Methyl Methacrylate-acrylic Acid Research Articles

Study on the poly(methyl methacrylate-acrylic acid)/calcium phosphate cement composite bound by chelation with enhanced water absorption and biomechanical properties

Polymethylmethacrylate (PMMA) bone cement has been widely used as a critical material for fixing prostheses and filling bone defects. The shrinkage of PMMA bone cement was addressed by the additives, however, the uneven integral water absorption and expansion performance as well as the deteriorated mechanical properties of the modified bone cement after immersion in phosphate buffered saline (PBS) and simulation body fluid (SBF) affected the long-term stability after implantation. Calcium phosphate cement (CPC) is a biomaterial with promising applications in orthopedics, whose hydration reaction provides an important driving force for the transfer of water. Besides, the mechanical properties of CPC can be enhanced with the curing process. In this study, CPC was utilized to modify the poly(methyl methacrylate-acrylic acid) [P(MMA-AA)] bone cement. The results demonstrated the successful construction of interconnected CPC water delivery networks in the P(MMA-AA)/CPC composite, the water absorption ratio and expansion ratio of the composite were up to 131.18 ± 9.14% and 168.19 ± 5.44%, respectively. Meanwhile, the transformation of CPC water delivery networks into rigid mechanical support networks as well as the chelation interaction between organic-inorganic enhanced the mechanical properties of the composite after immersion, the compressive strength after immersion reached 62.97 ± 0.97 MPa, which was 27.65% higher than that before immersion. The degradation ratio of the composite was up to 13.76 ± 0.23% after 9 days of immersion, which was 16.4% higher than that of CPC. Furthermore, composites exhibited superior biocompatibility as the release of Ca2+. Therefore, P(MMA-AA)/CPC composite serves as a promising medical filling material for clinical use.

Self-expanding PMMA composite bone cement with sustained release of gentamicin sulfate and alendronate using water absorption pathways

Although drug-loaded polymethyl methacrylate (PMMA) bone cement had been widely used in the vertebroplasty and arthroplasty, the mismatch between the drug release cycle and clinical demand, as well as low drug release rate and single therapeutic effect restricted the use of PMMA bone cement as the drug carrier in clinical applications. In this study, poly(methyl methacrylate-acrylic acid)-alendronate [P(MMA-AA)-ALN] drug-loaded nanoparticles with anti-osteoporosis function were synthesized and introduced into the gentamicin sulfate (GS) loaded PMMA bone cement. The rapidly expandable bone cement with water absorption pathways was constructed by adjusting the particle size of P(MMA-AA)-ALN nanoparticles. More importantly, the sustained release of GS and ALN were creatively achieved by their migration through the water absorption pathways composed of P(MMA-AA)-ALN nanoparticles. The results showed that the cumulative release ratios of GS and ALN in the composites were up to 74.67 ± 1.02 % and 75.23 ± 1.96 %. Meanwhile, the release cycles of GS and ALN were extended to 4 weeks and 15 weeks, effectively preventing infection, and matching the normal bone healing cycle. In addition, the swelling and dual drug release bone cement (SDBC) displayed superior antibacterial activity and biocompatibility.

Magnetically recoverable poly (methyl methacrylate-acrylic acid)/iron oxide magnetic composites nanomaterials with hydrophilic wettability for efficient oil-water separation

Due to the environmental and production problems of emulsion, it is important to efficiently separate oil-water emulsion to meet the refinery requirement and clean up oil spills. Synthesis of a universal demulsifier is not an easy task because the physical properties of crude oil vary, which makes its characterization and demulsification procedure difficult. To overcome this problem, hydrophilic and magnetically recoverable poly (methyl methacrylate-acrylic acid)/iron oxide magnetic composite nanoparticles ((P(MMA-AA)/Fe3O4 NPs) were developed as an efficient and economical demulsifier via soap-free emulsion polymerization. To characterize the magnetic composite NPs for their appropriate surface morphology and magnetic domain, TEM, FTIR, VSM, and TGA analyses were carried out. The newly synthesized NPs displayed good hydrophilic properties as they migrated quickly to the aqueous emulsion phase, which was also reassured by their water contact angle of 75°. They exhibit strong magnetic characteristics (20 amu/g) in the oil-water emulsion, makings the hydrophilic wettability capable and attractive to the external magnet. Experimental results revealed that the prepared magnetic composite NPs separated 99% of the water from stable emulsion in 30 min and could be recycled 8 times through magnetic separation. The recycled magnetic composite NPs maintain their hydrophilic wettability and efficiency in separating oil-water emulsion, making them economical and commercially viable. The migration of magnetic composite NPs to the aqueous phase in the stable emulsion with a strong magnetic domain explains the coalescence of emulsified water droplets and their quick separation from the stable emulsions through the external magnet.

