Method for preparing cross-linked solid-solid phase change energy storage material

Abstract

The invention provides a method for preparing a cross-linked solid-solid phase change energy storage material, which relates to a method for, after homogeneous preparing laurel acid cellulose ester with high substitution by using a cellulose / LiCl / DMAc solution system, synthesizing a cross-linked polyethylene glycol / laurel acid cellulose ester phase change energy storage material by using laurel acid cellulose ester and polyethylene glycol as main materials through solution grafted polymerization in the presence of cross-linking agent. Although both polyethylene glycol and laurel acid cellulose ester are solid-liquid phase change materials, polyethylene glycol and laurel acid cellulose ester are mutually dissolved and cross-linked in the process of grafted cross-linked polymerization to have typical polyether type segmented cross-linking network structures, thereby containing and restricting their respective microflow mutually. The phase change enthalpies of two components are overlapped mutually, thus final product has higher phase change enthalpy up to 194.7J / g. The obtained material has proper phase change temperature at 19 to 60 DEG C, stable heat performance, no liquid produced in phase change process and completely invertible phase change process, is a polymer solid-solid phase change energy storage material with bigger use valve and development prospect.

Description

technical field [0001] The invention relates to a cellulose / LiCl / DMAc solution system, after homogeneously preparing cellulose laurate with a high degree of substitution, using cellulose laurate and polyethylene glycol as main ingredients, in the presence of a crosslinking agent Next, a method for synthesizing a cross-linked polyethylene glycol / cellulose laurate phase-change energy storage material by solution graft polymerization. technical background [0002] Utilizing the latent heat of the phase change energy storage material to control energy absorption or release can improve the utilization rate of energy; the temperature of the system can be controlled by using the characteristic that the temperature of the phase change energy storage material is approximately constant when the phase changes. In today's increasingly tense energy supply, phase change materials will be widely used. At present, they have been used in civil and military fields such as solar energy utiliz...

AI Technical Summary

Problems solved by technology

But the phase change enthalpy is small, only about 100j / g

This is because in such products, the chain end with the phase change energy storage functional group is grafted on the main chain of the cellulose derivative skeleton material through a chemical reaction, so on the one hand, due to the steric hindrance effect inside the phase change material As a result, the chain segment of the energy storage group cannot be crystallized, and the number of chain segments that can be crystallized is reduced, resulting in a decrease in the phase change enthalpy; on the other hand, since the energy storage chain is fixed on the main chain of the cellulose skeleton material, its movement is free The extent is limited, resulting in the inability of the internal lattice to be arranged neatly, which affects the regularity of the crystal region of the energy storage group, and also causes a decrease in the phase change enthalpy.

US4616173 discloses a polyol and polymer composite solid-solid phase change energy storage material, but due to the high vapor pressure of the plastic crystal, it is volatile and has poor stability, which affects the use

US 4708812, CN1844269A, CN1903971A introduced phase change microcapsules, using organic polymer as capsule wall material to coat and seal the phase change material, the phase change enthalpy is large, but the volume change is large during phase change, repeated shrinkage and expansion make the material use The life is shortened, and there is a physical interaction between the core and the shell, leakage and phase separation still occur, and it is essentially a solid-liquid phase change material with stable properties

CN1482204A discloses a composite material of dispersed phase change energy storage components in a polyolefin crosslinked network, which is stable in shape and strength, but the preparation process is cumbersome and complicated