ABSTRACT
X-ray detectors based on conventional semiconductors with large atomic numbers are suffering from the poor stability under a high dose rate of ionizing irradiation. In this work, we demonstrate that a wide band gap ceramic-boron nitride with small atomic numbers could be used for sensitive X-ray detection. Boron nitride samples showed excellent resistance to ionizing radiation, which have been systematically studied with the neutron- and electron-aging experiments. Then, we fully analyzed the influence of these aging effects on the fundamental properties of boron nitride. Interestingly, we found that the boron nitride samples could maintain relatively good charge transport properties even after large dose of neutron irradiation. The fabricated X-ray detectors showed decent performance metrics, and the neutron-aged boron nitride even showed improved operational stability under continuous X-ray irradiation, suggesting the great potential for real applications.
ABSTRACT
A general way to prepare bio-based polymer colorant by reactive dyeing of regenerated cellulose (RC) in dimethyl sulfoxide (DMSO) was established. Up to 40% higher dye utilization was achieved compared with aqueous reactive dyeing of RC for two reasons. 1. Lower liquor ratio of 1:9 could be applied for the concentrated RC suspensions in DMSO was less viscous. 2. Dye loss from solvolysis was turned off in DMSO. The method was generally applicable to RCs made from wood pulp, waste cotton, and bamboo pulp. The dyeing process has minimum influence on the morphological, rheological, and thermal properties of RC. The colored RCs thus prepared were used to prepare colored polymer composites via a Pickering emulsion approach, and to color cotton, cotton blend, and viscose fabrics via a printing approach. Therefore, it holds great potential as renewable and biodegradable pigments for making colorful composites, ink, textile dyeing and finishing.
ABSTRACT
Silicon-containing compounds such as silica are effective heavy metal sorbents which can be employed in many applications. This is attributed to the porous nature of hydrothermally-stable silica, endowing such materials with high surface area and rich surface chemistry, all responsible for improving adsorption and desorption performance. However, to this day, the wide application of silica is limited by its skeletal brittleness and high production cost coupled with a risky traditional supercritical drying method. To solve the named problems, herein, precipitated silica agglomerates (referred to as PSA) was crosslinked with TEMPO-oxidized cellulose nanofibrils (TO-CNF) as a reinforcement in the presence of 3-aminopropyltriethoxysilane (APTES), via a facile dual metal synthesis approach, is reported. The resultant new silica-based sponges (TO-CNF PSA) showed desirable properties of flexibility, porosity and multifaceted sorption of various heavy metals with re-usability. The experimental results showed maximum adsorption capacities of 157.7, 33.22, 140.3 and 130.5 mg g-1 for Pb(ii), Hg(ii), Cr(iii) and Cd(ii) ions, respectively. Such a facile approach to modify silica materials by attaching active groups together with reinforcement can provide improved and reliable silica-based materials which can be applied in water treatment, gas purification, thermal insulation etc.
