Methyl Acrylate Copolymers Research Articles

THE INFLUENCE OF PROCESS VARIABLES ON THE MOLECULAR MASS OF AN/MA COPOLYMERS-II

Viscometry experiments were carried out on a range of laboratory-synthesized polyacrylonitrile precursors that were to be used for the manufacture of PAN/MA hollow-fiber carbon membranes. This was done to determine the effect of the polymerization process variables on the average molecular mass of copolymers of methylacrylate and acrylonitrile. Factors such as the concentrations of methylacrylate monomer (MA) and azo-bis-isobutyronitrile initiator (AIBN), stirrer speed and polymerization temperature were investigated as functions of the molecular mass. An empirical approach that employed statistical experimental designs, used to recognize analytical and statistical methods that translate the process responses into comprehensible terms was used. It was established that hollow-fiber carbon membranes can be reproducibly prepared if the polymerization conditions are controlled. Process variables such as stirrer speed, polymerization temperature, methylacrylate and azo-bis-isobutylonitrile concentrations influence the properties of the copolymer produced and hence the properties of the carbon membranes produced from precursors made from the copolymer. The highest molecular mass PAN was obtained when the concentrations of MA and AIBN were high, while a reduced polymerization temperature favored the synthesis of high molecular mass PAN. The stirrer speed had little or no effect on the molecular mass of the synthesized PAN-based materials. The process variables interactions were statistically processed with the “F-test” method. Interaction between the initiator, AIBN and temperature had a significant effect on the average molecular mass. Monomer MA concentration was of little significance.

Grafting, blending, and biodegradability of cellulose acetate

AbstractWe performed the graft copolymerization of methyl acrylate and methyl methacrylate on cellulose acetate (CA) by a free‐radical method. The grafting was confirmed by gravimetric analysis and IR spectroscopy. Low graft efficiency was observed for the benzoyl peroxide initiator used in the system. Melt blending of CA and nylon 6 was done for CA‐rich compositions. The physical and mechanical property measurements showed an improvement over virgin CA properties. The chemical properties, however, did not show any phenomenal advancement. A CA/starch (90/10) blend was prepared and studied for biodegradation during soil burial. The gravimetric and mechanical property results indicated possible degradation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1716–1723, 2004

Synthesis and enzymatic degradation of 2‐methylene‐1,3‐dioxepane and methyl acrylate copolymers

AbstractCopolymers of 2‐methylene‐1,3‐dioxepane (MDO) and methyl acrylate (MA) containing ester units both in the backbone and as pendant groups were synthesized by free‐radical copolymerization. The influence of reaction conditions such as the polymerization time, temperature, initiator concentration, and comonomer feed ratio on the yield, molecular weight, and copolymer composition was investigated. The structure of the copolymers was confirmed by 1H NMR, 13C NMR, and IR spectroscopy. Differential scanning calorimetry indicated that the copolymers had a random structure. An NMR study showed that hydrogen transfer occurred during the copolymerization. The reactivity ratios of the comonomers were rMDO = 0.0235 and rMA = 26.535. The enzymatic degradation of the copolymers obtained was carried out in the presence of proteinase K or a crude enzyme extracted from earthworms. The experimental results showed that the higher ester molar percentage in the backbone caused a faster degradation rate. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2898–2904, 2003

Poly(2-hydroxyethyl acrylate-co-methyl acrylate)/SiO 2/TiO 2 hybrid membranes

Random copolymers of 2-hydroxyethyl acrylate (HEA) and methyl acrylate (MA) and homopolymer PHEA were prepared by free radical polymerization. The hydroxyl groups of PHEA were reacted with 3-(triethoxysilyl)propyl isocyanate to introduce triethoxysilyl (TREOS) groups. Co-hydrolysis and condensation of the TREOS groups with titanium tetrabutoxide yielded polymer/SiO 2/TiO 2 hybrid materials. Water vapor permeability across such hybrid membranes could be changed by varying the PHEA content and was very high for PHEA/SiO 2/TiO 2 membranes. Incorporation of MA into the hybrid allowed membrane properties, such as water uptake and brittleness, to be controlled. Such hybrid materials may be of interest for biomedical applications and for development of perm-selective barriers used in commercial and military technologies.

