Effect of polyethyleneglycol on polymerization of methyl methacrylate initiated by sodium salt-type macromolecular electrolytes

Summary The effects of polyethyleneglycol (PEG) on the radical polymerizations of methyl methacrylate initiated with the aqueous solutions of such macromolecular electrolytes as sodium polyphenolate and sodium polycarboxylate were studied. PEG was found to promote the polymerizations initiated by such sodium salt-type's macromolecular electrolytes.Vinyl Polymerization. 415.     

Vinyl Polymerization. 218. Polymerization of Methyl Methacrylate in the Presence of Nylon-6 Fiber and Water

The polymerization of methyl methacrylate in the presence of nylon-6 fibers and water was carried out. It was found that the conversion in the absence of water was the same as that of thermal polymerization, but in the presence of water the conversion was much higher. When methyl methacrylate and water existed sufficiently in the polymerization system, the rate of polymerization (R_p) was given by the following equation; R_p = k (Nylon)^1,0 (Methyl methacrylate)⁰ (Water)⁰. The over-all activation energy of the polymerization was found to be 13 kcal/mole. The polymerization of styrene, acrylonitrile, vinyl acetate, and methyl acrylate could not be initiated by the system of nylon and water. Apparent grafting efficiency of polymethyl methacrylate onto nylon was calculated from the amount of polymer which was not extracted with acetone. The efficiency was independent on the reaction time and the amount of water, and increased with the amount of nylon, while it decreased with the amount of methyl methacrylate and with reaction temperature. From the fact that a major part of the polymethyl methacrylate could not be extracted, it was concluded that the polymerization of methyl methacrylate in the presence of nylon and water occured predominantly inside the fiber. The degree of the polymerization of polymethyl methacrylate formed inside the nylon fiber was considerably higher than that of homopolymethyl methacrylate formed outside the fiber. It was qualitatively recognized that the major part of the polymethyl methacrylate generated in the fiber was not grafted onto nylon, but existed as homopolymer.     

Thermal properties of PMMA/TiO2 nanocomposites prepared by in-situ bulk polymerization

The surface of anatase TiO₂ nanoparticles, obtained by the controlled hydrolysis of titanium tetrachloride, was modified by 6-palmitate ascorbic acid. The surface modified TiO₂ nanoparticles were dispersed in methyl methacrylate and mixed with a appropriate amount of poly(methyl methacrylate) to obtain a syrup. The nanocomposite sheets were made by bulk polymerization of the syrup in a glass sandwich cell using 2,2′-azobisisobutyronitrile as initiator. The molar masses and molar mass distributions of synthesized poly(methyl methacrylate) samples were determined by gel permeation chromatography. The content of unreacted double bonds in synthesized samples was determined by ¹H NMR spectroscopy. The influence of TiO₂ nanoparticles on the thermal stability of the poly(methyl methacrylate) matrix was investigated using thermogravimetric analysis and differential scanning calorimetry. The synthesized samples of poly(methyl methacrylate) have different molar mass and polydispersity depending on the content of the surface modified TiO₂ nanoparticles. The values of glass transition temperature of so prepared nanocomposite samples were lower than for pure poly(methyl methacrylate), while the glass transition temperature of samples preheated in inert atmosphere was very similar to the glass transition temperature of pure poly(methyl methacrylate). The thermal stability of nanocomposite samples in nitrogen and air was different from thermal stability of pure poly(methyl methacrylate). POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Acoustic analysis of composite soft materials. I. Characterization of the core and boundary layer from compressibility of core/shell particles dispersed in poly(vinyl chloride)

The sound velocity of butyl acrylate rubber particles modified by poly(methyl methacrylate) in poly(vinyl chloride) was measured as a function of particle concentration. A model for estimating the adiabatic compressibility of the particle and the boundary layer was proposed. From the model, the partial specific adiabatic compressibility of the particles and the rubber core were evaluated. The adiabatic compressibility of the rubber core was estimated as 3.82 × 10⁻¹⁰ Pa⁻¹. The adiabatic compressibility of the poly(methyl methacrylate) shell is discussed based on the modified model. The study indicates that the shell, including the boundary layer between butyl rubber and poly(methyl methacrylate), is perturbed by the butyl acrylate molecules and is so soft as to be comparable to the rubber. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2089–2094, 2001     

Influence of different alkyl side chains on solid surface tension of polymethacrylates

