Fan-Jie Lin's research while affiliated with National Taipei University of Technology and other places

Recycled poly(ethylene terephthalate) (r-PET) is a thermoplastic polyester. Repeated heat processing of r-PET may negatively affect physical properties due to thermal degradation. Therefore, to improve the physical properties of r-PET, poly(glycidyl methacrylate) (PGMA) samples with different molecular weights (low, medium, and high) were synthesized using atom transfer radical polymerization. The synthesized PGMA polymer was then subjected to 1H-NMR characterization and gel permeation chromatography for the analysis of molecular weight and its distribution. The intrinsic viscosity values of the r-PET/PGMA blend were increased from 0.61 to 0.8 dL g− 1 using high-molecular-weight PGMA at 2 wt%, and the glass transition temperature was increased from 71.8 °C for r-PET to 82.2 °C using high-molecular-weight PGMA at 1 wt%. Young’s modulus was increased by 1.1 times using 2 wt% high-molecular-weight PGMA compared with raw r-PET. All r-PET/PGMA blends samples exhibited notable shear thinning behavior and high viscosity compared with raw r-PET, and r-PET/PGMA blends are found with medium-molecular-weight PMGA polymers observing optimal physical properties. With these enhanced properties, the r-PET/PGMA blends can be applied in the recycling of PET, such as in eco-friendly yarn, packaging materials, and melt-brown non-woven fabric applications.

Novel multifunctional switchable chemosensors based on fluorescent electrospun (ES) nanofibers with sensitivity toward magnetism, temperature, and mercury ions (Hg²⁺) were prepared using blends of poly(N-isopropylacrylamide)-co-(N-methylolacrylamide)-co-(Acrylic acid), the fluorescent probe 1-benzoyl-3-[2-(2-allyl-1,3-dioxo-2,3-dihydro-1Hbenzo[de]isoquinolin-6-ylamino)- ethyl]-thiourea (BNPTU), and magnetite nanoparticles (NPs), and a single-capillary spinneret. The moieties of N-isopropylacrylamide, N-methylolacrylamide, acrylic acid, BNPTU, and Iron oxide (Fe3O4) NPs were designed to provide thermoresponsiveness, chemical cross-linking, Fe3O4 NPs dispersion, Hg²⁺ sensing, and magnetism, respectively. The prepared nanofibers exhibited ultrasensitivity to Hg²⁺ (as low as 10⁻³ M) because of an 80-nm blueshift of the emission maximum (from green to blue) and 1.6-fold enhancement of the emission intensity, as well as substantial volume (or hydrophilic to hydrophobic) changes between 30 and 60 °C, attributed to the low critical solution temperature of the thermoresponsive N-isopropylacrylamide moiety. Such temperature-dependent variations in the presence of Hg²⁺ engendered distinct on-off switching of photoluminescence. The magnetic ES nanofibers can be collected using a magnet rather than being extracted through alternative methods. The results indicate that the prepared multifunctional fluorescent ES nanofibrous membranes can be used as naked eye sensors and have the potential for application in multifunctional environmental sensing devices for detecting metal ions, temperature, and magnetism as well as for water purification sensing filters.