One-Pot Synthesis of Hydrophilic Superparamagnetic Fe<SUB>3</SUB>O<SUB>4</SUB>/Poly(methyl methacrylate-acrylic acid) Composite Nanoparticles with High Magnetization

Uniform superparamagnetic Fe3O4/poly(methyl methacrylate-acrylic acid) (P(MMA-AA)) composite nanoparticles with high saturation magnetization and good hydrophilicity were successfully and directly synthesized via a facile one-pot miniemulsion polymerization approach. The mixture of the ferrofluids, MMA and AA monomers, surfactants and initiator was co-sonicated and emulsified to prepare stable miniemulsion for polymerization. The as-prepared products were characterized by SEM, TEM, FT-IR, XRD, TGA and VSM. The results of SEM indicated that the morphology of the Fe3O4/P(MMA-AA) composite nanoparticles all assumed near spherical geometry with diameters about 60 nm, 60 nm, and 100 nm respectively corresponding to the weight ratios of Fe3O4 to MMA and AA at 1:8, 1:4, and 1:2. The TEM images implied that the Fe3O4/P(MMA-AA) composite nanoparticles showed a perfect core-shell structure with a polymeric shell of about 2 nm thickness and a core encapsulating uniform and close packed Fe3O4 nanoparticles. TGA and VSM showed that the Fe3O4/P(MMA-AA) composite nanoparticles with a maximum saturation magnetization up to 45 emu g(-1) corresponding to the magnetite content of 78% exhibited superparamagntism. The hydrophilic modification and the high saturation magnetization impart a promising potential for biomedical applications to the as-synthesized composite nanoparticles.

Biocompatible nano-micro-particles by solvent evaporation from multiple emulsions technique

In this study, a method based on a multiple emulsions system was developed for the production of polymeric nano and micro-vectors. The possibility to apply an unified preparation technique to different polymers, such as polyesters [polycaprolactone, poly-dl-lactide, poly(dl-lactide-co-caprolactone) = 70/30] and polyacrylates [poly(methylmethacrylate–acrylic acid) = 73/27], loaded with different model molecules (budesonide, tamoxifen, and α-tocopherol) was explored. After selecting the best operating conditions, especially for emulsification and separation, the technique proved to be readily adaptable for production of both nano and micro-particles with different morphologies, depending on type of polymer, and consequently on solvent used for solubilization: nano-particles, with a round shape and a smooth surface, for polyesters, otherwise micro-particles for the polyacrylate polymer, owing to the presence of hydrophilic co-solvents, that caused both an easy coalescence between the oil and water phases, thus enlarged particles size, and a high porosity. Even the yield of encapsulation was influenced by the presence of hydrophilic co-solvents, causing a higher yield for nano-vectors. Polyesters-based nano-vectors showed release times of molecules, linked to their degradation time, higher than 8 months that make them useful to formulate injectable or implantable drug delivery systems. Polyacrylate-based micro-vectors showed an enteric behavior, interesting for designing solid pharmaceutical formulations for oral delivery. Therefore, the technique demonstrated to assure a broad application in drug delivery research.

Synthesis of AA-MMA Block Copolymer by RAFT Polymerization and Used as Emulsifier cum Macroinitiator and Its Influence on the Film Properties

Blocked copolymer of acrylic acid-methyl methacrylate with controlled molecular architecture were prepared by reversible addition chain fragmentation polymerization and were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H NMR), and gel permeation chromatography (GPC) for structural evaluation. The neutralized copolymers were evaluated for the critical micelle concentration (CMC), hydrophilic lipophilic balance (HLB) and were utilized as polymeric emulsifier cum macro RAFT initiator for the synthesis of acrylic binder. The structure properties of the emulsifier were evaluated correlating with the film properties.

