Morphology-Property Relationships in EPDM-Polybutadiene Blends

1982 ◽  
Vol 55 (1) ◽  
pp. 151-160 ◽  
Author(s):  
Gary R. Hamed
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Interfacial Adhesion ◽  
Pure Component ◽  
Dispersed Phase ◽  
Minor Effect ◽  
Low Doses ◽  
High Doses ◽  
A Minor ◽  
Higher Doses

Abstract When mixing EPDM and BR in the Brabender a heterogeneous blend results; the dispersed phase is first sheared into fibrous strands and then broken down into micron sized particles. At low doses of irradiation, the morphology of the blend only has a minor effect on the energy to break, whereas at high doses the Eb may increase by a factor of three as the dispersed particle size is reduced from the 100 micron range. The Eb of the blend is the weight-average of the two pure components at low doses (independent of morphology), but is greater than either pure component at higher doses. Interfacial adhesion may play a key role in determining the mechanical properties in rubbery blends.

Effect of methacholine chloride on rheology and transport of canine tracheal mucus

1979 ◽  
Vol 47 (1) ◽  
pp. 26-31 ◽  
Author(s):  
M. King ◽  
N. Viires
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Base Line ◽  
Low Doses ◽  
Mucociliary Transport ◽  
Frog Palate ◽  
High Doses ◽  
Tracheal Mucus ◽  
Higher Doses ◽  
Cytology Brush

The effect of methacholine chloride (M) on tracheal mucus was investigated in three conscious tracheostomized dogs. Aerosols of M in concentrations of 2--32 mg/ml were delivered intratracheally for 1 min. Mucus was sampled with a cytology brush at 2 min postchallenge and at irregular intervals thereafter. The mechanical properties of each sample were determined in the magnetic microrheometer, and correlated with mucociliary transportability as assayed by the frog palate technique. With high doses of M, there was an increase in volume of secretion collected per unit time. The elastic modulus (G′) at 2 min postchallenge went up (to 1.5 x 2.3 x control for 16 and 32 mg/ml, respectively) then fell below control before returning to base line after 30 or 45 min. With low doses of M (2--8 mg/ml) the secretion rate was also above control, but only a decrease in G′ (to 0.54 x control) was observed. The decrease in G′ at low doses did not significantly alter the frog palate transport rate; however, the increase at higher doses did impede mucociliary transport.

Recycling Scrap Crosslinked Urethane Polymers

1975 ◽  
Vol 48 (5) ◽  
pp. 972-980 ◽  
Author(s):  
R. M. Gerkin ◽  
F. E. Critchfield ◽  
W. A. Miller ◽  
R. Roberts ◽  
C. G. Seefried
Keyword(s):  
Particle Size ◽  
Ambient Temperature ◽  
Size Reduction ◽  
Minor Effect ◽  
Particle Size Reduction ◽  
Foam Formulation ◽  
A Minor ◽  
High Degree ◽  
Sulfur Curing

Abstract A. Scrap LRM polymers can be ground to powder on the Banbury operating at ambient temperature with cooling of the rotors and jacket. Particle size reduction can be accomplished in 5 min at 180 rpm. B. Powdered LRM polymer can be blended with TPU up to 50 wt.% and the composite compression molded to give the same properties as the TPU. C. Powdered LRM polymer can be blended with nitrile, chloroprene, and EPDM rubbers to give incompatible composites. The powdered LRM polymer acts in a manner similar to typical nonreinforcing fillers. D. It is possible to degrade powdered LRM polymers to a tacky mass at 180°C, which behaves much like a typical extender oil, when blended with nitrile and chloroprene rubbers. It is speculated that the degraded urethane should show a high degree of permanency in such blends. E. Addition of the urethane polymer to the rubber stocks does not interfere with the standard sulfur-curing mechanisms. F. Scrap HR foam can be ground to a powder in the Banbury in a manner similar to LRM scrap. G. A blend of 5 phr of powdered foam with a new HR foam formulation was machine processable. Addition of the powder had only a minor effect on the properties of the new foam.