Low‐rate dynamic contact angles on poly(t‐butyl methacrylate) (PtBMA) were measured by an automated axisymmetric drop shape analysis profile (ADSA‐P). The solid surface tension of PtBMA is calculated to be 18.1 mJ/m², with a 95% confidence limit of ±0.6 mJ/m². This value was compared to previous results with different homopolymeric polymethacrylates [poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), and poly(n‐butyl methacrylate) (PnBMA)] and with copolymeric polymethacrylates {poly(methyl methacrylate/ethyl methacrylate, 30/70) [P(MMA/EMA, 30/70)] and poly(methyl methacrylate/n‐butyl methacrylate) [P(MMA/nBMA)]}. It was found that increasing length and size of the alkyl side chain decrease the solid surface tension, as expected. Comparison with pure alkyl surfaces suggests that the surface tension of PtBMA is dominated by the very hydrophobic t‐butyl group. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2493–2504, 2000     

Characterization and Properties of Poly(methyl methacrylate)/Graphene,Poly(methyl methacrylate)/Graphene Oxide and Poly(methyl methacrylate)/p-Phenylenediamine-Graphene Oxide Nanocomposites

In this study, poly(methyl methacrylate)/p-phenylenediamine-graphene oxide, poly(methyl methacrylate)/graphene, and poly(methyl methacrylate)/graphene oxide nanocomposite series were prepared using simple solution blending technique. In poly(methyl methacrylate)/p-phenylenediamine-graphene oxide series, graphene oxide modified with p-phenylenediamine was used to improve its dispersion and interfacial strength with matrix. Morphology study of poly(methyl methacrylate)/p-phenylenediamine-graphene oxide nanocomposite revealed better dispersion of p-phenylenediamine-graphene oxide flakes and gyroid patterning of poly(methyl methacrylate) over the filler surface. Due to nonconducting nature of graphene oxide, there was no significant variation in the thermal or electrical conductivity of these nanocomposites. Thermal conductivity of poly(methyl methacrylate)/p-phenylenediamine-graphene oxide 1.5 was 1.16 W/mK, while the electrical conductivity was found to be 2.3 × 10^?3 S/cm.     

Synthesis of polar vinyl monomer–olefin copolymers by α‐diimine nickel catalyst

Vinyl acetate, methyl methacrylate, acrylonitrile and methyl vinyl ketone were investigated for co‐ and terpolymerization with ethylene and ethylene–propylene. Precursor [bis(N,N ′‐dimesitylimino)acenaphthene]dibromonickel, activated by methylaluminoxane was used as a catalyst system and trialkylaluminium was employed to block the polar groups for these polymerizations. Polymerization activities of the order of magnitude of 10⁶ in the case of vinyl acetate and methyl methacrylate, and 10⁵ in the case of acrylonitrile were achieved. Microanalysis and GPC of acrylonitrile copolymers found about 17 units of acrylonitrile per polymer chain. Copolymers with very different properties from the parent homopolymers were obtained in all cases except that of methyl vinyl ketone. © 2001 Society of Chemical Industry     

On-line GPC/NMR analyses of block and random copolymers of methyl and butyl methacrylates prepared with t-C4H9MgBr

Summary The isotactic block and random copolymers of methyl methacrylate and butyl methacrylate prepared with t-C₄H₉MgBr in toluene, were analyzed by using a 500 MHz ¹H NMR spectrometer as a detector of gel permeation chromatography. The molecular weight dependence of the chemical compositions of these copolymers could be directly determined with this method by monitoring signal intensities of OCH₃ and OCH2 due to methyl methacrylate and butyl methacrylate units, respectively. From the results mechanism of the copolymerizations was discussed in some detail.     

Synthesis,characterization, and thermal behavior study of methyl methacrylate polymers containing 4‐carbazole substitutes

A new polymerizable monomer, [4‐(9‐ethyl)carbazolyl]methyl methacrylate ( 2 ), was synthesized by reacting of methacrylic acid and 4‐hydroxymethyl‐9‐ethyl carbazole ( 1 ) by esterification procedure in the presence of N,N′‐dicyclohexylcarbodiimide. The resulting monomer was then polymerized free‐radically to form the poly(methyl methacrylate) containing 4‐(9‐ethyl)carbazolyl pend ent groups. Also, copolymerization of monomer 2 with various acrylic monomers such as methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, and n‐butyl acrylate by azobisisobutyronitrile as a free radical polymerization initiator gave the related copolymers in high yields. The structure of all the resulted compounds was characterized and confirmed by FTIR and ¹H NMR spectroscopic techniques. The average molecular weight of the obtained polymers was determined by gel permeation chromatography using tetrahydrofurane as the solvent. The thermal gravimetric analysis and differential scanning calorimeter instruments were used for studying of thermal properties of polymers. It was found that, with the incorporation of bulky 4‐(9‐ethyl)carbazolyl substitutes in side chains of methyl methacrylate polymers, thermal stability and glass transition temperature of polymers are increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4989–4995, 2006     

Emulsion polymerization of methyl methacrylate using poly(methyl methacrylate-co-2-hydroxypropyl methacrylate)-graft-polyoxyethylene as the stabilizer

