TEM and image analysis to quantitatively describe the phase behavior in copolymer/homopolymer/homopolymer blends: Effect of the copolymer sequence distribution

1993 ◽  
Vol 51 ◽  
pp. 896-897
Author(s):  
Karen I. Winey ◽  
Mary E. Galvin
Keyword(s):  
Methyl Methacrylate ◽  
Phase Behavior ◽  
Visual Inspection ◽  
Monomer Unit ◽  
Copolymer Composition ◽  
Scanning Calorimetry ◽  
Sequence Distribution ◽  
Polymer Molecules ◽  
Transmission Electron ◽  
Homopolymer Blends

Polymers are typically immiscible with one another, that is phase separated, in the absence of specific favorable intermolecular interactions, because the combinatorial entropy of mixing is small. Copolymers, polymer molecules containing more than one type of monomer unit, are frequently used to induce miscibility in homopolymer mixtures. Extensive work has previously established the importance of the copolymer composition, though the sequence of monomers within the copolymer has received less attention. Copolymers with random and with alternating sequences of monomers have been synthesized and mixed with homopolymers to evaluate the importance of the sequence distribution on blend miscibility. Blend miscibility determinations using differential scanning calorimetry and visual inspection can be erroneous when the glass transition temperatures of the phases are similar or the domains are small compared to the wavelength of light. Thus, we have used transmission electron microscopy to study the phase behavior of these polymer blends.Blend samples (∼30 mg) of poly(styrene-co-methyl methacrylate) (PS-PMMA), homopolystyrene (PS), homopoly(methyl methacrylate) (PMMA) were prepared by casting from tetrahydrofuran and annealing at 150°C for 7 days.

Synthesis of n-octadecane/poly (styrene-methyl methacrylate) (St-MMA) energy-storage microcapsules via emulsion polymerization

2017 ◽  
Vol 31 (11) ◽  
pp. 1443-1454
Author(s):  
Weili Wu ◽  
Zhe Chen
Keyword(s):  
Particle Size ◽  
Energy Storage ◽  
Methyl Methacrylate ◽  
Phase Change ◽  
Emulsion Polymerization ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Size Dispersion

Poly (methyl methacrylate) block copolymer is interesting due to its good compatibility with many polymers. In this study, a novel phase-change energy storage material, n-octadecane/poly (styrene-methyl methacrylate) (OD/P(St-MMA)) microcapsules, were designed and synthesized by emulsion polymerization, in which n-OD was used as core materials, the copolymer of St and MMA as shell materials, and sodium dodecyl benzene sulfonate (SDBS) as emulsifier. The morphology, phase-change thermal properties and thermal stability of microcapsules were investigated by particle size analyzer, transmission electron microscope, thermogravimetric (TG) analyzer, and differential scanning calorimetry (DSC). The results showed that when the ratio of the two monomers, St and MMA, was 1/5 and the dosage of SDBS was 1.5 g (3% of the total mass), the particle size dispersion of microcapsules was uniform and microcapsule particles were well wrapped. TG analysis showed that the long-term use temperature of microcapsules could not exceed 131°C. DSC showed that the phase-change enthalpy of microcapsule was 148.39 J·g−1, which indicated the microcapsules had excellent energy storage property.

SYNTHESIS AND CHARACTERIZATION OF POLY(BUTYL ACRYLATE-CO-METHYL METHACRYLATE)/CLAY NANOCOMPOSITES VIA EMULSION POLYMERIZATION

2006 ◽  
Vol 05 (02n03) ◽  
pp. 291-297 ◽  
Author(s):  
ZHIYI ZHANG ◽  
NING ZHAO ◽  
WEI WEI ◽  
DONG WU ◽  
YUHAN SUN
Keyword(s):  
Methyl Methacrylate ◽  
Emulsion Polymerization ◽  
Butyl Acrylate ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Clay Nanocomposites ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Dodecyl Benzene Sulfonate ◽  
Clay Layers

Poly(butyl acrylate-co-methyl methacrylate)/clay nanocomposites were synthesized via emulsion polymerization with an emulsifier (sodium dodecyl benzene sulfonate, SDBS), an initiator (ammonium persulate, APS), acrylic acid ester monomer and Na -montmorillonite. It was found that the addition of SDBS and water widened the gap between clay layers and facilitated monomers to penetrate into clay. Through initiator, comonomers were polymerized in the montmorillonite galleries. The structure of extracted nanocomposites was confirmed by XRD, transmission electron microscopy (TEM). Their thermal property and molecule weight were investigated by differential scanning calorimetry (DSC) and gel-penetrate chromatogram (GPC).

