Methyl Methacrylate Comonomer Research Articles

Rheological Characterization of Polymeric Frustrated Lewis Pair Networks

Conventional Lewis acids and Lewis bases will react with each other to form thermodynamically stable Lewis adducts which are inherently unreactive. Sterically encumbered Lewis acids and Lewis bases are prevented from forming such adducts, resulting in the formation of frustrated Lewis pairs (FLPs) with latent reactivity. Extending this concept to polymer science permits the development of a new class of responsive, functional, self-healing materials. Here, we report the rheology of fully macromolecular FLPs based on both styrene and methyl methacrylate (MMA) backbones. When reacted with small molecule cross-linkers, a dynamic network is formed which is both heat-responsive and self-healing. The effect of the polymer backbone and cross-linking density on the formed networks is significant. First generation polymeric FLPs behave in a similar way to the noncovalently linked supramolecular assemblies, where switching from styrene to MMA co-monomers creates stiffer polymer networks as the likelihood of chain e...

Synthesis of Light-Responsive Pyrene-Based Polymer Nanoparticles via Polymerization-Induced Self-Assembly.

The use of an in situ, one-pot polymerization-induced self-assembly method to synthesize light-responsive pyrene-containing nanoparticles is reported. The strategy is based on the chain extension of a hydrophilic macromolecular chain transfer agent, poly(oligo(ethylene glycol) methyl ether methacrylate), using a light-responsive monomer, 1-pyrenemethyl methacrylate (PyMA), via a reversible addition-fragmentation chain transfer dispersion polymerization; yielding nanoparticles of various morphologies (spherical micelles and worm-like micelles). In this process, addition of comonomers, such as butyl methacrylate (BuMA) or methyl methacrylate (MMA), are required to obtain high PyMA monomer conversion (>80% in 24 h). The addition of comonomers reduces the π-π stacking of the pyrene moieties, which facilitates the diffusion of monomers in the nanoparticle core. The addition of BuMA (as a comonomer) offers P(PyMA-co-BuMA) core-forming chains with high mobility that enables the reorganization of chains and then the evolution of morphology to form vesicles. In contrast, when MMA comonomer is used, kinetically trapped spheres are obtained; this is due to the low mobility of the core-forming chains inhibiting in situ morphological evolution. Finally, the UV-light-induced dissociation of these light-responsive nanoparticles due to the gradual cleavage of the pyrene moieties and the subsequent hydrophobic-to-hydrophilic transitions of the core-forming blocks is demonstrated.

Luminescent methacrylic copolymers with side-chain cyclometalated iridium(III) complexes

A series of eight copolymers made of a poly (methyl methacrylate) backbone with a luminescent iridium(III)-based pendant is presented. These materials are obtained by radical copolymerization of different ratios of methyl methacrylate (MMA) with the reactive Ir-based MMA monomer [Ir(ppy)2(ptmma)]Cl (Hppy = 2-phenylpyridine, ptmma = 11-(4-pyridin-2-yltriazol-1-yl)undecyl 2-methylprop-2-enoate). The products are characterized by NMR, IR and DSC methods. The specific ratio among the two monomers, dictates the concentration of the emissive iridium-based centers along the polymer backbone, which affects the overall luminescence behavior of the material. The position of the absorption and emission maxima of the iridium-based monomer and of the related polymeric compounds are virtually identical, pinpointing the optically innocent character of the polymer matrix. Photophysical investigations show that the emission quantum yields (PLQYs) of the iridium-based emitters improve upon increasing the fraction of the inert MMA co-monomer, due to a progressive decrease in self-absorption and self-quenching, approaching the infinite-dilution limit at the relatively low [MMA]:[Ir] molar ratio of 500, with PLQY = 0.51 ± 0.05.The concentration-quenching rate process follows a power-law proportional to R–(2.6±0.9), where R is the calculated average distance between the emitting units of the copolymers. Such a deviation from the expected dipole-dipole interaction (i.e., R−6 dependence) suggests the partial formation of aggregates leading to the occurrence of static self-quenching in the solid matrix, as the concentration of the iridium centers increases. These results offer valuable hints for the formulation of strongly emitting hybrid materials in which a high concentration of triplet luminophores is embedded in organic polymers solely serving as solid transparent scaffolds.

