LAUSR

In order to develop a suitable washing mode for knapsack, mechanical agitation (1), water bath vibration (2), ultrasonic (3), micro-nano bubble (4) and complex washing mode of the two were systematically investigated. Results showed that regardless of fabric, the washing efficiency of composite washing mode {mechanical agitation + ultrasonic (1 + 3), mechanical agitation + micro-nano bubble (1 + 4)}, was highest among all washing modes. Moreover, the decrease of stiffness, tensile strength, smoothness and micro-morphology of knapsack by using complex washing mode {mechanical agitation + ultrasonic (1 + 3), mechanical agitation + micro-nano bubble (1 + 4)} significantly lower than that of mechanical agitation. This indicated that mechanical agitation was the key to remove stain, micro-nano bubbles and ultrasound only assisted its removal. But the addition of micro-nano bubbles and ultrasound was helpful to improve the washing efficiency and reduce the performance degradation caused by washing mode of mechanical agitation. Complex washing mode {mechanical agitation + ultrasonic (1 + 3), mechanical agitation + micro-nano bubble (1 + 4)} was optimal washing combination for knapsack, especially the composite mode of mechanical agitation + ultrasonic (1 + 3), due to its ability to remove residual stains in the inner layer and slit. Moreover, the complex washing mode was also more environmental-friendly and sustainable, compared to other washing mode, because of washing time and detergent dosage reducing occurred by its high washing efficiency. The results were not only helpful to guide manufacturers of washing machine to develop a program dedicated to the daily washing and care knapsack, but also provided scientific care guidance and optimization ideas for subsequent research and applications.