scholarly journals Free-Radical Photopolymerization of Acrylonitrile Grafted onto Epoxidized Natural Rubber

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 660
Author(s):  
Rawdah Whba ◽  
Mohd Sukor Su’ait ◽  
Lee Tian Khoon ◽  
Salmiah Ibrahim ◽  
Nor Sabirin Mohamed ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Chemical Structure ◽  
Functional Group ◽  
Loss Modulus ◽  
Epoxidized Natural Rubber ◽  
Thermal And Mechanical Properties ◽  
Sample Analysis ◽  
Free Radical Photopolymerization ◽  
Ft Ir

The exploitation of epoxidized natural rubber (ENR) in electrochemical applications is approaching its limits because of its poor thermo-mechanical properties. These properties could be improved by chemical and/or physical modification, including grafting and/or crosslinking techniques. In this work, acrylonitrile (ACN) has been successfully grafted onto ENR- 25 by a radical photopolymerization technique. The effect of (ACN to ENR) mole ratios on chemical structure and interaction, thermo-mechanical behaviour and that related to the viscoelastic properties of the polymer was investigated. The existence of the –C≡N functional group at the end-product of ACN-g-ENR is confirmed by infrared (FT-IR) and nuclear magnetic resonance (NMR) analyses. An enhanced grafting efficiency (~57%) was obtained after ACN was grafted onto the isoprene unit of ENR- 25 and showing a significant improvement in thermal stability and dielectric properties. The viscoelastic behaviour of the sample analysis showed an increase of storage modulus up to 150 × 103 MPa and the temperature of glass transition (Tg) was between −40 and 10 °C. The loss modulus, relaxation process, and tan delta were also described. Overall, the ACN-g-ENR shows a distinctive improvement in characteristics compared to ENR and can be widely used in many applications where natural rubber is used but improved thermal and mechanical properties are required. Likewise, it may also be used in electronic applications, for example, as a polymer electrolyte in batteries or supercapacitor.

Effect of Curing System on Morphological, Rheological, Thermal and Mechanical Properties of Thermoplastic Vulcanizates Based on Epoxidized Natural Rubber and Polypropylene

2012 ◽  
Vol 602-604 ◽  
pp. 690-695
Author(s):  
Hua Dong Wang ◽  
Rui Wang ◽  
Mao Fang Huang ◽  
Qi Yang
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Epoxidized Natural Rubber ◽  
Thermal And Mechanical Properties ◽  
Rheological Analysis ◽  
Elongation At Break ◽  
Thermoplastic Vulcanizates ◽  
Internal Mixer

Thermoplastic vulcanizates (TPVs) based on epoxidized natural rubber (ENR) and polypropylene (PP) were prepared in an internal mixer at 180°C. The effects of curing systems (i.e., sulfur and peroxide) on morphological, rheological, thermal and mechanical properties were studied. It is found that the sulfur cured TPVs show higher tensile strength, tear strength and elongation at break than those cured with the DCP systems. The rheological analysis indicates that TPVs cured with DCP system show lower apparent shear viscosity than those with sulfur system. SEM studies show that TPVs vulcanized with DCP system exhibit smaller and finely dispersed rubber domains, which provides it higher thermal stability than sulfur cured TPVs.

Influence of Surface Modification and Content of Nanosilica on Dynamic Mechanical Properties of Epoxidized Natural Rubber Nanocomposites

2013 ◽  
Vol 844 ◽  
pp. 289-292 ◽  
Author(s):  
Methakarn Jarnthong ◽  
Charoen Nakason ◽  
Zheng Peng ◽  
Natinee Lopattananon
Keyword(s):  
Mechanical Properties ◽  
Surface Modification ◽  
Natural Rubber ◽  
Loss Modulus ◽  
Complex Viscosity ◽  
Dynamic Mechanical Properties ◽  
Epoxidized Natural Rubber ◽  
Dynamic Mechanical ◽  
Modified Surface ◽  
Rubber Nanocomposites

Epoxidized natural rubber (ENR) nanocomposites were prepared in latex state by using unmodified and modified surface of nanosilica. Influence of surface modification and content of nanosilica on dynamic mechanical properties as a function of frequency (i.e., complex viscosity (η*), storage modulus (G ́) and loss modulus (G”) of ENR nanocomposites were investigated. It was found that surface modification of nanosilica improved rheological properties of nanosilica filled ENR nanocomposites. Moreover, greater nanosilica contents caused increasing of η*, G ́ and G”.

scholarly journals 5-((8-Hydroxyquinolin-5-yl)diazenyl)-3-methyl-1H-pyrazole-4-carboxylic Acid

Molbank ◽  
10.3390/m1238 ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. M1238
Author(s):  
Ion Burcă ◽  
Valentin Badea ◽  
Calin Deleanu ◽  
Vasile-Nicolae Bercean
Keyword(s):  
Chemical Structure ◽  
Functional Group ◽  
Coupling Reaction ◽  
2D Nmr ◽  
Azo Coupling ◽  
2D Nmr Spectroscopy ◽  
Azo Compound ◽  
Ft Ir ◽  
New Compounds ◽  
Carboxylic Functional Group

A new azo compound was prepared via the azo coupling reaction between 4-(ethoxycarbonyl)-3-methyl-1H-pyrazole-5-diazonium chloride and 8-hydroxyquinoline (oxine). The ester functional group of the obtained compound was hydrolyzed and thus a new chemical structure with a carboxylic functional group resulted. The structures of the new compounds were fully characterized by: UV–Vis, FT-IR, 1D and 2D NMR spectroscopy, and HRMS spectrometry.

Phase Morphology, Thermal and Mechanical Properties of Compatibilized Nylon12/Natural Rubber Blends Using PS/MNR

2013 ◽  
Vol 844 ◽  
pp. 53-56
Author(s):  
Saravalee Saengthaveep ◽  
Sadhan C. Jana ◽  
Rathanawan Magaraphan
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Moisture Absorption ◽  
Rubber Particle ◽  
Impact Resistance ◽  
Phase Morphology ◽  
Thermal And Mechanical Properties ◽  
Binary Blend ◽  
Polyamide 12 ◽  
The Impact

To produce a tough material for application demanding high impact resistance and low moisture absorption, melt blending of Nylon12 (Polyamide 12, PA12) and natural rubber (NR) was carried out in a brabender plasticorder at 210 °C with rotor speed of 70 rpm in the presence of polystyrene/maleated natural rubber (PS/MNR) blend as a compatibilizer. The effect of compatibilizer content (1, 3, 5, 7 and 10 phr) on phase morphology, thermal, and mechanical properties of [Nylon12/NR]/[PS/MNR] blends was investigated by using SEM, DSC, and Izod impact tester, respectively. The result revealed that PS/MNR blend improved the compatibility of Nylon12/NR blends efficiently due to the presence of amide linkage at the interfaces from the reaction between the reactive groups of MNR and the NH2 end groups of Nylon12 during mixing. A fine phase morphology (good dispersion and small dispersed phase size of NR domains in Nylon12 matrix) of [Nylon12/NR]/[PS/MNR] blends was observed at the optimum compatibilizer content of 7 phr, relating to the improvement of mechanical property. The impact energy of [Nylon12/NR]/[PS/MNR] blends was 503 J/m higher than that of neat Nylon12 (115 J/m) and Nylon12/NR binary blend (241 J/m) due to the toughening effect of rubber and proper morphology. The melting temperature of all blends did not change obviously from thermal analysis. However, the presence of rubber particle obstructed the crystallization of Nylon12 phase, leading to the decreasing of %crystallinity from 93% to around 70%.

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