Juan Torres-Rodríguez,Ricardo A. Pérez-Camargo,Yunxiang Shi,Kaojin Wang,Yong-Guang Jia,X. X. Zhu,Alejandro J. Müller
Poly(ε-caprolactone-ran-ω-pentadecalactone) (PCLx-PPDLy) copolymers were synthesized by using ring-opening polymerization with Candida antarctica lipase B as a catalyst across various compositions. The aim was to study their crystallization behavior and ascertain whether they are isomorphic or isodimorphic. Differential scanning calorimetry, polarized light optical microscopy, in situ wide- and small-angle X-ray scattering, and Fourier-transform infrared spectroscopy were employed to assess the crystallization mode. Various crystallization conditions were used to investigate their influence on the comonomer inclusion/exclusion balance. The copolymers exhibited pseudoeutectic behavior across all compositions, crystallizing in either PPDL-type or PCL-type unit cells and conformations, independent of crystallization conditions. This indicates that they are isodimorphic, contrary to previous reports. Self-nucleation tests showed that the Domain II width decreases with increasing comonomer content, supporting isodimorphism. The pseudoeutectic point was observed at CL contents above 83%, which explains the previously unrecognized isodimorphic character of these copolyesters.
The halloysite nanotubes surface molecularly imprinted polymers (HNTs-SMIPs) were prepared by precipitation polymerization, using halloysite nanotubes as the carrier material, coumarin-3-carboxylic acid and pentadecanolide as dummy templates of zearalenone, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. Then, the HNTs-SMIPs were treated with etching technique to obtain halloysite nanotubes hollow molecularly imprinted polymers (HNTs-HMIPs). HNTs-SMIPs and HNTs-HMIPs were characterized by scanning electron microscope, transmission electron microscope, fourier transform infrared spectrum and X-ray diffraction. The adsorption capacity of HNTs-HMIPs was compared with HNTs-SMIPs. The developed HNTs-HMIPs were applied as absorbents for solid phase extraction. A new method was established by combining with high performance liquid chromatography-fluorescence detector for the detection of zearalenone. The method was developed with a recovery of 77.13–102.4% and a relative standard deviation of less than 5.59%. The limit of detection of oats and wheat were 1.67 μg kg −1 and 0.5 μg kg −1 , respectively. The performance of self-made solid phase extraction column was compared with immune affinity column. The developed method has been successfully applied to the detection of zearalenone in complex grain matrices.
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