PMMA Copolymer Research Articles

Thermal degradation of poly(methyl methacrylate) polymers: Kinetics and recovery of monomers using a fluidized bed reactor

Poly(methyl methacrylate) (PMMA) is a versatile transparent thermoplastic that is used in a wide range of fields and applications, such as in the lenses of exterior lights of automobiles, in electronics, in food containers and in artificial marble. When PMMA is subject to thermal degradation conditions, it degrades mainly into its monomer, methyl methacrylate (MMA). In this study, a virgin PMMA copolymer composed of 97.5% methyl methacrylate, 2.5% methyl acrylate (MA) and PMMA waste plastics were investigated. Kinetic measurements of the thermal degradation of the virgin copolymer were carried out with a TGA. The Chatterjee–Conrad (CC) and Freeman–Caroll (FC) models were applied to determine the pyrolysis kinetic parameters. Both models simulated the experimental DTG curves fairly well. In addition, pyrolysis of the virgin copolymer and the PMMA wastes was carried out using a fluidized bed reactor to recover the monomer. The reaction temperatures ranged from 450 to 500 °C. In each case, the rate of oil recovery was over 97%, and the content of the MMA in the oils was up to 98 wt%. The MMA recovered from the experiments can be used as feedstock for the polymerization of PMMA.

Thermal and mechanical properties of poly(methyl methacrylate) and ethylene vinyl acetate copolymer blends

AbstractA series of poly(methyl methacrylate) (PMMA) blends have been prepared with different compositions viz., 5, 10, 15, and 20 wt % ethylene vinyl acetate (EVA) copolymer by melt blending method in Haake Rheocord. The effect of different compositions of EVA on the physico‐mechanical and thermal properties of PMMA and EVA copolymer blends have been studied. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) has been employed to investigate the phase behavior of PMMA/EVA blends from the point of view of component specific interactions, molecular motions and morphology. The resulting morphologies of the various blends also studied by optical microscope. The DSC analysis indicates the phase separation between the PMMA matrix and EVA domains. The impact strength analysis revealed a substantial increase in impact strength from 19 to 32 J/m. The TGA analysis reveals the reduction in onset of thermal degradation temperature of PMMA with increase in EVA component of the blend. The optical microscope photographs have demonstrated the PMMA/EVA system had a microphase separated structure consisting of dispersed EVA domains within a continuous PMMA matrix. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

Synthesis and characterization of poly ( n-butyl acrylate)-poly (methyl methacrylate) latex interpenetrating polymer networks by radiation-induced seeded emulsion polymerization

A series of latex interpenetrating polymer networks (LIPNs) were prepared via a two-stage emulsion polymerization of methyl methacrylate (MMA) or mixture of MMA and n-butyl acrylate ( n-BA) on crosslinked poly( n-butyl acrylate)(PBA) seed latex using 60Co γ-ray radiation. The particles of resultant latex were produced with diameters between 150 and 250 nm. FTIR spectra identified the formation of crosslinked copolymers of PMMA or P(MMA- co-BA). Dynamic light scattering (DLS) showed that with increasing n-BA concentration in second-stage monomers, the particle size of LIPN increased. Transmission electron microscope(TEM) photographs showed that the morphology of resultant acrylate interpenetrating polymer network (IPN) latex varied from the distinct core-shell structure to homogenous particle structure with the increase of n-BA concentration, and the morphology was mainly controlled by the miscibility between crosslinked PBA seed and second-stage copolymers and polarity of P(MMA- co-BA)copolymers. In addition, differential scanning calorimeter (DSC) measurements indicated the existence of reinforced miscibility between PBA seed and P(MMA- co-BA)copolymer in prepared LIPNs.

Nanocrystal‐Based Luminescent Composites for Nanoimprinting Lithography

CdSe@ZnS nanocrystals are incorporated in acrylic acid or amine-functionalized PMMA copolymers (see image) to obtain fluorescent nanocomposites characterized by homogeneous NC dispersion and a significant increase in emission efficiency, without modifying the excellent processability of the thermoplastic polymer. Such properties permit the fabrication of highly luminescent nanostructures at the micro- and nanoscale, extending the patterning resolution limit by means of nanoimprinting lithography.

Synthesis and characterization of Cu(II) containing PMMA co-polymer for optical applications

Homogenous, transparent, greenish blue Cu(II) containing PMMA co-polymer disks were prepared through the radical polymerization of the Cu(II) methacrylate, MMA and HMA using AIBN as an initiator. The dependence of the absorbance and transmittance spectra with the Cu(II) methacrylate concentration was investigated in the visible range (420–750 nm). From the transmittance measurements the refractive index and extinction coefficient spectral dependence were calculated by application of an inversion approach. To further characterize this co-polymer a thermogram was performed. The overall behavior of this material suggests its possible use as a standard solution for Spectroscopy Equipment Calibration and as a selective optical filter.

