Influence of the third monomer on lauryl methacrylate–methyl methacrylate emulsion terpolymerization

An experimental study shows how the emulsion terpolymerization of lauryl methacrylate (LMA) and methyl methacrylate is influenced by the nature of the third monomer. The third monomer is either glycidyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, or styrene. We report the synthesis of terpolymer particles with an appreciably high content of the very hydrophobic LMA (between 0.2515 and 0.238 molar fraction in the monomer mixture) in 60:40 weight water/ethanol mixture as the continuous phase, poly(vinyl pyrrolidone) as a polymeric steric stabilizer, and potassium peroxodisulfate as the initiator. The emulsion terpolymerization proceeds smoothly without the formation of coagulum and leads to particles with an average diameter clearly below 1 μm. We discuss the overall polymerization behavior regarding conversion–time curves, particle morphology, and glass transition temperature of the terpolymers in dependence of the lyophilicity/lyophobicity of the monomer mixture.     

Continuous styrene – methyl methacrylate – glycidyl methacrylate terpolymerizations in homogeneous mixtures with supercritical carbon dioxide

Free-radical terpolymerizations of styrene, methyl methacrylate, and glycidyl methacrylate were carried out in a tubular reactor in the presence of 20 wt.% CO₂ at temperatures between 120 and 180°C and pressures of 300 and 350 bar. The number average molecular weights, M_N, were mostly between 2000 and 3000 g·mol⁻¹ and polydispersity indices around 2. In part of the experiments molecular weights were controlled by n-dodecyl mercaptan serving as the chain-transfer agent. PREDICI modeling indicates that the targeted molecular weights of M_N∼2500 g·mol⁻¹ and polydispersities around 2 may also be reached by using an initiator cocktail, a mixture of two initiators with significantly different decomposition rate coefficients. The predictions are confirmed experimentally.     

Phase behavior and modeling of the poly(methyl methacrylate)–CO2–methyl methacrylate system

Cloud-point data for the system poly(methyl methacrylate) (PMMA)–CO₂–methyl methacrylate (MMA) are measured in the temperature range of 26 to 170°C, to pressures as high as 2500 bar, and with cosolvent concentrations of 10.4, 28.9, and 48.4 wt.%. PMMA does not dissolve in pure CO₂ to 255°C and 2550 bar. The cloud-point curve for the PMMA–CO₂–10.4 wt.% MMA system exhibits a negative slope that reaches 2500 bar at 105°C. With 28.9 wt.% MMA the cloud-point curve remains relatively flat at ∼900 bar for temperatures between 25 and 170°C. With 48.4 wt.% MMA the cloud-point curve exhibits a positive slope that extends to 20°C and ∼100 bar. Pressure-composition isotherms are also reported for the CO₂–MMA system at 40.0, 80.0, 105.5°C. This system exhibits type-I phase behavior with a continuous mixture–critical curve. The Peng–Robinson (PR) and SAFT equations of state model the CO₂–MMA data reasonably well without any binary interaction parameters, although the PR equation provides a better representation of the mixture-critical region. It is not possible to obtain even a qualitative fit of the PMMA–MMA–CO₂ data with the SAFT equation of state. The SAFT model qualitatively shows that the cloud-point pressure decreases with increasing MMA concentration and that the cloud-point curve exhibits a positive slope for very high concentrations of MMA in solution.     

The ATRP Synthesis of the Potential Thermoplastic Elastomer Poly(methyl methacrylate)–b-(lauryl methacrylate)-b-(methyl methacrylate) Hitherto Unrealized by Ionic Polymerization

The triblock copolymer poly(methyl methacrylate-b-lauryl methacrylate-b-methyl methacrylate) {P(MMA-b-LMA-b-MMA)} has been synthesized by a two stage atom transfer radical polymerization in bulk at near room temperature (ca. 35 °C) using CuCl/pentamethyldiethylenetriamine (PMDETA)/tricaprylylmethylammonium chloride (Aliquat®336) complex as the catalyst and 1,2-bis (bromoisobutyryloxy)ethane (BIBE) as the initiator for the polymerization of LMA in the first stage. The same catalyst was also used for the polymerization of MMA in the second stage. The dynamic mechanical thermal analysis of a sample with the middle block M_n = 82000 and each end block M_n = 14500 showed typical features of a thermoplastic elastomer.     

