scholarly journals Quasi-Solid Semi-Interpenetrating Polymer Networks as Electrolytes: Part I. Dependence of Physicochemical Characteristics and Ion Conduction Behavior on Matrix Composition, Cross-Link Density, Chain Length between Cross-Links, Molecular Entanglements, Charge Carrier Concentration, and Nature of Anion

2013 ◽  
Vol 118 (1) ◽  
pp. 159-174 ◽  
Author(s):  
Nimai Bar ◽  
Kota Ramanjaneyulu ◽  
Pratyay Basak
Keyword(s):  
Polymer Networks ◽  
Physicochemical Characteristics ◽  
Charge Carrier Concentration ◽  
Interpenetrating Polymer Networks ◽  
Matrix Composition ◽  
Cross Link ◽  
Link Density ◽  
Conduction Behavior ◽  
Cross Links ◽  
Cross Link Density

scholarly journals Magnetic composites based on NR and strontium ferrite

2019 ◽  
Vol 12 (1) ◽  
pp. 63-69
Author(s):  
Ján Kruželák ◽  
Andrea Kvasničáková ◽  
Rastislav Dosoudil ◽  
Ivan Hudec
Keyword(s):  
Carbon Black ◽  
Strontium Ferrite ◽  
Rubber Matrix ◽  
Cross Link ◽  
Magnetic Composites ◽  
Link Density ◽  
Cross Links ◽  
Cross Link Density ◽  
The Cross ◽  
Thermo Physical Properties

Abstract Two types of composites based on natural rubber (NR) and strontium ferrite were tested in this study. Composites of the first type were prepared by incorporation of strontium ferrite in the concentration range ranging from 0 to 100 phr (parts per hundred rubber) into pure NR based rubber matrix, while with those of the second type, strontium ferrite was dosed in the same concentration level into NR based rubber batch with constant amount of carbon black — 25 phr. For rubber matrices cross-linking, a standard sulfur based curing system was used. This work is focused on the effect of magnetic filler content on physico-mechanical, magnetic and thermo-physical properties of composite materials. Subsequently, the cross-link density and the structure of the formed sulfidic cross-links were examined. The results showed that the cross-link density of both types of composites increased with the increasing content of magnetic filler, while the structure of the sulfidic cross-links was almost not influenced by the amount of strontium ferrite. Tensile strength of rubber composites with pure rubber matrix was slightly improved by the incorporation of ferrite, while in case of composites based on a carbon black batch, the incorporation of magnetic filler resulted in the decrease of this characteristic. The presence of magnetic filler in both types of composites leads to a significant increase of the remanent magnetic induction.

PEROXIDE CROSS-LINKING OF EPDM USING MOVING DIE RHEOMETER MEASUREMENTS. I: EFFECTS OF THE THIRD MONOMER CONCENTRATION AND PEROXIDE CONTENT

2015 ◽  
Vol 88 (1) ◽  
pp. 40-52 ◽  
Author(s):  
He Wang ◽  
Ying Ding ◽  
Shugao Zhao ◽  
Claus Wrana
Keyword(s):  
Network Structure ◽  
Monomer Concentration ◽  
Cross Linking ◽  
Cross Link ◽  
Peroxide Content ◽  
Entanglement Density ◽  
The Third ◽  
Link Density ◽  
Cross Links ◽  
Cross Link Density

ABSTRACT The influence of the third monomer 5-ethylene-2-norbornene (ENB) and peroxide content on cure behavior and network structure of peroxide-cured EPDM were investigated by moving die rheometer, NMR relaxation, and dynamic mechanical thermal spectroscopy. According to the rubber elasticity theory, the torque measurement results showed the network structure of peroxide-cured EPDM contained chemical cross-links via combination reaction (Ccom), chemical cross-links via addition reaction (Cadd), and the contribution of entanglement density and network defects to the total cross-link density (CEN). The total cross-link density (Ctot) increased linearly with the peroxide content. The increase of ENB concentration was beneficial for the improvement of cross-linking efficiency of peroxide, but it made the diene conversion of EPDM decrease. CEN was dependent on the third monomer content, which also provided the dominant contribution to the Ctot at low peroxide contents. Furthermore, Ccom and Cadd were dependent on peroxide content linearly, and the latter also was governed by the ENB level.

scholarly journals From Natural Oils to Epoxy Resins: A New Paradigm in Renewable Performance Materials

2021 ◽  
Author(s):  
Dragana Radojčić ◽  
Jian Hong ◽  
Zoran S. Petrovic
Keyword(s):  
Epoxy Resins ◽  
Linseed Oil ◽  
Polymer Networks ◽  
Regular Structure ◽  
Glass Transitions ◽  
Cross Link ◽  
New Paradigm ◽  
Natural Oils ◽  
Link Density ◽  
Cross Link Density

Abstract The direct conversion of natural products to useful engineering materials is desirable from both economic and environmental considerations. We are describing the synthesis and properties of 100 % oil-based epoxy resins generated from three epoxidized oils. The catalyst, tris(pentafluorophenyl)borane (B(C6F5)3) in toluene, allowed for controlled cationic polymerization at a very low concentration. Epoxidized oils (derived from triolein, soybean, and linseed oil) had varying epoxy content, rendering resins of different cross-link density. The polymerization was carried out at room temperature followed by post-curing at elevated temperature to speed up conversion. Epoxy resins were amorphous transparent glasses with glass transitions below glass transitions and hard rubbers above. Despite their high cross-link density, these materials show relatively low Tg’s reflecting the aliphatic nature of fatty acids and the presence of plasticizing “dangling” chains. The structure of the triglyceride starting oils influenced the properties of the resulting materials: the more regular structure of triolein compared to the very heterogeneous structures of soybean and linseed oils seemed to have enhanced some properties of the polymer networks. These epoxy polymers are potentially useful as encapsulating and potting compounds for electronic applications.

Effect of the cure system on aging resistance of natural rubber compounds

2019 ◽  
Vol 52 (5) ◽  
pp. 397-409 ◽  
Author(s):  
Luciana Ribeiro Honorato ◽  
Regina Celia Reis Nunes ◽  
Jaqueline Guimarães Lima Cosme ◽  
Leila Lea Yuan Visconte ◽  
Augusto Cesar de Carvalho Peres ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Mechanical Performance ◽  
Dynamic Properties ◽  
Lower Number ◽  
Cross Link ◽  
Rubber Compounds ◽  
Before And After ◽  
Link Density ◽  
Cross Links ◽  
Cross Link Density

This work investigates natural rubber (NR) composites vulcanized with different combinations of accelerators in efficient cure systems. The NR compounds were characterized for cross-link density, hardness, tensile strength, and dynamical–mechanical properties, before and after aging. Among the cure systems used, that containing the highest amount of free sulfur presented the best mechanical performance, before and after aging; concerning dynamic properties after the aging, the composition with a lower number of cross-links was the best.

scholarly journals Multivalency in healable supramolecular polymers: the effect of supramolecular cross-link density on the mechanical properties and healing of non-covalent polymer networks

2014 ◽  
Vol 5 (11) ◽  
pp. 3680-3688 ◽  
Author(s):  
Lewis R. Hart ◽  
James H. Hunter ◽  
Ngoc A. Nguyen ◽  
Josephine L. Harries ◽  
Barnaby W. Greenland ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polymer Blends ◽  
Crosslink Density ◽  
Polymer Networks ◽  
Supramolecular Polymers ◽  
Supramolecular Polymer ◽  
Cross Link ◽  
Link Density ◽  
Cross Link Density

Mechanical properties of healable supramolecular polymer blends correlate to non-covalent “crosslink density”.

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