Study of High-Performance Chloroprene Sponge in Diving Suit Application
A diving-suit-used foam neoprene with high performance has been developed and its aging behaviors in QUV accelerated aging tank and temperature cyclic chamber were investigated. The results show that the tensile strength and tear strength of the material are decreased after 9d QUV accelerated aging due to the obvious cracks in the foaming cell. In temperature cycling the mechanical properties increased arising from cross linking reaction in the aging process. Besides, the chloride ion penetration resistance of the material was tested by dielectric flux intelligent tester, and the result shows that the material is of excellent chloride ion penetration resistance capability. The infiltration coefficient is 8.1×10-11cm2/s.
Changes of core temperature of diver in low temperature water
Object:To study the changes of core temperature when a diver didn't wear the cold- proofing and heating clothing in the low temperature water.Methods:The subject in dry diving suit dived in the water of the average 13.6℃temperature.His core body temperature was observed on the real time and recorded once every 5 min.Results:The total diving time was 155 min and the core temperature dropped from 37.25℃to 35.80℃.The temperature curve rose slowly in the initial stage and then dropped quick- ly.The phenomenon of afterdrop also could be observed in this study.Conculsion:Under the condition of no cold-proofing and heating,a diver can dive only for a short time.The study of medical protection for divers exposed in the low temperature surroundings for a long time should be strengthened.
ANALYSIS AND COMPARISON OF THE BARRETT, FREEMAN-CARROL AND THE TIME-TEMPERATURE-TRANSFORMATION (TTT) SUPERPOSITION METHODS: THE CASE OF A HIGH Tg DIAMINE/EPOXY SYSTEM
Abstract In the present work the curing process of the epoxy system diglycidylether of bisphenol A (DGEBA) with 4,4′-diaminodiphenylmethane (DDM) has been studied by differential scanning calorimetry (DSC) techniques. Dynamic methods (Barrett and Freeman-Carrol) and the isothermal time-temperature-transformation (TTT) superposition method were applied in order to obtain kinetic features of the curing process. The time-temperature evolution of the glass transition temperature (Tg) and the extent of reaction (α) were used as parameters in order to monitor the curing process. Three different reaction ranges have been observed: the initial range of cure (0.05