Preparation and characterization of star ABC triblock copolymer of ethylene oxide,styrene and methyl methacrylate

A universally significant method,which combines the anionic polymerization with photoinduced charge transfer polymerization,for preparation of soluble star ABC triblock copolymer of ethylene oxide,styrene and methyl methacrylate,was described.The poly(ethylene oxide) (PEO) block was formed by initiation of phenoxy an-ions using p-aminophenol protected by Schiff's base as the parent compound Then the charge transfer system composed of PEO chains with deprotected-amino end groups and benzophenone initiated the polymerization of styrene and methyl metnacrylate sequentially under UV irradiation.The formed star triblock copolymer of styrene,ethylene oxide and methyl methacrylate could be purified by thin-layer chromatography (TLC) and characterized by IR,1H NMR,GPC (gel permeation chromatogrphy) and PGC (pyrolysis gas chromatography).     

Synthesis and Characterization of Poly(methyl methacrylate‐co‐hydroxyethyl methacrylate)‐b‐polyisobutylene‐b‐poly(methyl methacrylate‐co‐hydroxyethyl Methacrylate) Triblock Copolymers

The synthesis of poly[(methyl methacrylate‐co‐hydroxyethyl methacrylate)‐b‐isobutylene‐b‐(methyl methacrylate‐co‐hydroxyethyl methacrylate)] P(MMA‐co‐HEMA)‐b‐PIB‐b‐P(MMA‐co‐HEMA) triblock copolymers with different HEMA/MMA ratios has been accomplished by the combination of living cationic and anionic polymerizations. P(MMA‐co‐HEMA)‐b‐PIB‐b‐P(MMA‐co‐HEMA) triblock copolymers with different compositions were prepared by a synthetic methodology involving the transformation from living cationic to anionic polymerization. First, 1,1‐diphenylethylene end‐functionalized PIB (DPE‐PIB‐DPE) was prepared by the reaction of living difunctional PIB and 1,4‐bis(1‐phenylethenyl)benzene (PDDPE), followed by the methylation of the resulting diphenyl carbenium ion with dimethylzinc (Zn(CH₃)₂). The DPE ends were quantitatively metalated with n‐butyllithium in tetrahydrofuran, and the resulting macroanion initiated the polymerization of methacrylates yielding triblock copolymers with high blocking efficiency. Microphase separation of the thus prepared triblock copolymers was evidenced by the two glass transitions at ?64 and +120°C observed by differential scanning calorimetry. These new block copolymers exhibit typical stress‐strain behavior of thermoplastic elastomers. Surface characterization of the samples was accomplished by angle‐resolved X‐ray photoelectron spectroscopy (XPS), which revealed that the surface is richer in PIB compared to the bulk. However, a substantial amount of P(MMA‐co‐HEMA) remains at the surface. The presence of hydroxyl functionality at the surface provides an opportunity for further modification.     

Hydroformylation of methyl methacrylate via “in-situ” phosphinerhodium catalysis

It has been shown that in hydroformulation of methyl methacrylate with rhodium phosphine catalysts prepared “in situ” the regioselectivity is very sensitive not only to the reaction conditions but also to the basicity of the phosphine and to the presence of added Et₃N. At low P/Rh ratio chlororhodium species are catalytically active. No side reactions have been detected.     

Synthesis of a novel centipede-like copolymer of styrene and methyl methacrylate

A well-defined,A2B-type,centipede-like copolymer of styrene and methyl methacrylate(PS-PS-PMMA) was synthesized by the combination of living anionic polymerization and atom transfer radical polym-erization(ATRP) . The synthetic approach involves the coupling reaction of polystyrene(PS) backbone bearing 1,1-diphenylethene(DPE) pendant groups,produced by ATRP and Wittig reaction,with living polystyryllithium(PSLi) ,and subsequent polymerization of the resulting 1,1-diphenylmethyl anions with methy methacrylate. The centipede-like copolymer was characterized by 1H NMR,IR,SEC,SLS,and DSC measurements.     

