scholarly journals Effect of SiO2 Particles on the Relaxation Dynamics of Epoxidized Natural Rubber (ENR) in the Melt State by Time-Resolved Mechanical Spectroscopy

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 276
Author(s):  
Rossella Arrigo ◽  
Leno Mascia ◽  
Jane Clarke ◽  
Giulio Malucelli
Keyword(s):  
Natural Rubber ◽  
Rheological Behavior ◽  
Loss Modulus ◽  
Chain Scission ◽  
Epoxidized Natural Rubber ◽  
Simultaneous Occurrence ◽  
Relaxation Dynamics ◽  
Mechanical Spectroscopy ◽  
Time Resolved ◽  
Two Parameters

The rheological behavior of an epoxidized natural rubber (ENR) nanocomposite containing 10 wt.% of silica particles was examined by time-resolved mechanical spectroscopy (TRMS), exploiting the unique capability of this technique for monitoring the time-dependent characteristics of unstable polymer melts. The resulting storage modulus curve has revealed a progressive evolution of the elastic component of the composite, associated with slower relaxations of the ENR macromolecular chains. Two major events were identified and quantified: one is associated with the absorption of the epoxidized rubber macromolecules onto the silica surface, which imposes further restrictions on the motions of the chains within the polymer phase; the second is related to gelation and the subsequent changes in rheological behavior resulting from the simultaneous occurrence cross-linking and chain scission reactions within the ENR matrix. These were quantified using two parameters related to changes in the storage and loss modulus components.

scholarly journals Structure Evolution of Epoxidized Natural Rubber (ENR) in the Melt State by Time-Resolved Mechanical Spectroscopy

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 946
Author(s):  
Rossella Arrigo ◽  
Leno Mascia ◽  
Jane Clarke ◽  
Giulio Malucelli
Keyword(s):  
Natural Rubber ◽  
Rheological Behavior ◽  
Structural Changes ◽  
Viscoelastic Behavior ◽  
Relaxation Modulus ◽  
Epoxidized Natural Rubber ◽  
Structure Evolution ◽  
Gradual Transition ◽  
Mechanical Spectroscopy ◽  
Time Resolved

In this work, time-resolved mechanical spectroscopy (TRMS) was used to accurately characterize the rheological behavior of an epoxidized natural rubber (ENR) containing 25 mol% of epoxy groups. Conventional rheological tests are not suitable to characterize with accuracy the frequency-dependent linear viscoelastic behavior of materials, such as ENR, in a transient configurational state. For this reason, TRMS was used to determine the true rheological behavior of ENR, as well as to gain some insights into the changes of its macromolecular architecture under the dynamic conditions experienced during the measurements. The constructed master curves for the moduli revealed a gradual transition of the ENR rheological state from liquid-like to solid-like through the formation of an “elastic gel” throughout the bulk of the polymer. Furthermore, the evolution of the stress relaxation modulus revealed a slow relaxation mechanism, resulting from thermally activated reactions in the molten state attributed to the formation of crosslinks. Finally, the crosslink density evolution was estimated from the TRMS data and compared with results derived from equilibrium solvent-swelling measurements. These demonstrated the accuracy of the TRMS data in the prediction of the structural changes that can take place in polymers during processing.

Rheological Behavior Characterization of Natural Rubber Containing Different Gel

2014 ◽  
Vol 970 ◽  
pp. 320-323 ◽  
Author(s):  
Saengchao Thongseenuch ◽  
Wirach Taweepreda ◽  
Krisda Suchiva
Keyword(s):  
Molecular Structure ◽  
Natural Rubber ◽  
Rheological Behavior ◽  
Loss Modulus ◽  
Natural Rubber Latex ◽  
Gel Structure ◽  
Gel Content ◽  
Molecular Weights ◽  
Branching Points

This research, natural rubber containing different gel contents were prepared by deproteinization and saponification treatment from high ammonium natural rubber latex. Deproteinization natural rubber was further treated as acetone extraction and then transesterification. It was founded that gel content and molecular weights of treated natural rubber were decreased and almost absented for transesterification treatment. Rheological respond on small amplitude oscillating shear (SAOS) and large amplitude oscillating shear (LAOS) deformation of treated natural rubber were captured by using rubber process analyzer (RPA 2000). Firs harmonic rheological properties, storage modulus, G and loss modulus, G decreased as gel content and molecular weight decreased. It was believed that gels, explicitly branching points, were destroyed after the natural rubber was deproteinized, transesterification, or saponification according to the molecular structure of natural rubber presumed by Tanaka et al, which functional groups contain protein and fatty acid are participated in branching to forming gel structure. It was concluded that gel content as the same as molecular structure of natural rubber could be characterized as rheological behavior.

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.

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”.

Preparation coated of urea beads from banana peel bioplastic and epoxidized natural rubber 50

2020 ◽  
Author(s):  
H. K. Abdulkadir ◽  
S. A. Abdul Shukor ◽  
R. Hamzah ◽  
N. Z. Noriman ◽  
Omar S. Dahham ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Epoxidized Natural Rubber ◽  
Banana Peel

scholarly journals Biocomposites of Epoxidized Natural Rubber/Poly(lactic acid) Modified with Natural Fillers (Part I)

2021 ◽  
Vol 22 (6) ◽  
pp. 3150
Author(s):  
Anna Masek ◽  
Stefan Cichosz ◽  
Małgorzata Piotrowska
Keyword(s):  
Tensile Strength ◽  
Lactic Acid ◽  
Natural Rubber ◽  
Epoxidized Natural Rubber ◽  
Poly Lactic Acid ◽  
Uv Aging ◽  
High Elasticity ◽  
Natural Fillers ◽  
Natural Additives

The study aimed to prepare sustainable and degradable elastic blends of epoxidized natural rubber (ENR) with poly(lactic acid) (PLA) that were reinforced with flax fiber (FF) and montmorillonite (MMT), simultaneously filling the gap in the literature regarding the PLA-containing polymer blends filled with natural additives. The performed study reveals that FF incorporation into ENR/PLA blend may cause a significant improvement in tensile strength from (10 ± 1) MPa for the reference material to (19 ± 2) MPa for the fibers-filled blend. Additionally, it was found that MMT employment in the role of the filler might contribute to ENR/PLA plasticization and considerably promote the blend elongation up to 600%. This proves the successful creation of the unique and eco-friendly PLA-containing polymer blend exhibiting high elasticity. Moreover, thanks to the performed accelerated thermo-oxidative and ultraviolet (UV) aging, it was established that MMT incorporation may delay the degradation of ENR/PLA blends under the abovementioned conditions. Additionally, mold tests revealed that plant-derived fiber addition might highly enhance the ENR/PLA blend’s biodeterioration potential enabling faster and more efficient growth of microorganisms. Therefore, materials presented in this research may become competitive and eco-friendly alternatives to commonly utilized petro-based polymeric products.

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