Silica, also known as precipitated Silica or hydrated silica, is a commonly used chemical raw material and is widely used in chemical, plastic, coating, rubber and other industries. The following is a study on the hygroscopicity and moisture resistance of Silica:

1. Hygroscopicity of Silica

Hygroscopic principle:

There are a large number of hydroxyl and silanol groups on the surface of Silica, which have strong hydrophilicity. When Silica comes into contact with water, these groups will quickly absorb water to form a hydration layer.

With the continuous adsorption of water, the hydration layer gradually thickens, causing the volume of Silica to expand and the fullness to increase. However, when the water adsorbed by Silica reaches a certain level, the hydroxyl and silanol groups on its surface will be completely occupied by water molecules, and the Silica reaches the hygroscopic saturation point at this time.

Hygroscopic effect:

In the process of water absorption, as Silica absorbs water, its fullness will gradually decrease and its performance will also be affected. For example, in industries such as rubber and plastics, Silica is often used as a reinforcing agent or filler. If silica absorbs too much moisture, it may affect its compatibility with the matrix, thereby reducing the mechanical properties of the composite material.

After silica absorbs water, the viscosity will decrease, thus affecting its application effect. Especially in a humid environment, silica is particularly sensitive to it.

2. Moisture-proof performance of silica

Moisture-proof measures:

In order to prevent silica from absorbing moisture, a series of moisture-proof measures need to be taken. For example, ensure that the storage environment is dry and ventilated, and control the temperature and humidity. Dehumidifiers or desiccants can be used to reduce the humidity of the environment.

In terms of packaging, moisture-proof packaging materials such as aluminum foil bags or plastic bags are used, and desiccants are placed in the packaging to absorb the small amount of moisture that may enter.

Before using silica, it can be dried to remove the absorbed moisture. However, attention should be paid to the drying temperature and time to avoid excessive temperature from damaging the silica structure.

Moisture-proof effect evaluation:

The effect of moisture-proof measures can be evaluated by observing the appearance of silica, measuring its water content, and evaluating its application performance. If the appearance of silica remains dry and free of lumps, the water content is within the control range, and the application performance is stable, it means that the moisture-proof measures are effective.

3. Application recommendations for hygroscopicity and moisture-proof performance of silica

Application areas:

When selecting silica products, it is necessary to comprehensively consider its various performance indicators to meet the actual application needs. For example, in rubber products that require high reinforcement performance, silica products with large surface area and high structure can be selected; while in application scenarios that require moisture-proof performance, silica products with better moisture-proof performance need to be selected.

Precautions for use:

When using silica, it is necessary to pay attention to the vulcanization speed. The pH value of silica will affect the vulcanization speed of the rubber compound, so it is necessary to understand the pH value of silica before use and make corresponding adjustments.

At the same time, in order to give full play to the role of silica, it is also necessary to pay attention to the selection of formulation and mixing conditions to avoid the tendency to scorch and damage the fatigue resistance and wear resistance of the rubber compound.

In summary, silica has a certain hygroscopicity, and special attention should be paid to moisture-proof measures during storage and use to ensure its stable performance. By controlling the storage environment, improving the packaging method and drying before use, the moisture absorption of silica can be effectively reduced, thereby ensuring its application effect.