Investigation of the Polymers Formed in Reactor Irradiated Aniline and Pyridine

1973 ◽  
Vol 51 (23) ◽  
pp. 3860-3865 ◽  
Author(s):  
Mahmoud F. Barakat ◽  
Fawzi M. Abdelkerim
Keyword(s):  
Polymer Chains ◽  
Polymerization Reaction ◽  
Aromatic Rings ◽  
Radioactive Materials ◽  
Initial Amount ◽  
Great Capacity ◽  
Polymer Formation ◽  
Pure Compounds ◽  
Recoil Atoms ◽  
Individual Polymer

In reactor irradiated aniline or pyridine most of the radiocarbon generated by the 14N(n,p)14C reaction was found preferentially localized in a polymer-like material, brown in color, frequently lustrous and constituting 15–30% of the initial amount of the irradiated material. This stimulated us to try to obtain an idea about the chemical groupings existing in these highly radioactive materials and thereafter to deduce their possible formation pathways.By comparing the i.r. spectra of these polymers with those of the corresponding pure compounds it was possible to detect some changes in the spectra on polymerization and consequently it was possible to identify some basic structural groups existing. Based on these findings some polymerization reaction mechanisms have been suggested. In general, polymer formation was assumed to take place through the formation of polymerization centers produced by the rupture of the aromatic rings to give highly unsaturated fragments and radicals. These are capable of adding different radicals and fragments formed in the irradiated material by radiolysis or by the action of energetic recoil atoms. Cross linking between individual polymer chains was observed. The preferential localisation of 14C in the polymer fraction could be attributed to the great capacity of the recoil atoms to form reactive secondary species such as 14CH3•, 14CH2••, or 14CH••• which participate in polymer formation.

SuFExable Polymers with Helical Structures Derived from Thionyl Tetrafluoride (SOF4)

2019 ◽  
Author(s):  
Suhua Li ◽  
Gencheng Li ◽  
Bing Gao ◽  
Sidharam P. Pujari ◽  
Xiaoyan Chen ◽  
...  
Keyword(s):  
Functional Polymers ◽  
Polymer Chains ◽  
New Materials ◽  
Helical Structures ◽  
Polymer Backbone ◽  
Silyl Ethers ◽  
Helical Polymer ◽  
Key Characteristics ◽  
Post Modification ◽  
Individual Polymer

The first SuFEx click chemistry synthesis of SOF<sub>4</sub>-derived copolymers based upon the polymerization of bis(iminosulfur oxydifluorides) and bis(aryl silyl ethers) is described. This novel class of SuFEx polymer presents two key characteristics: First, the newly created [-N=S(=O)F-O-] polymer backbone linkages are themselves SuFExable and primed to undergo further high-yielding and precise SuFEx-based post-modification with phenols or amines to yield branched functional polymers. Second, studies of individual polymer chains of several of these new materials indicate the presence of helical polymer structures, which itself suggests a preferential approach of new monomers onto the growing polymer chain upon the formation of the stereogenic linking moiety.

scholarly journals Advances in the Multi-Orthogonal Folding of Single Polymer Chains into Single-Chain Nanoparticles

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 293
Author(s):  
Agustín Blazquez-Martín ◽  
Ester Verde-Sesto ◽  
Angel J. Moreno ◽  
Arantxa Arbe ◽  
Juan Colmenero ◽  
...  
Keyword(s):  
Computer Simulations ◽  
Chemical Species ◽  
Synthetic Polymers ◽  
Review Article ◽  
Polymer Chains ◽  
Single Chain ◽  
High Dilution ◽  
Covalent Bonds ◽  
Covalent Interactions ◽  
Individual Polymer

