A series of novel liquid crystalline epoxides with lateral substituents were cured with anhydrides and the cure kinetics was investigated by non-isothermal DSC technique. The results showed that the lengths of lateral...A series of novel liquid crystalline epoxides with lateral substituents were cured with anhydrides and the cure kinetics was investigated by non-isothermal DSC technique. The results showed that the lengths of lateral substituents have great effect on the value of Ea. The curing reaction became less active, when the liquid crystalline epoxides have long lateral substituents and were controlled by diffusion at the late stage of cure. A nematic structure was observed by POM and XRD.展开更多
Glass fiber reinforced epoxy (GFRE) composite materials are prone to suffer from water absorption due to their heterogeneous structure. The main process governing water absorption is diffusion of water molecules throu...Glass fiber reinforced epoxy (GFRE) composite materials are prone to suffer from water absorption due to their heterogeneous structure. The main process governing water absorption is diffusion of water molecules through the epoxy matrix. However, hydrolytic degradation may also take place during components service life specially due high temperatures. In order to mitigate the effects of the water diffusive processes in the deterioration of in-service behavior of epoxy matrix composites, the use of chemically modified nanoclays as an additive has been proposed and studied in previous works [1]. In this work, an Artificial Neural Network (ANN) model was developed for better understanding and predicting the influence of modified and unmodified bentonite addition on the water absorption behavior of epoxy-anhydride systems. An excellent correlation between model and experimental data was found. The ANN model allowed the identification of critical points like the precise temperature at which a particular system’s water uptake goes beyond a predefined threshold, or which system will resist an immersion longer than a particular time.展开更多
文摘A series of novel liquid crystalline epoxides with lateral substituents were cured with anhydrides and the cure kinetics was investigated by non-isothermal DSC technique. The results showed that the lengths of lateral substituents have great effect on the value of Ea. The curing reaction became less active, when the liquid crystalline epoxides have long lateral substituents and were controlled by diffusion at the late stage of cure. A nematic structure was observed by POM and XRD.
文摘Glass fiber reinforced epoxy (GFRE) composite materials are prone to suffer from water absorption due to their heterogeneous structure. The main process governing water absorption is diffusion of water molecules through the epoxy matrix. However, hydrolytic degradation may also take place during components service life specially due high temperatures. In order to mitigate the effects of the water diffusive processes in the deterioration of in-service behavior of epoxy matrix composites, the use of chemically modified nanoclays as an additive has been proposed and studied in previous works [1]. In this work, an Artificial Neural Network (ANN) model was developed for better understanding and predicting the influence of modified and unmodified bentonite addition on the water absorption behavior of epoxy-anhydride systems. An excellent correlation between model and experimental data was found. The ANN model allowed the identification of critical points like the precise temperature at which a particular system’s water uptake goes beyond a predefined threshold, or which system will resist an immersion longer than a particular time.