This study involved the use of an amphipathic graft copolymer, poly(methyl methacrylate-co-2-hydroxypropyl methacrylate)–graft–polyoxyethylene, as a stabilizer in the emulsion polymerization of methyl methacrylate. The stabilizing effectiveness of this graft copolymer was studied as a function of its chemical structure. It was found that the stabilizing effectiveness of the graft copolymer was independent of the molecular weight of the backbone within the investigated range of 4 × 10³ g/mol to 2 × 10⁴ g/mol. In all cases, stable emulsion polymerizations of methyl methacrylate were observed. Effective stabilization also occurred when the graft moieties possessed a molecular weight of either 2 × 10³ g/mol or 5 × 10³ g/mol. However, the stabilizing effectiveness was found to be dependent on the amount of polyoxyethylene (POE) contained in the graft copolymer. In this case, graft copolymers possessing 67% by weight POE were poor stabilizers, but ones with 85% POE were very good stabilizers. Moreover, the graft copolymers were found to be superior stabilizers as compared to POE homopolymers.     

High yield synthesis of diverse well‐defined end‐functionalized polymers by combination of anionic polymerization and “click” chemistry

Well‐defined poly(methyl methacrylate) (M_n = 3630 g mol^?1, PDI = 1.06) with a primary benzylic bromide prepared using anionic polymerization was successfully transformed into diverse end‐functionalities (ω‐carboxyl, ω‐hydroxy, ω‐methyl‐vinyl, ω‐trimethylsilane, and ω‐glycidyl‐ether) via “click” reaction. The bromine end‐terminated poly(methyl methacrylate) was first substituted by an azide function and sequentially was reacted with various functional alkynes (propiolic acid, propargyl alcohol, 2‐methyl‐1‐buten‐3‐yne, propargyl trimethylsilane, and propargyl glycidylether). In all the cases, ¹H‐NMR, ¹³C NMR, FT‐IR, and GPC measurements show qualitative and quantitative transformation of the chain‐end poly(methyl methacrylate) into the desired functionalities with high conversion (above 99%). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Polyallene-based graft copolymer via 6-methyl-1,2-heptadien-4-ol and methyl methacrylate

A series of well-defined graft copolymers with a polyallene-based backbone and poly(methyl methacrylate) side chains were synthesized by the combination of living coordination polymerization of 6-methyl-1,2-heptadien-4-ol and atom transfer radical polymerization of methyl methacrylate. We first prepared poly(alcohol) with polyallene repeating units via 6-methyl-1,2-heptadien-4-ol by living coordination polymerization initiated by [(η³-allyl)NiOCOCF₃]₂, followed by transforming the pendant hydroxyl groups into halogen-containing ATRP initiation groups. Next, grafting-from route was used for the synthesis of the well-defined graft copolymer with excellent solubility: poly(methyl methacrylate) was grafted to the backbone via ATRP of methyl methacrylate. This kind of graft copolymer is the first example of graft copolymer via allene derivative and methacrylic monomer.     

Poly(polyethylene glycol methyl ether methacrylate) as novel solid-solid phase change material for thermal energy storage

Poly(polyethylene glycol methyl ether methacrylate) as novel solid–solid phase change materials (PCMs) for thermal energy storage was prepared via the facile bulk polymerization of polyethylene glycol methyl ether methacrylate and was characterized by Fourier transform infrared, ¹³C-NMR, X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis measurements. Based on the results, it is indicated that the poly (polyethylene glycol methyl ether methacrylate) as novel PCM showed solid–solid properties with suitable transition temperature, high transition enthalpy, and good thermal stability, which was apt to crystallize due to the flexibility of long polyether side chain. This novel PCMs have advantages for the potential application in energy storage. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thickness variation in the thermoforming of poly(methyl methacrylate) and high-impact polystyrene sheets

The influence of material flow properties on the variation of wall thickness in a thermoformed part was investigated by measuring the thickness reduction at the pole of free-formed axisymmetric domes of poly(methyl methacrylate) and high-impact polystyrene. It was found that at a given pole height, the thickness reduction in poly(methyl methacrylate) was less than in high-impact polystyrene, i.e., the wall thickness in a part formed from poly(methyl methacrylate) will be more uniform than in a part formed from high-impact polystyrene by the same technique. This difference in formability was ascribed to a difference in the dependence of the flow stress σ at the thermoforming temperatures on time. The flow stress of both materials was given by σ = Kt^m′?ⁿ, but whereas n was approximately 1 for both materials, m′ was ?0.052 and ?0.33 for poly(methyl methacrylate) and high-impact polystyrene, respectively. A physical argument and simple analysis led to the conclusion that a large (negative) value of the “stress relaxation index” in a material reduces the degree of uniformity of sheet thickness in a formed part.     

