Methyl Methacrylate Content Research Articles

Study of acrylic emulsion for ultraviolet curable pressure sensitive adhesives and its properties

PurposeThe purpose of this paper is to synthesise UV curable emulsion latex and to study characteristics and various performance properties such as tackiness, peel adhesion and cohesive strength for pressure sensitive adhesive (PSA) application after UV curing.Design/methodology/approachThe two component water‐based ultraviolet (UV) curable acrylate PSAs were synthesised by emulsion copolymerization. The synthesised emulsion samples were characterised and various performance properties such as tackiness, peel adhesion and cohesive strength for PSAs were tested after UV curing.FindingsThe thermal analysis showed the effect of methyl methacrylate (MMA) content on the glass transition temperature of emulsions, which had significant effect on tack. Effects of varying concentration of multifunctional monomer trimethylolpropane triacrylate (TMPTA) and UV exposure time on properties of UV curable PSA were also studied.Research limitations/implicationsThe results associated with the UV curable water based PSA has certain advantages, such as low VOC and fast curing rate and with the scope for further research by using the radiations with different intensities or other radiation systems such as electron beam curing.Practical implicationsPractically the UV water based PSAs are already in industrial use for glass lamination, silicon semiconductor dicing, and in medical use for band aids and drug delivery systems and for dental applications for cavity filling.Originality/valueThe water based UV curable PSA synthesised by emulsion polymerization had very good tackiness properties with lower MMA content. It was observed that the lower the concentration of TMPTA, the better the performance properties, such as tack and peel strength. It was also observed that with increasing TMPTA concentration the cohesive strength increased.

Effect of post-polymerization heat-treatments on degree of conversion, leaching residual MMA and in vitro cytotoxicity of autopolymerizing acrylic repair resin

Objectives This study evaluated the effect of post-polymerization heat-treatments on degree of conversion (DC), residual methyl methacrylate concentration (MMA r) and in vitro cytotoxicity of autopolymerizing acrylic repair resin. Methods A total of 336 specimens were prepared by bench- and hydroflask-curing and subjected to post-polymerization heat-treatments: a) water immersion at 60 °C for 30 min, b) microwaving at 500 W for 3 min, c) combined use of water immersion and microwaving d) no treatment (as control). Specimens were eluted in cell culture medium for 1, 2, 5 and 7 days. DC and MMA r in eluates were measured by FTIR spectrometry and HPLC, respectively. In vitro cytotoxicity of eluates on L-929 fibroblasts was determined by XTT assay. Data were statistically analyzed with Dunn's multiple comparison and Pearson correlation tests ( p ≤ 0.05). Results DC was highest (99.9%) in bench- and hydroflask-cured groups which were subjected to water immersion. At all elution periods, MMA r was detected in eluates of all treatment groups and were higher in bench-cured groups than hydro-flask cured groups. Cell proliferation values indicated slightly cytotoxic effect throughout 7 days; regardless of the curing method or post-polymerization treatment. The correlation between MMA r and cell proliferation was negative after elution of 1, 2, 5 days and was only statistically significant ( p < 0.05) at 5 days. At elution of 7 days, the correlation was positive with no significance. Significance Post-polymerization heat-treatment of autopolymerizing acrylic repair resin by immersion in water at 60 °C for 30 min is clinically recommended to improve the DC while reducing the leaching residual MMA.

A comparative study on the mechanical and degradation properties of plant fibers reinforced polyethylene composites

AbstractCoir and abaca fiber‐reinforced linear low density polyethylene (LLDPE) composites (30 wt% fiber) were prepared by compression molding. Coir and abaca fibers were treated with methyl methacrylate (MMA) using ultraviolet radiation to improve the mechanical properties of the composites. Concentration of MMA and radiation dose was optimized. It was found that 30% MMA in methanol along with photoinitiator Darocur‐1173 (2%) and 15th pass of radiation rendered better performance. Chemically treated fiber‐reinforced specimens yielded better mechanical properties compared to the untreated composites, whereas coir fiber composites had better mechanical properties than abaca fiber reinforced ones. For the improvement of the properties, optimized coir (coir fiber treated with 30% MMA) and abaca (abaca fiber treated with 40% MMA) fibers were again treated with aqueous starch solution (2%–8%, w/w) for 2–7 min. Composites made of 3%‐starch‐treated coir fiber (5 min soaking time) showed the best mechanical properties than that of abaca‐fiber‐based composites. Water uptake and soil degradation tests of the composites were also performed. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers

Effect of methyl methacrylate content on coatings’ properties of palm oleic acid-based macromer

The macromer was synthesized using medium oil length oleic acid, phthalic anhydride, and glycerol. The synthesized macromer and methyl methacrylate (MMA) were copolymerized by free radical polymerization in toluene. The ratio between the macromer and MMA changed, and the effects on different properties of the copolymers, such as glass transition temperature (T g) and film properties, were studied. The macromer and copolymer structures were characterized by FTIR and 1H NMR spectroscopies. The coatings prepared with the highest ratio of MMA exhibited better overall physico-chemical properties. Alternatively, Tafel polarization curves showed that the corrosion rate value in NaCl solution decreases significantly when the MMA content is increased. Dynamic mechanical analysis results revealed that the increasing amounts of MMA lead to increasing T g values of copolymers.

In situ preparation of cross‐linked polystyrene/poly(methyl methacrylate) blend foams with a bimodal cellular structure

In situ preparation of a cross‐linked poly(methyl methacrylate) (PMMA) and polystyrene (PS) blend and its foaming were investigated for creating a bimodal cellular structure in the foam. Methyl methacrylate (MMA) monomer was dissolved in PS under supercritical CO2 at a temperature of 60 °C and a pressure of 8 MPa, and the polymerization of MMA was conducted at 100 °C and 8 MPa CO2, with a cross‐linking agent in PS. The blend was successively foamed by depressurizing the CO2. CO2 played the roles of plasticizing the PS and enhancing the monomer dispersion in PS during the sorption process and as a physical blowing agent in the foaming process. The cross‐linking agent was used for controlling the elasticity of polymerized PMMA domains and differentiating their elasticity from that of the PS matrix. The difference in elasticity delayed the bubble nucleation in the PMMA domains from that in the PS and made the cell size bimodal distribution, in which the smaller cells ranging from 10 to 30 µm in diameter were located in the wall of large cells of 200–400 µm in diameter. The effects of the initial MMA content, the concentration of cross‐linking agent, and the depressurization rate on the bimodal cell structure and bulk foam density were investigated. Copyright © 2011 John Wiley &amp; Sons, Ltd.

Thermo-mechanical properties of semi-degradable Poly(β-amino ester)-co-methyl methacrylate networks under simulated physiological conditions

Poly(β-amino ester) networks are being explored for biomedical applications, but they may lack the mechanical properties necessary for long term implantation. The objective of this study is to evaluate the effect of adding methyl methacrylate on networks’ mechanical properties under simulated physiological conditions. The networks were synthesized in two parts: (1) a biodegradable crosslinker was formed from a diacrylate and amine, (2) and then varying concentrations of methyl methacrylate were added prior to photopolymerizing the network. Degradation rate, mechanical properties, and glass transition temperature were studied as a function of methyl methacrylate composition. The crosslinking density played a limited role on mechanical properties for these networks, but increasing methyl methacrylate concentration improved the toughness by several orders of magnitude. Under simulated physiological conditions, networks showed increasing toughness or sustained toughness as degradation occurred. This work establishes a method of creating degradable networks with tailorable toughness while undergoing partial degradation.

