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As we all know, although there are many advantages of plastic wood composite materials, there are also some problems. For example, the particle size of wood flour material will affect the thermal stability, and there are some unsolvable problems in the dispersion and compatibility of the plastic matrix resin. This is because wood flour contains a lot of fibers, and the fibers have a certain degree of hydrophilicity and polarity, but most plastic matrix resins are non-polar and hydrophobic. Therefore, the compatibility between the two has been poor, which has also led to the poor bonding between the plastic matrix resin and the wood powder particles. Sometimes the wood flour will self-polymerize, resulting in the wood flour particles cannot be completely uniformly dispersed in the plastic matrix resin. Therefore, in order to obtain excellent performance plastic wood composite materials, solving the compatibility of the two becomes the primary task.
The effect of wood flour
First of all, the quality of wood flour has a great influence on plastic wood composite materials. The types of wood flour are different, and the fiber texture of pine wood flour, willow wood flour, and basswood flour are all different. The size of wood powder particles is also different, and the uniformity of dispersion in the matrix resin during polymerization is different. The temperature drying treatment of wood flour will result in different levels of moisture in the wood flour particles, so that the wood flour will occupy a different volume in the plastic wood composite under the same amount. These are all factors that affect wood flour, leading to different properties of plastic wood composites prepared from different wood flours.
Influence of interface compatibility
Modifiers and manufacturing methods will affect the interface compatibility of plastic wood composites, which makes the performance of plastic wood composites different. Modifiers can adjust the bonding part of the plastic matrix resin and wood powder particles, and some can even act as bridges. The impact on the mechanical properties of plastic wood composites is also different. Different manufacturing methods can also affect the interface compatibility between the plastic matrix resin and wood flour particles. The sequence of the process of preparing the material, the processing temperature, the pressure and time of hot pressing and cold pressing, all have different degrees of influence on the final properties of the plastic wood composite material.
Influence of processing temperature
Processing temperature has a great influence on plastic wood composites. Take HDPE/WF/HDPE-g-MAH composite material as an example. The preparation is completed on a two-roll mill, and the two-roll mill needs to be set at 170°C. If the temperature is too high, it will cause the cellulose coke in the wood flour material to fail to react with the modifier HDPE-g-MAH, and will not produce molecular bond bridges, which will make the HDPE/WF/HDPE-g-MAH composite material mechanical performance drops drastically. When the temperature is too low, HDPE-g-MAH cannot be uniformly dispersed in the HDPE/WF/HDPE-g-MAH composite during the reaction, and self-polymerization may even occur, which can also cause HDPE/WF/HDPE-g- The mechanical properties of MAH composites are reduced.