On Polymer Mixture Thermodynamics

1977 ◽  
Vol 10 (5) ◽  
pp. 1166-1167 ◽  
Author(s):  
R. Koningsveld ◽  
R. F. T. Stepto
Keyword(s):  
Polymer Mixture ◽  
Mixture Thermodynamics

Specific volume and features of compressibility during the molding of powder-polymer mixtures with wax-polypropylene binder

2019 ◽  
pp. 25-33
Author(s):  
Alexander Muranov ◽  
Alexey Semenov ◽  
Anatoly Kutsbakh ◽  
Boris Semenov
Keyword(s):  
Phase Transition ◽  
Comparative Analysis ◽  
Powder Metallurgy ◽  
Injection Molding ◽  
Polymer Binder ◽  
Polymer Mixture ◽  
Powder Injection ◽  
Polymer Mixtures ◽  
Pvt Data ◽  
Mathematical Processing

The article discusses one of the modern areas of powder metallurgy – the technology of manufacturing shaped parts by the powder injection molding (PIM). For the powder-polymer mixture (feedstock) with a wax-polypropylene binder of the solvent-thermal type of removal by isobaric volume dilatometry, the dependence of PVT state parameters was studied. For each component of the polymer binder, the dependence of pressure on the temperature of phase transition was obtained. As a result of mathematical processing and analysis of PVT data for the feedstock of the studied type, a technological window of parameters has been determined that allows injection molding of «green parts» with minimal volume shrinkage. The results of a comparative analysis of the compaction of feedstock with a polymer binder catalytic and solution-thermal type of removal are presented.

scholarly journals Hybrid Biopolymer and Lipid Nanoparticles with Improved Transfection Efficacy for mRNA

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 2034 ◽  
Author(s):  
Christian D. Siewert ◽  
Heinrich Haas ◽  
Vera Cornet ◽  
Sara S. Nogueira ◽  
Thomas Nawroth ◽  
...  
Keyword(s):  
Small Angle ◽  
Messenger Rna ◽  
Physicochemical Characterization ◽  
Single Step ◽  
Model Systems ◽  
Molecular Organization ◽  
Hybrid Nanoparticles ◽  
Polymer Mixture ◽  
Internal Organization ◽  
Transfection Efficacy

Hybrid nanoparticles from lipidic and polymeric components were assembled to serve as vehicles for the transfection of messenger RNA (mRNA) using different portions of the cationic lipid DOTAP (1,2-Dioleoyl-3-trimethylammonium-propane) and the cationic biopolymer protamine as model systems. Two different sequential assembly approaches in comparison with a direct single-step protocol were applied, and molecular organization in correlation with biological activity of the resulting nanoparticle systems was investigated. Differences in the structure of the nanoparticles were revealed by thorough physicochemical characterization including small angle neutron scattering (SANS), small angle X-ray scattering (SAXS), and cryogenic transmission electron microscopy (cryo-TEM). All hybrid systems, combining lipid and polymer, displayed significantly increased transfection in comparison to lipid/mRNA and polymer/mRNA particles alone. For the hybrid nanoparticles, characteristic differences regarding the internal organization, release characteristics, and activity were determined depending on the assembly route. The systems with the highest transfection efficacy were characterized by a heterogenous internal organization, accompanied by facilitated release. Such a system could be best obtained by the single step protocol, starting with a lipid and polymer mixture for nanoparticle formation.

scholarly journals Development of Controlled-Release Carbamide Peroxide Loaded Nanoemulgel for Tooth Bleaching: In Vitro and Ex Vivo Studies

2021 ◽  
Vol 14 (2) ◽  
pp. 132
Author(s):  
Siriporn Okonogi ◽  
Adchareeya Kaewpinta ◽  
Sakornrat Khongkhunthian ◽  
Pisaisit Chaijareenont
Keyword(s):  
Drug Release ◽  
Solid Dispersion ◽  
Solid Dispersions ◽  
Tooth Bleaching ◽  
Polymer Mixture ◽  
Release Mechanism ◽  
Burst Release ◽  
Order Kinetic ◽  
Carbamide Peroxide ◽  
Periodontal Tissues

Burst release of carbamide peroxide (CP) from traditional hydrogels causes severe inflammation to periodontal tissues. The present study explores the development of a novel CP nanoemulgel (CP-NG), an oil-in-water nanoemulsion-based gel in which CP was loaded with a view to controlling CP release. CP solid dispersions were prepared, using white soft paraffin or polyvinylpyrrolidone-white soft paraffin mixture as a carrier, prior to formulating nanoemulsions. It was found that carrier type and the ratio of CP to carrier affected drug crystallinity. Nanoemulsions formulated from the optimized CP solid dispersions were used to prepare CP-NG. It was found that the ratio of drug to carrier in CP solid dispersions affected the particle size and zeta potential of the nanoemulsions as well as drug release behavior and tooth bleaching efficacy of CP-NG. Drug release from CP-NG followed a first-order kinetic reaction and the release mechanism was an anomalous transport. Drug release rate decreased with an increase in solid dispersion carriers. CP-NG obtained from the solid dispersion with a 1:1 ratio of CP to the polymer mixture is suitable for sustaining drug release with high tooth bleaching efficacy and without reduction of enamel microhardness. The developed CP-NG is a promising potential tooth bleaching formulation.

