Poly(methacrylic acid)

• CAS: 25087-26-7
• Catalog Number: ACM25087267-1
• Category: Polymer/Macromolecule
• Molecular Weight: 86.09g/mol
• Molecular Formula: C4H6O2;CH2=C(CH3)COOH;C4H6O2;C4H6O2
• Description: Methacrylic acid appears as a clear colorless liquid (or low-melting solid) with a pungent odor. Corrosive to metals and tissue. Flash point 170°F. Melting point 61°F. May polymerize exothermically if heated or contaminated. If the polymerization takes place inside a container, the container may rupture violently. Less dense than water. Vapors heavier than air. Used to make plastics.;Liquid;COLOURLESS LIQUID OR COLOURLESS CRYSTALS WITH CHARACTERISTIC ODOUR.;Colorless liquid or solid (below 61°F) with an acrid, repulsive odor.;Colorless liquid or solid (below 61°F) with an acrid, repulsive odor.
• IUPAC Name: 2-methylprop-2-enoic acid
• Canonical SMILES: CC(=C)C(=O)O
• InChI: InChI=1S/C4H6O2/c1-3(2)4(5)6/h1H2,2H3,(H,5,6)
• InChI Key: CERQOIWHTDAKMF-UHFFFAOYSA-N
• Boiling Point: 325 °F at 760 mm Hg (NTP, 1992);163.0 °C;163 °C at 760 mm Hg;159-163 °C;325°F;325°F
• Melting Point: 61 °F (NTP, 1992);16.0 °C;16 °C;16 °C;61°F;61°F
• Flash Point: 170 °F (NTP, 1992);76 °C (open cup);153 °F (67 °C) (closed cup);68 °C c.c., 77 °C o.c.;171°F (open-cup);(oc) 171°F
• Density: 1.015 at 68 °F (USCG, 1999);1.0153 at 20 °C/4 °C;Relative density (water = 1): 1.02;1.015 at 68°F;1.02 (Liquid)
• Solubility: greater than or equal to 100 mg/mL at 63° F (NTP, 1992);1.03 M;Soluble in chloroform; miscible with ethanol, ether;In water solubility, 89 g/L at 20 °C;Solubility in water: moderate;(77°F): 9%
• Autoignition Temperature: 752 °F (USCG, 1999);752 °F (400 °C)
• Color/Form: Clear colorless liquid or colorless crystals;Long prisms
• Complexity: 83.5
• Corrosivity: Forms corrosive liquid at melting point
• Covalently-Bonded Unit Count: 1
• Decomposition: When heated to decomposition it emits acrid smoke and irritating fumes.;Hazardous decomposition products include carbon monoxide and acrid fumes. /Methacrylic acid, inhibited/
• EC Number: 201-204-4
• Exact Mass: 86.036779g/mol
• Formal Charge: 0
• Hazard Statements: Irritant; , Unknown
• H-Bond Acceptor: 2
• H-Bond Donor: 1
• Heat of Vaporization: 0.418 kJ/mol at 101.3 kPa (760 mm Hg)
• Heavy Atom Count: 6
• ICSC Number: 0917
• LogP: 0.93 (LogP);log Kow = 0.93;0.93
• Monoisotopic Mass: 86.036779g/mol
• NSC Number: 7393
• Odor: Acrid, repulsive odor
• Other Experimental: Specific heat capacity: 2.1 J/g K; critical volume: 270 cu cm/mol;Its vapors are heavier than air. /Methacrylic acid, glacial/;Heat capacity: 2.1-2.3 J/kg; heat of polymerization: 56.5 KJ/mole;Boiling point: 81 °C at 30 mm Hg; 63 °C at 12 mm Hg; polymer forms ceramic-looking mass, sol in absolute alcohol, from which it is precipitated by ether; polymerizes easily, especially on heating or in the presence of traces of HCl;Saturated concn in air: 3.0 g/cu m at 20 °C; 6.3 g/cu m at 30 °C.;Henry's Law constant = 3.9X10-7 atm-cu m/mole at 25 °C;Hydroxyl radical rate constant: 1.9X10-11 cu cm/molecule sec at 25 °C (est);Ozone reaction rate: 4.1X10-18 cu cm/molecule-sec at 23 °C
• Refractive Index: Index of refraction: 1.43143 at 20 °C/D
• Rotatable Bond Count: 1
• RTECS Number: OZ2975000
• Stability: Acrylic acid and methacrylic acid readily polymerize in the presence of light, heat and oxygen, and also under the action of oxidizing agents such as peroxides.
• UNII: 1CS02G8656
• UN Number: 2531;2531;2531;2531;2531
• Vapor Density: 2.97 (NTP, 1992) (Relative to Air);2.97 (Air = 1);Relative vapor density (air = 1): 2.97;2.97
• Vapor Pressure: 0.65 mm Hg at 68 °F ; 1 mm Hg at 77° F (NTP, 1992);0.99 mmHg;0.99 mm Hg at 25 °C;Vapor pressure, Pa at 25 °C: 130;0.65 mmHg at 68°F;0.7 mmHg
• Viscosity: 1.38 mPa.s at 24 °C
• XLogP3: 0.9

Case Study

Preparation of Polymethacrylic Acid/Nanosilver Composite Materials

Solomon, M. M., et al. Journal of Molecular Liquids, 2015, 212, 340-351.