Preferential surface segregation of homopolymer and copolymer blend films

Surface film properties of the homopolymers polystyrene (PS), poly(methyl methacrylate) (PMMA), poly(butyl methacrylate) (PBMA) and the copolymer poly(methyl methacrylate)- co-poly(butyl methacrylate) (PMMA- co-PBMA) and their blends with PS have been examined by atomic force microscopy (AFM) and contact angle measurements. The total and the Lifshitz–van der Waals, acid and base components of the surface free energy together with the work of adhesion and its components, the cohesive energy density and the solubility parameters of the homopolymer, copolymer and blend films were determined. Films of about 3 μm were considered. The results are discussed in terms of surface migration mechanisms based on surface free energy and solubilities of the polymers in the solvent, toluene in this paper. AFM imaging and contact angles revealed surface enrichment at the air polymer interface of PBMA for both the PS/PBMA blend and the copolymer PMMA- co-PBMA, whereas the PS/PMMA and PS/PMMA- co-PBMA blend film surfaces show island-like phase-separated structure of typical size 27.4–86.5 nm in diameter and 6.9–15.6 nm in height for PS/PMMA, while for PS/ PMMA- co-PBMA film surface the typical size is 49.6–153.3 nm in diameter and 1.6–14.2 nm in height.

Novel polymers based on atom transfer radical polymerization of 2‐methoxyethyl acrylate

AbstractAtom transfer radical polymerization (ATRP) has been employed in the polymerization of 2‐methoxyethyl acrylate (MEA) initiated by ethyl 2‐bromoisobutyrate in bulk or in toluene solution at 90–95 °C with the catalytic systems Cu(I)Br/PMDETA or HMTETA. Kinetics investigations revealed that ATRP of MEA proceeds in a controlled manner with a first‐order plot of monomer consumption, an almost linear molecular weight evolution and polydispersities < 1.29 in the entire conversion range. Well‐defined diblock copolymers with PMMA, PMEA‐b‐PMMA have been produced by use of both PMEA and PMMA macroinitiators, however, for the latter the controlled conditions were somehow difficult to maintain. The amphiphilic behavior of the diblock copolymers lead to phase separation resulting in two glass transition temperatures as detected by DSC. Contact angle (Θ) investigations with water on PMEA, PMMA, and diblock copolymers surfaces reveal PMEA as an intermediate hydrophilic with Θ ∼ 50°, whereas PMMA and the diblock copolymers all fall in the hydrophobic region with Θ > 70°. © 2006 Wiley Periodicals, Inc. J Polym Sci Part Polym Chem45: 333–340, 2007

Poly(methylphenylphosphazene)–Graft–Poly(methyl Methacrylate) Copolymers Via Atom Transfer Radical Polymerization

Atom transfer radical polymerization (ATRP) was used to graft poly(methyl methacrylate), PMMA, onto poly(methylphenylphosphazene), [(Me)(Ph)PN] n , PMPP. A two-step process was used to convert a portion of the methyl substituents on [(Me)(Ph)PN] n to –CH2C(CH3)2OH groups and then to bromoalkyl groups, –CH2C(CH3)2OC(=O)C(CH3)2Br, the latter of which served as initiation sites for ATRP of methyl methacrylate (MMA) in the presence of CuCl/bipyridine. Variations in the length of the grafted chains were investigated and the graft copolymers were compared to the parent polymer and blends of similar composition. The new bromoalkyl derivatives of [(Me)(Ph)PN] n and the PMPP–graft–PMMA copolymers were characterized by elemental analysis, 1H and 31P NMR spectroscopy, size exclusion chromatography (SEC), and differential scanning calorimetry (DSC).

