variation of crystalline behavior in copolyperoxide materials with the incorporation of MMA units in the copolyperoxide chains.

Design and fabrication of a transparent, tough and UVC screening material as a substitute for glass substrate in display devices

A series of copolymers P(MMAx-co-ANy) constituting of methyl methacrylate (MMA) and acrylonitrile (AN) monomer unit and a homopolymer PMMA have been synthesized by solution polymerization method. The foremost purpose of this research is to obtain tough, transparent, lightweight materials, which will be able to substitute glass in all display devices. Complete characterizations of all the polymers have been carried out along with their absorption properties to understand the effect of introduction of AN comonomer unit on MMA backbone. Among all synthesized copolymers, P(MMA70-co-AN30) is found to be the best composition based on both mechanical and optical properties compared to the same of the other polymers. The optical study of this polymer shows only 5% transmittance at wavelength 256 nm, which is almost equivalent to UV-shielding properties of glass, and this selective UV-screening is achieved without addition of any additives or fillers in copolymer matrix.

In situ hydrogel formation for biomedical applications using acoustic cavitation from high intensity focused ultrasound

There is a growing interest in polymer mechanochemistry for their industrial applications. For example, stress-induced crosslinking gel formation from polymer networks is a rapidly growing field of study. Recent work utilizes a variety of different polymer structures and crosslinking mechanisms. However, these polymers are typically soluble in only organic solvents and require the use of a sonicating probe or bath at frequencies below 100 kHz. These requirements limit their use in biomedical applications that require in situ gel formation within a patient (e.g., blocking of varicose veins, internal wound healing, etc.). Here we report on the development of a water soluble block copolymer that forms a hydrogel in the presence of acoustic cavitation from high intensity focused ultrasound. These block copolymers are comprised of hydrophilic polyethylene glycol methyl methacrylate units and hydrophobic tridentate crosslinkers. The tridentate crosslinker forms bonds with free metal ions in solution only in the presence of acoustic cavitation induced mechanical stress. We show that the block copolymer is capable of forming a hydrogel in under 90 seconds and will also block a liquid channel formed in an agarose cylinder.

Relationship between water structure and properties of poly(methyl methacrylate-b-2-hydroxyethyl methacrylate) by solid-state NMR

We previously reported that the platelet compatibility of methyl methacrylate (MMA)–2-hydroxyethyl methacrylate (HEMA) diblock copolymers is related to the characteristic water structure in the copolymer, as the copolymer has an excess amount of nonfreezing water when compared with that estimated from the amounts of water in HEMA and MMA homopolymers. Thus, in this study, the relationship between water structure and polymer structure, including the heterogeneity and mobility of the copolymer, was investigated using differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) spectroscopy. The prepared copolymers were classified into two groups: copolymers with a short, constant polyMMA segment length (Mn = ~2900) and copolymers with a constant polyHEMA segment length (Mn = ~9500), whereas the lengths of the counter segments varied. DSC analysis showed that when the polyMMA and polyHEMA segment lengths are similar, the amount of nonfreezing water increases, regardless of the total molecular weight of the copolymer. NMR analysis showed that heterogeneity of the copolymer is enhanced and the mobility of the copolymer decreases when the segment lengths are similar. These findings suggested that the excess amount of nonfreezing water is formed when the properties of water near the HEMA unit change from freezing to nonfreezing owing to interactions with the MMA unit. In addition, it is suggested that the heterogeneity of the copolymer structure or the mobility of the polymer are involved in the generation of excess nonfreezing water.

The effect of the solvent employed in the synthesis of hydrogels of poly (acrylamide-co-methyl methacrylate) on their structure, properties and possible biomedical applications

Polyacrylamide and poly(acrylamide-co-methyl methacrylate) hydrogels were synthesized in three different solvents: water, aqueous dioxane 50vol% and aqueous ethanol 80vol%. The obtained hydrogels were characterized by swelling behavior, FTIR, SEM, optical microscopy (OM) and DSC. The hydrogels showed a significant dependence of their microstructure and other properties with the solvent used during the synthesis. Hydrogels synthesized in water showed a poor incorporation of methyl methacrylate (MMA) units as evidenced by FTIR, while those synthesized in aqueous ethanol 80vol% exhibited a higher incorporation of MMA as compared to the hydrogels obtained in aqueous dioxane 50vol%. Although the incorporation of MMA is higher for the hydrogels synthesized in aqueous ethanol 80vol%, these hydrogels displayed the highest swelling values (e.g., 6500% for the polyacrylamide hydrogel). These values are approximately 7-times higher than the swelling of equivalent hydrogels synthesized in water (900%). DSC results are consistent with swelling behavior, since the difference in the content of free water was 70, 9 and 6mg of free water/mg of xerogel for the hydrogels of acrylamide synthesized in aqueous ethanol 80vol%, water and aqueous dioxane 50vol%, respectively. OM and SEM results reveal highly porous microstructures characteristic of superabsorbent materials. Only hydrogels synthesized in aqueous dioxane 50vol% were studied as potential carriers for ciprofloxacin. Results demonstrated that most of the drug load is released during the first 6h.

Spacer Monomer in Polymer Chain Influencing Affinity of Ethylene Glycol Methacrylate Phosphate toward UO22+ and Pu4+ Ions

The complexation behavior of ligating groups bearing ethylene glycol methacrylate phosphate (EGMP) units spaced in the polymer chain was studied to understand the coordination ability of segregated EGMP toward UO22+ and Pu4+ ions. The EGMP units in the polymer chain were copolymerized with a varying mol proportion of spacer monomer N-isopropylacylamide (NIPA) and methyl methacrylate (MMA) along with a cross-linker. These copolymer gels were characterized by FTIR, SEM/EDS, and thermal analysis. It was observed that the copolymer gels had homogeneity and concentration of phosphate groups systematically decreased with an increase in mol proportion of spacer monomer units. The hydrophlicity of (EGMP-co-MMA) copolymer gels decreased with an increase in mol proportion of MMA units whereas hydrophilicty of EGMP-co-NIPA copolymer increased with an increase in mol proportion of NIPA units in the copolymer gels. It was observed that UO22+ ions sorption decreased with an increase in MMA units in the polymer chain at...