Reactive compatibilization of blends of polybutyleneterephthalate with epoxide-containing rubber. The effect of the concentrations in reactive functions

The influence of the functional groups concentrations on the reactive compatibilization of polybutylene terephthalate (PBT)/epoxide-containing rubber blends has been investigated by using various PBT and ethene-(methyl acrylate)-(glycidyl methacrylate) terpolymer (E-MA-GMA) grades. The reactivity of the rubber phase was modified using different strategies, including the use of commercial terpolymer grades, modification of E-MA-GMA or diluting E-MA-GMA terpolymers with non-reactive ethene-(methyl acrylate) (E-MA) copolymer. The reactive blends were analyzed amongst others by electron microscopy and fractionation experiments. It was shown that the final particle size is directly related to the amount of copolymer formed in situ at the blend interface, i.e. chain area density Σ. A value of approximately 0.05 chains/nm 2 for Σ is necessary to suppress dynamic coalescence and to obtain very fine dispersion (<0.2 μm). This requires a sufficiently high concentration in reactive functions at the interface vicinity. In this context, the time required for equilibrium morphology is rather independent of the GMA content in the terpolymer but is, however, intimately related to the PBT chain ends concentration. Investigation of PBT/(E-MA-GMA/E-MA) ternary blends revealed unambiguously that the formation of the copolymer at the interface is not controlled by the diffusion of the reactive chains towards the interface. The performed experiments offer new opportunities for modulating the final morphology and the properties of the PBT/rubber blends.

Laser removal of water repellent treatments on limestone

Protective and water repellent treatments are applied on stone materials used on buildings or sculptures of artistic value to reduce water intrusion without limiting the natural permeability to water vapour of the material. The effect of the wavelength associated with the laser removal of two water repellent treatments applied on limestone, Paraloid B-72, a copolymer of methyl acrylate and ethyl methacrylate, and Tegosivin HL-100, a modified polysiloxane resin, was investigated by using the four harmonics of a Q-switched Nd:YAG laser (1064, 532, 355 and 266 nm). The modifications induced on the surface of limestone samples by laser irradiation were studied using colorimetry, roughness measurements and scanning electron microscopy (SEM). The removal of the treatments was found to be dependent on the laser irradiation conditions and on the characteristics of the coatings. The fundamental laser radiation was effective in removing both treatments, but thermal alteration processes were induced on the constituent calcite crystals. The best results were obtained by irradiation in the near UV at 355 nm.

Graft copolymerizaztion of methyl acrylate onto chitosan initiated by potassium diperiodatocuprate (III)

AbstractA novel redox system, potassium diperiodatocuprate [Cu (III)–chitosan], was employed to initiate the graft copolymerization of methyl acrylate (MA) onto chitosan in alkali aqueous solution. The effects of reaction variables such as monomer concentration, initiator concentration, pH and temperature were investigated. By means of a series of copolymerization reactions, the grafting conditions were optimized. Cu (III)–chitosan system was found to be an efficient redox initiator for this graft copolymerization. The structures and the thermal stability of chitosan and chitosan‐g‐poly(methyl acrylate) (PMA) were characterized by infrared spectroscopy (IR) and thermogravimetric analysis (TGA). In this article, a mechanism is proposed to explain the formation of radicals and the initiation. Finally, the graft copolymer was used as the compatibilizer in blends of poly(vinyl chloride) (PVC) and chitosan. The scanning electron microscope (SEM) photographs and differential scanning calorimetry (DSC) thermograms indicate that the graft copolymer improved the compatibility of the blend. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2283–2289, 2003

Biexponential 13C spin–lattice relaxation behavior of the crystalline region of ethylene copolymers and its origin

In this work, two series of ethylene–dimethylaminoethylmethacrylate (EDAM) and ethylene–methyl acrylate copolymers (EMA) with different comonomer content were studied by high-resolution solid-state 13C NMR spectroscopy. Biexponential 13C spin–lattice relaxation behaviors of the crystalline region were observed for all copolymer samples either melt-quenched or isothermally crystallized. The relative content of the shorter 13C T 1 component to that of the longer 13C T 1 component was found to increase with comonomer content. By employing a new pulse sequence which can be considered as a combination of Goldman–Shen's and Torchia's pulse sequences, it was demonstrated that the shorter 13C T 1 component is corresponding to the intermediate part of the crystalline region. The thickness of the intermediate part is estimated to be about 0.85 nm.