Influence of titania on the morphological and mechanical properties of 1,3-butanediol dimethacrylate based polyHIPE composites

Macroporous polymer/TiO2 composites were synthesized by the polymerisation of 1,3-butanediol dimethacrylate (1,3-BDDMA) based water-in-oil high internal phase emulsions. High internal phase emulsions (HIPEs) having 80 vol% of internal phase were used as templates for inducing porosity in the resulting polymer composites. Apart from the monomer, either methyl methacrylate (MMA) or 2-ethylhexyl acrylate (EHA) was used as a co-monomer. In order to investigate the influence of nanoparticle loading on the morphological and mechanical properties of highly porous polymers, 1 to 10 wt% of colloidal TiO2 nanoparticles were introduced into emulsion templates. It was found that increasing the amount of nanoparticle loading from 1 wt% to 10 wt%, average cavity sizes decreased from 14.1 μm to 5.9 μm in the case of MMA co-monomer, and from 18.6 μm to 5.1 μm in the case of EHA co-monomer. Moreover, it was found that introducing 1 wt% of nanoparticle significantly improved the mechanical properties of both MMA and EHA copolymerized polyHIPEs. In order to explain the influence of nanoparticle loading and comonomer type on the physical properties appropriate regression analyses were conducted.

Preparation of Fast Photoresponsive Cellulose and Kinetic Study of Photoisomerization

Exploitation of a polymer carrier for introducing photochromic properties to cellulose matrix has several advantages such as photostability, photoreversibility, elimination of dye aggregation, and elimination of undesirable negative photochromism. The switching rate of a photochromic compound in the polymer matrix depends on steric restrictions, polarity, protic characteristics, and flexibility of the surrounding media. Here, the copolymerization of a spiropyran-based monomer with butyl acrylate and methyl methacrylate comonomers is reported through semicontinuous emulsion polymerization and the kinetics of isomerization and switching rate are investigated. The obtained latex was incorporated into cellulosic paper through chemical modification. The analysis confirmed a ring-opening reaction between hydroxyl groups in cellulose and epoxy functional groups in the low Tg latex. Morphological studies and contact angle measurements demonstrated an improved uniformity and enhanced hydrophobicity in the modified...

Structure evolution and mechanism of polyacrylonitrile and related copolymers during the stabilization

The structure evolution and thermal behaviors of polyacrylonitrile homopolymer (PAN) and terpolymer [P(AN–MMA–IA)] containing about 4.19 wt% methyl methacrylate (MMA), 0.98 wt% itaconic acid (IA) and 94.83 wt% acrylonitrile (AN) during heat treatments were studied by Fourier transform infrared (FTIR), differential scanning calorimetry and thermogravimetry. It was found that the presence of IA comonomer in PAN promoted the cyclization reactions significantly though initiating the cyclization reactions at lower temperature and proceeding at a faster rate than these of PAN homopolymer. Moreover, it was found that the dehydrogenation was based on the formation of cyclized structures. From the results of FTIR analysis, we found the MMA comonomer blocked the cyclization reactions to some extent. Extent of cyclization reactions at different temperatures was calculated through the data of FTIR. The sequence of reactions happened during the stabilization was oxidation > cyclization > dehydrogenation. The higher rate constant k implied that the ionic mechanism actually showed a kinetic advantage at low temperature over the free radical mechanism, even though the MMA comonomer inhibited cyclization reactions to some extent.

Preparation of PS Colloids with DMA and MMA Comonomers and Suitability of P(S/DMA) for Colloidal Silica Deposition

There is a lack of investigation on the effects of hydrophilic comonomer and pH on the particle size of functionalized polystyrene colloids. In this study, polystyrene (PS) colloids were prepared via emulsifier-free emulsion copolymerization of styrene (S) with 2-(dimethylamino)ethyl methacrylate (DMA) and methyl methacrylate (MMA) at pH 3.0 and 7.0. The sizes of the colloidal particles greatly depended on the comonomer type and pH. The hydrodynamic diameters of the particles ranged from 95 nm to 265 nm and their polydispersity index (PDI) values were less than 0.1. The particles containing comonomer moieties had spherical morphology and good stabilities. P(S/DMA) particles, especially showed excellent colloidal stability and had positive zeta potential values at the acidic pH range as a result of protonation of tertiary amine group of the DMA moiety. In addition, DMA functionalized PS colloids enabled to easy way for the preparation of PS/SiO2 composites. By physically deposition of silica nanoparticles onto the P(S/DMA) at acidic medium, PS/SiO2 core/shell composite particles were obtained. Both preparations of PS colloids and PS/SiO2 composites were easy and one-pot syntheses.

