The Influence of Filler Size and Crosslinking Degree of Polymers on Mullins Effect in Filled NR/BR Composites

Abstract

Two factors, the crosslinking degree of the matrix (ν) and the size of the filler (Sz), have significant impact on the Mullins effect of filled elastomers. Herein, the result. of the two factors on Mullins effect is systematically investigated by adjusting the crosslinking degree of the matrix via adding maleic anhydride into a rubber matrix and controlling the particle size of the filler via ball milling. The dissipation ratios (the ratio of energy dissipation to input strain energy) of different filled natural rubber/butadiene rubber (NR/BR) elastomer composites are evaluated as a function of the maximum strain in cyclic loading (εm). The dissipation ratios show a linear relationship with the increase of εm within the test range, and they depend on the composite composition (ν and Sz). With the increase of ν, the dissipation ratios decrease with similar slope, and this is compared with the dissipation ratios increase which more steeply with the increase in Sz. This is further confirmed through a simulation that composites with larger particle size show a higher strain energy density when the strain level increases from 25% to 35%. The characteristic dependence of the dissipation ratios on ν and Sz is expected to reflect the Mullins effect with mathematical expression to improve engineering performance or prevent failure of rubber products.

Magnetic Soft Materials and Robots

“…It is likely, however, that the increase in the average size of particulate fillers due to the inclusion of the meltable solid phase (i.e., the phase-changing beads encasing the magnetic particles) in an elastomer matrix may affect the mechanical properties and behavior of the composite, 219,220 such as more pronounced softening after stretching due to the Mullins effect. 221 4.4. Characterization Methods 4.4.1.…”

“…Allowing the use of magnetized particles with high remanence and coercivity, this reprogramming method based on solid–liquid phase transition would not inherently sacrifice the actuation performance of hard-magnetic soft composites in terms of the torque density. It is likely, however, that the increase in the average size of particulate fillers due to the inclusion of the meltable solid phase (i.e., the phase-changing beads encasing the magnetic particles) in an elastomer matrix may affect the mechanical properties and behavior of the composite, , such as more pronounced softening after stretching due to the Mullins effect …”

Mechanical reinforcement of waterborne latex pressure‐sensitive adhesives with polymer‐grafted nanoparticles

“…Conversely, at high filler loadings (>4 wt%, above the maximum improvement), the PGNPs were observed forming very large (>400 nm), typically with very extended morphologies (Figure S2i,j). We hypothesize that these morphologies correlate to an effective increase in filler particle size, which would be expected to lead to an increase in local strain energy density (resulting in mechanical failure at lower applied load, as has been observed in prior systems) 32,33 . Moreover, the formation of low‐aspect‐ratio filler aggregates reduces the surface area contact between the PGNP additives and the surrounding elastomeric matrix, thereby resulting in a smaller effective interface through which to reinforce the surrounding adhesive 34 …”

“…We hypothesize that these morphologies correlate to an effective increase in filler particle size, which would be expected to lead to an increase in local strain energy density (resulting in mechanical failure at lower applied load, as has been observed in prior systems). 32,33 Moreover, the formation of low-aspect-ratio filler aggregates reduces the surface area contact between the PGNP additives and the surrounding elastomeric matrix, thereby resulting in a smaller effective interface through which to reinforce the surrounding adhesive. 34 At PGNP loadings corresponding to the maximum improvement in shear strength (between 2 and 4 wt% loading), the PSAs exhibited both the well-dispersed PGNPs and clusters in the lower loading samples, and also high aspect-ratio chains and branched arrangements of PGNPs (Figure S2e-h).…”

Fabrication of novel strain sensors from green TPV nanocomposites based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/silicone rubber/silicon-modified graphene oxide

“…It was due to the softening of the matrix stress from the Mullins effect and the higher contact area between the fillers. 32 The repeated stretching and contracting during cyclic strain tests resulted in additional conductive pathways between the conductive particles, which decreased electrical resistance. TPV5, with an optimal SMGO content, exhibited higher resistivity than TPV7 due to constructing more agglomerated networks in the composites.…”