Effect of high molecular weight acrylic copolymers on the viscoelastic properties of engineering resins

AbstractIn this work, the viscoelastic properties of acrylic‐based copolymer blends with poly(methyl methacrylate) (PMMA) and polycarbonate were investigated in the molten and solid states. High molecular weight copolymers of methyl methacrylate with butyl acrylate (MMA‐co‐BA) having varying molecular weight and composition were used to enhance the rheological properties in shear and extension. Blends containing up to 15 wt% of copolymer were prepared at 200°C and 150 rpm by using a DSM micro‐compounder. The samples were characterized by size exclusion chromatography (SEC), dynamic mechanical analysis (DMA), and rheology. The rheological properties were determined by using small amplitude oscillatory measurements (SAOM) in shear and a Rheotens™ device for melt strength determination. For PMMA, the effects of high molecular weight PMMA copolymer on the matrix were related to the molecular weight, the tacticity of the copolymer, and the individual components. The rheological properties in shear showed enhanced storage and loss moduli at low frequency, while no change was observed at high frequency. In addition, extensional viscosity measurements made by using the filament stretching technique showed a significant increase in melt strength compared to that of the base PMMA with the blend containing the highest molecular weight copolymer showing the maximum force and a reduced drawdown ratio. For polycarbonate, its blends with acrylic copolymer were found to be immiscible. Similar enhancement in the moduli at low frequencies was observed, but a significant increase in the viscosity was obtained as well, resulting from the response of the two‐phase system. This change in the rheological properties was further increased at 15 wt% loading. Owing to the formation of a phase‐separated morphology, the melt strength was found to increase only slightly. J. VINYL. ADDIT. TECHNOL., 12:143–150, 2006. © 2006 Society of Plastics Engineers

Polymer based optical interconnect components for high-speed Datacom approaches – Micromachining supported manufacturing

Abstract Optical data communication will play an important role in future high speed data links. Especially in Datacom applications data rates in Gbps area will be desired. An overall low cost approach is needed on both sides, for the opto-electronic integration and for the passive optical interconnects. Opto-electronic integration will be reached through the use of one- or bidirectional transceivers for Datacom based – in future – on surface emitting lasers (VCSEL), instead of LEDs used today, and economically favorable silicon detectors. This additionally requires passive optical interconnects using beam shaped low-cost micro-optical components such as, microlenses for in- and out-coupling which are more and more popular in recently developed opto-electronic devices. Ideally, micro-optical components can be integrated in passive optical interconnects and replicated in polymer materials for the cost reducing. Hence, the increase of data rate depends on the quality of the optical surfaces. In this paper the micromechanical manufacturing technologies of microcomponents with optical surfaces are discussed. Furthermore, polymer based components are presented which can be used for coupling and routing of optical signals, e.g. a passive optical interconnect for the passive coupling into photodiode or from VCSEL and optical N × M star couplers. The polymer based interconnect module has been realized in different polymers (polymethyl methacrylate, PMMA, and cycloolefin copolymer, COC). Total loses and data rates achieved are 3.3 dB and 2 Gbps, respectively. Average total loss an e.g., polymer based 16 × 16 optical star coupler is better than 17 dB per channel with a uniformity of 3 dB. For replication of polymer substrates of these components hot embossing tools have been produced by combination of deep lithography, ultra-precise milling and micro-machining.

Microwave‐induced rapid one‐pot synthesis of κ‐carrageenan‐g‐PMMA copolymer by potassium persulphate initiating system

Abstractκ‐Carrageenan‐g‐PMMA copolymer has been synthesized by copolymerizing κ‐carrageenan with methyl methacrylate (MMA) in aqueous medium at about pH 7. The copolymerization was carried out under microwave irradiation in the presence of a water‐soluble initiator potassium persulphate. Optimum microwave irradiation conditions for obtaining maximum yields are described. The structural characteristics and thermal stability of κ‐carrageenan‐g‐PMMA was studied by FTIR, NMR, and thermo gravimetric (TGA) measurements. Crystallinity of the copolymer was studied by powder X‐ray diffraction. TGA, IR, and XRD data indicated that the κ‐carrageenan was considerably modified. Optical micrograph of the copolymer was also studied. A probable mechanism of formation of the copolymer is proposed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 161–166, 2006

Photosensitivity and grating development in trans-4-stilbenemethanol-doped poly(methyl methacrylate) materials

Abstract This paper reports the photosensitivity of poly(methyl methacrylate) (PMMA) and its copolymer doped with trans -4-stilbenemethanol. UV irradiation of the doped-PMMA at 325 nm induced the trans - to cis -isomerization of the dopant. This process was confirmed by 1 H NMR spectra of trans -4-stilbenemethanol in CDCL 3 solvent before and after irradiation. The isomerization can be initiated by the irradiation with an intensity of 0.62 mW/cm 2 . Photo-induced refractive index change of −0.0024 was obtained when a PMMA copolymer film doped with 5.1 wt% dopant was exposed to 325 nm light. Lorentz–Lorenz equation was used to estimate the refractive index of a trans -4-stilbenemethanol–PMMA composite and a trans -4-stilbenemethanol–PMMA copolymer composite from the mole refraction and van der Waals volume of each component. A slight elevation of molecular packing coefficient ( K ) for PMMA and its copolymer containing the dopant implies a denser aggregation as compared to the polymer without the dopant. Long period gratings were created in doped-PMMA films and doped-PMMA copolymer fibers using amplitude mask technique. Gratings were confirmed by microscopic observation and diffraction patterns.

