Generating particulate silica fillers in situ to improve the mechanical properties of natural rubber (NR)

Abstract This investigation focused on the study of dynamic mechanical losses in silica-filled networks of poly(dimethylsiloxane) (PDMS). Some of the samples were filled using a novel method, specifically the in situ precipitation of particulate silica either after or during network formation. Others were filled using the customary method of mechanically blending already-prepared silica into the elastomer prior to its crosslinking, and some were prepared without any filler at all. The resulting materials exhibited a variety of relaxation behaviors over the temperature range 120–260 K. The glass transition temperatures Tg showed only a slight dependence on the presence of the filler particles and crosslinks, but the filler was found to reduce both the degree and rate of crystallization for the in situ filled networks. The results obtained document how the techniques employed for incorporating particulate fillers change the viscoelastic properties of an elastomeric network, and how dynamic testing can yield a great deal of insight and useful information on the mechanical properties of polymers in general.

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Mechanical properties, thermal behaviors and oil resistance of epoxidized natural rubber/multiwalled carbon nanotube nanocomposites prepared via in situ epoxidation

Journal of Elastomers & Plastics ◽

10.1177/0095244316639634 ◽

2016 ◽

Vol 49 (2) ◽

pp. 99-119 ◽

Cited By ~ 5

Author(s):

Saowaroj Chuayjuljit ◽

Piyaphorn Mungmeechai ◽

Anyaporn Boonmahitthisud

Keyword(s):

Mechanical Properties ◽

Thermal Stability ◽

Carbon Nanotube ◽

Natural Rubber ◽

Multiwalled Carbon Nanotube ◽

Epoxidized Natural Rubber ◽

Multiwalled Carbon ◽

Oil Resistance ◽

In Situ Epoxidation

Epoxidized natural rubber (ENR)/multiwalled carbon nanotube (MWCNT) nanocomposites were prepared via in situ epoxidation of natural rubber (NR) using a molar ratio of formic acid/hydrogen peroxide to isoprene unit at 0.75/0.75 with five loadings of MWCNTs, ranging from 0.5–2.5 parts per hundred parts of rubber (phr), at 50°C for 4 h. Based on Fourier transform infrared spectra, the epoxide content of ENR in the nanocomposites was about 32.5–33.2 mole%. Accordingly, the products were referred to ENR30/MWCNT nanocomposites. The curing characteristics, mechanical properties (tensile properties, tear strength, and hardness), glass transition temperature ( Tg), thermal stability, and oil resistance of these in situ ENR30/MWCNT nanocomposites were investigated and compared with NR and neat ENR30. The results showed that the scorch and cure times of ENR30/MWCNT nanocomposites were the longest followed by NR and ENR30. The incorporation of an appropriate amount of MWCNTs into the in situ epoxidation apparently improved the properties of NR. Among them, the nanocomposites filled with 2 phr MWCNTs exhibited the highest mechanical properties, Tg, thermal stability, and oil resistance. The mechanical properties of the in situ nanocomposites were also compared with those of the control nanocomposites prepared by adding MWCNTs directly in the prepared ENR30 latex. It was found that at similar MWCNT loadings, the in situ nanocomposites exhibited higher mechanical properties than the control nanocomposites.

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Effect of Fillers on the Recovery of Rubber Foam: From Theory to Applications

Polymers ◽

10.3390/polym12112745 ◽

2020 ◽

Vol 12 (11) ◽

pp. 2745

Author(s):

Thridsawan Prasopdee ◽

Wirasak Smitthipong

Keyword(s):

Mechanical Properties ◽

Natural Rubber ◽

Compression Strength ◽

Activation Enthalpy ◽

Physical And Mechanical Properties ◽

Filler Loading ◽

Compression Force ◽

Compression Set ◽

Silica Fillers ◽

Rubber Filler

Natural rubber foam (NRF) can be prepared from concentrated natural latex, providing specific characteristics such as density, compression strength, compression set, and so on, suitable for making shape-memory products. However, many customers require NRF products with a low compression set. This study aims to develop and prepare NRF to investigate its recoverability and other related characteristics by the addition of charcoal and silica fillers. The results showed that increasing filler loading increases physical and mechanical properties. The recoverability of NRF improves as silica increases, contrary to charcoal loading, due to the higher specific surface area of silica. Thermodynamic aspects showed that increasing filler loading increases the compression force (F) as well as the proportion of internal energy to the compression force (Fu/F). The entropy (S) also increases with increasing filler loading, which is favorable for thermodynamic systems. The activation enthalpy (∆Ha) of the NRF with silica is higher than the control NRF, which is due to rubber–filler interactions created within the NRF. A thermodynamic concept of crosslinked rubber foam with filler is proposed. From theory to application, in this study, the NRF has better recoverability with silica loading.

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Improved mechanical properties and special reinforcement mechanism of natural rubber reinforced by in situ polymerization of zinc dimethacrylate

Journal of Applied Polymer Science ◽

10.1002/app.31612 ◽

2009 ◽

pp. n/a-n/a ◽

Cited By ~ 2

Author(s):

Yijing Nie ◽

Guangsu Huang ◽

Zhiyuan Liu ◽

Liangliang Qu ◽

Peng Zhang ◽

...

Keyword(s):

Mechanical Properties ◽

Natural Rubber ◽

In Situ Polymerization ◽

Reinforcement Mechanism

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Dynamics of Nanoparticle Chain Aggregates of Carbon Under Tension

MRS Proceedings ◽

10.1557/proc-778-u4.4 ◽

2003 ◽

Vol 778 ◽

Author(s):

Rajdip Bandyopadhyaya ◽

Weizhi Rong ◽

Yong J. Suh ◽

Sheldon K. Friedlander

Keyword(s):

Mechanical Properties ◽

Carbon Black ◽

Polymer Film ◽

Elastic Behavior ◽

Small Strains ◽

Transmission Electron ◽

Chain Aggregates ◽

Nanoparticle Chains ◽

Reinforcing Filler

AbstractCarbon black in the form of nanoparticle chains is used as a reinforcing filler in elastomers. However, the dynamics of the filler particles under tension and their role in the improvement of the mechanical properties of rubber are not well understood. We have studied experimentally the dynamics of isolated nanoparticle chain aggregates (NCAs) of carbon made by laser ablation, and also that of carbon black embedded in a polymer film. In situ studies of stretching and contraction of such chains in the transmission electron microscope (TEM) were conducted under different maximum values of strain. Stretching causes initially folded NCA to reorganize into a straight, taut configuration. Further stretching leads to either plastic deformation and breakage (at 37.4% strain) or to a partial elastic behavior of the chain at small strains (e.g. 2.3% strain). For all cases the chains were very flexible under tension. Similar reorientation and stretching was observed for carbon black chains embedded in a polymer film. Such flexible and elastic nature of NCAs point towards a possible mechanism of reinforcement of rubber by carbon black fillers.

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