Natural Rubber Cooperative Innovation Center of Hainan Province & Ministry of Education of PRC, School of Materials Science and Engineering, Hainan University, Haikou 570228, China.
ACS Appl Mater Interfaces. 2020 Mar 25;12(12):14468-14475. doi: 10.1021/acsami.0c01994. Epub 2020 Mar 13.
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/m, 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.
力学强度和韧性通常是相互排斥的，但它们都可以出现在天然橡胶（NR）中。先前的研究将 NR 的这些优异性能归因于其高度顺式立构规整性。令我们惊讶的是，通过离心去除非橡胶成分（NRC）后，NR 的强度和韧性会显著下降。我们仍然难以理解 NRC 如何影响 NR 的性质。我们的研究小组将 NR 的优越机械鲁棒性归因于 NRC。为了进一步验证这一观点，我们在没有 NRC 的情况下将磷脂（磷脂酰胆碱）加入 NR 中。磷脂酰胆碱构建了一个牺牲网络，在变形时优先破裂以耗散能量。此外，一些磷脂酰胆碱参与硫化反应，这进一步提高了机械强度和能量耗散。结果，样品的力学强度和韧性分别高达 21.1 MPa 和 49.6 kJ/m，达到了与 NR 相同的水平。因此，这项工作不仅模仿了 NR 的优异机械鲁棒性，而且为具有优异机械鲁棒性的弹性体提供了合理的设计。