The folding of certain proteins (e.g., enzymes) into perfectly defined 3D conformations via multi-orthogonal interactions is critical to their function. Concerning synthetic polymers chains, the “folding” of individual polymer chains at high dilution via intra-chain interactions leads to so-called single-chain nanoparticles (SCNPs). This review article describes the advances carried out in recent years in the folding of single polymer chains into discrete SCNPs via multi-orthogonal interactions using different reactive chemical species where intra-chain bonding only occurs between groups of the same species. First, we summarize results from computer simulations of multi-orthogonally folded SCNPs. Next, we comprehensively review multi-orthogonally folded SCNPs synthesized via either non-covalent bonds or covalent interactions. Finally, we conclude by summarizing recent research about multi-orthogonally folded SCNPs prepared through both reversible (dynamic) and permanent bonds.

scholarly journals Oxidative regulation of the mechanical strength of a C–S bond

2020 ◽  
Vol 11 (38) ◽  
pp. 10444-10448
Author(s):  
Yangju Lin ◽  
Stephen L. Craig
Keyword(s):  
Fracture Toughness ◽  
Mechanical Strength ◽  
Performance Metrics ◽  
Polymer Chains ◽  
Bulk Materials ◽  
Oxidative Regulation ◽  
Individual Polymer

The mechanical strength of individual polymer chains is believed to underlie a number of performance metrics in bulk materials, including adhesion and fracture toughness.

The Fate of Hazardous Materials in the Biosphere

2006 ◽  
Author(s):  
Gary M. Sandquist
Keyword(s):  
Energy Source ◽  
Nuclear Waste ◽  
Nuclear Power ◽  
Fuel Cycle ◽  
Hazardous Materials ◽  
Nuclear Fuel Cycle ◽  
Hazardous Wastes ◽  
Radioactive Materials ◽  
Great Capacity ◽  
Stable Elements

Although nuclear power appears to be expanding as a major global energy source, the disposal of radioactive waste from the nuclear fuel cycle still poses formidable challenges to the full expansion of the nuclear enterprise. The perception that nuclear wastes represent unique and insoluble threats to humans is ill founded. The risk from these radioactive materials is comparable and many ways less severe than other more familiar hazardous materials that are ubiquitous in the biosphere. Radioactive materials decay and reduce in time unlike stable elements. Besides the reduction of radioactive materials through decay, the dilution and dispersion of all hazardous materials by natural forces and events provides the reduction required to make adequate and safe disposal of nuclear waste possible. The ultimate sink for essentially all of these hazardous wastes will prove to be the oceans with their great capacity of dilution and containment.

Covalent Connection of Two Individual Polymer Chains on a Surface: An Elementary Step towards Molecular Nanoconstructions

2003 ◽  
Vol 42 (17) ◽  
pp. 1932-1935 ◽  
Author(s):  
Jörg Barner ◽  
Frank Mallwitz ◽  
Lijin Shu ◽  
A. Dieter Schlüter ◽  
Jürgen P. Rabe
Keyword(s):  
Elementary Step ◽  
Polymer Chains ◽  
Individual Polymer

scholarly journals Advances in Single-Chain Nanoparticles for Catalysis Applications

2017 ◽  
Author(s):  
Jon Rubio-Cervilla ◽  
Edurne González ◽  
José A. Pomposo
Keyword(s):  
Chemical Compounds ◽  
Inorganic Nanoparticles ◽  
Polymer Chains ◽  
Carbon Nanodots ◽  
Aqueous Environment ◽  
High Catalytic Activity ◽  
Artificial Enzyme ◽  
Single Chain ◽  
Capture And Release ◽  
Individual Polymer

Enzymes are the most efficient catalysts known working in an aqueous environment near room temperature. The folding of individual polymer chains to functional single-chain nanoparticles (SCNPs) offers many opportunities for the development of artificial enzyme-mimic catalysts showing both high catalytic activity and specificity. In this review, we highlight recent results obtained in the use of SCNPs as bioinspired, highly-efficient nanoreactors (3&ndash;30 nm) for the synthesis of a variety of nanomaterials (inorganic nanoparticles, quantum dots, carbon nanodots), polymers and chemical compounds, as well as nanocontainers for CO2 capture and release.