Effect of the MMA content on the emulsion polymerization process and adhesive properties of poly(BA‐co‐MMA‐co‐AA) latexes

AbstractIn the past work, the shear resistance of pure poly(n‐butyl acrylate) was low, even incorporation of inorganic filler, silica in the composition. It is well‐known that the copolymerization of n‐butyl acrylate (BA) with methyl methacrylate (MMA) will increase the glass transition temperature, and enhance the shear resistance of acrylic polymers. In the current work, the preparation of a series of acrylic water‐borne pressure‐sensitive adhesives (PSAs) with the controlled composition and structure for the copolymerization of BA and acrylic acid (AA) with different MMA contents, poly(BA‐co‐MMA‐co‐AA) was reported and its effects on adhesive properties of the latices were investigated. The latices of poly(BA‐co‐MMA‐co‐AA) were prepared at a solid content of 50% by two‐stage sequential emulsion polymerization, and this process consisted of a batch seed stage giving a particle diameter of 111 nm, which was then grown by the semicontinuous addition of monomers to final diameter of 303 nm. Dynamic light scattering (DLS) was used to monitor the particle diameters and proved that no new nucleation occurred during the growth stage. Copolymerization of BA with MMA raised the glass transition temperature (Tg) of the soft acrylic polymers, and had the effect of improving shear resistance, while the loop tack and peel adhesion kept relatively high. The relationship between pressure‐sensitive properties and molecular parameters, such as gel content and molecular weight, was evaluated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Formation of Hybrid Wormlike Micelles upon Mixing Cetyl Trimethylammonium Bromide with Poly(methyl methacrylate-co-sodium styrene sulfonate) Copolymers in Aqueous Solution

The association of cetyltrimethylammonium bromide, CTAB, with a series of P(MMAx-co-SSNa) random copolymers of sodium styrene sulfonate (SSNa) with methyl methacrylate (MMA) was explored in aqueous solution as a function of the MMA molar content, x, of the copolymers. The polyelectrolyte/surfactant complexation in aqueous solution was verified through pyrene fluorescence probing. In addition, turbidimetry studies in dilute or more concentrated aqueous solutions elucidated the phase separation behavior of the P(MMAx-co-SSNa)/CTAB systems as a function of the copolymer composition x and the surfactant to polyelectrolyte mixing charge ratio. It is found that practically phase separation is completely suppressed within the studied mixing range when the MMA content of the copolymers is ∼30-40 mol%. For lower MMA contents the polyelectrolyte/surfactant complex separates out from water, while for higher x values the solubility limits of the copolymers in water are attained. For the intermediate MMA contents, viscoelastic systems are obtained in more concentrated polymer/surfactant solutions provided that the polyelectrolyte is fully complexed with the cationic surfactant ((1)H NMR results). Moreover, the (1)H NMR studies indicate that hybrid P(MMAx-co-SSNa)/CTAB wormlike micelles are formed in water under these conditions. Finally, it is shown that addition of salt prevents syneresis problems and facilitates the rheological investigation.

Waterborne Polyurethane−Acrylic Hybrid Nanoparticles by Miniemulsion Polymerization: Applications in Pressure-Sensitive Adhesives

Waterborne polyurethane-acrylic hybrid nanoparticles for application as pressure-sensitive adhesives (PSAs) were prepared by one-step miniemulsion polymerization. The addition of polyurethane to a standard waterborne acrylic formulation results in a large increase in the cohesive strength and hence a much higher shear holding time (greater than seven weeks at room temperature), which is a very desirable characteristic for PSAs. However, with the increase in cohesion, there is a decrease in the relative viscous component, and hence there is a decrease in the tack energy. The presence of a small concentration of methyl methacrylate (MMA) in the acrylic copolymer led to phase separation within the particles and created a hemispherical morphology. The tack energy was particularly low in the hybrid containing MMA because of the effects of lower energy dissipation and greater cross-linking. These results highlight the great sensitivity of the viscoelastic and adhesive properties to the details of the polymer network architecture and hence to the precise composition and synthesis conditions.