Polymethacrylic acid (PMAA) has multiple adsorption centers and can be used to prepare well-dispersed and highly stable nanoparticle composites, such as silver nanoparticles (AgNPs) composites. The PMAA/AgNPs composite material can effectively inhibit the corrosion of low carbon steel in 0.5 M H2SO4 solution.
Synthesis procedure of PMAA/AgNPs composites
· PMAA/AgNPs composites were prepared in situ by mixing aqueous polymethacrylic acid (PMAA) solution and AgNO3 solution.
· Firstly, different concentrations (50 ppm, 100 ppm, 500 ppm, 750 ppm, and 1000 ppm) of the PMAA were prepared in 0.5 M H2SO4 solution.
· Secondly, the respective concentration of the polymer solution was used to prepare 0.001 M AgNO3 solution.
· Thirdly, to every 100 cm3 of the respective mixture, 5 cm3 of natural honey which served as reducing and capping agent was added. The resulting mixture was left standing at room temperature for four days to obtain the product.

Synthetic polymer networks of poly(methacrylic acid)

Interpenetrating polymer network (IPN) hydrogels composed of temperature-sensitive poly(N-isopropylacrylamide) (PNIPAAm) and pH-sensitive poly(methacrylic acid) (PMAA) have been prepared by continuous UV polymerization. The temperature and pH responsive behavior of IPN hydrogels have been characterized by equilibrium swelling studies, oscillatory swelling studies, and differential scanning calorimetry. The permeability of these IPNs has been studied under various pH and temperature conditions. The results showed that these hydrogels exhibited a combined sensitivity to pH and temperature in the temperature range of 31-32 °C and a pH of about 5.5. The results of the permeation studies showed that there was a significant size exclusion behavior for the permeation of model drugs of different sizes through the IPN membranes. The permeability of the IPN membranes was significantly affected by the changes in pH and temperature conditions.
Purified MAA was dissolved in methanol (40/60 by volume) along with 1 mol% of a crosslinker, tetraethylene glycol dimethacrylate (TEGDMA) and 1 wt% of an initiator, 2,2-dimethoxy-2-phenylacetophenone (DMPA). Nitrogen was bubbled through the monomer/solvent mixture for 20 min to remove oxygen dissolved in the reaction mixture. The solution was cast on a glass plate equipped with a spacer and reacted under a UV source with an intensity of 1 mW/cm for 30 min. The polymer was then removed from the plate and immersed in deionized water to remove unreacted monomers. The gel was removed and placed in fresh deionized water 3 times a day for 5 days and then dried first in air and then in a vacuum oven. The dried PMAA polymer network was swollen in a solution of NIPAAm and methanol with the same crosslinker and initiator concentrations until equilibrium. The swollen gel was placed under the same UV source and polymerized for 10 min to form the IPN. The reaction time was shorter for the second polymerization reaction than the first. This is due to the higher conversion in the second polymerization. The IPNs were subsequently washed as previously described to remove unreacted monomers. IPNs can also be synthesized using PNIPAAm as the first network. However, the results showed that PNIPAAmrich IPN systems are easier to prepare using PMAA as the first network.

Interaction of poly(methacrylic acid) with metal ions

Konradi, Rupert, and Jürgen Rühe. Macromolecules 38.10 (2005): 4345-4354.

The swelling behavior of poly(methacrylic acid) brushes in contact with aqueous sodium, silver, alkaline earth metals, copper, and aluminum nitrate solutions was investigated using multi-angle zero ellipsometry. Fundamentally different swelling behaviors were found for the interaction of poly(methacrylic acid) brushes with metal cations of increasing valence or when switching from host groups to transition metal ions of constant valence. The different cations were classified according to the nature of their interaction with the surface-attached poly(carboxylic acid) and the results were compared with theoretical predictions as well as experimental studies of related systems, such as free poly(methacrylic acid) in solution or poly(acid) gels interacting with different metal cations.
Surface-bound azo functional groups were thermally cleaved to initiate free radical polymerization of methacrylic acid. Polymerizations were performed in neat methacrylic acid or in 50 vol% aqueous methacrylic acid solutions. In each case, the reaction mixture was carefully degassed by repeated sonication and application of vacuum before the addition of the initiator-functionalized substrate under nitrogen. Polymerizations were performed in a thermostat at 60.0± 0.1 °C. This technique allows independent control of grafting density and molecular weight. The grafting density can be controlled by varying the conversion of the surface-attached initiator. The molecular weight of the surface-attached polymer chains can be controlled by the monomer concentration. To remove free polymer chains, the PMAA-grafted substrates were extracted in methanol and water for about 15 hours, respectively. The weight of the surface-attached polymer molecules could not be accurately measured by gel permeation chromatography (GPC) because the higher molecular weight fraction of the polymer exceeded the exclusion limit of the available GPC columns and also exceeded the limit of the available GPC standards.