A photosensitive material based on methyl methacrylate-acrylic acid copolymer

The possibility of recording holographic images in a photosensitive material based on methyl methacrylate-acrylic acid copolymer, which is more heat-resistant than poly(methyl methacrylate) used as a base for optical recording media, was examined. Introduction of acrylic acid units into poly(methyl methacrylate) macromolecule does not prevent recording and reconstruction of holographic images, but, at the same time, affects the dynamics of variation of the diffraction efficiency of diffraction lattices recorded in this polymer.

Preparation of thermoresponsive Fe3O4/P(acrylic acid–methyl methacrylate–N-isopropylacrylamide) magnetic composite microspheres with controlled shell thickness and its releasing property for phenolphthalein

In this work, Fe3O4/P(acrylic acid–methyl methacrylate–N-isopropylacrylamide) (Fe3O4/P(AA–MMA–NIPAm)) thermoresponsive magnetic composite microspheres have been prepared by controlled radical polymerization in the presence of 1,1-diphenylethene (DPE). The shell thickness of thermosensitive polymer (PNIPAm), which was on the surface of the microspheres, can be controlled by using DPE method. The morphology and thermosensitive properties of the composite microspheres, polymerization mechanism of the shell were characterized by TEM, FTIR, VSM, Laser Particle Sizer, TGA, NMR, and GPC. The microspheres with narrow particle size distribution show high saturation magnetization and superparamagnetism. The thermosensitive properties of the composite microspheres can be adjusted indirectly via controlling the addition amount of monomer (NIPAm) in the second step during controlled radical polymerization. Phenolphthalein was chosen as a model drug to investigate drug release behavior of the thermoresponsive magnetic composite microspheres with different shell thickness. Controlled drug release testing reveals that the release behavior depends on the thickness of polymer on the surface of the microspheres.

Preparation and characterization of acrylic bone cement with high drug release

Drug-loaded bone cement is used as an application method to prevent and treat prosthesis-related infection. Despite the commercial availability of drug-loaded bone cement, low release rate of drugs from drug-loaded bone cement may result in the emergence of drug-resistant coagulase-negative staphylococci in subsequent deep infection. This work presents a method to control and increase both the drug release rate and total release amounts of drugs for drug-loaded bone cement without losing the mechanical properties of cement. A novel drug-loaded bone cement is also developed by introducing cross-linked poly(methylmethacrylate-acrylic acid sodium salt) particles into bone cement. Capable of increasing the hydrophilicity of the cement and allowing fluids to pass into the cement, the bone cement developed here supplements both the drug release rate and total release amounts of drugs.

Acrylic acid–methyl methacrylate (2.5:7.5/2:8) enteric copolymer for colon targeted drug delivery

Enteric copolymers of acrylic acid and methyl methacrylate (2.5:7.5 and 2:8) were prepared using tetrahydrofuran as solvent and AIBN as free radical initiator for colon targeting. FTIR and (1)H NMR spectra of the copolymers showed absence of vinyl bond/protons present in the monomers suggesting successful polymerization. Flurbiprofen sodium microspheres (M1 and M2) made with the copolymers, by oil/oil solvent evaporation, were spherical, anionic (zeta potential -57.8 and -53.7 mV) and contained 5.47 and 5.89% drug. FTIR spectrum of microspheres showed peaks for aromatic C = C stretching and substituted benzene ring, indicating entrapment of flurbiprofen. PXRD revealed crystalline structure of flurbiprofen while copolymer and microspheres were amorphous. DSC thermograms showed a sharp melting endotherm of flurbiprofen sodium at 129.26°C against broad endotherms of copolymers and microspheres. The microspheres released 43 and 36% drug at pH 6.8 in 2 h and 99 and 96% at pH 7.4 in next 3-4 h.The microspheres did not adhere on gastric-mucosa at pH 1.2 but showed mucoadhesion time of 18 min and 9 min on intestinal mucosa at pH 6.8. Thus, the microspheres on oral administration, would release the drug in colon, suggesting the potential of the hemocompatible copolymers for pH dependent colon targeted drug delivery system.

