This work is licensed under Creative Commons Attribution 4.0 License AJBSR.MS.ID.001682.

No abstract

Environmental factors such as climate change, temperature fluctuations, and mechanical forces hinder long-term space, transportation, and research missions due to structural damage. We report an innovative system to overcome this problem. The self-healing structure under examination is an epoxy as a polymeric matrix, which includes microcapsules embedded with epoxypolydimethylsiloxane (PDMS), as a healing agent, separately combined by microcapsules embedded with triethylenetetramine (TETA) as a hardener or curing agent. Scanning electron microscopy confirmed the presence and size of the microcapsules. It was shown that the rough appearance of microcapsules improves mechanical bonding. The diameter of microcapsules varied between 40 and 200 μm, with an average diameter of ~100 μm. The information of microcapsules and their structures were scrutinized through Fourier transformed infrared spectroscopy for chemical structure confirmation. It was determined that epoxy-PDMS practical liquids have been effectively encapsulated. The thermal performance of the microcapsules was investigated utilizing thermogravimetric analysis. The results showed that the microcapsules have thermal stability up to 220 C without degradation and decomposition. Additionally, the flexural test was used to evaluate the samples manually scratched with blade and compared with the pure epoxy sample. The results showed the sample containing 15% microcapsules has 105% recovery efficiency after 55 h.

In the current work, a rapid and simple dispersive liquid-liquid microextraction method (DLLME) was used to determine Bisphenol A (BPA). High performance liquid chromatography with the photodiode-array detector (HPLC-DAD) coupled DLLME method was employed to analyze BPA in food samples packaged including cans, paper boxes, and glass jars. The calibration curve was obtained to be in the linear range 0.009–25 ngg −1 with a correlation coefficient of R2 = 0.9981. The mean relative standard deviations (RSDs) was of 5.2% ( n = 3). The limit of detection (LOD) and the limit of quantification (LOQ) of the method were obtained to be 0.001 ngg −1 and 0.08 ng.g −1 , respectively. In sum, this method presents: A rapid, simple and efficient modified DLLME method was used to measure BPA in packaged foods. The advantages of this method were low detection limit, fast preparation, and high BPA recovery. The DLLME-HPLC method consists of low detection limit and high recoveries to determine BPA in samples. The results indicated that DLLME –HPLC-DAD was an applied method to measure BPA in food samples.