Effect of leaching residual methyl methacrylate concentrations on in vitro cytotoxicity of heat polymerized denture base acrylic resin processed with different polymerization cycles

ObjectivesResidual methyl methacrylate (MMA) may leach from the acrylic resin denture bases and have adverse effects on the oral mucosa. This in vitro study evaluated and correlated the effect of the leaching residual MMA concentrations ([MMA]r) on in vitro cytotoxicity of L-929 fibroblasts. Material and MethodsA total of 144 heat-polymerized acrylic resin specimens were fabricated using 4 different polymerization cycles: (1) at 74ºC for 9 h, (2) at 74ºC for 9 h and terminal boiling (at 100ºC) for 30 min, (3) at 74ºC for 9 h and terminal boiling for 3 h, (4) at 74ºC for 30 min and terminal boiling for 30 min. Specimens were eluted in a complete cell culture medium at 37ºC for 1, 2, 5 and 7 days. [MMA]r in eluates was measured using high-performance liquid chromatography. In vitro cytotoxicity of eluates on L-929 fibroblasts was evaluated by means of cell proliferation using a tetrazolium salt XTT (sodium 3´-[1-phenyl-aminocarbonyl)-3,4-tetrazolium]bis(4-methoxy-6-nitro)benzenesulphonic acid) assay. Differences in [MMA]r of eluates and cell proliferation values between polymerization cycles were statistically analyzed by Kruskal-Wallis, Friedman and Dunn's multiple comparison tests. The correlation between [MMA]r of eluates and cell proliferation was analyzed by Pearson's correlation test (p<0.05). Results[MMA]r was significantly (p≤0.001) higher in eluates of specimens polymerized with cycle without terminal boiling after elution of 1 and 2 days. Cell proliferation values for all cycles were significantly (p<0.01) lower in eluates of 1 day than those of 2 days. The correlation between [MMA]r and cell proliferation values was negative after all elution periods, showing significance (p<0.05) for elution of 1 and 2 days. MMA continued to leach from acrylic resin throughout 7 days and leaching concentrations markedly reduced after elution of 1 and 2 days. ConclusionDue to reduction of leaching residual MMA concentrations, use of terminal boiling in the polymerization process for at least 30 min and water storage of the heat-polymerized denture bases for at least 1 to 2 days before denture delivery is clinically recommended for minimizing the residual MMA and possible cytotoxic effects.

Reactivity of Methacrylates in Insertion Polymerization

Polymerization of ethylene by complexes [{(P^O)PdMe(L)}] (P^O = κ(2)-(P,O)-2-(2-MeOC(6)H(4))(2)PC(6)H(4)SO(3))) affords homopolyethylene free of any methyl methacrylate (MMA)-derived units, even in the presence of substantial concentrations of MMA. In stoichiometric studies, reactive {(P^O)Pd(Me)L} fragments generated by halide abstraction from [({(P^O)Pd(Me)Cl}μ-Na)(2)] insert MMA in a 1,2- as well as 2,1-mode. The 1,2-insertion product forms a stable five-membered chelate by coordination of the carbonyl group. Thermodynamic parameters for MMA insertion are ΔH(++) = 69.0(3.1) kJ mol(-1) and ΔS(++) = -103(10) J mol(-1) K(-1) (total average for 1,2- and 2,1-insertion), in comparison to ΔH(++) = 48.5(3.0) kJ mol(-1) and ΔS(++) = -138(7) J mol(-1) K(-1) for methyl acrylate (MA) insertion. These data agree with an observed at least 10(2)-fold preference for MA incorporation vs MMA incorporation (not detected) under polymerization conditions. Copolymerization of ethylene with a bifunctional acrylate-methacrylate monomer yields linear polyethylenes with intact methacrylate substituents. Post-polymerization modification of the latter was exemplified by free-radical thiol addition and by cross-metathesis.