Thermal Properties of Oligo(2‐ethyl‐2‐oxazoline) Containing Comb and Graft Copolymers and their Aqueous Solutions

AbstractSummary: The cationic ring opening polymerization of 2‐ethyl‐2‐oxazoline (EtOx) was applied for the synthesis of methacrylate end‐functionalized well‐defined macromonomers that could be polymerized in a controlled manner using reversible addition‐fragmentation chain transfer polymerization. The obtained comb polymers revealed lower critical solution temperature behavior in aqueous solution. The cloud points of these solutions could be tuned in a range from 35 °C to 85 °C by the incorporation of hydrophobic methyl methacrylate comonomer in varying amounts into the graft copolymers whereas copolymerization with methacrylic acid rendered temperature and pH sensitive copolymers. Thermo‐gravimetric analysis showed a two‐step decomposition of the graft copolymers and differential scanning calorimetry revealed glass transition temperatures that are significantly lowered in comparison to linear PEtOx.

Effect of nanoclay and macroinitiator on the kinetics of atom transfer radical homo- and copolymerization of styrene and methyl methacrylate initiated with CCl 3-terminated poly (vinyl acetate) macroinitiator

Effect of nanoclay on the kinetics of atom transfer radical bulk homo- and copolymerization of styrene (St) and methyl methacrylate (MMA) initiated with CCl 3-terminated poly (vinyl acetate) macroinitiator at 90 °C was investigated. CuCl/PMDETA was used as a catalyst system. Results showed that nanoclay significantly enhances the homopolymerization rate of MMA. It was attributed to the activated conjugated C C bond of MMA monomer via interaction between the carbonyl group of MMA monomer and the hydroxyl moiety (Al O H) of nanoclay as well as to the effect of nanoclay on the dynamic equilibrium between the active (macro)radicals and dormant species. Homopolymerization rate of St (a noncoordinative monomer with nanoclay) decreased slightly in the presence of nanoclay. It could be explained by inserting of a portion of macroinitiator into the clay galleries, where no sufficient St monomer exists due to the low compatibility or interaction of St monomer with nanoclay to react with the macroinitiator. Controlled/living characteristic of all the reactions were confirmed by GPC results. More reliable reactivity ratios of the St and MMA in the presence of nanoclay were calculated by using the cumulative average copolymer composition at the moderate to high conversion to be r St = 0.290 ± 0.082, r MMA = 0.443 ± 0.093 (extended Kelen–Tudos method) and r St = 0.293 ± 0.071, r MMA = 0.447 ± 0.080 (Mao–Huglin method). Results indicated that the rate of incorporation of MMA comonomer into the copolymer increases in the presence of nanoclay, verifying the existence of interaction between the carbonyl group of MMA comonomer and the hydroxyl moiety of nanoclay. It was found that in the presence of nanoclay, tendency of the random copolymerization of St and MMA toward an alternating copolymerization increases.

The Role of Polymer/Polymer Miscibility in Interfacial Healing Kinetics and Equilibrium Adhesion Energy: A Universal Approach

Interfacial strengthening of different polymers has a crucial role in blending them into new materials. Healing is one way to strengthen the interface via polymer interdiffusion across and forming new entanglements. In this research work, interfacial healing kinetics and equilibrium adhesion energy of polystyrene and poly(styrene-co-methyl methacrylate) containing different amounts of methyl methacrylate comonomer were studied using asymmetric wedge cleavage test. The results showed higher interfacial adhesion energy and enhanced healing kinetics by raising styrene monomer content of the copolymer. This may be attributed to the degree of segregation, χN, between the joint components. Interfacial healing rate depended on χN to the power –0.1. Interfacial adhesion energy, however, scaled as χN to the power –0.33, where χ is the Flory–Huggins interaction parameter and N is average degree of polymerization of the components. On the other hand, correlation of interfacial adhesion energy (G IC) with the characteristic number of interfacial entanglements (N ent) showed a fairly good agreement with the Cole et al.'s theory. Finally, joint interfacial adhesion energy enhanced with interfacial width divided by the product of mean entanglement length and degree of segregation, χN, irrespective of copolymer composition.