Graft Copolymerization of Methyl Acrylate onto Poly(Vinyl Alcohol) Initiated by Potassium Diperiodatocuprate(III)

A novel redox system, potassium diperiodatocuprate(III) [Cu (III)]-poly(vinyl alcohol) (PVA) redox system, was employed to initiate the graft copolymerization of methyl acrylate (MA) onto PVA in alkaline medium. The grafting parameters varied with concentrations of monomer, initiator, macromolecular backbone (DP=1750, M=80 000) and temperature. The formation of the graft copolymer was confirmed by Fourier transfer infrared spectroscopy (IR), scanning electron microscope (SEM), X-ray diffraction and thermogravimetric analysis (TGA). It was found that [Cu (III)]-PVA system is an efficient redox initiator for this graft copolymerization. A mechanism is introduced to explain the formation of radicals and the initiation. At the same time, the other acrylate monomers, such as methyl methacrylate, ethyl acrylate and n-butyl acrylate, were used as reductant to produce graft copolymerization. It was definitely observed that these reactions could occur in some degree. Thermal stabilities were checked by TGA and this indicated that graft copolymer was resistant to moisture absorption.

Thermogravimetric analysis of compatibilized blends of low density polyethylene and poly(dimethyl siloxane) rubber

The thermogravimetric (TG) and derivative thermogravimetric (DTG) analysis of compatibilized blends of low density polyethylene (LDPE) and poly(dimethyl siloxane) rubber (PDMS) in the proportion of 50:50 containing different proportions of ethylene methyl acrylate co-polymer (EMA) as compatibilizer have been studied. EMA acts as a chemical polymeric compatibilizer for the binary blend system of LDPE and PDMS, the proportion of which varied from 0 to 15 wt.%. The TG and DTG of the blends show that the thermal degradation takes place in two stages, where as neat LDPE shows a three stage degradation and neat EMA and PDMS show only single stage degradations respectively. The activation energies at 10% degradation have been determined using Freeman and Carroll's method and found to be maximum (171 kJ/mol) for the blend containing 6 wt.% of EMA. Half life periods at 200 °C have been evaluated by the Flynn and Wall method and found to be maximum for the blend containing 6 wt.% of EMA.

Graft copolymerization of methyl acrylate onto poly(vinyl alcohol) initiated by potassium diperiodatonickelate(IV)

AbstractThe graft copolymerization of methyl acrylate onto poly(vinyl alcohol) (PVA) with a potassium diperiodatonickelate(IV) [Ni(IV)]–PVA redox system as an initiator was investigated in an alkaline medium. The grafting parameters were determined as functions of the temperature and the concentrations of the monomer and initiator. The structures of the graft copolymers were confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. The Ni(IV)–PVA system was found to be an efficient redox initiator for this graft copolymerization. A single‐electron‐transfer mechanism was proposed for the formation of radicals and the initiation. Other acrylate monomers, such as methyl methacrylate, ethyl acrylate, n‐butyl acrylate, and n‐butyl methacrylate, were used as reductants for graft copolymerization. These reactions definitely occurred to some degree. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 529–534, 2003

Compatibilized Blends of Low Density Polyethylene and Poly Dimethyl Siloxane Rubber: Part I: Acid and Alkali Resistance Properties

Acid and alkali resistance properties of cross linked blends of low-density polyethylene (LDPE) and polydimethyl siloxane rubber (PDMS) have been studied. Ethylene methyl acrylate (EMA) copolymer acts as a compatibilizer and dicumyl peroxide (DCP) acts as the crosslinking agent for the blend systems. Tensile properties of the individual components and the blends before and after treatment with different acids and two various concentrations of alkali are reported. Treatment with nitric acid has resulted in severe deterioration of tensile properties of all samples compared to all other acids studied. Retention of tensile properties of all the blends is found to improve significantly as compared to the reference sample, the PDMS rubber. This has been further supported by the scanning electron microscopic (SEM) studies.

