Reactive group content was a key parameter in polymer curing process. However, the conventional methods to measure the curing were destructive and time consuming. In this article, near-infrared spectra technology had been applied for reactive group analysis of the photothermal curing silicone to achieve rapid nondestructive and quantitative detection. The calibration model was developed about epoxy value and CC double bond value, with determination coefficient ( R 2 ) of 0.9631 and 0.9689. Root mean square error of prediction were 0.0179 and 0.0143 by partial least square regression. The optimized calibration model was used to predict the content of epoxy value and CC double bond value in the photothermal curing process, it proved that the silicone resin cured under UV-radiation and heat. This novel method provided a promising approach to analysis the curing mechanism and quality parameters of resin.
Development of a titanium silicalite-1 (TS-1) catalyst with good crystallinity and a four-coordinate Ti framework is critical for efficient catalytic oxidation reaction under mild conditions. Herein, a size-controlled TS-1 zeolite (TS-1#0.1ACh (acetylcholine)) was synthesized via steam-assisted crystallization by introducing acetylcholine as a crystal growth modifier in the preparation process, and TS-1#0.1ACh was also employed in epoxidations of different substrates containing C=C double bonds. The crystalline sizes of the as-synthesized TS-1#0.1ACh catalysts were controlled with the acetylcholine content, and characterization results showed that the particle sizes of highly crystalline TS-1#0.1ACh zeolite reached 3.0 µm with a good Ti framework. Throughout the synthetic process, the growth rate of the crystals was accelerated by electrostatic interactions between the connected hydroxyl groups of the acetylcholine modifier and the negatively charged skeleton of the pre-zeolites. Furthermore, the TS-1#0.1ACh catalyst demonstrated maximum catalytic activity, good selectivity and high stability during epoxidation of allyl chloride. Importantly, the TS-1#0.1ACh catalyst was also highly versatile and effective with different unsaturated substrates. These findings may provide novel, easily separable and large TS-1 catalysts for efficient and clean industrial epoxidations of C=C double bonds.
危险品化学品经营许可证（带存储）