Mimicking the Mechanical Robustness of Natural Rubber Based on a Sacrificial Network Constructed by Phospholipids

Abstract

Mechanical strength and toughness are usually mutually exclusive, but they can both appear in natural rubber (NR). Previous studies ascribe such excellent properties to highly cis stereoregularity of NR. To our surprise, after the removal of non-rubber components (NRC) by centrifugation, the strength and toughness of NR decrease dramatically. It is still a challenge for us to make out for the problem of how NRC affect the properties of NR. Our group ascribes the superior mechanical robustness of NR to NRC. To further verify such a viewpoint, we add phospholipids (phosphatidylcholines) into NR without NRC. Phosphatidylcholines construct a sacrificial network, which ruptures preferentially upon deformation to dissipate energy. Moreover, some of phosphatidylcholines participate in the vulcanization reaction, which further improves the mechanical strength and energy dissipation. As a result, the mechanical strength and toughness of samples are as high as 21.1 MPa and 49.6 kJ/m2, respectively, which have reached the same level as that of NR. Therefore, this work not only imitates the excellent mechanical robustness of NR but also further provides a rational design for elastomers with excellent mechanical robustness.

Effect of protein on the thermogenesis performance of natural rubber matrix

“…The mass proportion of protein in NR is about 1.5–4 m%, which is the most representative of non-rubber components 22 . Our research found that proteins and phospholipids act as sacrificial network in the NR matrix, thus enhance the network structure toughness and strength 23 , 24 . Moreover, it has always been difficult to study the effect of a single non-rubber component on the rubber properties.…”

“…The enhancement of the interaction force between molecular chains makes movement of molecular chains more difficult, and the heat generated by its friction behavior is reduced accordingly. We recently observed the spatial organization of non-rubber components through high-resolution TEM and found that the protein formed a sacrificial network tangled in a cross-linked network 23 , 24 . According to the calculation of the tube model, it can be known that the free protein can be effect as the entanglement-like point, which can “pinning” the molecular chain and restrict the movement of the molecular chain.…”

“…Our recent research found that protein constitutes a sacrificial network embedded in the cross-linked network, which breaks preferentially upon deformation to dissipate energy 23,24 . So we can infer that when stress is loading, the preferential break of the protein network will absorb part of the energy to reduce heat generation.…”

MXene Enabling the Long-Term Superior Thermo-Oxidative Resistance for Elastomers

“…Elastomers, such as natural rubber (NR) and butadiene styrene rubber, are widely used because of their large strain reversible deformability [1][2][3][4]. In application, one of the problems with elastomers is thermo-oxidative aging, leading to the deterioration of properties and early failure.…”

The dynamic mechanical properties of magnetorheological elastomer: Catalytic effect of carbonyl iron powder

“…Consequently, the rubber’s transition from viscoelastic fluid to viscoelastic solid takes place during the process (Kannan and Rajagopal, 2004). Natural or synthetic rubber is converted into valuable vulcanized rubber, to improve its tensile, hardness, and elastic properties (Steudel et al, 2008; Wei et al, 2020).…”