Copolymerization of Methyl Acrylate with Norbornene Derivatives by Atom Transfer Radical Polymerization

ADVERTISEMENT RETURN TO ISSUEPREVNoteCopolymerization of Methyl Acrylate with Norbornene Derivatives by Atom Transfer Radical PolymerizationSharon Elyashiv-Barad, Nils Greinert, and Ayusman SenView Author Information Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802 Cite this: Macromolecules 2002, 35, 19, 7521–7526Publication Date (Web):August 16, 2002Publication History Received28 March 2002Revised1 July 2002Published online16 August 2002Published inissue 1 September 2002https://doi.org/10.1021/ma020487rCopyright © 2002 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views1419Altmetric-Citations48LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (104 KB) Get e-AlertsSUBJECTS:Alkyls,Copolymerization,Copolymers,Hydrocarbons,Organic compounds Get e-Alerts

Synthesis and characterization of acrylonitrile methyl acrylate statistical copolymers as melt processable carbon fiber precursors

Statistical (random) copolymers of acrylonitrile (AN) and methyl acrylate (MA) have been synthesized by free radical homogeneous (solution) and heterogeneous (suspension) methods. Selected compositions can be fabricated by environment friendly, solvent-free melt spinning and are of interest as precursors for carbon fibers. The dynamic and steady state melt viscosities of these copolymers were studied as a function of molecular weight and copolymer composition. Melt processability at 200–220 °C depends on the copolymer composition, and also on the molecular weight, which was controlled by chain transfer agent concentration and reaction temperature. Copolymers of controlled molecular weight containing 10 or more mol[percnt] of methyl acrylate show good melt processability, which can be further enhanced by stabilizers. This thermoplastic behavior is supported by a significant increase in temperature by the cyclization exotherm. Thermal analysis (differential scanning calorimetry, dynamic mechanical analysis) further illustrates that the comonomers retarded the cyclization, which permits thermoplastic processing.

Radiation Induced Graft Copolymerization of Methyl Acrylate and Ethyl Acrylate onto Poly(tetrafluoroethylene-co-ethylene) Film

To introduce functional moieties into Tefzel® film, a copolymer of tetrafluoroethylene and ethylene, graft copolymerization of vinyl monomers such as methyl acrylate (MA) and ethyl acrylate (EA) was attempted by a pre-irradiation method in aqueous medium. Optimum conditions for obtaining the maximum grafting was evaluated for both monomers. Maximum grafting of MA (306.0%) and EA (462.1%) was obtained at a total dose of 25.4 and 31.9kGy respectively, using [MA] = 2.20 mol/L and [EA] 0.032 moles. The effect of aliphatic alcohols of varying chain length, such as methanol, ethanol, n-butanol, 1-Pentanol and cyclohexanol on the percentage grafting of MA &amp; EA was also studied. Characterization of Tefzel® and grafted Tefzel® films was carried out by IR spectroscopy and thermogravimetric analysis. Grafted Tefzel® film was found to have improved thermal resistance.

One‐ and two‐dimensional NMR characterization of N‐vinyl‐2‐pyrrolidone/methyl acrylate copolymers

AbstractN‐vinyl‐2‐pyrrolidone/methyl acrylate (V/M) copolymers were prepared by free‐radical bulk polymerization using benzoyl peroxide as an initiator. The copolymer composition of these copolymers was calculated from 1H NMR spectra. The radical reactivity ratios for N‐vinyl‐2‐pyrrolidone (V) and methyl acrylate (M) were rV = 0.09, rM = 0.44. These reactivity ratios for the copolymerization of V and M were determined using the Kelen–Tudos and nonlinear least‐squares error‐in‐variable methods. The 13C{1H} and 1H NMR spectra of these copolymers overlapped and were complex. The complete spectral assignment of the 13C and 1H NMR spectra were done with distortionless enhancement by polarization transfer and two dimensional 13C‐1H heteronuclear single quantum correlation spectroscopic experiments. The two‐dimensional 1H‐1H homonuclear total correlation spectroscopic NMR spectrum showed the various bond interactions, thus inferring the possible structure of the copolymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2225–2236, 2002