Effect of copolymer composition on flow properties and film-forming of functionalised latex binders

Acrylic and styrene/acrylic latex binders comprising functional monomers such as acrylic acid, methacrylic acid, methacrylamide, methyl methacrylate, and hydroxyethyl methacrylate in different concentration levels were synthesised. It was shown that the extent of particle swelling and the hydroplasticisation of the alkali-swellable particles was affected by the polarity of the ‘hard’ comonomer. The effect of dissociated carboxylic groups on the increase in latex viscosity and on the lowering of its minimum film-forming temperature was much more pronounced in the case of the methyl methacrylate comonomer. The thickening of the latices with hydrophobe-modified ethylene oxide urethane (HEUR) associative thickeners was considerably affected by the hydrophobicity of the particles. Thickening with hydrophically-modified alkali-soluble emulsion (HASE) thickeners depends predominantly on the excluded volume of swollen thickener particles. The influence of the hydrophobic styrene content was negligible.

Effect of styrene and methyl methacrylate comonomers in ethyl acrylate/methacrylic acid latex on particle alkali-swellability, film formation and thickening with associative thickeners

Series of emulsion copolymers were synthesized from methacrylic acid, ethyl acrylate as a “soft” comonomer and different amounts of methyl methacrylate or styrene as “hard” comonomers. It was shown that the extent of particle swelling and hydroplasticization at constant content of methacrylic acid was affected by the “hard” comonomer content due to its polarity. The minimum film forming temperature (MFT) results were found to be in good agreement with the titration curves, with zeta-potential measurements and with the flow behavior of the copolymer latices. Viscosity increase caused by particle swelling strongly influences thickening of latex material also being dependent on the comonomer polarity.

Acrylamide–Methylmethacrylate Graft Copolymerization onto Cellulose Using Ceric Ammonium Nitrate

The graft copolymerization of acrylamide (AAm) and methylmethacrylate (MMA) onto cellulose has been carried out from their mixtures using ceric ammonium nitrate (CAN) as initiator in the presence of nitric acid at 25.0±0.1°C. The extent of graft copolymerization of acrylamide onto cellulose has shown a substantial increasing trend in the presence of methylmethacrylate comonomer. On varying the feed molarity from 7.5×10−2 mol dm−3 to 60×10−2 mol dm−3, the graft yield has shown a linear increase with grafted chains of almost constant composition (FAAm=0.57). The composition of the grafted chains (FAAm) has been found to be dependent on the feed composition (fAAm) and temperature of reaction mixture. The effect of ceric (IV) ions concentration, reaction time and temperature was also studied and grafting parameters were determined to evaluate the effect of these reaction variables. The grafting parameters have shown an increasing trend up to 8.0×10−3 mol dm−3 concentration of ceric ammonium nitrate at a feed morality of 45.0×10−2 mol dm−3 and shown a decreasing trend on further increasing the concentration of ceric ammonium nitrate (>8.0×10−3 mol dm−3) while keeping fixed concentrations of nitric acid (9.0×10−2 mol dm−3). The IR and nitrogen percent data were used to determine the composition of the grafted chains (FAAM), which was further used to determine reactivity ratios of acrylamide (r1) and methylmethacrylate (r2) using the Mayo and Lewis plot. The reactivity ratios of acrylamide (r1) and methylmethacrylate (r2) were found to be 0.82 and 1.10 respectively. This indicated an alternate arrangement of average sequence lengths of acrylamide (m¯M1) and methylmethacrylate (m¯M2) in the grafted chains as the product of reactivity ratios (r1r2) was less then unity. The rate of graft copolymerization of comonomers onto cellulose has been found to be dependent on the square concentration of comonomers and square root of the ceric ammonium nitrate concentration. The activation energy (ΔEa) of graft copolymerization was found to be low (14.36 kJ mol−1) within the temperature range of 20°C to 45°C. On the basis of experimental observations, suitable reaction steps for graft copolymerization of acrylamide and methylmethacrylate have been proposed to explain the grafting of these comonomers onto cellulose.

