Poly(Butadiene)/Poly(Styrene) Interpenetrating Polymer Networks

1972 ◽  
Vol 45 (6) ◽  
pp. 1582-1596 ◽  
Author(s):  
A. J. Curtius ◽  
M. J. Covitch ◽  
D. A. Thomas ◽  
L. H. Sperling
Keyword(s):  
Polymer Networks ◽  
Impact Resistance ◽  
Charpy Impact ◽  
Theoretical Work ◽  
Interpenetrating Polymer Networks ◽  
Molecular Mixing ◽  
Recent Theoretical Work ◽  
Wide Range ◽  
Electron Microscopical ◽  
Two Phases

Abstract Interpenetrating polymer networks (IPN's) of poly (butadiene) (PB) and poly(styrene) (PS) were prepared using both random (containing 36 per cent cis, 55 per cent trans, and 9 per cent 1,2 vinyl) PB and high-cis PB. For both series, a wide range of PB/PS compositions were synthesized. Using samples stained with osmium tetroxide, electron microscopical studies revealed an irregular cellular structure of a few hundred A˚ngstrom diameter with the first component, PB, making up the cell walls. The size of the cells was found to depend on the PB crosslink density for the random materials. Modulus-temperature data revealed two distinct glass transitions, confirming the finding of two phases by microscopy. However, the transition temperature and transition slope varied with composition, and with the microstructure of the poly (butadiene), giving evidence of significant molecular mixing. Stress-strain data on the IPN's showed that materials rich in PB behave like self-reinforced elastomers. Charpy impact resistance experiments on materials rich in PS indicated values of 5 ft-lb/in. of notch, which compares well with graft-type polyblends of similar PB/PS composition. The results were interpreted in the light of the recent theoretical work of Bragaw, who considered the importance of the distances between domain boundaries with respect to crack acceleration mechanics. Although the IPN's considered herein exhibited somewhat less than the predicted optimum phase dimensions, the arrangement of the domains is different from ordinary impact resistant plastics.

scholarly journals Influence of normalizing post carburizing treatment on microstructure, mechanical properties and fracture behavior of low alloy gear steels

2021 ◽  
Vol 8 (5) ◽  
pp. 836-851
Author(s):  
Hiremath Pavan ◽  
◽  
M. C. Gowrishankar ◽  
Shettar Manjunath ◽  
Sharma Sathyashankara ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Resistance ◽  
Charpy Impact ◽  
Carbon Steels ◽  
Mode Analysis ◽  
Low Carbon ◽  
The Core ◽  
Wide Range ◽  
Before And After ◽  
Fine Pearlite

<abstract> <p>Steel is a versatile metal, got a wide range of applications in all the fields of engineering and technology. Generally, low carbon steels are tough and high alloy carbon steels are hard in nature. Certain applications demand both properties in the same steel. Carburization is one such technique that develops hard and wear resistant surfaces with a soft core. The objective of this work is to study the influence of post carburizing treatment (normalizing) on three grades of steels (EN 3, 20MnCr5, and EN 353). Post carburizing treatments are necessary to overcome the adverse effects of carburization alone. Here carburization was carried out in the propane atmosphere by heating the gas carburizing furnace to 930 ℃ for more than a day. Normalizing was carried out at 870 ℃ for 1 h and cooled in air. Tensile, hardness, Charpy impact tests along with SEM (scanning electron microscopy) and EDAX (energy dispersive X-ray analysis) were conducted to analyze the phase transformation, failure mode analysis in all the samples. Carburized steels displayed the formation of ferrite, pearlite, and sometimes bainite phases in the core and complete coarse pearlite in the case regions, whereas in the post carburized steels, increased amount of ferrite, fine pearlite, and bainite in the core and fine pearlite with traces of bainite in the case region was observed. Normalizing also refines the grain with increased UTS (ultimate tensile strength), hardness, and impact resistance. EN 353 showed higher UTS among the steels with 898 MPa after carburization and 1370 MPa after normalizing treatment. Maximum hardness of 48 HRC was observed in 20MnCr5 and toughness was superior in EN 3 with energy absorbed during test i.e., 8 and 12 J before and after normalizing treatment. Based on the fracture surface analysis, in EN 353 steel, a finer array of dimples with voids and elongated bigger clustered dimples containing ultrafine dimples array are observed in the core and case respectively during carburizing whereas, more density of river pattern and cleavage failure (brittle) are observed in the core and case respectively after post carburizing (normalizing) treatment. There is a reduction in the ductility of the steels after post carburizing treatment. It was observed that normalizing treatment produces superior mechanical properties in the carburized steels by grain refinement and strong microstructures like bainite. Normalizing as post carburizing treatment can be recommended for engineering applications where ductile core and hard surface are of great importance.</p> </abstract>