scholarly journals Vascular-confined multi-passage discoidal nanoconstructs for the low-dose docetaxel inhibition of triple-negative breast cancer growth

Nano Research ◽  
2021 ◽  
Author(s):  
Alessia Felici ◽  
Daniele Di Mascolo ◽  
Miguel Ferreira ◽  
Simone Lauciello ◽  
Luca Bono ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Survival Rate ◽  
Triple Negative Breast Cancer ◽  
Near Infrared ◽  
Triple Negative ◽  
Tumor Regression ◽  
Polymer Mixture ◽  
Poly Vinyl Alcohol ◽  
Glycol Diacrylate ◽  
Breast Cancer Growth

AbstractTaxane efficacy in triple negative breast cancer (TNBC) is limited by insufficient tumor accumulation and severe off-target effects. Nanomedicines offer a unique opportunity to enhance the anti-cancer potency of this drug. Here, 1,000 nm × 400 nm discoidal polymeric nanoconstructs (DPN) encapsulating docetaxel (DTXL) and the near infrared compound lipid-Cy5 were engineered. DPN were obtained by filling multiple times cylindrical wells in a poly(vinyl alcohol) template with a polymer mixture comprising poly(lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) diacrylate (PEG-DA) chains together with therapeutic and imaging agents. The resulting “multi-passage” DPN exhibited higher DTXL loading, lipid-Cy5 stability, and stiffness as compared to the conventional “single-passage” approach. Confocal microscopy confirmed that DTXL-DPN were not taken up by MDA-MB-231 cells but would rather sit next to the cell membrane and slowly release DTXL thereof. Empty DPN had no toxicity on TNBC cells, whereas DTXL-DPN presented a cytotoxic potential comparable to free DTXL (IC50 = 2.6 nM ± 1.0 nM vs. 7.0 nM ± 1.09 nM at 72 h). In orthotopic murine models, DPN accumulated in TNBC more efficiently than free-DTXL. With only 2 mg/kg DTXL, intravenously administered every 2 days for a total of 13 treatments, DTXL-DPN induced tumor regression and were associated to an overall 80% survival rate as opposed to a 30% survival rate for free-DTXL, at 120 days. All untreated mice succumbed before 90 days. Collectively, this data demonstrates that vascular confined multi-passage DPN, biomimicking the behavior of circulating platelets, can efficiently deliver chemotherapeutic molecules to malignant tissues and effectively treat orthotopic TNBC at minimal taxane doses.

Anticorrosion response of polymer mixture on mild steel in hydrochloric acid environment

2020 ◽  
Vol 3 (5) ◽  
pp. 663-673
Author(s):  
S. C. Nwanonenyi ◽  
H. C. Obasi ◽  
M. U. Obidiegwu ◽  
I. C. Chukwujike
Keyword(s):  
Hydrochloric Acid ◽  
Mild Steel ◽  
Polymer Mixture ◽  
Acid Environment

BRIDGING OF CARBON FIBERS IN CF/EPOXY COMPOSITES USING ELECTROSTATICALLY INDUCED CNT ALIGNMENT

2021 ◽  
Author(s):  
DANDAN ZHANG ◽  
XINGKANG SHE ◽  
YIPENG HE ◽  
WESLEY A. CHAPKIN, ◽  
VI T. BREGMAN ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Electric Field ◽  
Carbon Fibers ◽  
Hybrid Composites ◽  
Tensile Modulus ◽  
Tensile Tests ◽  
Polymer Mixture ◽  
Ac Electric Field ◽  
Reinforced Polymer ◽  
Electric Field Direction

Carbon fiber reinforced polymer (CFRP) composites are lightweight materials with superior strength but are expensive due to the increased cost of carbon fibers (CFs). The addition of carbon nanotubes (CNTs) to polymer nanocomposites are becoming an excellent alternative to CF due to their unique combination of electrical, thermal, and mechanical properties. With the application of an electric field across the CNT/polymer mixture before curing, CNTs will not only be aligned along the electric field direction, but also form networks after reaching to a certain degree of alignment. In this study, an alternating current (AC) electric field was applied continuously to CNT/CF/Epoxy hybrid composites before curing. By cutting off the applied voltage when the monitored electric current increased, the degree of networking of CNTs between two CF tows was controlled. The relative electric field strength around the end of conductive carbon fiber tows in the epoxy matrix was modeled using COMSOL Multiphysics. It increased after applying AC electric field parallel to the CF tows, thereby increasing the alignment degree of CNTs and building a network to bridge the CF tows. The preliminary results indicate that the microhardness and tensile modulus between two CF tows are increased due to the networking of CNTs in this area. The fracture surface of the specimens after tensile tests were characterized to reveal more details of the microstructure.

Continuous wave measurements of acoustic attenuation in an oil/polymer mixture

1979 ◽  
Vol 5 (1) ◽  
pp. 87-90 ◽  
Author(s):  
F.Earl Fyke ◽  
James F. Greenleaf ◽  
Steven A. Johnson
Keyword(s):  
Continuous Wave ◽  
Polymer Mixture ◽  
Acoustic Attenuation ◽  
Wave Measurements

The fluid-fluid interface of a model colloid-polymer mixture

2000 ◽  
Vol 49 (5) ◽  
pp. 678-684 ◽  
Author(s):  
J. M Brader ◽  
R Evans
Keyword(s):  
Polymer Mixture ◽  
Fluid Interface
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