A study of sequence distribution of chloroprene and methyl methacrylate copolymers by 1H-NMR

The ¹H-NMR spectra of poly(chloroprene-methyl methacrylate) which was copolymerized with ethylaluminum dichloride (EtAlCl₂) and vanadyl trichloride (VOCl₃) were measured with the radical copolymers. The split signals of the OCH₃ and α-CH₃ protons in the spectra were assigned to triads and pentads with methyl methacrylate as a center, respectively, and the fomer concentrations were in reasonable agreement with the latter concentrations in triads. Moreover, it was found that the α-CH₃ signal was split into peaks of different tacticity when the mole fractional ratio of methyl methacrylate (MMA) to chloroprene (CP) in the copolymer was approximately 3.0 or greater.     

Graft copolymerization onto starch. I. Complexes of Mn3+ as initiators

Advantages in using the pyrophosphate complex of trivalent managanese over the sulfate complex as initiator for graft copolymerization onto starch are discussed. The first successful attempts to graft copolymerize acrylonitrile, methyl methacrylate, and acrylamide to starch and starch derivatives are described using managanic pyrophosphate as initiator. Selective solvent extraction of the reaction products and very low conversions of monomer to homopolymer in absence of starch substrates provide evidence for high grafting efficiencies obtained with acrylonitrile and methyl methacrylate. With acrylamide as monomer, however, low grafting efficiencies and considerable amounts of homopolymer are obtained under the experimental conditions investigated. Reaction mechanisms responsible for initiation of graft copolymerization are discussed. These are (a) glycol cleavage in the anhydroglucose units by Mn³⁺ ions leading to formation of a radical, and (b) enolization and further oxidation of oxidized starch by Mn³⁺ ions also leading to radical species. Mechanisms are also proposed for homopolymerization through Mn³⁺ oxidation of enols which probably are formed by “vinylogous” addition of water molecules to acrylamide and methyl methacrylate.     

End-groups in polymers of 2-vinylnaphthalene and 4-vinylbiphenyl,prepared by polymerisations initiated by azobis(isobutyronitrile)

Polymerisations of 2-vinylnaphthalene and 4-vinylbiphenyl and copolymerisations of these monomers with methyl methacrylate have been initiated by azobis(isobutyronitrile) enriched in its methyl groups with carbon-13. The environments of (CH₃)₂C(CN)- end-groups in the copolymers have been examined by ¹³C nuclear magnetic resonance. It has been concluded that both aromatic monomers are more than twice as reactive as methyl methacrylate towards the primary radical.     

Interactions in poly(vinylidene fluoride)/poly(methyl methacrylate-co-ethyl methacrylate) blends

Summary The interaction parameters B for blends of poly(vinylidene fluoride) (PVDF) with poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA) and five methyl methacrylate/ ethyl methacrylate copolymers (PMEMA) were determined by measurements of melting point depression of PVDF. The B values are negative, indicating an attractive intermolecular interaction. The intramolecular interaction parameter between MMA and EMA segments in PMEMA was found to be +3.25 cal/cm³, indicating a repulsive interaction between different monomer segments in the copolymer.     

Modification of pristine multiwalled carbon nanotube by grafting with poly(methyl methacrylate) using benzoyl peroxide initiator

Multiwalled carbon nanotube was successfully grafted with poly(methyl methacrylate) by free radical mechanism using benzoyl peroxide initiator. The reaction was carried out in situ, where the initiator and methyl methacrylate monomer generated the polymer‐free radical that was subsequently grafted to the surface of the pristine multiwalled carbon nanotube. The multiwalled carbon nanotube grafted poly(methyl methacrylate) (MWCNT‐g‐PMMA) were characterized using Fourier transform infrared, differential scanning calorimetry, thermogravimetric analysis, ¹³ C‐solid NMR spectroscopy, X‐ray photoelectron spectroscopy, and scan electron microscopy. From the result of the characterizations, the grafting of poly(methyl methacrylate) on to multiwalled carbon nanotube was confirmed, and a percentage grafting of 41.51% weight was achieved under optimized conditions with respect to the temperature and the amount of the initiator. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43270.     

Synthesis and characterization of poly(methyl methacrylate-co-2-hydroxypropyl methacrylate)-graft-polyoxyethylene

This study involved the synthesis and characterization of an amphipathic graft copolymer, poly(methyl methacrylate-co-2-hydroxypropyl methacrylate)-graft-polyoxyethylene. This amphipathic graft copolymer was synthesized utilizing a “grafting-onto” technique in which α-hydroxy-ω-methoxypolyoxyethylene was reacted with prepolymerized poly(methyl methacrylate-co-glycidyl methacrylate). Proof of copolymer formation was illustrated using water solubility, GPC, FTIR spectroscopy, and ¹³C-NMR spectroscopy. In all cases, proof of copolymer formation is demonstrated unequivocally.