First，Physical properties
1. Mechanical properties
Generally speaking, the smaller the grain size of wood powder, the higher the strength of wood plastic products. This is because the fine wood powder can better combine with the plastic matrix, increase the interface compatibility, thereby improving the mechanical properties of the product such as tensile strength, bending strength and impact strength.
However, when the grain size of wood powder is too small, it may lead to a decline in the toughness of the product. Because the fine wood powder is easy to agglomerate, it affects the continuity of the plastic matrix, so that the product is prone to brittle fracture when it is impacted.
2. Density and dimensional stability
The finer wood powder can increase the density of wood-plastic products and make the products more dense. This helps to improve the dimensional stability of the product and reduce the deformation caused by changes in temperature and humidity.
On the contrary, the coarse wood powder will reduce the density of the product, and there may be more gaps inside, thereby reducing the dimensional stability of the product.
Second, processing performance
1. Liquidity
The particle size of wood powder has an important effect on the fluidity of wood plastic composites. The finer wood powder will make the flow of the material worse, because the friction between the fine wood powder is greater, and higher pressure is required in the extrusion or injection process to make the material flow smoothly.
Rough wood powder is relatively easy to flow, but it may cause the surface of the product to be rough and affect the appearance quality.
2. Mixing uniformity
The fine wood powder is easier to mix evenly with the plastic matrix, which is conducive to improving the performance uniformity of the product. The coarse wood flour may appear local agglomeration phenomenon, resulting in the performance of different parts of the product is very different.
Third, appearance quality
1. Surface finish
Fine wood powder can make the surface of wood plastic products more smooth and delicate, with better appearance quality. This is because the fine wood powder can fill the small gaps in the plastic matrix, making the surface of the product more flat.
Coarse wood powder will make the surface of the product relatively rough, may require additional surface treatment to achieve a better appearance.
2. Color uniformity
The mixture of fine wood powder and plastic matrix is more uniform, so the color of the product is more uniform. The coarse wood powder may cause the product to appear uneven color phenomenon, affecting the beauty.
In summary, the particle size of wood powder has an important impact on the performance of wood plastic products. In actual production, it is necessary to select the appropriate particle size of wood powder according to the specific requirements of the product to achieve the best performance and appearance quality.
