Preparation And Cooling Performance Test Of Fiber Reinforced Hydrogel

Hydrogel has the advantage of absorbing water but not dissolving in water,and it can be used as a cooling material.When the hydrogel is subjected to temperature and light,it will respond to change the size and shape.when it is used as a cooling material,it needs to be strengthened to maintain the stability of the structure.In addition,hydrogels have poor mechanical properties and are easily broken by force.These defects greatly limit the application of hydrogels in the field of cooling and cooling.In order to improve the physical and mechanical properties of the hydrogel and explore its cooling and cooling effect after covering the surface of the building,in this paper,the hot air adhesive formed polyester / kapok batt is introduced as a reinforcing material in the preparation of PAAM hydrogel.The fiber-reinforced hydrogel have good mechanical properties and dimensional stability,and the LED light source to simulate the sun.The thermal cycle of the building after the hydrogel is used as a cooling material to cover the roof is systematically studied,and the cooling of the hydrogel is clarified.Cooling mechanism.The main research contents and conclusions of this topic are as follows:(1)Preparation and characterization of fiber-reinforced hydrogel(TRH)Adding the polyester / kapok batt to the polyacrylamide mixture solution and preparing the fiber-reinforced hydrogel(TRH)by free radical solution polymerization.Compared with PAAM hydrogel,the formed TRH hydrogel has fewer bubbles and better molding.The surface morphology analysis found that the surface of TRH hydrogel has a uniform and dense honeycomb pore structure.These pore structures provide a channel for moisture transportation.The structure of the large kapok cavity in TRH hydrogel is complete,and it can also provide a channel for moisture.In addition,TRH added polyester / kapok batt,the fibers interspersed between the holes,forming a threedimensional network structure,to some extent increase the mechanical properties of the hydrogel.The infrared spectrum shows that TRH and PAAM hydrogels have the same characteristic absorption peaks as polyacrylamide,indicating that PAAM gels are formed in TRH,and there are no other characteristic peaks in TRH,indicating that the polyester / kapok flakes in TRH do not The solution reacted.(2)TRH swelling performance and mechanical performance testThe size change of TRH hydrogel after water absorption and swelling in horizontal direction is not obvious,and the size change after water absorption and swelling in vertical direction is obvious,indicating that TRH hydrogel has better water absorption ability in vertical direction.As a cooling material for building surfaces,the horizontal deformation of TRH hydrogel is helpful to reduce the interface stress and improve the durability,while the larger thickness deformation can help store more water and ensure the cooling effect;The swelling performance of the whole gel,the swelling ratio of TRH hydrogel and the equilibrium swelling degree are lower than that of PAAM hydrogel.For the unswollen hydrogel,the Young's modulus of TRH hydrogel is 5 times that of PAAM;when compressed at a deformation rate of 40%,the stress of TRH hydrogel is six times that of PAAM hydrogel,TRH is stronger than PAAM.However,because the fiber flakes added to the TRH hydrogel limit its ability to deform in the horizontal direction,when the vertical direction is greatly compressed(45%),the horizontal elongation deformation exceeds the limit of the TRH hydrogel The internal fiber batt was irreversibly damaged,resulting in damage to the overall structure of TRH hydrogel.For hydrogels that reach a swelling equilibrium state,the Young's modulus of TRH hydrogels is 6 times that of PAAM hydrogels.The compressive strength of TRH hydrogels is better than that of PAAM,but the maximum deformation rate is lower than PAAM hydrogels.The mechanical properties of both hydrogels decreased after swelling,but the mechanical properties of TRH hydrogels were still better than PAAM hydrogels.(3)Application of TRH on the surface of buildingsUsing LED lights to simulate the solar light source,and spreading the hydrogel on the surface of the self-built hut.Explore the temperature changes of the upper and lower surfaces of the roof and the air in the same hut surface without hydrogel,TRH and PAAM hydrogel.Regularly,it is found that when TRH hydrogel is spread on the surface of the cabin,the effect of cooling and cooling the cabin is more obvious.Light and water absorption cycle experiments were carried out on the hydrogel.The side length,thickness and weight changes of the hydrogel during the light swelling and water absorption swelling cycle were studied.The results showed that the side length change of the TRH hydrogel during light and water absorption was relatively Small,the size in the horizontal direction is more stable;in the vertical direction,the TRH thickness changes significantly after the TRH hydrogel is exposed to light and absorbs water.In addition,the water loss speed and water absorption speed of TRH hydrogel during light and water absorption are higher than that of PAAM hydrogel,and the hydrogel swells after light exposure.The swelling performance of TRH hydrogel is better than PAAM,indicating that PAAM water after light exposure The structure of the gel is destroyed.The thermal cycling process inside the cabin under the condition of uncovered hydrogel and covered hydrogel,the radiant heat transfer coefficient of the hydrogel is calculated,and then the temperature of the roof of the cabin under the condition of real solar light source is deduced.Adhesive as the cooling and cooling material covers the roof to cool the roof best.It is also calculated that when the ambient temperature is 30 ° C,the sunshine duration is 6 hours,and the air conditioner maintains a room temperature of 20 ° C,the hydrogel can save 651 kWh within 1 year and reduce 365 kg of carbon dioxide.