A novel epoxy methacrylate resin containing phthalazinone moiety for UV coatings

A novel phthalazinone modified epoxy acrylate resin for the high temperature resistant ultravioet (UV) curable coating was synthesized. The methacrylated epoxy resins obtained were utilized to UV radiation curing by taking 2.5% (wt%) of photoinitiator in combination with 20% (wt%) of diluent, and generated the interpenetraring polymer networks. The cured film had good thermal and chemical stability.     

Studies of aminolysis of acrylonitrile–divinylbenzene–methyl methacrylate copolymers

Aminolysis of nitrilacrylate–divinylbenzene–methyl methacrylate copolymers by diethylenetriamine is studied under various conditions. The effect of temperature and catalyst concentration on the properties of synthesized anion exchangers depending on the duration of aminolysis is investigated. The conditions for synthesizing anion exchangers with high capacity characteristics are proposed according to the study results.     

Preparation and characterization of blended solid polymer electrolyte 49% poly(methyl methacrylate)-grafted natural rubber:poly(methyl methacrylate)–lithium tetrafluoroborate

The preparation and characterization of blended solid polymer electrolyte 49% poly(methyl methacrylate)-grafted natural rubber (MG49):poly(methyl methacrylate) (PMMA) (30:70) were carried out. The effect of lithium tetrafluoroborate (LiBF₄) concentration on the chemical interaction, structure, morphology, and room temperature conductivity of the electrolyte were investigated. The electrolyte samples with various weight percentages (wt.%) of LiBF₄ salt were prepared by solution casting technique and characterized by Fourier transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy. Infrared analysis demonstrated that the interaction between lithium ions and oxygen atoms occurred at symmetrical stretching of carbonyl (C=O) (1,735 cm^?1) and asymmetric deformation of (O–CH₃) (1,456 cm^?1) via the formation of coordinate bond on MMA structure in MG49 and PMMA. The reduction of MMA peaks intensity at the diffraction angle, 2θ of 29.5° and 39.5° was due to the increase in weight percent of LiBF₄. The complexation occurred between the salt and polymer host had been confirmed by the XRD analysis. The semi-crystalline phase of polymer host was found to reduce with the increase in salt content and confirmed by XRD analysis. Morphological studies by SEM showed that MG49 blended with PMMA was compatible. The addition of salt into the blend has changed the topological order of the polymer host from dark surface to brighter surface. The SEM analyses supported the enhancement of conductivity with the addition of salt. The conductivity increased drastically from 2.0 to 3.4?×?10^?5 S cm^?1 with the addition of 25 wt.% of salt. The increase in the conductivity was due to the increasing of the number of charge carriers in the electrolyte. The conductivity obeys Arrhenius equation in higher temperature region from 333 to 373 K with the pre-exponential factor σ _o of 1.21?×?10^?7 S cm^?1 and the activation energy E _a of 0.46 eV. The conductivity is not Arrhenian in lower temperature region from 303 to 323 K.     

Photoinitiated polymerization of β-cyclodextrin/methyl methacrylate host/guest complex in the presence of water soluble photoinitiator, thioxanthone-catechol-O,O′-diacetic acid

β-Cyclodextrin (β-CD) was used to complex the monomer, methyl methacrylate (MMA), yielding a water-soluble host/guest complex. Photoinitiated polymerization of β-CD/MMA complex was achieved in the presence of thioxanthone-catechol-O,O′-diacetic acid (TX-Ct), a one component water soluble photoinitiator. Photodecarboxylation of TX-Ct in water seems to be an important reaction mechanism. Therefore, resulting alkyl radicals are able to initiate the polymerization of β-CD/MMA host/guest complex in water.     