Enteric Micro-Particles for Targeted Oral Drug Delivery

This work is focused on production of enteric-coated micro-particles for oral administration, using a water-in-oil-in-water solvent evaporation technique. The active agent theophylline was first encapsulated in cellulose acetate phthalate (CAP), a pH-sensitive well-known polymer, which is insoluble in acid media but dissolves at neutral pH (above pH6). In this first step, CAP was chosen with the aim optimizing the preparation and characterization methods. The desired release pattern has been obtained (low release at low pH, higher release at neutral pH) but in presence of a low encapsulation efficiency. Then, the CAP was replaced by a novel-synthesized pH-sensitive poly(methyl methacrylate-acrylic acid) copolymer, poly(MMA-AA). In this second step, the role of two process parameters was investigated, i.e., the percentage of emulsion stabilizer (polyvinyl alcohol, PVA) and the stirring power for the double emulsion on the encapsulation efficiency. The encapsulation efficiency was found to increase with PVA percentage and to decrease with the stirring power. By increasing the PVA content and by decreasing the stirring power, a high stable double emulsion was obtained, and this explains the increase in encapsulation efficiency found.

Acrylic acid–methyl methacrylate copolymer for oral prolonged drug release

Acrylic acid (AA)-methyl methacrylate (MMA) based copolymers, in different molar ratios (3:7, 4:6, 5:5, 6:4, and 7:3) were synthesized using tetrahydrofuran as solvent and AIBN as free radical initiator. Increase in acrylic acid concentration promoted pH-dependent swelling of copolymer and copolymer AA:MMA (3:7) was selected due to minimum swelling. ATR/FTIR and (1)H NMR spectra of the copolymer showed absence of vinyl bond/protons present in the monomers suggesting successful polymerization. The copolymer was hemocompatible. Flurbiprofen sodium microspheres made with the copolymer, by oil/oil solvent evaporation, were spherical, anionic (zeta potential -59.0 mV) and contained 4.53% drug. ATR spectrum of microspheres showed peaks for aromatic C=C stretching and substituted benzene ring, indicating entrapment of flurbiprofen. XRD analysis revealed crystalline structure of flurbiprofen while copolymer and microspheres were amorphous. DSC thermograms showed a sharp melting endotherm of flurbiprofen sodium at 129.26 degrees C against broad endotherms of copolymer and microspheres having peaks at 82.24 and 86.59 degrees C, respectively. The thermogram of microspheres did not show the melting peak of flurbiprofen. The microspheres exhibited no drug release at pH <6.8 and released 83.4 and 99% drug at pH 6.8 and 7.4 in 3 h. The microspheres did not adhere on gastric mucosa at pH 1.2 but showed mucoadhesion time of 28 min on intestinal mucosa at pH 6.8. Thus, the microspheres on oral administration, would release the drug in distal ileum, suggesting the potential of the hemocompatible copolymer for enteric coating for prolonged drug release.

Synthesis and Spray Drying of Water-Redispersible Polymer

The present work reveals the preparation of waterborne acrylic emulsion for interior coating. The emulsion was prepared by sequential core-shell polymerization method. The prepared acrylic emulsions were then spray dried and converted into redispersible powder. The effect of different neutralizing agents on the powder transformation yield and redispersibility properties of the polymer powder was studied. The mother emulsion and redispersible emulsion showed similar flexibility, impact resistance, and adhesion property. In addition, this article describes the preparation of redispersible aid by solution polymerization of acrylic acid–methyl methacrylate. The resultant spray-dried powder showed very good redispersibility.

