ABSTRACT
Natural rubber (NR) is extensively utilized in numerous industries, such as aerospace, military, and transportation, because of its exceptional elasticity and all-around mechanical qualities. However, commercial NR made using various techniques typically has distinct mechanical characteristics. For instance, whole field latex rubber (SCR-WF) cured with accelerator 2-Mercaptobenzothiazole exhibits poor mechanical properties. This work attempts to enhance the mechanical property of SCR-WF via the addition of lanthanum stearate (LaSt). The influence of LaSt on strain-induced crystallization (SIC) and the mechanical properties of SCR-WF were investigated. The results of crosslinking density measured by the equilibrium swelling method demonstrate that the presence of LaSt significantly increases the crosslinking density of SCR-WF with lower loading of LaSt. The results of the mechanical properties show that the introduction of LaSt can enhance the tensile strength and fracture toughness of SCR-WF. To reveal the mechanism of LaSt improving the mechanical properties of SCR-WF, synchrotron radiation wide-angle X-ray diffraction (WAXD) experiments were used to investigate the SIC behaviors of SCR-WF. We found that the LaSt leads to higher crystallinity of SIC for the strain higher than 3.5. The tube model indicates the contribution of LaSt in both crosslinking and topological constraints. This work may provide an instruction for developing SCR-WF with superior mechanical properties.
ABSTRACT
This research developed a signal amplification strategy to construct a highly sensitive electrochemiluminescent (ECL) aptasensor by incorporating dysprosium metal-organic framework (Dy-MOF) as a co-reaction accelerator (CRA) in gadolinium (Gd) luminescent complex based ECL system. A new Gd(III) complex GdPc(acac) (Pc = phthalocyanine, acac = acetylacetonate) with semi-sandwich structure was rationally selected as ECL emitter, exhibiting excellent luminescence performance owing to the "antenna effect" from the conjugated macrocyclic ligand. For further improving the sensitivity of the ECL biosensor, Dy-MOF was introduced into the ECL system as CRA. The purposive design and configuration of the Dy-MOF structure accelerated the separation and transport of photogenerated charges, and the nanosheets formed by the composite material provided more active sites, which could not only greatly increased the luminophore loading, but also effectively shorten the transport distance of ions and co-reactants. The constructed biosensor showed superior performance to monitor kanamycin within 0.001 pg/mL-1000 ng/mL and a detection limit down to 0.3 fg/mL (S/N = 3). The current work opened up a skillful strategy to amplify ECL singnal, extending the application field of lanthanide complexes and providing valuable information for the future biosensor design.