scholarly journals Multiscale Experimental Evaluation of Agarose-Based Semi-Interpenetrating Polymer Network Hydrogels as Materials with Tunable Rheological and Transport Performance

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2561
Author(s):  
Monika Trudicova ◽  
Jiri Smilek ◽  
Michal Kalina ◽  
Marcela Smilkova ◽  
Katerina Adamkova ◽  
...  
Keyword(s):  
Complex Modulus ◽  
Specific Binding ◽  
Polymer Network ◽  
Polymer Networks ◽  
Interpenetrating Polymer Networks ◽  
Interpenetrating Polymer Network ◽  
Analytical Methodology ◽  
Wide Range ◽  
Polymer Component ◽  
Poly Styrene Sulfonate

This study introduces an original concept in the development of hydrogel materials for controlled release of charged organic compounds based on semi-interpenetrating polymer networks composed by an inert gel-forming polymer component and interpenetrating linear polyelectrolyte with specific binding affinity towards the carried active compound. As it is experimentally illustrated on the prototype hydrogels prepared from agarose interpenetrated by poly(styrene sulfonate) (PSS) and alginate (ALG), respectively, the main benefit brought by this concept is represented by the ability to tune the mechanical and transport performance of the material independently via manipulating the relative content of the two structural components. A unique analytical methodology is proposed to provide complex insight into composition–structure–performance relationships in the hydrogel material combining methods of analysis on the macroscopic scale, but also in the specific microcosms of the gel network. Rheological analysis has confirmed that the complex modulus of the gels can be adjusted in a wide range by the gelling component (agarose) with negligible effect of the interpenetrating component (PSS or ALG). On the other hand, the content of PSS as low as 0.01 wt.% of the gel resulted in a more than 10-fold decrease of diffusivity of model-charged organic solute (Rhodamine 6G).

The Renaissance Beard: Masculinity in Early Modern England*

2001 ◽  
Vol 54 (1) ◽  
pp. 155-187 ◽  
Author(s):  
Will Fisher
Keyword(s):  
Early Modern ◽  
Theoretical Work ◽  
Early Modern England ◽  
Sexual Differences ◽  
Facial Hair ◽  
Recent Theoretical Work ◽  
Wide Range ◽  
Important Means ◽  
Medical Treatises ◽  
Boy Actors

This essay builds on Judith Butler's recent theoretical work in Bodies that Matter by suggesting that the sexual differences that “mattered” in early modern England are not exactly the same as those that “matter” today. In particular, it suggests that facial hair often conferred masculinity during the Renaissance: the beard made the man. The centrality of the beard is powerfully demonstrated by both portraits and theatrical practices. Indeed, virtually all men in portraits painted between the mid-sixteenth and the mid-seventeenth century have some sort official hair. Beards were also quite common on the Renaissance stage, and the essay goes on to analyze the use of false beards as theatrical props. These are not, however, the only “texts “from the period that equate being a man with having a beard. Similar formulations appear in a wide range of sources: medical treatises, physiognomy books, poetical works, and tracts on gender. In many of these texts, moreover, facial hair is not simply imagined as a means of constructing sexual differences between men and women; it is also a means of constructing distinctions between men and boys. Thus, it would appear that boys were considered to be a different gender from men during the Renaissance. This division had important ramifications for theater practice. It meant, for example, that boy actors would have been as much “in drag” when playing the parts of men as when playing the parts of women. Finally, we need to bear in mind that if facial hair thus served as an important means of materializing masculinity in early modern England, it was also crucially malleable and prosthetic. As a result, we can say that both masculinity and the beard had to be constantly made (to) matter.