Effect of polymerisation techniques on residual monomer amount released from different acrylic resins

The purpose of this study was to investigate the influence of different polymerisation methods (heat, auto-, injection moulding and microwave) with curing processes (conventional, short- and long-term terminal boiled heat polymerisation and room temperature polymerisation) in combination with varied water storage periods (24 h, 7 and 30 days) on the residual methyl methacrylate (MMA) contents of different dental acrylic resins. Twelve discs were fabricated for each denture base material. Specimens were immersed immediately in separate light proof glass bottles containing 20 mL 75% ethanol and 25% deionised water. Residual monomer (MMA) which eluted from acrylic resins was analysed with high performance liquid chromatography. Data were analysed by two-way analysis of variance and Tukey honestly significant difference tests. The MMA monomer amount eluted from autopolymerised acrylic resin groups (p<0·01) was higher than that from the other groups. Microwave polymerised acrylic resin showed the lowest residual monomer amount compared to the other acrylic resins (p<.01).

Poly(sodium styrene sulfonate)-b-poly(methyl methacrylate) diblock copolymers through direct atom transfer radical polymerization: Influence of hydrophilic–hydrophobic balance on self-organization in aqueous solution

A series of poly(sodium styrene sulfonate)-b-poly(methyl methacrylate), PSSNa-b-PMMA, amphiphilic diblock copolymers have been synthesized through atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in N,N-dimethylformamide/water mixtures, starting from a PSSNa macroinitiator. The kinetics of the polymerization was followed by 1H NMR, while the chemical composition of the copolymers was verified by a variety of techniques, such as 1H NMR, FTIR and TGA. The MMA content of the copolymers ranges from 0 up to 60mol%, while the number–average molecular weight of the PSSNa macroinitiator was 9000g/mol. The self-association of the diblock copolymers in aqueous solution was compared to the respective behavior of similar random P(SSNa-co-MMA) copolymers through optical density measurements, pyrene fluorescence probing, dynamic light scattering and surface tension measurements. It is shown that the diblock copolymers form micellar structures in water, characterized by an increasing hydrophobic character and a decreasing size as the length of the PMMA block increases. These micelle-like structures turn from surface inactive to surface active as the length of the PMMA block increases. Moreover, contrary to the MMA-rich random copolymers, the respective diblock copolymers form water insoluble polymer/surfactant complexes with cationic surfactants such as hexadecyltrimethyl ammonium bromide (HTAB), leading to materials with antimicrobial activity.

Synthesis and Properties of [60] Fullerene-Polymethyl Methacrylate Conjugates in Supercritical Carbon Dioxide

[60] Fullerene (C60) almost completely inhibits the polymerization of most vinyl monomers, but our investigation shows that the concentration of radical initiators and reaction conditions greatly enhances conjugation formation. In the present investigation, a series of [60] fullerene-polymethyl methacrylate conjugates was synthesized through 2,2-azobisisobutyronitrile (AIBN)-initiated in situ polymerization of methyl methacrylate (MMA) under different reaction conditions in supercritical carbon dioxide (scCO2). This has afforded corresponding [60] fullerene-PMMA conjugates with [60] fullerene content (%) and rheoviscosity range of 0.79–4.69% and 1.069–1.345 Mpa s, respectively. The process of in situ polymerization was monitored at different concentrations (mol/dL) of AIBN (304.50–761.25 × 10−3) and MMA (9.41–23.53 × 10−3), and temperatures (60°–90°C), pressures (1400–2000 psi), and time (2–8 h). The progress of in situ polymerization was monitored rheoviscometrically in tetrahydrofuran at 25 ± 1°C. Selected [60] fullerene-PMMA conjugates were characterized through UV-vis, GPC, FT-IR, 1HMMR, 13CNMR spectra, and thermal characterization by TG.

