Modified phenolic resin and preparation method thereof

Abstract

The invention relates to a modified phenolic resin, and the resin is characterized in that the resin is prepared from the following raw materials in parts by mass: 70 to 110 parts of phenol, 15 to 40 parts of 4-maleimido phenol, 20 to 30 parts of resorcinol, 80 to 110 parts of formaldehyde and 25 to 40 parts of furfural. According to the invention, the selection and proportion of each monomer are screened, 4-maleimido benzene, resorcinol and furfural are added into the formula of common phenolic resin, and two-stage reaction is carried out under different reaction conditions. In the first reaction stage, ammonia water is used as a catalyst at relatively low temperature, and a mixture of resorcinol and formaldehyde is added; in the second reaction stage, barium hydroxide is adopted as a catalyst at a relatively high temperature, and a mixture of resorcinol and furfural is added. Finally, the modified phenolic resin with excellent comprehensive performance is obtained. Compared with common phenolic resin in the current market, the phenolic resin prepared by the preparation method disclosed by the invention is lower in curing temperature, more excellent in heat resistance, higher in residual carbon rate and better in mechanical property.

Description

technical field [0001] The present application relates to the technical field of phenolic resins, in particular to a modified phenolic resin and a preparation method thereof. Background technique [0002] Phenolic resin (PF) has beneficial mechanical properties and processing properties, and is cheap and widely used in many fields. However, the phenolic hydroxyl group and methylene in phenolic resin will be oxidized at a temperature above 200 ° C, which affects heat resistance, and the cured PF is brittle because only the methylene links are present. Therefore, the defects of high brittleness and poor toughness of PF limit its application and need to be improved urgently. In the prior art, many adopt maleimide groups to modify phenolic resins, such as CN103360558A, CN101531880A, and CN110483713A, which mostly use bismaleimides to modify, but the bismaleimide resins after curing High brittleness and high molding temperature limit its use in composite materials. There are a...

AI Technical Summary

Problems solved by technology

However, the curing temperature is high and the curing rate is slow, which causes inconvenience in construction; and it is easy to release small molecular substances during curing, resulting in different degrees of defects inside or on the surface of the product.

In addition, in the modified phenolic resin reported in the literature, N-(4-hydroxyphenyl)maleimide can only improve the mechanical properties under the situation of adding 1-2%, and when it exceeds 3%, , the impact strength has decreased, and the analysis suggests that the introduction of imide rings may have greatly increased the degree of crosslinking, resulting in a decrease in the toughness of the modified PF

In fact, such a small amount of N-(4-hydroxyphenyl)maleimide cannot effectively improve the heat resistance of modified PF

Images