The light-scattering Mueller matrices for Rayleigh and Rayleigh-Gans-Debye approximation

1990 ◽  
Vol 55 (12) ◽  
pp. 2889-2897
Author(s):  
Jaroslav Holoubek
Keyword(s):  
Light Scattering ◽  
Theoretical Work ◽  
Matrix Elements ◽  
Elastic Light Scattering ◽  
Yield Information ◽  
Recent Theoretical Work ◽  
Particle Parameters ◽  
Complete Set ◽  
Single Matrix ◽  
Scattering Matrix Elements

Recent theoretical work has shown that the complete set of polarized elastic light-scattering studies should yield information about scatterer structure that has so far hardly been utilized. We present here calculations of angular dependences of light-scattering matrix elements for spheres near the Rayleigh and Rayleigh-Gans-Debye limits. The significance of single matrix elements is documented on examples that show how different matrix elements respond to changes in particle parameters. It appears that in the small-particle limit (Rg/λ < 0.1) we do not loose much information by ignoring "large particle" observables.

scholarly journals Magnetospheric Structure of Rotation-Powered Neutron Stars

1992 ◽  
Vol 128 ◽  
pp. 56-77 ◽  
Author(s):  
Jonathan Arons
Keyword(s):  
Radio Emission ◽  
Gamma Radiation ◽  
Heavy Ions ◽  
Theoretical Work ◽  
Future Research ◽  
Observational Constraints ◽  
Polar Caps ◽  
Recent Theoretical Work ◽  
Density Flow ◽  
Promising Avenue

AbstractI survey recent theoretical work on the structure of the magnetospheres of rotation-powered pulsars, within the observational constraints set by their observed spindown, their ability to power synchrotron nebulae and their ability to produce beamed collective radio emission, while putting only a small fraction of their energy into incoherent X- and gamma radiation. I find no single theory has yet given a consistent description of the magnetosphere, but I conclude that models based on a dense outflow of pairs from the polar caps, permeated by a lower density flow of heavy ions, are the most promising avenue for future research.

scholarly journals The microscopic distribution of hydrophilic polymers in interpenetrating polymer networks (IPNs) of medical grade silicone

Polymer ◽  
2021 ◽  
Vol 224 ◽  
pp. 123671
Author(s):  
Gregory N. Smith ◽  
Erik Brok ◽  
Martin Schmiele ◽  
Kell Mortensen ◽  
Wim G. Bouwman ◽  
...  
Keyword(s):  
Polymer Networks ◽  
Interpenetrating Polymer Networks ◽  
Hydrophilic Polymers ◽  
Microscopic Distribution ◽  
Medical Grade

Organic-solvent-free electromembrane extraction based on semi-interpenetrating polymer networks

2021 ◽  
Author(s):  
Hang Mei ◽  
Huajing Liu ◽  
Qianqian Shang ◽  
Ying Dong ◽  
Stig Pedersen-Bjergaard ◽  
...  
Keyword(s):  
Organic Solvent ◽  
Polymer Networks ◽  
Interpenetrating Polymer Networks ◽  
Solvent Free ◽  
Electromembrane Extraction ◽  
Acidic Analytes

A versatile organic-solvent-free electromembrane extraction (EME) system, which could be successfully used for the extraction of both basic and acidic analytes, is proposed based on semi-interpenetrating polymer networks.

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