Poly(methyl methacrylate)/silica/titania ternary nanocomposites with greatly improved thermal and ultraviolet-shielding properties

Poly(methyl methacrylate) (PMMA)/silica/titania ternary nanocomposites with covalent bonding interaction between polymer and inorganic phases have been prepared using a novel non-hydrolytic sol–gel method. Transmission electron microscope (TEM) image of silica/titania binary inorganic component indicates a core-shell-like structure. Scanning electron microscope (SEM) images suggest that the well dispersed silica/titania particles in the hybrid are on the nanometer-scale. The transparencies of nanocomposites are maintained in visible region while the absorption band in ultraviolet (UV) region is red shifted with increasing inorganic content. The thermogravimetric analysis (TGA) results show that the thermal stability of PMMA copolymer increases dramatically with the addition of silica/titania moieties both in nitrogen and in air.

Rheological, thermal, and curing properties of natural rubber‐g‐poly(methyl methacrylate)

AbstractGraft copolymers of NR and PMMA (i.e., NR‐g‐PMMA) were prepared with the bipolar redox initiation system, using various percentages of molar ratios of NR/MMA at 95/5, 90/10, 80/20, 70/30, and 60/40. It was found that the Mooney viscosity, shear stress, and shear viscosity of the NR‐g‐PMMA increased with an increase in the molar ratio of MMA used in the graft copolymerization. This may be attributed to an increasing trend of the chemical interaction between polar functional groups within the grafted PMMA molecules. Furthermore, a decreasing trend of storage moduli was observed with increasing molar ratios of MMA. The glass transition temperature was obtained from the tan δ curves. We found a slightly increasing trend of the Tg's with an increase in molar ratios of MMA used in the grafting reaction. The NR‐g‐PMMA was later compounded using TBBS as an accelerator. With an increase in molar ratios of MMA in the grafting reaction, we observed an increasing trend of minimum torque, maximum torque, cure time, and scorch time, but quite similar levels of torque difference and crosslink density. Furthermore, the tensile strength of the NR‐g‐PMMA gum vulcanizate increased with an increase in molar ratios of MMA, whereas the elongation at break decreased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1600–1614, 2006

Synthesis of rod-coil diblock copolymers by ATRP and their honeycomb morphologies formed by the ‘breath figures’ method

We have synthesized rod-coil diblock PPQ- b-PMMA copolymers by using the versatile atom-transfer radical polymerization method and have characterized them by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The methyl ketone-terminated rod-coil diblock PMMA copolymer has a higher value of T g, because of its syndiotactic-like structure, and a higher decomposition temperature than does the PMMA homopolymer. The presence of the PPQ block tends to retard the early decomposition of the PMMA chain. A regularly porous, honeycomb-structured film was prepared from the dichloromethane solution of the diblock copolymers under a flow of moist air. The diameters of the spherical pores can be controlled in the range from 0.8 to 3 μm by modifying both the rod-coil copolymers' relative molecular weights and the casting conditions. The wall thickness of the film is varied linearly with the relative molecular mass ( M r).

Controlled Radical Polymerization and Copolymerization of 5-Methylene-2-phenyl-1,3-dioxolan-4-one by ATRP

The polymerization and copolymerization of a cyclic acrylate, 5-methylene-2-phenyl-1,3-dioxolan-4-one (MPDO), by conventional radical polymerization and atom transfer radical polymerization (ATRP), were determined to occur by 1,2-vinyl addition according to 13C NMR spectroscopy. Copolymerization of MPDO with methyl methacrylate (MMA) or styrene (S) led to copolymers with a much higher MPDO content than originally in the feed, suggesting high reactivity due to its captodative structure. PMPDO−PS copolymers were stable to UV irradiation and basic environments, confirming that copolymerization of MPDO also proceeded by 1,2-vinyl addition rather than ring opening. DSC heating scans of PMPDO−PMMA copolymers show a single Tg that increases with increasing MPDO content.

