Preparation method of polyhedral oligomeric silsesquioxane crosslinking agent containing epoxy group

Abstract

The invention relates to a preparation method of a polyhedral oligomeric silsesquioxane crosslinking agent containing an epoxy group. The polyhedral oligomeric silsesquioxane crosslinking agent containing the epoxy group is adopted to improve the strength and flame retardancy of a soybean protein adhesive and improve the application effect of the soybean protein adhesive in order to well solve theproblems of poor strength, poor water resistance, flammability and the like of the soybean protein adhesive. The polyhedral oligomeric silsesquioxane containing the epoxy group branched chain is prepared by utilizing a hydrolysis-condensation reaction principle through adopting gamma-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560) as a main body. A hydrolysis reaction of a KH560 ethanol solutionis carried out under an ultraviolet irradiation condition to remove methanol to form silanol containing a silicon hydroxyl group; and the prepared silanol undergoes a high-temperature condensation reaction in weakly alkaline ammonia water, and finally rotary evaporation, cleaning and rotary evaporation are carried out to obtain the polyhedral oligomeric silsesquioxane crosslinking agent containing the epoxy group.

Description

technical field [0001] The invention relates to a preparation method for an organic-inorganic hybrid cross-linking agent, in particular for improving the water resistance and flame retardancy of soybean protein adhesives. Background technique [0002] At present, the number of natural forest timbers in the world is decreasing sharply, and the human demand for wood products is increasing. In order to solve the human demand for wood products, it is an effective solution to prepare a variety of wood-based panels based on fast-growing materials. However, most of the adhesives used in the preparation of wood-based panels currently on the market contain harmful chemical substances such as formaldehyde and VOC. The harmful volatile gas released by the above-mentioned adhesive during use will cause great harm to the human body. Soybean-based protein adhesives with soybean protein isolate, soybean meal and other soybean products as the main materials are environmentally friendly, ec...

AI Technical Summary

Problems solved by technology

At present, because soybean protein itself is mostly hydrophilic groups, which combine a large amount of bound water and free water, and most of the protein structure is connected by hydrogen bonds, and hydrogen bonds are hydrophilic groups that are easy to absorb water, so this type of bio-based adhesive There are disadvantages such as poor water resistance, low strength, and flammability, which are prone to cracking, warping, weak adhesion, and substandard fire safety when manufacturing wood-based panels.

In order to improve the disadvantages of poor water resistance, low strength and flammability of soybean protein, some scholars have proposed acid-base modification, graft modification, acylation modification, urea guanidine hydrochloride modification, and enzymatic modification to solve the above problems. sex etc.

Among them, acid-base modification uses strong acid and strong alkali to modify soybean protein, which will strengthen the hydrogen bond and increase the strength of the adhesive, but the relative water resistance of the adhesive will decrease significantly.

Although the method of modifying soybean protein adhesive by acetylation can strengthen the strength of the adhesive, it still has the characteristics of poor water resistance.

Urea guanidine hydrochloride modified soybean protein adhesive can effectively improve the dry and wet strength of the adhesive, but it will release ammonia gas with a pungent smell during use, which seriously affects the normal use of plywood; enzymatic modification Soybean protein adhesives can be modified in a mild environment to control the degree of protein hydrolysis and even the breaking position of peptide bonds. loss of activity

The preparation of soybean protein adhesive by graft modification can form a network structure with large molecular weight, and the connection between different functional groups makes the molecular structure criss-cross, which can effectively improve the strength and water resistance of the adhesive; however, graft modification has disadvantages. Disadvantages of poor flame retardancy