SuFExable Polymers with Helical Structures Derived from Thionyl Tetrafluoride (SOF4)

2019 ◽  
Author(s):  
Suhua Li ◽  
Gencheng Li ◽  
Bing Gao ◽  
Sidharam P. Pujari ◽  
Xiaoyan Chen ◽  
...  
Keyword(s):  
Functional Polymers ◽  
Polymer Chains ◽  
New Materials ◽  
Helical Structures ◽  
Polymer Backbone ◽  
Silyl Ethers ◽  
Helical Polymer ◽  
Key Characteristics ◽  
Post Modification ◽  
Individual Polymer

The first SuFEx click chemistry synthesis of SOF<sub>4</sub>-derived copolymers based upon the polymerization of bis(iminosulfur oxydifluorides) and bis(aryl silyl ethers) is described. This novel class of SuFEx polymer presents two key characteristics: First, the newly created [-N=S(=O)F-O-] polymer backbone linkages are themselves SuFExable and primed to undergo further high-yielding and precise SuFEx-based post-modification with phenols or amines to yield branched functional polymers. Second, studies of individual polymer chains of several of these new materials indicate the presence of helical polymer structures, which itself suggests a preferential approach of new monomers onto the growing polymer chain upon the formation of the stereogenic linking moiety.

scholarly journals Simulation of Individual Polymer Chains and Polymer Solutions with Smoothed Dissipative Particle Dynamics

Fluids ◽  
2016 ◽  
Vol 1 (1) ◽  
pp. 7 ◽  
Author(s):  
Sergey Litvinov ◽  
Qingguang Xie ◽  
Xiangyu Hu ◽  
Nikolaus Adams ◽  
Marco Ellero
Keyword(s):  
Polymer Solutions ◽  
Dissipative Particle Dynamics ◽  
Particle Dynamics ◽  
Polymer Chains ◽  
Individual Polymer

Design, Preparation and Characterization of Thermotropic Liquid Crystal Polyamides

1996 ◽  
Vol 8 (3) ◽  
pp. 433-444 ◽  
Author(s):  
P Alder ◽  
J G Dolden
Keyword(s):  
Hydrogen Bonding ◽  
Liquid Crystalline ◽  
Polymer Chains ◽  
Acid Chlorides ◽  
Unit Size ◽  
Aromatic Rings ◽  
Aromatic Polyamides ◽  
Symmetry Index ◽  
Index Approach

There are few examples of thermotropic polyamides reported in the literature due to the strong tendency for hydrogen bonding between polymer chains. The vast majority of reported liquid crystalline (LC) polyamides are aromatic, highly crystalline and consequently infusible— and can only exhibit LC behaviour in solution (lyotropic behaviour). In this paper, the authors set out to synthesize novel amorphous wholly aromatic and semi-aromatic thermotropic polyamides. As crystalline aromatic polyamides are normally infusible, it was necessary to ensure that the target polyamides were amorphous with a definable softening point below their temperature of decomposition. The ‘Symmetry Index’ approach first developed by Dolden was used to ensure that the chosen monomer compositions were able to produce amorphous polyamides. Aharoni has reported that three amide linked aromatic rings is the minimum unit size needed to obtain mesogenic polyamides. Building on this principle, a new empirical predictive technique called the ‘Mesogenic Index’ is introduced and combined with the Symmetry Index to predict polyamides which are both amorphous and thermotropic. This approach was validated by the preparation of a whole new series of thermotropic amorphous polyamides which were based on 3,3′-dimethoxy benzidine, and the acid chlorides of terephthalic, isophthalic and adipic acids. Furthermore, this led on to the preparation of two more series of amorphous polyamides, believed by the authors to be the first wholly aromatic thermotropic polyamides to be reported, based on 3,3′-dimethoxy and 3,3′-dimethyl benzidine in conjunction with a variety of aromatic and cyclic diacids.

Use of multidetector light-scattering experiments to study the flexibility of individual polymer chains in solution

1987 ◽  
Vol 20 (9) ◽  
pp. 2187-2194 ◽  
Author(s):  
William G. Griffin ◽  
Mary C. A. Griffin ◽  
Francois Boue
Keyword(s):  
Light Scattering ◽  
Polymer Chains ◽  
Individual Polymer
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