Synthesis and characterization of P(MMA-AA) copolymers for targeted oral drug delivery

This paper describes the development of pH-sensitive poly(methyl methacrylate-acrylic acid) copolymers for the enteric coating of pharmaceutical products for oral administration. To obtain the dissolution at the desired pH level, different pH-sensitive polymers are available on the market. Usually, for each desired dissolution pH, an ad hoc polymer is designed. Thus, different dissolution pH values could ask for completely different polymers. Instead, the materials proposed in this work are copolymers of the same two monomers, and the different dissolution pH was obtained by changing the volume fraction of the hydrophobic methyl methacrylate monomer to the hydrophilic acrylic acid monomer. Increasing the volumetric percentage of methyl methacrylate causes the polymer to dissolve at increasing pH, until the dissolution does not take place at all, and it is replaced by a slow swelling phenomenon. The copolymers obtained were characterized by differential scanning calorimetry, in order to evaluate their glass transition temperature, and these latter were related to %MMA. The molecular weights of the pure polymers (PAA, PMMA) were measured by intrinsic viscosity, to further validate the glass transition temperatures observed. The dissolution of the copolymers was carefully tested in buffer solutions for a dense set of pH values. A linear relationship between dissolution pH and volumetric percentage of methyl methacrylate was obtained from these measurements. As a result, for any physiological compartment, the copolymer which dissolves at the pH of interest can be easily synthesized.

Composite membranes modified with recognition-able nanobeads as potential adsorbers for purification of biological fluids.

Therapeutic approaches in the clinical field require advanced properties for delivery or recognition of clinical species. The molecular imprinting method allows selective cavities to be inserted into a polymeric material built ""around"" a stamp molecule (template) through polymerization or phase inversion. This study focuses on the application of both methods in the realization of polymeric membranes with selective recognition and adsorption properties. Imprinted polymethacrylic acid (PMAA) particles, exhibiting specific binding sites for cholesterol molecule (template), were realized via precipitation polymerization in the shape of nanobeads and loaded in the bulk or on the surface of methylmethacrylate-acrylic acid P(MMA-co-AA) membranes obtained by the non-solvent induced phase separation (NIPS) technique. In this way, specific cavities were introduced into the membrane network to enhance and specialize uptake performances of the porous membranes taking advantage of the particle characteristics. Rebinding performances towards cholesterol in a physiological environment were tested showing very interesting results: the adsorption of cholesterol molecules from physiological solution was increased by using composite membrane-nanobead systems instead of control membranes (a quantitative increase of 14 mg of cholesterol per g of polymer matrix in respect of blank membrane was detected). The results obtained showed an improved performance of composite membranes, but also an unmodified behavior of loaded nanobeads (with respect to free ones) concerning the recognition capability in aqueous medium, which is the most difficult obstacle to overcome in molecular imprinting. The absolute rebinding capacity and the imprinting efficiency of membranes were in the range (and in some case higher) of other efficient systems, but the real improvement was that molecularly imprinted embranes showed an excellent recognition capacity in physiological medium instead of organic solvents.

Partial volume and compressibility at infinite dilution of functionalized multilayer latex particles

A series of functionalized multilayer latex particles of P(butyl acrylate–methyl methacrylate–acrylic acid) was synthesized. The total acrylic acid concentration inside particles was varied from 0 to 25 wt.% and the number of particles in the system was held constant. The polymeric particles were studied by means of specific partial volume and specific partial compressibility at infinite dilution, which were calculated from density and sound speed measurements. From the behaviour of the partial properties at infinite dilution of the polar and non-polar groups of the polymer chain, it was concluded that the particle swells at low acrylic acids content due to the electrostatic repulsion between the carboxylic groups of the polymer chain. From 15 wt.% of acrylic acid up, the particle swells due to the electrostatic repulsion and to the incorporation of water molecules in the bounds of the particle layers. In this way, the hydration is non-homogeneous in the interior of each layer. These results are in agreement with the behaviour of the hydrodynamic radius determined by the quasi-elastic light scattering technique.