Nanoscale localization of poly(vinylidene fluoride) in the lamellae of thin films of symmetric polystyrene–poly(methyl methacrylate) diblock copolymers

We employed thin film blends of diblock copolymers with functional homopolymers as a simple strategy to incorporate organic functional materials into nanodomains of diblock copolymers without serious synthesis. A blend pair of polystyrene–poly(methyl methacrylate) (PS–PMMA) diblock copolymers and poly(vinylidene fluoride) (PVDF) was selected as a model demonstration because PVDF is a well-known ferroelectric polymer and completely miscible with amorphous PMMA. Thin films of symmetric PS–PMMA copolymers provided the nanometer-sized PMMA lamellae, macroscopically parallel to the substrate, in which PVDF chains were dissolved. Thus, amorphous PVDF chains were effectively confined in the PMMA lamellae of thin film blends. The location of PVDF chains in the PMMA lamellae was investigated by the dependence of the lamellar period on the volume fraction of PVDF, from which we found that PVDF chains were localized in the middle of the PMMA lamellae. After the crystallization of PVDF, however, some of PVDF migrated to the surface of the film and formed small crystallites.

Living radical polymerisation in heterogeneous conditions—suspension polymerisation

Transition metal mediated living radical polymerisation of butyl methacrylate has been demonstrated with a copper(I) halide N-alkyl-2-pyridylmethanimine ligands based catalyst. Optimum conditions were found to be with copper(I) chloride and N-octyl-2-pyridylmethanimine catalyst at 65 °C where conversions of 85% were achieved with polymers of M n = 8900 g mol −1 (theoretical = 8400 g mol −1) and PDI = 1.23. Both non-ionic and ionic surfactants were employed which were also made by living radical polymerisation. The non-ionic surfactant was a block copolymer of PMMA from a polyethyleneglycol macroinitiator (total M n = 7600 g mol −1, PDI = 1.20) and the ionic surfactant PDMEAMA–PMMA (total M n = 8000 g mol −1, PDI = 1.21) with the PDMEAMA block quaternized with MeI (13.8%, 28.4%, 47.7% and 100%). A range of ligands were employed in the suspension polymerisation by varying the alkyl group on the ligand increasing the hydrophobicity (alkyl = propyl (PrMI), pentyl (PMI), octyl (OMI), dodecyl (DMI) and octadecyl (ODMI)). The more hydrophobic ligands were found to be more effective due to lower partitioning into the aqueous phase. Block copolymers of P(EMA)–P(BMA) and P(MMA)–P(BMA) were prepared by first preparing macroinitiators via living radical polymerisation ( M n = 1600 g mol −1 (PDI = 1.23) for P(EMA) and M n = 1500 g mol −1 (PDI = 1.22) for P(MMA)) and using them for initiation of BMA in suspension polymerisation. Block copolymers had M n between 12,800 and 13,700 g mol −1 with PDI between 1.33 and 1.54. Block copolymer growth showed excellent linear first order kinetics wrt monomer and demonstrated characteristics expected of a living radical polymerisation. Particle sizes were measured by SEM and DLS with good agreement (1.4–2.8 μm) and SEM showed spherical particles were formed.

Interfacial behaviors of PMMA-PEO block copolymers at the air/water interface

Diblock copolymer of PMMA 291 - b -PEO 114 and triblock copolymer of PMMA 120 - b - PEO 227 - b -PMMA 120 were synthesized and their interfacial properties at the air-water interface were investigated, where both blocks of polyethylene oxide (PEO) and poly(methyl methacrylate) (PMMA) are surface active but the former is soluble in water while the latter is not. Both the block copolymers could form monolayers with two obvious transition regions. The first transition point is around 10 mN/m, which could be assigned to the pancake-brush change of the PEO chains. The other is around 18 mN/m, which could be ascribed to the condensed packing of PMMA. The surface morphological changes during the compression of the Langmuir monolayers are investigated by using the AFM and SEM methods for the films deposited at different surface pressure or molecular areas. At a lower surface pressure, a typical morphology of PEO-containing lipopolymers is observed. Upon compression, sphere-dominant morphologies were observed. While the diblock copolymer is easy to folding, the triblock copolymer is in favor of formation of circular domains through vesiculation.

One-Step Preparation of Highly Monodisperse Micron-Size Particles in Organic Solvents

In this communication, we report the first simple and fast one-step method for synthesizing highly monodisperse micron-size PMMA particles in organic media through dispersion polymerization in the presence of PHSA (a polyhydroxyl-stearic-acid graft PMMA copolymer) as a stabilizer. There are two significant advantages of our method over earlier methods. First, by optimizing the composition of a solvent mixture of hexane and dodecane, we were able to increase the concentration of monomer up to 50-56% and obtain unusually large (up to 10 mum in diameter) PMMA particles. Second, by strictly controlling the nucleation time, we were able to make PMMA particles with a low polydispersity of around 1%, much lower than has ever before been achieved for such large particles. We also report an unusual apparent metastable state in the nucleation stage.