Solvent effects on the miscibility of PMMA/PVAc blends: II. Using two-dimensional NMR method, NOESY

Crispim, Edson Golembievski; Schuquel, Ivânia T.A.; Rubira, Adley F.; Muniz, Edvani C.

doi:10.1016/s0032-3861(99)00222-0

Cited by 26 publications

(13 citation statements)

References 12 publications

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“…The 1 H NMR spectrum contains signals attributed to CH 3 (0.8-1.1 ppm), CH 2 (1.7-2.2 ppm), and OCH 3 (3.5-3.8 ppm) protons, which is in accordance to results published in the literature [33,34].…”

Section: Characteristics Of Neat Pmmasupporting

confidence: 90%

Nano-Mechanical Properties of Modified Poly(Methyl Methacrylate) Films Studied by Atomic Force Microscopy

Kaczmarek

Gałka

2010

Tribol Lett

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Atomic force microscopy (AFM) has been used to study the effect of various photoinitiators doped into poly(methyl methacrylate) (PMMA) on the mechanical properties of PMMA films at the nanometer scale. Pure and modified PMMA films (containing four different photoinitiators) were exposed to a mercury vapor lamp in air atmosphere. Force-distance curves for hardness, Young modulus, and adhesion forces were obtained using different AFM modes (tapping or contact-mode) and different tips (diamond or silicon nitride). The results revealed that the added photoinitiators slightly changed the nanomechanical properties of PMMA as a result of alterations in the photochemical reactions and physical processes occurring in the studied systems. tert-Butyl peroxybenzoate had the most efficient effect on the measured parameters in UV-irradiated PMMA, whereas benzoyl peroxide was less active. The mechanism of the observed processes is discussed.

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Section: Characteristics Of Neat Pmmasupporting

confidence: 90%

Nano-Mechanical Properties of Modified Poly(Methyl Methacrylate) Films Studied by Atomic Force Microscopy

Kaczmarek

Gałka

2010

Tribol Lett

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“…In the light of this, attractive interactions among side groups or polymer segments are, in most of the cases, responsible for polymer-polymer miscibility. Different techniques have been used for evaluating the miscibility, for example, thermal analysis through determination of the glass transition temperature (T g ) [3][4][5], microscopy (Optical Microscopy -OM, Scanning Electronic Microscopy -SEM, Atomic Force Microscopy -AFM, Transmission Electronic Microscopy -TEM, and so on) [5][6][7][8] and spectroscopy (Fourier Transform Infrared -FTIR-Image, Raman-Image, Nuclear Magnetic Resonance -NMR, and so on) [9][10][11][12]. The presence of an amorphous (or slightly crystalline) component affects the crystallization process of the other polymer component significantly.…”

Section: Introductionmentioning

confidence: 99%

“…The mixing of an amorphous (or slightly crystalline) polymer with a highly crystallizable one forming a polymer blend allows the new chemical potential of the liquid phase to be lower than that of the crystalline phase and, therefore, the equality of the chemical potentials of the liquid and the crystalline phases will be settled at lower temperature [13]. In this way, when the polymer blend consists of a crystallizable polymer and an amorphous polymer, the depression in equilibrium melting temperature (T m 0 ) may be used for evaluating the polymer-polymer interaction parameter (χ 12 ) and thus the system miscibility [14]. Starch is a polysaccharide constituted by portions of amylose (linear) and amylopectin (branched) usually in a ratio of 20%:80%, respectively [15,16].…”

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confidence: 99%

Polymer-polymer miscibility in PEO/cationic starch and PEO/hydrophobic starch blends

Pereira¹,

Paulino²,

Rubira³

et al. 2010

Express Polym. Lett.

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IntroductionBlending of polymers is an interesting route for producing new materials, basically due to economics aspects [1]. The miscibility between the polymers is a very important factor in the development of polymer blends [1,2]. Considering the low entropy associated to the polymers mixture, ΔS m , the miscibility between the components of a polymer blend is mainly driven by the enthalpy of mixing, ΔH m . Thus, effects that decrease ΔH m will favor to the miscibility due to the decrease of the Gibbs energy of mixture, ΔG m . In the light of this, attractive interactions among side groups or polymer segments are, in most of the cases, responsible for polymer-polymer miscibility. Different techniques have been used for evaluating the miscibility, for example, thermal analysis through determination of the glass transition temperature (T g ) [3][4][5], microscopy (Optical Microscopy -OM, Scanning Electronic Microscopy -SEM, Atomic Force Microscopy -AFM, Transmission Electronic Microscopy -TEM, and so on) [5][6][7][8] and spectroscopy (Fourier Transform Infrared -FTIR-Image, Raman-Image, Nuclear Magnetic Resonance -NMR, and so on) [9][10][11][12]. The presence of an amorphous (or slightly crystalline) component affects the crystallization process of the other polymer component significantly. When a given system is miscible, the equilibrium melting temperature (T m 0 ) is expected to be lower Abstract. The main purposes were evaluating the influence of different starches on the miscibility with Poly(ethylene oxide) (PEO) and their effects on the spherulite growth rate. Polymer-polymer miscibility in PEO/cationic starch and PEO/hydrophobic starch blends consisting of different w/w ratios (100/0, 95/05, 90/10, 80/20, 70/30, 65/35 and 60/40) was investigated. This analysis was based on the depression in the equilibrium melting temperature (T m 0 ). By treating the data of thermal analysis (Differential Scanning Calorimetry -DSC) with Nishi-Wang equation, a positive value (0.68) was found for the interaction parameter of PEO/cationic starch. For PEO/hydrophobic starch blends, a negative value (-0.63) was obtained for the interaction parameter. The results suggested that PEO/cationic starch system should be immiscible. However, the system PEO/hydrophobic starch was considered to be miscible in the whole range of studied compositions. Through optical microscopy analysis, it was concluded that the spherulite growth rate is significantly affected by changing the amount and the type of starch as well. Keywords

