Controllable Design and Preparation of Hydroxyl-Terminated Solution-Polymerized Styrene Butadiene for Polyurethane Elastomers with High-Damping Properties.

Vibration and noise are ubiquitous in social life, which severely damage machinery and adversely affect human health. Thus, the development of materials with high-damping performance is of great importance. Rubbers are typically used as damping materials because of their unique viscoelasticity. However, they do not satisfy the requirements of different applications with various working conditions. In this study, the advantages of the high loss factor of styrene butadiene rubber (SBR) are combined with the strong designability of polyurethane. Hydroxyl-terminated solution-polymerized styrene butadiene rubbers (HTSSBRs) with different structures are prepared using anionic polymerization. HTSSBRs are then used as the soft segment during the synthesis of temperature-tunable high-damping performance polyurethanes (HTSSBR-polyurethanes (PUs)). The prepared HTSSBR-PUs with different structures exhibit excellent loss performance, a maximum loss factor (tan δmax ) of above 1.60, and an effective damping performance over a wide temperature range compared to traditional SBR and polyurethane. Therefore, this work offers an effective method for the design of damping materials with adjustable properties.

Development and calibration of a single UV LED based bioaerosol monitor.

A high-sensitivity bioaerosol monitor based on a single 365 nm LED is developed and a calibration approach is discussed for the first time. The fluorescence detection system, which is the core part of the monitor, contains an optical detection module and a fluorescence signal processor configured with a phase sensitive detector (PSD). B800 fluorescent microspheres and staphylococcus are used for performance evaluation of the monitor. B800 microspheres are appropriate as calibration material. The experimental results demonstrate the PSD plays a significant role in improving sensitivity and signal-to-noise ratio (SNR) of detection. Our monitor can detect staphylococcus concentration above 1800 cfu/L of air stably.