IBR Block Copolymers as Compatibilizers in NR/BR Blends

1993 ◽  
Vol 66 (4) ◽  
pp. 538-549 ◽  
Author(s):  
David J. Zanzig ◽  
Fred L. Magnus ◽  
W. L. Hsu ◽  
Adel F. Halasa ◽  
Marty E. Testa
Keyword(s):  
Electron Microscopy ◽  
Block Copolymers ◽  
Copolymer Composition ◽  
Rubber Compound ◽  
Scanning Calorimetry ◽  
Filled Rubber ◽  
Transmission Electron ◽  
Low Concentrations ◽  
Polybutadiene Rubber ◽  
Polymer Compatibility

Abstract The effect of the addition of 1,4-polyisoprene-1 ,4-polybutadiene (IBR) block copolymers on polymer compatibility and vulcanizate properties of a natural rubber/cis-1,4-polybutadiene rubber blend is studied. Differential scanning calorimetry and transmission electron microscopy are used to determine the degree of polymer compatibility and vulcamzate properties are measured in a sulfur cured, carbon-black filled rubber compound Block copolymer composition, concentration and molecular weight are found to be critical. Improvements in compatibility and vulcamzate properties are observed at low concentrations of IBR block copolymers.

Synthesis, Characterization and Reactivity Ratios of Poly Phenyl Acrylamide-Co-Methyl Methacrylate

2020 ◽  
Vol 1002 ◽  
pp. 66-74
Author(s):  
Ameen Hadi Mohammed ◽  
Tamador Ali Mahmood ◽  
Selvana Adwar Yousif ◽  
Aminu Musa ◽  
Nerodh Nasser Dally
Keyword(s):  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Methyl Methacrylate ◽  
Reactivity Ratios ◽  
Monomer Reactivity Ratios ◽  
Scanning Calorimetry ◽  
Sequence Distribution ◽  
Alternating Copolymers ◽  
Linearization Methods ◽  
Ft Ir

The monomer phenyl acrylamide was synthesized by reacting acrylamide with chloro benzene in the presence of pyridine. Copolymer of phenyl acrylamide (PAM) with methyl methacrylate (MMA) was synthesized by free radical technique using dimethylsulfoxide (DMSO) as solvent and benzoyl peroxide (BPO) as initiator. The overall conversion was kept low (≤ 15% wt/wt) for all studies copolymers samples. The synthesized copolymers were characterized using fourier transform infrared spectroscopy (FT-IR), and their thermal properties were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The copolymers compositions were determined by elemental analysis. The monomer reactivity ratios have been calculated by linearization methods proposed by Kelen-Tudos and Fineman-Ross. The derived reactivity ratios (r1, r2) for (PAM-co-MMA) are: (0.03, 0.593). The microstructure of copolymers and sequence distribution of monomers in the copolymers were calculated by statistical method based on the average reactivity ratios and found that these values are in agreement with the derived reactivity ratios. Copolymers of PAM with MMA formed alternating copolymers.

scholarly journals Study of Copolymerization Acrylamide with Methyl Methacrylate

2020 ◽  
pp. 01-09
Author(s):  
Ameen Hadi Mohammed ◽  
Susan Rasheed Jubair
Keyword(s):  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Methyl Methacrylate ◽  
Reactivity Ratios ◽  
Monomer Reactivity Ratios ◽  
Scanning Calorimetry ◽  
Sequence Distribution ◽  
Alternating Copolymers ◽  
Linearization Methods ◽  
Ft Ir

Copolymer of acrylamide (AM) with methyl methacrylate (MMA) was synthesized by free radical technique using dimethylsulfoxide (DMSO) as solvent and benzoyl peroxide (BPO) as initiator. The overall conversion was kept low (≤ 15% wt/wt) for all studies copolymer’s samples. The synthesized copolymers were characterized using fourier transform infrared spectroscopy (FT-IR), and their thermal properties were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The copolymers compositions were determined by elemental analysis. The monomer reactivity ratios have been calculated by linearization methods proposed by Kelen-Tudos and Fineman-Ross. The derived reactivity ratios (r1, r2) for (AM-co-MMA) are: (0.03, 0.593). The microstructure of copolymers and sequence distribution of monomers in the copolymers were calculated by statistical method based on the average reactivity ratios and found that these values are in agreement with the derived reactivity ratios. Copolymers of AM with MMA formed alternating copolymers. Keywords: Acrylamide; Methyl methacrylate; Reactivity ratios; Sequence distribution