Styrene/potassium persulfate/water systems: effects of hydrophilic comonomers and solvent additives on the nucleation mechanism and the particle size

Emulsifier-free emulsion polymerizations based on styrene/potassium persulfate/water (St/kps/H 2O) in the presence of a relatively hydrophilic comonomer, such as vinyl acetate (VAc) or methyl methacrylate (MMA), or the nonpolar solvent, such as ethyl acetate (EAc) or methyl isobutyrate (MIB) having structural similarity with VAc and MMA respectively, or the polar solvent such as glycerin or acetone etc., have been carried out. From the gel permeation chromatograph (GPC) analysis of polymers obtained in the presence of VAc or MMA comonomer, or even MIB or EAc nonpolar solvent, the presence of oligomers having the molecule weight of 1000 at the early stage of polymerization suggests a micellar nucleation mechanism. From the study for effects of additives on the rate of polymerization, we found that all curves for the conversion versus time showed concave upward at about the conversion of 45% but level off at about 80%. Moreover, when the polar or nonpolar solvent was used as an additive, a controllable particle size of monodisperse microspheres with the ranges 270–750 nm could be expected. Besides, the particle size of monodisperse microspheres was decreased with increasing of the addition amount of the polar solvent. Monosize polystyrene microspheres with smaller particle sizes can be obtained by adding of the polar solvent; on contrary, microspheres with larger particle sizes can be generated by a limited addition amount of the nonpolar solvent.

Preparation and characterisation of some nickel(II) tetra-aza macrocyclic complexes bearing pendant polymerisable groups as part of the ligand superstructure

The synthesis and characterisation of some new nickel(II) macrocyclic complexes of the ‘lacunar’ type have been performed where the ligand has, as part of the ligand superstructure, either 4-vinylphenyl or allyl groups capable of undergoing polymerisation reactions with selected comonomers. The n.m.r. spectra of a number of these new complexes show them to be fluxional on the n.m.r. time-scale and the nature of this fluxional behaviour is discussed. Some copolymerisation reactions of these complexes, with styrene or methyl methacrylate comonomers, have been performed.

Qualitative and quantitative analysis of methyl acrylate or methyl methacrylate of acrylonitrile fibers by pyrolysis gas chromatography

AbstractDegradation gases evolved from methyl acrylate or methyl methacrylate of acrylonitrile fibers were analyzed by pyrolysis gas chromatography. For determining polymer composition, optimum pyrolysis conditions were determined and calibration was accomplished by using acrylonitrile–methylacrylate and acrylonitrile–methyl methacrylate model copolymers. Out of the 23 samples examined, 10 were found to contain methyl acrylate and five methyl methacrylate comonomers, in the range of 3.5–8.0%. The reproducibility of the method was good, the coefficient of variations was ±2% for methyl acrylate and ±2.5% for methyl methacrylate. Compositions were in agreement with those determined by other methods.

Polymethacrylate‐supported linear polyethers as solid‐liquid phase transfer catalysts

AbstractOligo(oxyethylene)s immobilized as pendant groups on a polymethacrylate‐based resin were used as phase transfer catalysts in the reaction of solid alkali phenoxides with octyl halides in toluene and in the synthesis of benzyl acetate from benzyl bromide and solid alkali acetates in chloroform. The resins are cross‐linked homopolymers or copolymers of methyl ethers of oligo(ethylene glycol) methacrylates of the general formula H2CC(CH3)COO(CH2CH2O)n CH3 with n = 4 (MG4), 8 (MG8) or 22 (MG22), the comonomers being styrene, methyl methacrylate (MMA), acrylonitrile or 4‐vinylpyridine. The conversion of the organic halides into the respective products were found to be all pseudo first order reactions and the observed rate constants are proportional to the amount of added catalyst and decrease with increasing crosslinking density of the catalyst. Catalysts with longer oligo(oxyethylene) chains have considerably higher activity. Incorporation of more than 50 mol‐% MMA comonomer decreases the catalytic activity at least for the benzyl bromide reaction, but the structure of the comonomer has no significant effect. The catalysts are easily synthesized in large quantities from commercially available monomers.

Polymerization of macromers

The possibility of group transfer polymerization of methyl methacrylate-terminated polystyrene macromer (MA-PSt) was explored by using 1-methoxy-1-(trimethylsiloxy)-2-methyl-1-propene and tris(dimethylamino)sulfonium difluorotrimethylsilicate as initiator and catalyst, respectively. The results obtained at the polymerization temperature of 0°C were undesirable. However, the oligomerization at -78°C gave almost quantitatively oligo(MA-PSt) of which the degree of polymerization was in good agreement with the mole ratio of macromer to initiator. The GPC curve of oligo(MA-PSt) was sharp and symmetrical. In addition, it was shown by the copolymerization with methyl methacrylate that the polymerizability of the macromer was markedly enhanced in the presence of methyl methacrylate comonomer.