Pseudoliving radical polymerization of methyl methacrylate in the presence of S,S′-bis(methyl-2-isobutyrate) trithiocarbonate

The polymerization of MMA mediated by symmetric trithiocarbonate as a reversible addition-fragmentation chain-transfer agent is studied. It is shown that the process proceeds according to the two-stage pseudoliving radical mechanism. The polymeric reversible addition-fragmentation chain-transfer agent is more efficient than its low-molecular-mass analog. The use of the polymeric reversible addition-fragmentation chain-transfer agent makes it possible to synthesize narrowly dispersed homopolymers of MMA and related copolymers with a controllable molecular mass. Both chain-transfer agents have practically no effect on the initial rate of copolymerization but allow weakening or even suppression of the gel effect at high conversions.     

Investigation of Hydrogen Bonded Interpolymer Complexes Based on Poly (n-butyl methacrylate–co-methacrylic acid) and Poly (n-butyl methacrylate -co-4-vinyl pyridine). Temperature Effect

Summary: Two kinds of interpolymer complexes as soluble or precipitate of different structures were obtained in both THF and butan-2-one as common solvents by monitoring the hydrogen-bonding density within homoblends of poly(n-butyl methacrylate-co-4-vinylpyridine) (BM4VP) and poly(n-butyl methacrylate-co-methacrylic acid) (BMMA). A viscometry study confirmed such differences between these two types of interpolymer complexes from the behavior of the reduced viscosity of their blend solutions with feed blend composition. Qualitative and quantitative analyses of the interactions that occurred between these copolymers of relatively bulky side chain length containing various amounts of methacrylic acid and 4-vinylpyridine were carried out by FTIR. The fraction of associated pyridine groups to the carboxylic groups of the BMMA increases as the content of these latter increases in the BMMA/BM4VP blends. The obtained results also showed that the fractions of associated pyridine within the BMMA25/BM4VP26 blends are higher than those within BMMA18/BM4VP19 or BMMA8/BM4VP10. The FTIR analysis of a selected BMMA18/BM4VP19 1:1 ratio, carried out from 80 °C to 160 °C, above the glass transition temperatures of the two constituents of the blend, confirms the presence of strong hydrogen bonding interactions between the pyridine and the carboxylic groups within these blends even at 160 °C. A LCST is expected to occur at higher temperature as shown from the progressive decrease of the fraction of the associated pyridine.     

Thermal stability of sol–gel derived methacrylate oligosiloxane-based hybrids for LED encapsulants

Methacrylate oligosiloxane-based hybrid materials (methacrylate hybrimers) were fabricated by curing the methacrylate oligosiloxane resins synthesized by sol–gel condensation reaction of 3-(trimethoxysilyl)propyl methacrylate (MPTS) and diphenylsilanediol (DPSD) for the LED encapsulant application. The fabricated hybrimers are optically transparent and have a high refractive index up to 1.565 depending on the precursor composition. The lower DPSD content hybrimer, which is the more polymerized and heated in a vacuum to remove the non-polymerized methacrylate groups, produces higher optical transmittance and thermal stability. This behavior is interpreted by thermal degradation of methacylate groups in the hybrimers.     

Electrochemical Properties of Poly (ethyl acrylate-co-lithium methacrylate) Latex Film Solid Electrolyte

Muchattentionhasbeenpaidtothedevelopmentofnewpolymerelectrolytewithspecialmorphology,soastoimprovetheirelectrochemicalpropertiestomeettheneedsoflithium(ion)battery.Inthiswork,PEMlatexwassynthesizedbyemulsion-fi-eepolymerization.ThemicrophotoofPEMlate...     