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“…Significant studies have been carried out on polycarbonate (PC)/ poly(methyl methacrylate) (PMMA) and PMMA/ Poly(vinyl acetate) (PVAc)blends, while only a few studies have been reported on the PC/PVAc blend system 4–23. The effects of solvent, solubility parameter, temperature, evaporation rate of the solvent, weight composition of the polymer components, molecular weight, tacticity, and so forth on generating miscible blends of these pairs were investigated.…”

Section: Introductionmentioning

confidence: 99%

“…To summarize, the homogeneity and phase behavior of the PMMA/PVAc, PC/PMMA and PC/PVAc blends showed some ambiguity because of their instability at different temperatures and in different solvent environments and show phase separation and incompatibility when they are prepared by traditional methods. Moreover, it has been revealed that the effects of solvent and temperature have played a key role in the homogeneity of their blends 5–11, 18–23. Processing polymer blends via the formation of and coalescence from their common cyclodextrin (CD) inclusion compounds (ICs) eliminates the effects of both solvent and temperature.…”

Section: Introductionmentioning

confidence: 99%

Intimate blending of binary polymer systems from their common cyclodextrin inclusion compounds

Uyar

Rusa

Wang

et al. 2005

J Polym Sci B Polym Phys

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A procedure for the formation of intimate blends of three binary polymer systems polycarbonate (PC)/poly(methyl methacrylate) (PMMA), PC/poly(vinyl acetate) (PVAc) and PMMA/PVAc is described. PC/PMMA, PC/PVAc, and PMMA/PVAc pairs were included in γ‐cyclodextrin (γ‐CD) channels and were then simultaneously coalesced from their common γ‐CD inclusion compounds (ICs) to obtain intimately mixed blends. The formation of ICs between polymer pairs and γ‐CD were confirmed by wide‐angle X‐ray diffraction (WAXD), fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). It was observed [solution 1H nuclear magnetic resonance (NMR)] that the ratios of polymers in coalesced PC/PMMA and PC/PVAc binary blends are significantly different than the starting ratios, and PC was found to be preferentially included in γ‐CD channels when compared with PMMA or PVAc. Physical mixtures of polymer pairs were also prepared by coprecipitation and solution casting methods for comparison. DSC, solid‐state 1H NMR, thermogravimetric analysis (TGA), and direct insertion probe pyrolysis mass spectrometry (DIP‐MS) data indicated that the PC/PMMA, PC/PVAc, and PMMA/PVAc binary polymer blends were homogeneously mixed when they were coalesced from their ICs. A single, common glass transition temperature (Tg) recorded by DSC heating scans strongly suggested the presence of a homogeneous amorphous phase in the coalesced binary polymer blends, which is retained after thermal cycling to 270 °C. The physical mixture samples showed two distinct Tgs and 1H T1ρ values for the polymer components, which indicated phase‐separated blends with domain sizes above 5 nm, while the coalesced blends exhibited uniform 1H spin‐lattice relaxation values, indicating intimate blending in the coalesced samples. The TGA results of coalesced and physical binary blends of PC/PMMA and PC/PVAc reveal that in the presence of PC, the thermal stability of both PMMA and PVAc increases. Yet, the presence of PMMA and PVAc decreases the thermal stability of PC itself. DIP‐MS observations suggested that the degradation mechanisms of the polymers changed in the coalesced blends, which was attributed to the presence of molecular interactions between the well‐mixed polymer components in the coalesced samples. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2578–2593, 2005

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Solvent effects on the miscibility of PMMA/PVAc blends: II. Using two-dimensional NMR method, NOESY

Cited by 26 publications

References 12 publications

Nano-Mechanical Properties of Modified Poly(Methyl Methacrylate) Films Studied by Atomic Force Microscopy

Nano-Mechanical Properties of Modified Poly(Methyl Methacrylate) Films Studied by Atomic Force Microscopy

Polymer-polymer miscibility in PEO/cationic starch and PEO/hydrophobic starch blends

Intimate blending of binary polymer systems from their common cyclodextrin inclusion compounds

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