对二二酸盐功能化硫酸盐的结构和分子洞察力,以改善青老化抵抗力

Introduction
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.

The Diels–Alder reaction brings together a diene and a dienophile to form a six-membered ring. Both components have unique characteristics that influence the rate of the reaction.
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is...

The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.

Retarders are chemical admixtures designed to extend the setting time, which is especially useful when there is a delay in sequential concrete pours to prevent cold joints and to achieve a cohesive structure. Retarders, when used in appropriate amounts, can also enhance the architectural appearance of exposed aggregate finishes.
The function of retarders is to delay the setting of concrete, and this effect can be measured using a penetration test. The retardation process involves adding...

Sulfate attack on concrete is a deterioration process characterized by a whitish discoloration beginning at the edges and corners, accompanied by cracking and spalling. This phenomenon occurs when sulfates react with the components of hardened concrete, forming compounds like calcium sulfate and calcium sulfoaluminate which occupy more space than the substances they replace, causing the concrete to expand and disrupt.
Sulfates from sources like soil, groundwater, or industrial effluents...