Pharmacokinetic Evaluation of 99mTc-radiolabeled Solid Lipid Nanoparticles and Chitosan Coated Solid Lipid Nanoparticles

2020 ◽  
Vol 20 (13) ◽  
pp. 1044-1052
Author(s):  
Nasrin Abbasi Gharibkandi ◽  
Sajjad Molavipordanjani ◽  
Jafar Akbari ◽  
Seyed Jalal Hosseinimehr
Keyword(s):  
Solid Lipid Nanoparticles ◽  
Lipid Nanoparticles ◽  
High Resistivity ◽  
Scanning Calorimetry ◽  
Liver Uptake ◽  
Solid Lipid ◽  
Transmission Electron ◽  
Main Portion ◽  
Pharmacokinetic Behavior

Background: Solid Lipid Nanoparticles (SLNs) possess unique in vivo features such as high resistivity, bioavailability, and habitation at the target site. Coating nanoparticles with polymers such as chitosan greatly affects their pharmacokinetic behavior, stability, tissue uptake, and controlled drug delivery. The aim of this study was to prepare and evaluate the biodistribution of 99mTc-labeled SLNs and chitosan modified SLNs in mice. Methods: 99mTc-oxine was prepared and utilized to radiolabel pre-papered SLNs or chitosan coated SLNs. After purification of radiolabeled SLNs (99mTc-SLNs) and radiolabeled chitosan-coated SLNs (99mTc-Chi-SLNs) using Amicon filter, they were injected into BALB/c mice to evaluate their biodistribution patterns. In addition, nanoparticles were characterized using Transmission Electron Microscopy (TEM), Fourier-transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), X-ray Powder Diffraction (XRD) and Dynamic Light Scattering (DLS). Results: 99mTc-oxine with high radiochemical purity (RCP~100%) and stability (RCP > 97% at 24 h) was used to provide 99mTc-SLNs and 99mTc-Chi-SLNs with high initial RCP (100%). TEM image and DLS data suggest 99mTc- SLNs susceptibility to aggregation. To that end, the main portion of 99mTc-SLNs radioactivity accumulates in the liver and intestines, while 99mTc-Chi-SLNs sequesters in the liver, intestines and kidneys. The blood radioactivity of 99mTc-Chi-SLNs was higher than that of 99mTc-SLNs by 7.5, 3.17 and 3.5 folds at 1, 4 and 8 h post-injection. 99mTc- Chi-SLNs uptake in the kidneys in comparison with 99mTc-SLNs was higher by 37.48, 5.84 and 11 folds at 1, 4 and 8h. Conclusion: The chitosan layer on the surface of 99mTc-Chi-SLNs reduces lipophilicity in comparison with 99mTc- SLNs. Therefore, 99mTc-Chi-SLNs are less susceptible to aggregation, which leads to their lower liver uptake and higher kidney uptake and blood concentration.

scholarly journals Study on Structure, Thermal Behavior, and Viscoelastic Properties of Nanodiamond-Reinforced Poly (vinyl alcohol) Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1426
Author(s):  
Tomáš Remiš ◽  
Petr Bělský ◽  
Tomáš Kovářík ◽  
Jaroslav Kadlec ◽  
Mina Ghafouri Azar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Single Step ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Primary Particles ◽  
Solution Casting Method ◽  
Average Size

In this work, advanced polymer nanocomposites comprising of polyvinyl alcohol (PVA) and nanodiamonds (NDs) were developed using a single-step solution-casting method. The properties of the prepared PVA/NDs nanocomposites were investigated using Raman spectroscopy, small- and wide-angle X-ray scattering (SAXS/WAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was revealed that the tensile strength improved dramatically with increasing ND content in the PVA matrix, suggesting a strong interaction between the NDs and the PVA. SEM, TEM, and SAXS showed that NDs were present in the form of agglomerates with an average size of ~60 nm with primary particles of diameter ~5 nm. These results showed that NDs could act as a good nanofiller for PVA in terms of improving its stability and mechanical properties.

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