Effects of Prepolymerized Particle Size and Polymerization Kinetics on Volumetric Shrinkage of Dental Modeling Resins

Dental modeling resins have been developed for use in areas where highly precise resin structures are needed. The manufacturers claim that these polymethyl methacrylate/methyl methacrylate (PMMA/MMA) resins show little or no shrinkage after polymerization. This study examined the polymerization shrinkage of five dental modeling resins as well as one temporary PMMA/MMA resin (control). The morphology and the particle size of the prepolymerized PMMA powders were investigated by scanning electron microscopy and laser diffraction particle size analysis, respectively. Linear polymerization shrinkage strains of the resins were monitored for 20 minutes using a custom-made linometer, and the final values (at 20 minutes) were converted into volumetric shrinkages. The final volumetric shrinkage values for the modeling resins were statistically similar (P>0.05) or significantly larger (P<0.05) than that of the control resin and were related to the polymerization kinetics (P<0.05) rather than the PMMA bead size (P=0.335). Therefore, the optimal control of the polymerization kinetics seems to be more important for producing high-precision resin structures rather than the use of dental modeling resins.

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Inhalation of nail dust from onychomycotic toenails. Part I. Characterization of particles. 1984

Journal of the American Podiatric Medical Association ◽

10.7547/87507315-82-2-111 ◽

1992 ◽

Vol 82 (2) ◽

pp. 111-115 ◽

Cited By ~ 1

Author(s):

C Abramson ◽

J Wilton

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Particle Size ◽

Total Mass ◽

Particle Size Analysis ◽

Dust Particles ◽

Size Analysis ◽

Scanning Electron

Nail dust particles were analyzed by scanning electron microscopy for size and topography. The percentage of "fines" that could be inhaled and deposited in the alveoli and bronchioles were determined by quantitative particle size analysis. Distribution representing the largest total mass was graphed between 1 and 2 microns. The authors found that 86% of nail dust would reach the bronchioles and alveoli, and 31% could be expected to deposit in these areas.

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Particle Size Analysis of Cotton Dust Using Scanning Electron Microscopy

Journal of Engineering for Industry ◽

10.1115/1.3439165 ◽

1977 ◽

Vol 99 (1) ◽

pp. 56-60 ◽

Cited By ~ 5

Author(s):

R. E. Fornes ◽

M. M. Kleinfelter ◽

S. P. Hersh

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Particle Size ◽

Average Particle Size ◽

Particle Size Analysis ◽

Dust Particles ◽

Size Analysis ◽

Average Particle ◽

Cotton Dust ◽

Scanning Electron

Particle size distributions of dusts generated in a model card room and collected on filter media by a vertical elutriator having a particle size cut-off of 15 μm dia have been determined using scanning electron microscopy. Photomicrographs, usually at 3000×, were made of the samples and the particle diameters were estimated by the Martin method. It was found that the average particle size of cotton dust samples measured by this technique was smaller than that reported in the literature obtained by light microscopy. It was also found that the distribution of particle sizes does not follow a simple log-normal distribution unless the smallest particles observed in this study are omitted. A bimodal or perhaps a multimodal distribution yields a better representation of the data. It is concluded that scanning electron microscopy is a practical and accurate method for sizing cotton dust particles on filter surfaces.

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Functional Properties and Molecular Degradation of Schizostachyum Brachycladum Bamboo Cellulose Nanofibre in PLA-Chitosan Bionanocomposites

Molecules ◽

10.3390/molecules26072008 ◽

2021 ◽

Vol 26 (7) ◽

pp. 2008

Author(s):

Samsul Rizal ◽

N. I. Saharudin ◽

N. G. Olaiya ◽

H. P. S. Abdul Khalil ◽

M. K. Mohamad Haafiz ◽

...

Keyword(s):

Electron Microscopy ◽

Particle Size ◽

Moisture Content ◽

Polymeric Materials ◽

Particle Size Analysis ◽

Size Analysis ◽

Thickness Swelling ◽

Compression Moulding ◽

Ft Ir ◽

Degradation Properties

The degradation and mechanical properties of potential polymeric materials used for green manufacturing are significant determinants. In this study, cellulose nanofibre was prepared from Schizostachyum brachycladum bamboo and used as reinforcement in the PLA/chitosan matrix using melt extrusion and compression moulding method. The cellulose nanofibre(CNF) was isolated using supercritical carbon dioxide and high-pressure homogenisation. The isolated CNF was characterised with transmission electron microscopy (TEM), FT-IR, zeta potential and particle size analysis. The mechanical, physical, and degradation properties of the resulting biocomposite were studied with moisture content, density, thickness swelling, tensile, flexural, scanning electron microscopy, thermogravimetry, and biodegradability analysis. The TEM, FT-IR, and particle size results showed successful isolation of cellulose nanofibre using this method. The result showed that the physical, mechanical, and degradation properties of PLA/chitosan/CNF biocomposite were significantly enhanced with cellulose nanofibre. The density, thickness swelling, and moisture content increased with the addition of CNF. Also, tensile strength and modulus; flexural strength and modulus increased; while the elongation reduced. The carbon residue from the thermal degradation and the glass transition temperature of the PLA/chitosan/CNF biocomposite was observed to increase with the addition of CNF. The result showed that the biocomposite has potential for green and sustainable industrial application.

