Shear and Biaxial Extension Measurements of Reinforcement from in-situ Precipitated Silica

1991 ◽  
Vol 64 (5) ◽  
pp. 746-759 ◽  
Author(s):  
Shuhong Wang ◽  
Ping Xu ◽  
James E. Mark
Keyword(s):  
Mechanical Properties ◽  
Pure Shear ◽  
Energy Increase ◽  
Uniaxial Elongation ◽  
Biaxial Extension ◽  
Precipitated Silica ◽  
Rupture Energy ◽  
End Linking ◽  
Reinforcing Effects

Abstract Elastomeric networks were prepared by tetrafunctionally end-linking hydroxyl-terminated polydimethylsiloxane (PDMS) chains and were then filled by the in-situ precipitation of silica. The resulting networks were investigated in shear and biaxial extension. The method employed to produce large shears was to stretch a short, wide strip between two clamps. The deformation produced in this way is pure shear; simple shear was calculated directly from the pure-shear data. Biaxial extension measurements were carried out by inflation of circular sheets of the networks. Compared to the unfilled networks, the silica-filled samples showed large reinforcing effects. Specifically, their values of the modulus, ultimate strength, and rupture energy increase significantly. The results thus indicate that the PDMS networks filled by the in-situ precipitation of silica have good mechanical properties, not only in uniaxial elongation, but in shear and biaxial extension as well.

Reinforcement from In-Situ Precipitated Silica in Polysiloxane Elastomers under Various Types of Deformation

1992 ◽  
Vol 274 ◽  
Author(s):  
James E. Mark ◽  
Shuhong Wang ◽  
Ping Xu ◽  
Jianye Wen
Keyword(s):  
Mechanical Properties ◽  
Uniaxial Elongation ◽  
Compression Set ◽  
Precipitated Silica ◽  
Equilibrium Swelling ◽  
Rupture Energy ◽  
End Linking ◽  
Reinforcing Effects

ABSTRACTElastomeric networks prepared by tetrafunctionally end linking hydroxyl-terminated poly(dimethylsiloxane) chains (PDMS) were filled by the in-situ precipitation of silica. The resulting networks were investigated under uniaxial elongation, biaxial extension, shear, and torsion in order to characterize the resulting changes in mechanical properties. Compared with the unfilled networks, the silica-filled materials showed large reinforcing effects. Specifically, their values of the modulus, ultimate strength, and rupture energy increased significantly. The results thus indicate that the PDMS networks filled by the in-situ precipitation of silica have very good mechanical properties in several, rather different deformations. Examples of other deformations of interest are equilibrium swelling, and dynamic cycling for characterization of compression set.

scholarly journals Properties of Vulcanized Polyisoprene Rubber Composites Filled with Opalized White Tuff and Precipitated Silica

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Suzana Samaržija-Jovanović ◽  
Vojislav Jovanović ◽  
Gordana Marković ◽  
Ivana Zeković ◽  
Milena Marinović-Cincović
Keyword(s):  
Mechanical Properties ◽  
Production Efficiency ◽  
Average Particle Size ◽  
Rubber Matrix ◽  
Average Particle ◽  
Cross Link ◽  
Rubber Composites ◽  
Precipitated Silica ◽  
Reinforcing Effects ◽  
Cure Characteristic

Opalized white tuff (OWT) with 40 μm average particle size and 39.3 m2/g specific surface area has been introduced into polyisoprene rubber (NR). Their reinforcing effects were evaluated by comparisons with those from precipitated silica (PSi). The cure characteristic, apparent activation energy of cross-link (Eac) and reversion (Ear), and mechanical properties of a variety of composites based on these rubbers were studied. This was done using vulcanization techniques, mechanical testing, and scanning electron microscopy (SEM). The results showed that OWT can greatly improve the vulcanizing process by shortening the time of optimum cure (tc90) and the scorch time (ts2) of cross-linked rubber composites, which improves production efficiency and operational security. The rubber composites filled with 50 phr of OWT were found to have good mechanical and elastomeric properties. The tensile strengths of the NR/OWT composites are close to those of NR/PSi composites, but the tear strength and modulus are not as good as the corresponding properties of those containing precipitated silica. Morphology results revealed that the OWT is poorly dispersed in the rubber matrix. According to that, the lower interactions between OWT and polyisoprene rubber macromolecules are obtained, but similar mechanical properties of NR/OWT (100/50) rubber composites compared with NR/PSi (100/50) rubber composites are resulted.

Tear Strengths of Poly(Dimethylsiloxane) Networks Reinforced with in-Situ Precipitated Silica

1999 ◽  
Vol 576 ◽  
Author(s):  
Chandima Kumudinie ◽  
James E. Mark
Keyword(s):  
Thermal Stability ◽  
Thermogravimetric Analysis ◽  
Silica Particles ◽  
Stick Slip ◽  
Precipitated Silica ◽  
Increase With Increase ◽  
Transmission Electron ◽  
Hydrolysis And Condensation ◽  
End Linking

ABSTRACTThe tear strengths of in-situ filled poly(dimethylsiloxane) (PDMS) networks were investigated using “trouser-tear” tests. The filled PDMS networks were prepared by the simultaneous curing and in-situ precipitation technique, the silica reinforcing phase being obtained by the hydrolysis and condensation of tetraethoxysilane present in excess of that required for the chain end-linking process. Transmission electron micrographs showed well-dispersed and unagglomerated silica particles, and thermogravimetric analysis indicated that the silica particles gave some improvements in thermal stability. In the tearing tests, “stick-slip” tearing was observed at higher rates, especially for the filled networks. The tear strengths were found to increase with increase in the amount of silica incorporated, with the largest increases occurring at the low silica contents.

Dynamics of Nanoparticle Chain Aggregates of Carbon Under Tension

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.

Effect of TiB2 particle addition on the mechanical properties of Al/TiB2 in situ formed metal matrix composites

2018 ◽  
Vol 60 (12) ◽  
pp. 1221-1224 ◽  
Author(s):  
Balachandran Gobalakrishnan ◽  
P. Ramadoss Lakshminarayanan ◽  
Raju Varahamoorthi
Keyword(s):  
Mechanical Properties ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Tib2 Particle ◽  
Matrix Composites ◽  
Particle Addition
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