The cure kinetics of epoxy resin cured by D-EP, D-EP/CNT composites and D-EP/CNTs-H20 were investigated by non-isothermal differential scanning calorimetry (DSC).

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In this study, effects of heat setting treatment (preset heat setting ratio λ and heat setting temperature T setting ) on the crystalline structures, orientation status, microporous structures, gas permeability, and electrochemical performance of the separators were studied in detail by means of differential scanning calorimetry (DSC), infrared dichroism, scanning electron microscope (SEM), ultrasmall angle X-ray scattering (U-SAXS), Gurley value test, and electrochemical measurement. It was found that with the decrease of λ or the increase of T setting , the melting temperature and degree of crystallinity change regularly and the orientation degree decreases gradually, resulting in small-sized micropores and lower porosity and S/V ratio of the separator. Finally, the gas permeability and ionic conductivity of the separator decreased while the dimensional stability increased. By tuning λ and T setting , the microstructure, morphology, and performance of the separators can be efficiently controlled.

Compression stress on thickness direction of separators exists in assembling and operation of all lithium ion batteries (LIBs). In this study, influences of compression on microporous morphologies, electrolyte uptake behavior, and electrochemical properties of three types of commercial separators (PP-U, PP-B, and PE-B) for LIBs manufactured via different processes, were investigated. Results of scanning electronic microscope (SEM) and X-ray measurements revealed special stacked-multilayer structures of PP-B and PE-B, while PP-U was featured of micropores arranged in lines separated by lamellae in both surface view and section view. Compression was found to be key factor influencing the microporous structures, electrolyte uptake, and electrochemical properties of separators. Different microporous structures of separators were important factors determining the structural stability (tolerance to compression) of the separator and therefore influencing their performances before and after compression. A novel delamination experiment was designed to explain different structural stabilities of separators under compression. A related mechanism was proposed.

In this study, the hyperbranched polyester were successfully grafted onto graphene oxide (GO). The mechanical performance and curing kinetics of epoxy resin (EP), EP/ graphene oxide (EP/GO), and EP/ hyperbranched polyester grafted GO (EP/GO‐B) were investigated by means of mechanical tests and differential scanning calorimetry (DSC). Results revealed that the presence of GO lowered the cure temperature and accelerated the curing of EP, and the addition of GO‐B exhibited a stronger effect in accelerating the cure of EP compared with GO. Activation energies were calculated using Kissinger approach, and Ozawa approach, respectively. Results revealed lowered activation energy after the addition of GO or GO‐B at low degrees of cure, indicating that GO had a large effect on the curing reaction. The presence of GO facilitated the curing reaction, especially the initial epoxy‐amine reaction. Moreover, GO‐B exhibited better performance. Related mechanism was proposed.