Identification and quantification of leachable substances from polymer-based orthodontic base-plate materials

The aim of this study was to analyse leachable monomers, additives, and degradation products from polymer-based orthodontic base-plate materials. One heat-cured resin (Orthocryl), one light-cured (Triad VLC), and three thermoplastic materials (Biocryl C, Essix A+, and Essix Embrace) were investigated. Elution was performed in water at 37°C for 10 days. The extract medium was changed and analysed daily. Chromatographic methods were used to identify and quantify the leachables. In addition, the content of residual methyl methacrylate (MMA) was quantified in the poly(methyl methacrylate) (PMMA)-based materials. Statistical analysis of the quantitative results was performed using a t-test for comparison of two independent samples. Monomers and additives leached from the materials polymerized in situ and from the thermoplastic PMMA-based material. No leachable substances were found in the extracts from the other thermoplastic materials. Accumulated over 10 days, a larger amount of MMA leached from the powder-and-liquid material, Orthocryl (42 μg/cm(2)), than from the thermoplastic material, Biocryl C (0.49 μg/cm(2)). The accumulated amounts of monomers leached from Triad VLC were 91 μg/cm(2) of urethane dimethacrylate and 2.2 μg/cm(2) of 2-hydroxyethyl methacrylate. Formaldehyde was found to leach from methacrylate-based materials: 3.2 μg/cm(2) from Orthocryl and 0.16 μg/cm(2) from Triad VLC. However, formaldehyde was not detectable in extracts from Biocryl C. Residual MMA was 5.4 wt % in Orthocryl and 0.4 wt % in Biocryl C. No phthalates were detected in the tested materials. In this in vitro study, minimal leaching was found from the thermoplastic materials, while leaching of methacrylates and formaldehyde was observed from the powder-and-liquid type and the paste material. Within the limitations of this study, the results suggest that prefabricated thermoplastic plates should be preferred for patients with an allergy to methacrylates.

AC CONDUCTIVITY AND DIELECTRIC PROPERTIES OF PMMA/FULLERENE COMPOSITES

Dielectric properties and electrical conductivity of different concentrations of Poly methylmethacrylate (PMMA)/fullerene C60 composites have been reported at room temperature in the frequency range from 1 kHz to 5 MHz. The frequency dependence of complex permittivity, ε*, and complex electrical modulus, M*, have been measured. Frequency dependence of dielectric constant, follows Cole–Cole dielectric relaxation equations, was investigated diagrammatically. Moreover, equations of Tsangaris et al. have been tested for our case to describe the dielectric behavior of particulate polymeric composite containing fillers which give a satisfactory agreement taking into account the variation of the aspect ratio with the volume fraction of fullerene C60 doped in the PMMA matrix.

Copolymerization of Fullerene (C60) and Methyl Methacrylate (MMA) using Triphenylbismuthonium Ylide as a Novel Initiator and Characterization of the Copolymers (C60-MMA)

Copolymerization of fullerene (C60) with methyl methacrylate (MMA) was carried out using triphenylbismuthonium ylide (abbreviated as Ylide) as a novel initiator in dioxan at 60°C for 4 h in a dilatometer under a nitrogen atmosphere. The reaction follows ideal kinetics: Rp∝ [Ylide]0.5[C60]−1.0[MMA]1.0. The rate of polymerization increases with an increase in concentration of initiator and MMA. However, it decreases with increasing concentration of fullerene due to the radical scavenging effect of fullerene. The overall activation energy of copolymerization was estimated to be 57 KJ mol−1. The fullerene-MMA copolymers (C60-MMA) were characterized by FTIR, UV–Vis, NMR and GPC analyses.

Manipulation of chain transfer agent and cross-linker concentration to modify latex micro-structure for pressure-sensitive adhesives

Abstract N -Dodecyl mercaptan (NDM) chain transfer agent and allyl methacrylate (AMA) cross-linker were used to manipulate latex properties in a starved seeded semi-batch emulsion polymerization of butyl acrylate (BA) and methyl methacrylate (MMA) or with a third monomer, acrylic acid (AA). Latexes with higher gel content and lower sol polymer molecular weight ( M w ) were produced by adding only AMA. On the other hand, latexes with lower gel content and M w were produced by adding only NDM. In addition, at a constant AMA concentration (0.2 phm), the addition of NDM (0.2 phm) decreased gel content, increased molecular weight between cross-linking points ( M c ), and decreased M w . Adding more NDM (to a total of 0.4 phm) further decreased the gel content, while decreasing the tested M c and increasing M w . It was also found that using higher concentrations of both AMA and NDM could produce latex with similar gel content, but smaller M c and M w , compared to the latex produced at lower concentrations of both NDM and AMA. Regarding the influence of AA, gel content was increased and M w was significantly decreased with an increase in AA concentration and a decrease in MMA concentration. The performance of the latexes was evaluated for application as a pressure-sensitive adhesive (PSA).