Effect of Different Types of PLA on the Properties of PLA/PBAT Blown Films

2021 ◽  
Vol 885 ◽  
pp. 115-120
Author(s):  
Arianna Pietrosanto ◽  
Paola Scarfato ◽  
Luciano Di Maio ◽  
Loredana Incarnato
Keyword(s):  
Mechanical Properties ◽  
Interfacial Adhesion ◽  
Mechanical Performance ◽  
Dispersed Phase ◽  
Mass Ratio ◽  
Blown Films ◽  
Different Types

In this work, blown films made by blends of poly (lactide) (PLA) and poly (butylene-adipate-co-terephthalate) (PBAT) in a 40/60 mass ratio were developed and characterized. Two types of PLA, differing for their viscosities, were employed, in order to evaluate their effect on the morphology and on the mechanical properties of the films. The blends exhibited a coarse morphology when the viscosity of the PLA employed was much higher than PBAT. Instead, the use of a PLA whose viscosity was closer to PBAT led to a decrease of the dimensions and to a better distribution and interfacial adhesion of the dispersed phase. Moreover, the finer and more homogenous morphology of the blend resulted in better mechanical performance of the system.

scholarly journals Alginate/Poly(γ-glutamic Acid) Base Biocompatible Gel for Bone Tissue Engineering

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Wing P. Chan ◽  
Fu-Chen Kung ◽  
Yu-Lin Kuo ◽  
Ming-Chen Yang ◽  
Wen-Fu Thomas Lai
Keyword(s):  
Mechanical Properties ◽  
Glutamic Acid ◽  
Blood Compatibility ◽  
Cross Linking ◽  
Temperature Sensitive ◽  
Minor Effect ◽  
Acid Base ◽  
A Minor ◽  
Sodium Form ◽  
Alginate Matrix

A technique for synthesizing biocompatible hydrogels by cross-linking calcium-form poly(γ-glutamic acid), alginate sodium, and Pluronic F-127 was created, in which alginate can be cross-linked by Ca2+from Ca–γ-PGA directly andγ-PGA molecules introduced into the alginate matrix to provide pH sensitivity and hemostasis. Mechanical properties, swelling behavior, and blood compatibility were investigated for each hydrogel compared with alginate and forγ-PGA hydrogel with the sodium form only. Adding F-127 improves mechanical properties efficiently and influences the temperature-sensitive swelling of the hydrogels but also has a minor effect on pH-sensitive swelling and promotes anticoagulation. MG-63 cells were used to test biocompatibility. Gelation occurred gradually through change in the elastic modulus as the release of calcium ions increased over time and caused ionic cross-linking, which promotes the elasticity of gel. In addition, the growth of MG-63 cells in the gel reflected nontoxicity. These results showed that this biocompatible scaffold has potential for application in bone materials.

Effect of naloxone on ethanol- and pentobarbital-induced narcosis

1982 ◽  
Vol 60 (10) ◽  
pp. 1315-1318 ◽  
Author(s):  
J. M. Khanna ◽  
J. M. Mayer ◽  
H. Kalant ◽  
G. Shah
Keyword(s):  
Sleep Duration ◽  
Low Doses ◽  
Small Reduction ◽  
High Doses ◽  
Higher Doses ◽  
Convulsant Effect

Single or repeated subcutaneous administrations of naloxone in doses of up to 4 mg∙kg−1 did not alter the time for onset or the duration of ethanol- or pentobarbital-induced narcosis in rats. An increase in the naloxone dosage to 50 mg∙kg−1 s.c. resulted in a small reduction of ethanol-induced sleep duration. Repeated i.p. or i.v. administrations of much higher doses of naloxone (300–400 mg∙kg−1 and 120–180 mg∙kg−1, respectively) did produce significant reductions in ethanol-induced narcosis. However, similar naloxone doses, when administered alone, i.v., had marked convulsant effect. It appears that naloxone, in low doses, is not an effective antidote for narcosis caused by ethanol or pentobarbital at the ethanol and pentobarbital doses tested, whereas the antagonism of ethanol-induced sleep by high doses of naloxone may be due to the analeptic action of this drug.

scholarly journals Differential effects of corticosteroids and anti-TNF on tumor-specific immune responses - implications for the management of irAEs

2018 ◽  
Author(s):  
Arianna Draghi ◽  
Troels Holz Borch ◽  
Haja Dominike Radic ◽  
Christopher Aled Chamberlain ◽  
Aishwarya Gokuldass ◽  
...  
Keyword(s):  
T Cell Activation ◽  
Cell Activation ◽  
Tumor Infiltrating Lymphocytes ◽  
High Dose ◽  
Minor Effect ◽  
Tumor Killing ◽  
High Doses ◽  
A Minor ◽  
The Impact

