Several factors affecting the modulus of filled modified plastics by hollow board machine
DATE：2021/3/5 9:11:47 / READ： / SOURCE：This station
Several factors affecting the modulus of filled modified plastics by hollow board machine
(1) The smaller the particle size of the filler, the greater the elastic modulus of the modified plastics. The reason is: the particle size of the filler decreases and the specific surface area increases; if the adhesive strength of the interface between the resin matrix and the filler particles is relatively high, the increase of the specific surface area of the particles will increase the proportion of the interface area and increase the constraint on the rearrangement movement of some moving units of the resin matrix, such as chain segments; 2; In most cases, the products have a layer rich in resin. The existence of this layer will reduce the bending modulus of elasticity. The degree of the layer is related to the particle size. The larger the layer is, the thicker the layer is. The particle size of the filling material varies. Especially when the particle size ratio reaches 71, the small particles can be filled in the gap between the large particles and the large particles At the same filling amount, the elastic modulus of filled modified plastics is lower. Hollow plate machine www.handern.com(2) "Cortical effect"
The influence of resin rich "skin" on the elastic modulus of filled modified plastic products is quite obvious, especially for thin products, which is 10% ~ 20% lower than that without considering "skin". The larger the thickness of the part is, the smaller the particle weight of the filling material is, and the smaller the "cortical effect" is.
(3) Interfacial bonding strength
If the interfacial adhesion is not good, there is no strong interaction between filling material and resin matrix, and no thermal shrinkage and compressive stress. Under the action of external force, the particles at the two poles of the filling material will produce holes. The particles can move relative in the hole, a little like foam plastics, and the measured elastic modulus is lower than that calculated. Moreover, with the increase of the volume fraction of the filling material, the elastic modulus of the filled modified plastics does not increase, but gradually decreases on the basis of the corresponding pure matrix resin. Hollow plate machine www.handern.com
(4) Temperature
When the test temperature is lower than the glass transition temperature or melting point of the resin matrix, the modulus of the filled modified plastics often decreases obviously with the decrease of the test temperature. The reason for this phenomenon is that the expansion coefficient of the filled materials is different from that of the resin matrix, and the shrinkage stress in the interface area increases with the decrease of the temperature. The shrinkage stress is a compressive stress on the filler particles and a tensile stress on the resin in the interface area, which leads to the decrease of the resin modulus in the interface area and the modulus of the filled modified plastics. Hollow plate machine www.handern.com
(5) Rigid particles coated with elastomer
If a considerable number of rigid particles in the filled modified plastics are coated with a layer of elastomer, the measured value of the elastic modulus of the filled modified plastics will be lower than that calculated by the above formula. When the thickness of the elastomer layer on the surface of the rigid particles exceeds a certain value, the rigid particles show the mechanical behavior of the elastomer, which not only does not increase the elastic modulus of the resin matrix, but also decreases the modulus. Moreover, the rigid particles in the elastomer coating increase the volume fraction of the elastomer phase and decrease the modulus of the resin matrix.
Author：admin