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The Evaporative Decomposition of Solutions Method (Eds) for the Production of Ultrafine Y1Ba2Cu3O7 from Nitrate and Mixed Anion Precursor Solutions

MRS Proceedings ◽

10.1557/proc-169-385 ◽

1989 ◽

Vol 169 ◽

Cited By ~ 2

Author(s):

Rollin E. Lakis ◽

Sidney R. Butler

Keyword(s):

Electron Microscopy ◽

Particle Size ◽

Barium Carbonate ◽

Hollow Spheres ◽

Particle Size Analysis ◽

Size Analysis ◽

Gravimetric Analysis ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron

AbstractY1Ba2Cu3O7 has been prepared by the evaporative decomposition of solutions method. Nitrate and mixed anion solutions were atomized and decomposed at temperatures ranging from 300°C to 950°C. The resulting materials have been characterized using x-ray powder diffraction, Thermal Gravimetric Analysis (TGA), particle size analysis, Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The powder consists of 0.3 micron agglomerated hollow spheres with a primary particle size of 0.06 micron. TGA and x-ray diffraction indicate the presence of barium nitrate and barium carbonate due to incomplete decomposition and/or product contamination by the process environment.

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Adequacy of laser diffraction for soil particle size analysis

PLoS ONE ◽

10.1371/journal.pone.0176510 ◽

2017 ◽

Vol 12 (5) ◽

pp. e0176510 ◽

Cited By ~ 29

Author(s):

Peter Fisher ◽

Colin Aumann ◽

Kohleth Chia ◽

Nick O'Halloran ◽

Subhash Chandra

Keyword(s):

Particle Size ◽

Particle Size Analysis ◽

Laser Diffraction ◽

Soil Particle ◽

Size Analysis ◽

Soil Particle Size

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PREPARATION AND CHARACTERIZATION OF ANTI-ACNE ETHOSOMES USING COLD AND THIN-LAYER HYDRATION METHODS

International Journal of Applied Pharmaceutics ◽

10.22159/ijap.2018.v10s1.75 ◽

2018 ◽

Vol 10 (1) ◽

pp. 338

Author(s):

Rachmawati Ramadhana Mustofa ◽

Iskandarsyah .

Keyword(s):

Electron Microscopy ◽

Particle Size ◽

Thin Layer ◽

Particle Size Analysis ◽

Size Analysis ◽

Multilamellar Vesicles ◽

Zeta Potentials ◽

Small Unilamellar Vesicles

Objective: This study aimed to prepare and characterize anti-acne ethosomes using the cold- and thin-layer hydration methods.Methods: A sonication step was included during ethosome preparation to improve the quality of the cold method. Azelaic acid, Phospholipon 90G,ethanol, propylene glycol, and phosphate buffer (pH 7.4) were used in the procedures. Prepared ethosomal suspensions were characterized usingtransmission electron microscopy, particle-size analysis, and spectrophotometry.Results: Ethosomes prepared using the thin-layer hydration method (F1) had small unilamellar vesicles, while those prepared using the cold methodwith 15-min sonication (F4) showed spherical, elliptical, unilamellar, and multilamellar vesicles. F1 ethosomes had a Dmean volume of 648.57±231.26,whereas those prepared using the cold method with 5- (F2), 10- (F3), and 15-min (F4) sonication had Dmean volumes of 2734.04±231.49 nm,948.90±394.52 nm, and 931.69±471.84 nm, respectively. Polydispersity indices of F2, F3, and F4 ethosomes were 0.74±0.21, 0.86±0.05, and 0.91±0.03,respectively, with a poor particle-size distribution, compared to that of F1 (0.39±0.01). Zeta potentials of F1–F4 ethosomes were −38.27±1.72 mV,−23.53±1.04 mV, −31.4±1.04 mV, and −34.3±1.61 mV, respectively. Entrapment efficiencies of F1–F4 ethosomes were 90.71±0.11%, 53.84±3.16%,72.56±0.28%, and 75.11±1.42%, respectively.Conclusion: Anti-acne ethosomes produced using the thin-layer hydration method had superior properties than those produced using the coldmethod with 15-min sonication.

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