ABSTRACT
The demand for an efficient oil sorbent with high sorption capacity, low cost, scalable fabrication, and high selectivity for the cleanup of spreading oil on water is increasingly urgent due to the frequent occurrence of oil spill accidents in seawater all over the world. In this study, porous polystyrene (PS) fibers with high hydrophobicity and superoleophilicity were directly fabricated by a centrifugal spinning method (CS). The effect of solvents, tetrahydrofuran (THF), and dimethylformamide (DMF) on the morphology and porous structure of the polystyrene fibers was evaluated by using scanning electron microscopy and nitrogen adsorption-desorption experiments. The formation mechanism for the porous structure on the fibers was also evaluated. The oil sorption capacities of the PS fibers for silicon oil, pump oil, and vegetable oil were investigated. The highest oil sorption capacity was found in PS fibers fabricated from PS solution with a THF/DMF weight ratio of 1/3, which exhibited the highest specific surface area, pore volume, and porosity. The high productivity and highly porous structure of PS fibers indicate that CS is a promising method to fabricate porous fibers for the cleanup of oil spills.
ABSTRACT
A polystyrene (PS)-based composite resin dosimeter (CRD) film comprising 2-(phenylamino)-6-(dipentylamino)-3-methylspiro[9H-xanthene-9,3'-phthalide] (Black305) fluoran leuco dye, cerium-doped yttrium aluminum perovskite YAlO3:Ce (YAP:Ce) scintillator, and 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine (MBTT) photoacid generator was developed for the visualization of X-ray exposure doses in the range of 18-170 Gy. The color of the CRD film changed from yellow to black within this range based on the X-ray exposure dose. A CRD film based on Black305/YAP:Ce/MBTT/PS could be used to produce a dosimeter with various color change sensitivities by controlling the thermodynamic parameters of the constituent materials. A CRD film is a promising tool for measuring the X-ray exposure dose and can be used as an alternative to the existing radiochromic dosimeters.
ABSTRACT
Centrifugal spinning, which is a high-productivity fiber fabrication technique, was used to produce a value-added product from recycled poly(ethylene terephthalate) (rPET). In the present study, rPET fibers, with fiber diameters ranging from submicron to micrometer in scale, were fabricated by spinning a solution of rPET in a mixture of dichloromethane and trifluoroacetic acid. The influence of the polymer solution concentration (the viscosity), the rotational speed of the spinneret, and the inner diameter of the needles on the formation and morphology and mechanical properties of the fibers were examined through scanning electron microscopy and using a tensile testing machine. The thermal behaviors of fibrous mats with various average diameters were also investigated through differential scanning calorimetry. The smoothest and smallest fibers, with an average diameter of 619 nm, were generated using an rPET solution of 10 wt % under a rotation speed of 15,000 rpm using needles having an inner diameter of 160 µm. The fibrous mats have an average tensile strength and modulus of 4.3 MPa and 34.4 MPa, respectively. The productivity and the mechanical properties indicate that centrifugal spinning is an effective technique to fabricate high-value product from rPET.