Effect of oil absorption value on the performance of magnesium hydroxide

Hebei Messi Biology Co., Ltd. stated that the oil absorption value is also called the resin adsorption capacity, which indicates the amount of resin absorbed by the filler. It is usually expressed in terms of the amount of linseed oil or dibutyl phthalate required for 100g of filler (ml/100g) , is a physical index to test the performance of inorganic materials.

Flame Retardant Magnesium Hydroxide

The oil absorption value has important guiding significance for the selection of fillers. Most fillers use the oil absorption value to roughly predict the demand for resin by the filler. It can characterize the adsorption performance of fillers under different particle sizes and specific surface areas; when the oil absorption value is smaller, the resin adsorption capacity is smaller, which means the higher the filling ratio. In the field of thermally conductive polymer materials, a higher filling amount of thermally conductive filler often represents a higher thermal conductivity.

Oil absorption value measurement method: Taking the magnesium hydroxide oil absorption measurement method as an example, the steps include: accurately weighing the mass of the dropper bottle containing refined linseed oil (accurate to 0.001g) and recording; weighing the dried talc sample About 5g <accurate to 0.001g), place it on the flat plate; add the refined linseed oil in the dropper bottle to the sample on the flat plate by dripping. The amount of oil added should not exceed 10 drops each time. After adding the oil, press it with an ink-adjusting knife to allow the oil to penetrate into the sample. Continue adding drops until the oil and sample can form agglomerates. From this point on, after each drop of oil is added, it needs to be fully pressed with an ink-adjusting knife to form a clump of uniform consistency that just wets the powder, is not cracked or broken, and can adhere to the flat plate, which is the end point; weigh After the end point, record the mass of the dropper bottle and refined linseed oil (accurate to 0.001g).

Hebei Messi Biology Co., Ltd. stated that during the modification process of magnesium hydroxide: the change curve of the oil absorption value of magnesium hydroxide in the pre-hydrolysis time increases as the hydrolysis time increases. The oil absorption value of the modified magnesium hydroxide powder first decreases. A tendency of increasing and then decreasing after a small period. This is because the silane coupling hydrolysis was incomplete at the beginning and was accompanied by self-polymerization, resulting in only part of the magnesium hydroxide powder interacting with the modifier, which alleviated the ineffective absorption of dioctyl ester by the magnesium hydroxide powder. , the oil absorption value is reduced to a certain extent. When the pre-hydrolysis time reaches 60 minutes, the oil absorption value reaches the lowest 40.25ml/100g. It can be considered that the coupling agent at this time has been completely hydrolyzed and the degree of self-polymerization is low, so the modification effect of magnesium hydroxide powder is the best. good.

Comprehensive analysis shows that when the hydrolysis time increases to 60 minutes, the activation index of the magnesium hydroxide powder also increases, indicating that the silane coupling agent is completely hydrolyzed and most of the magnesium hydroxide powder is coated with the modifier. Therefore, the activation index is the largest. When the oil absorption value reaches the lowest, the activation index reaches the highest, indicating that the modification effect is optimal.

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