AbstractUp to 60% of patients treated with cancer immunotherapy develop severe or life threatening immune-related adverse events (irAEs). Immunosuppression with high doses of corticosteroids or, in refractory cases, with tumor necrosis factor (TNF) antagonists, are the mainstay of treatment for irAEs. It is currently unknown what is the impact of corticosteroids and anti-TNF on the activity of antitumor T cells. In this study, the influences of clinically relevant doses of dexamethasone (corresponding to an oral dose of 10 to 125 mg prednisolone) and infliximab (anti-TNF) on the activation and killing ability of tumor-infiltrating lymphocytes (TILs) was tested in vitro. Overall, dexamethasone at low or intermediate/high dose impaired the activation (respectively −46% and −62%) and tumor-killing ability (respectively −48% and −53%) of tumor-specific TILs. In contrast, a standard clinical dose of infliximab only had a minor effect on T cell activation (−20%) and tumor killing (−10%). A brief resting following exposure to dexamethasone was sufficient to rescue the in vitro activity of TILs. In conclusion, clinically-relevant doses of infliximab only influenced to a lesser extent the activity of tumor-specific TILs in vitro, whereas even low doses of corticosteroids markedly impaired the antitumor activity of TILs. These data support steroid-sparing strategies and early initiation of anti-TNF for the treatment of irAEs in immuno-oncology.

Compatibilizing Modification of Polyethersulfone/Polycarbonate Blend

2013 ◽  
Vol 750-752 ◽  
pp. 858-862
Author(s):  
Cheng You Ma ◽  
Yan Mei Ma ◽  
Zhi He ◽  
Chen Yan ◽  
Dong Jiang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Thermal Properties ◽  
Block Copolymers ◽  
Interfacial Adhesion ◽  
Tensile Modulus ◽  
Ternary Blend ◽  
Dispersed Phase ◽  
Elongation At Break

Double block copolymers of polyethersulfone (PES)/polycarbonate (PC) were used as a compatibilizer for a blend of PES/PC. The morphology, thermal properties, mechanical properties, etc. of the resulting ternary blend systems were investigated. The addition of the compatibizer improved the compatibility between PES and PC. It was found that the interfacial adhesion was enhanced; the size of the dispersed phase was reduced. This resulted in an improvement of elongation at break and tenacity of PES/PC blends, while the tensile modulus slightly increased, and tensile strength was almost constant.

Effect of Zn and Zr Concentration and Extrusion Conditions on the Mechanical Properties of Lean ZK Alloys

2015 ◽  
Vol 828-829 ◽  
pp. 279-284
Author(s):  
N.G. Ross ◽  
A. Elrefaey ◽  
Richard Kretz ◽  
Helmut Kilian
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Element Concentration ◽  
Weight Percent ◽  
Al Alloys ◽  
Mg Alloys ◽  
Minor Effect ◽  
Alloying Element ◽  
Extrusion Speed ◽  
A Minor

Compared to Al alloys Mg alloys are generally slower to extrude and this makes them expensive to process. However, making alloys easier to extrude usually equates to reduced extrudate strength. The effects of extrusion parameter, billet heat treatments and alloying element concentration on extrudability and extrudate mechanical properties are compared using four lean ZK alloys. By weight percent there was a greater increase in peak extrusion pressure and extrudate yield strength from increasing Zr than from Zn. Homogenising the extrusion billets had no effect on the lean alloys and only a minor effect on the richer alloys. Alloying element concentration has the most effect on alloy mechanical properties, while changing the extrusion speed and temperature has little influence on the extrudate mechanical properties.

scholarly journals Paclobutrazol Reduces Photosynthetic Carbon Dioxide Uptake Rate in Grapevines

1994 ◽  
Vol 119 (3) ◽  
pp. 486-491 ◽  
Author(s):  
David M. Hunter ◽  
John T.A. Proctor
Keyword(s):  
Uptake Rate ◽  
Feedback Inhibition ◽  
Photosynthetic Electron Transport ◽  
Soluble Form ◽  
Minor Effect ◽  
Carbon Dioxide Uptake ◽  
Photosynthetic Carbon ◽  
Effect Of Treatment ◽  
A Minor ◽  
Higher Doses

Paclobutrazol applied as a soil drench at 0, 1, 10, 100, or 1000 μg a.i./g soil reduced photosynthetic CO2 uptake rate of leaves formed before paclobutrazol treatment within 3 to 5 days of treatment and the reductions were maintained for 15 days after treatment. The percentage of recently assimilated 14C exported from the source leaf was reduced only at the highest paclobutrazol dose, and there was little effect of treatment on the partitioning of exported 14C between the various sinks. In response to increasing doses of paclobutrazol, particularly at the higher doses, an increasing proportion of recent photoassimilates was maintained in a soluble form in all plant components. Reduced demand for photoassimilates as a result of the inhibition of vegetative growth may have contributed to a reduction in photosynthetic CO2 uptake rate, but this reduction in photosynthesis rate could not be attributed to a feedback inhibition caused by a buildup of starch in the leaves. Paclobutrazol had only a minor effect, if any, on photosynthetic electron transport. Chemical name used: β-[(4-chlorophenyl) methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).

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