Co-polymers of acrylic acid and methyl methacrylate as stabilizers for suspension polymerization of styrene

The synthesis of homo-polymers of acrylic acid and co-polymers of acrylic acid–methyl methacrylate as suspension agents (SA) was performed in aqueous media, and SA were used as stabilizer in the suspension polymerization of styrene. The behavior of water solutions in the interfacial tension of SA against styrene was studied. The composition of the co-polymers and their molecular weights are related to the Zykonski model coefficients and to the molecular configuration of the stabilizer at the interface. It was found that the molecular weight, the composition of SA, the concentration used in the reaction system and the time at which it was added had a marked effect on the stability of the suspension during the reaction and on the final particle size distribution of the polystyrene beads. The homo-polymers of acrylic acid do not prevent correctly the coalescence during the suspension polymerization, while the co-polymers of acrylic acid and methyl methacrylate are well adsorbed into the oil/water interface and then work as good stabilizers for styrene suspension polymerizations. Provided a good stabilizer was used, i.e., with a high molecular weight and enough hydrophobic character, its addition delayed up to the beginning of the sticky stage produced a quite narrow particle size distribution.

Study on swelling behavior and pervaporation properties of AA–MMA–BA copolymers for separation of methanol/MTBE/C5 mixtures

AbstractIn this study, the copolymers with different ratios of AA(acrylic acid)–MMA(methyl methacrylate)–BA (butyl acrylate) are synthesized to prepare pervaporation membrane for the separation of methanol/MTBE (methyl tert‐butyl ether)/C5 mixtures. Swelling experiment of these copolymers in pure methanol, MTBE, C5, and methanol/MTBE mixtures are carried out, respectively. The results show that there is a strong interaction between MTBE and copolymer with high content of BA. The pervaporation characteristics of the membranes prepared with different copolymer are measured in the separation of methanol/MTBE mixture. The experimental results show that the pervaporation ability changes with swelling degree in the same direction. The copolymers are characterized by FTIR. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2267–2271, 2003

Swelling of crosslinked poly(methylmethacrylate-acrylic acid) copolymers in serum and saline solutions

In recent articles, our research group explored the use of crosslinked Poly(methylmethacrylate-acrylic acid) and composites based on this copolymer for bone implant applications such as suture anchors. The swelling response of this system was studied first in vitro, using a 0.85 g/100-mL saline solution (chosen because it simulates well the in vivo environment), and later in vivo by using samples implanted for various time periods in the lateral femoral condyles of New Zealand white rabbits. It was found that the swelling response of the crosslinked copolymer in vivo was much greater than that in the saline solution. The present investigation was conducted to determine the mechanism of excessive swelling in the in vivo tests. The approach used was to establish the changes occurring in the chemical structure of the copolymer due to immersion in serum. A number of hypotheses that can potentially explain the observed excessive swelling in serum were investigated and are discussed in this article. The results of this study indicate that the mechanism of excessive swelling in serum was the neutralization of COOH groups in the copolymer to produce salts of acrylic acid, which are known to result in greater swell due to their higher degree of dissociation compared to free acid. It was also found that, for compositions containing the acrylic salts (produced by preswelling in high pH solutions and drying), the swelling behavior in serum was similar to that in saline solution, and more importantly, equilibrium swelling was reached in a relatively shorter time period, which has several practical advantages for bioimplant applications. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1653–1664, 2001

Luminescence Studies of Polymer Matrices: 4. Phosphorescence of Benzophenone Dispersed in Acrylic Acid Based Polymer Films

The thermal dependence of the phosphorescence characteristics of benzophenone (BP) dispersed in thin films of poly(acrylic acid), PAA, and acrylic acid-methyl methacrylate, AA-MMA, copolymers is described. At all temperatures (between 77 K and 410 K), and in each of the systems studied, the triplet state decay kinetics of the phosphor are complex: a minimum of three exponential terms is required for adequate modelling of the time dependence of BP phosphorescence. This complexity is considered to reflect the breadth and heterogeneity of the distribution of sites accessed by the probe within each of the polymer matrices. Both phosphorescence intensity and lifetime measurements are affected by the onset of macromolecular relaxations within each of the film samples. However, the temperature dependence of the BP phosphorescence data seems to also reflect the presence of specific interactions between the probe and polymer. Consequently the data do not allow a definitive picture of the relaxation behaviour or phase morphology of the copolymer samples to be derived. The data also illustrate the fact that, in designing a high-performance phosphorescent coding system, trends in the photophysical characteristics of one dopant in a given matrix do not necessarily translate into predictions of the behaviour of another phosphor even in the same matrix.