Amines play vital roles in agricultural, pharmaceutical, and food industries, but volatile amine vapors are serious threats to human health. Previously reported fluorescent sensors for amine vapor detection usually suffer from aggregation-caused quenching (ACQ) effect and need to be dispersed in solution or matrix materials. Herein, based on the fluorogen of 2-(2-hydroxyphenyl)quinazolin-4(3H)-one (HPQ) with aggregation-induced emission (AIE) properties, we have developed a fluorescent sensor HPQ-Ac for light-up detection of amine vapors through aminolysis reaction. The portable HPQ-Ac sensor can be easily prepared by directly depositing on filter paper, and it can only light up via exposure to amine vapors among various volatile organic compounds. Taking advantage of its portability and high sensitivity for amine vapors, HPQ-Ac sensor can also be used for food spoilage detection and fluorescent invisible ink.
Fused deposition modeling (FDM) is one of the trendiest three-dimensional printing (3DP) technologies. However, FDM products based on virgin polyamide-6 (PA6) are seriously warped due to the accumulation of shrinkage stress generated from the crystallization of PA6. To solve this problem, maleic anhydride grafted poly(ethylene 1-octene) (POE-g-MAH) is added into PA6 to disturb the crystallization and reduce the shrinkage stress. Besides, rigid polystyrene (PS) with good flowability is further introduced to PA6/POE-g-MAH blend because too much addition of POE-g-MAH will weaken the PA6/POE-g-MAH, which will interrupt the printing process. The POE-g-MAH and PS both act as amorphous phase in the blends, which will reduce the shrinkage stress and is helpful to the shape stability of the printed products. Finally, a new kind of PA6-based filament with good toughness for FDM is prepared via this facile method.
Thermally conductive composites consisting of polymer/ boron nitride (BN) fabricated by conventional molding method can hardly achieve high through-plane thermal conductivities (TPTCs) because the alignment of BN sheets would orient along the direction of melt flow. Based on the characteristics of fused deposition modeling (FDM), we design three printing methods to research on the orientation of BN sheets. In this article, enhanced TPTC samples of PA6/BN composites with vertical alignment of BN are achieved by FDM, and the maximum of TPTC of samples is 2.03 WÁm −1 ÁK −1 . Suitable design can reduce the negative effects of voids produced during the deposition of filaments. It's proved that FDM is an effective method to fabricate high TPTC products using less fillers by reasonable design. POLYM. COMPOS., 40:3375-3382, 2019.
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