Formation and structure of chitosan–poly(sodium methacrylate) complex nanoparticles

Interpolyelectrolyte complex (IPEC) dispersions were prepared from chitosan and poly(sodium acrylate), NaPMA, by mixing their solutions, at different carboxyl-to-aminium molar ratios, r_CA. Gyration radius was determined by small angle x-ray scattering (SAXS) and showed that, as r_CA was increased, IPEC dimensions decreased and reached a minimum at r_CA?=?0.75, which was considered the ratio at which IPEC cluster dimensions were minimum, following collapse, phase segregation, nucleation, and growth of larger particles. Pair distance distributions, P(r), became narrower up to r_CA?=?0.75, increasing its width from this point. Relaxation-related parameters from dynamic light scattering (DLS) intensity correlation functions (ICFs) identified three main relaxation processes. The fast process, related to free polyelectrolyte molecules random motion disappeared as r_CA, was increased. The other two relaxation processes also were a function of r_CA and presented marked changes at r_CA?=?0.75. At the same value of r_CA, the energy of activation for the average relaxation rate showed the occurrence of a clear change in the nature of IPEC-related interactions. As hydrodynamic diameter, determined by DLS, was much larger than the gyration radius determined by SAXS, IPEC particles could be described as being composed by a core, rich in segregated, insoluble material, enveloped by IPEC soluble clusters, possibly in the form of water-rich gels.     

Radical methyl methacrylate—methacrylic acid copolymerization in isopropyl alcohol,acetone, and their mixtures. Application of the copolymer products for microencapsulation of ampicylline trihydrate

The copolymerization ratios of radical methyl methacrylate (MMA)-methacrylic acid (MA) copolymerization in mixtures of isopropyl alcohol (IPA) with acetone (A), xylene (X), and water (W) are determined. Their values and those in IPA are smaller than unity. The established alternating tendency of the monomer parts in the obtained copolymers is somewhat larger than the theoretically expected one and this is explained by the donor-acceptor interaction either between comonomers or between them and the propagating radicals. It is suggested that the reason for this tendency is the difference in H-bond formation between comonomers and solvents used. The dependencies of the apparent mass average molecular weight of the copolymers (M_{w, ap}) on their composition are also determined as well as the -composition of the A-heptane (H) mixture for these copolymers. These data are used for ampicyl line trihydrate (AT) microencapsulation by phase separation of the AT suspension in copolymer solutions in A after H addition. The AT microencapsulation characteristics (yield, degree and efficiency) as dependent on the copolymer composition as well as the influence of this composition on the solution kinetics of the microencapsulated AT at pH=4.5 and 6.5 and temperature of 37°C are established.     

The Relationship of Reaction Temperature,Tg and Rich‐Syndiotacticity of Poly(alkyl methacrylate)s in Modified Microemulsion Polymerization

Nanoscale poly(alkyl methacrylate)s including poly(methyl methacrylate), poly(ethyl methacrylate), poly(cyclohexyl methacrylate), poly(iso‐butyl methacrylate) and poly(benzyl methacrylate) were prepared by a modified microemulsion polymerization procedure. NMR analysis suggested that these poly(methacrylate)s samples were higher in syndiotactic content, lower in isotactic content and the glass transition temperatures (T_gs) of them were also higher than those reported in the literature. The tacticities of the poly(methacrylate)s, beside the restricted volume effect of nanoparticles during the modified microemulsion polymerization, were mainly influenced by the reaction temperature, the lower the reaction temperature, the higher the syndiotacticity of the products. The syndiotacticity of the product decreased obviously when the polymerization was carried out at a temperature far above the T_g of the resulting polymer. It was also shown that the tacticity of the polymer was affected by the monomer structure, a monomer with the bulkier alkyl side group would liable to result in a polymer with richer syndiotacticity. Possible mechanism of rich‐syndiotacticity was also discussed.     

Molecular recognition by indoleacetic acid-imprinted polymers – effects of 2-hydroxyethyl methacrylate content

Molecularly imprinted polymers for indole-acetic acid were prepared by co-polymerizing N,N-dimethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate (HEMA), and ethylene glycol dimethacrylate. The dependence of the affinity and selectivity of the imprinted polymers on HEMA content was evaluated chromatographically. The affinity was improved by increasing the HEMA content; the selectivity of the imprinted polymer was best when the HEMA content was approximately 30%, irrespective of monomer content.