Study on Dental Plastic IPN Post Composite

In this research, the fiber-reinforced-IPN dental post composite material was synthesized by mutual combining of the interpenetrating polymer networks technology and fiberglass composite technology, in which the IPN structure was produced by the method of step-by-step polymerization with bisphenol A-glycidyl methacrylate (Bis-GMA)/polymethyl methacrylate (PMMA). The post material can be cured by light and made into the dental post with specific required shape. The results of the thermal test of the material showed that the glassing transition temperature was reduced, and the transition temperature area was wider with the addition of methyl methacrylate (MMA) than pure Bis-GMA system. The results of the flexural test of the material showed that 34.6 wt.% of the matrix, containing 20 wt.% of the MMA content and 80 wt.% of the PMMA content, embedding 65.4 wt.% of the glass fiber content made the flexural properties of the material reach the peak value. The flexural strength was 446.12 MPa and the flexural modulus was 54.651 GPa.

Treatment of methyl methacrylate from semiconductor wastewater by catalytic wet oxidation

Treatment of methyl methacrylate (MMA) from semiconductor wastewater via catalytic wet oxidation (CWAO) was studied. Effects of major operating parameters on the system performances in terms of the normalized concentrations of MMA and chemical oxygen demand (COD) relative to their initial values, namely C MMA/ C MMA0 and C COD/ C COD0, were investigated. These parameters include (1) the setting temperature T ST of operation, (2) the presence of catalyst Pt/Al 2O 3, (3) the presence of working gas, (4) the amount of Pt/Al 2O 3 ( m Pt) and (5) the partial pressure of O 2 ( p O 2 ). The change of pH value during the course of CWAO was also examined to elucidate the extents of decomposition of MMA and mineralization of COD. The results indicate that the effects of T ST on the C MMA/ C MMA0 are very vigorous for the case of sole wet oxidation (WAO) without catalyst. At the reaction time t FR = 180 min, the C MMA/ C MMA0 decreases from 0.89 at T ST = 180 °C to 0.62 at 200 °C and 0.09 at 220 °C with p O 2 = 2 MPa (based on the reference temperature T rf of 180 °C). The effects of T ST on the C COD/ C COD0 are not strong for the WAO, reducing the C COD/ C COD0 only to about 0.78–0.87 at t FR = 180 min with T ST in 160–220 °C. As for the CWAO in the presence of Pt/Al 2O 3 with m Pt = 30.38 g, the C MMA/ C MMA0 reduces greatly to 0.15 and 0.01–0.05 at t FR = 180 min with T ST at 160 °C and in 180–220 °C, respectively, while the C COD/ C COD0 decreases to about 0.16–0.34 with T ST in 160–220 °C. The use of Pt/Al 2O 3 not only improves the removal of MMA and COD but also reduces the T ST required for the efficient removal of MMA and COD, saving the energy needed. The results also reveal that the oxidizing gas such as O 2 is required for effective mineralization of COD via CWAO. However, the enhancement effect of increasing p O 2 is not significant if the supplied p O 2 is high enough, say 1–2 MPa, to proceed the CWAO in liquid phase with sufficient dissolved oxygen. Further, the CWAO is more efficient than the advanced oxidation processes of direct ultra violet irradiation (UV), sole ozonation (OZ) and combined process of OZ and UV for the effective removal of COD in the treatment of MMA. The information obtained in this study is useful for the proper operation and rational design of the CWAO system for the effective treatment of MMA-containing wastewater from the semiconductor industry.