One‐ and two‐dimensional NMR characterization of N‐vinyl‐2‐pyrrolidone/methyl acrylate copolymers

AbstractN‐vinyl‐2‐pyrrolidone/methyl acrylate (V/M) copolymers were prepared by free‐radical bulk polymerization using benzoyl peroxide as an initiator. The copolymer composition of these copolymers was calculated from 1H NMR spectra. The radical reactivity ratios for N‐vinyl‐2‐pyrrolidone (V) and methyl acrylate (M) were rV = 0.09, rM = 0.44. These reactivity ratios for the copolymerization of V and M were determined using the Kelen–Tudos and nonlinear least‐squares error‐in‐variable methods. The 13C{1H} and 1H NMR spectra of these copolymers overlapped and were complex. The complete spectral assignment of the 13C and 1H NMR spectra were done with distortionless enhancement by polarization transfer and two dimensional 13C‐1H heteronuclear single quantum correlation spectroscopic experiments. The two‐dimensional 1H‐1H homonuclear total correlation spectroscopic NMR spectrum showed the various bond interactions, thus inferring the possible structure of the copolymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2225–2236, 2002

GRAFT COPOLYMERIZATION OF METHYL ACRYLATE ONTO CHITOSAN INITIATED BY POTASSIUM DIPERIODATONICKELATE (IV)

ABSTRACT A novel redox system, potassium diperiodatonickelate [Ni (IV)]‐chitosan, was employed to initiate the graft copolymerization of methyl acrylate (MA) onto chitosan in alkali aqueous solution. The effects of reaction variables such as monomer concentration, initiator concentration, reaction time, pH and temperature were determined. By means of a series of copolymerization, the grafting conditions were optimized. The maximum grafting percentage obtained was 404.1% when 0.3 g chitosan was copolymerized with 1.8 mL monomer at 35°C for 5 hours with [Ni (IV)]=9.4×10−4 M and the total volume was 20 mL. Ni (IV)-chitosan system is found to be an efficient redox initiator for this graft copolymerization. A single electron transfer mechanism is proposed to explain the formation of radicals and the initiation. The grafted copolymers were characterized by IR and X-ray diffraction diagrams. The thermal stability of chitosan and chitosan-g-PMA was studied by thermogravimetric analysis (TGA).

Analysis of sequence distribution in methyl methacrylate–methyl acrylate copolymers by 13C NMR spectroscopy

Methyl methacrylate (MMA)–methyl acrylate (MA) copolymers, prepared in bulk at 50°C using AIBN as initiator, were characterized by 150MHz 13C NMR spectroscopy, including use of the Distortionless Enhancement by Polarization Transfer (DEPT) experiment to obtain methylene and methine carbon resonances as subspectra. Dyad, triad, tetrad and partial pentad distributions were measured from the α-methyl, methine and methylene carbon resonances. These were in good agreement with distributions calculated for the copolymers based on monomer feed compositions, conversions and reactivity ratios of 2.60 and 0.27 for methyl methacrylate and methyl acrylate, respectively.

Aplicação de um Modelo Reológico Não-Linear em Sistemas Poliméricos Dilatantes

A dilatância é um comportamento reológico comum a vários sistemas poliméricos embora não ocorra em polímeros puros. Existem várias teorias aplicáveis à explicação desse fenômeno e alguns modelos matemáticos para o ajuste de dados experimentais de quatro de suas seis formas de ocorrência. Neste trabalho é dado enfoque à dilatância antecedida por um comportamento newtoniano e sucedida pelo comportamento pseudoplástico. Para ajustar dados constantes da literatura para sistemas desse tipo, é apresentado um modelo híbrido e não-linear. Para o teste do modelo foram utilizados dados existentes na literatura para solução de alfa,ômega poli(t-butilestireno) em óleo mineral e suspensão de partículas do copolímero de estireno com acrilato de metila em solução aquosa de poli(ácido acrílico). O modelo proposto apresenta boa concordância com os dados experimentais.