Talcum powder has become an important inorganic mineral filler for plastic modification, and has attracted attention in the research and application of filled modified polypropylene (PP) plastics. There is room for research in the development of talc filled modified PP plastics, talc filled modified PP to improve its quality, and it is used in the field of automobiles and electrical appliances, which has huge market prospects.
Talcum powder is a commonly used mineral powder filler for PP polypropylene plastics, which has attracted widespread attention due to its abundant resources, low price and excellent filling performance. Talcum powder filled composite materials have been widely used in the automobile industry and daily necessities, and its products have good apparent quality, low shrinkage rate and high heat deflection temperature compared with unfilled talcum powder, but due to the weak affinity of the two-phase interface, the direct filling of talcum powder often leads to the decline of some mechanical properties, so that the application of composite materials is limited.
The surface modification treatment can effectively improve the interface affinity between talc and polymer, improve the wetting ability of polymer to talc, and improve the dispersion state of talc filler in the polymer base material, so as to improve the physical and mechanical properties of the composite materials. There have been many studies on the enhanced properties of mineral powders at home and abroad, and a large number of analyses and discussions have been carried out on the strengthening mechanism, and some models have been established for the proposed mechanisms, which have promoted the theoretical and practical application of mineral particle-reinforced polymer preparation of composite materials.
Superior properties of talc fillerInorganic filler plays an important role in plastic modification and becomes an indispensable modification aid. In different application fields, talcum powder, as an extender, reinforcing agent, and functional modifier, has been recognized by the industry. This is inseparable from the characteristics of talc itself: the connection between the layers is very weak, which makes it soft and reduces the wear and tear of the equipment during processing; The lamellar structure can give the best balance between the stiffness and impact strength of the filling system. It has a certain affinity for organic matter; The talc surface is both hydrophobic and inert; Higher whiteness.
However, the poor compatibility between the filler and the plastic matrix affects the final performance of the system, and the talc surface must be modified in order to improve the organic interface between the two.
Compared with other general-purpose thermoplastics, PP talcum powder has the advantages of small relative density, low price, good processability and good comprehensive properties. Because it can be well compounded with a variety of materials, it can simulate the performance of high-priced engineering resins at a low price, and it can be thinner and reduce weight, which makes it advantageous to meet the demanding requirements of automotive and electrical plastics in automotive and electrical material applications.
PP has the disadvantages of low temperature brittleness, low low impact strength, poor rigidity, large molding shrinkage, and easy aging. PP sheet extrusion extrusion machine plus talcum powder can increase the heat deflection temperature of filled PP plastics, increase the dimensional stability of products, reduce the molding shrinkage, and improve rigidity. The addition of ultrafine talc masterbatch, as a reinforcing filler for polypropylene, can not only significantly improve the rigidity, surface hardness, creep resistance and electrical insulation of polypropylene products, but also improve the impact strength of polypropylene, improve the impact resistance of PP, and endow the system with excellent surface properties. Talc also acts as a melt flow promoter, as well as a synergistic agent with certain flame retardants.
When a small amount of talcum powder is added to propylene, it can play the role of nucleating agent, refine the grains, improve the crystallinity of polypropylene, so that the mechanical properties of polypropylene are improved, and its transparency is improved.
Effect of surface modification of talcum powder on the enhancement properties of PP: the reinforcement properties of talc filled with PP were significantly improved after coupling agent treatment. The effect of various coupling agents on PP enhancement is very different, among which silane is the best, phosphate ester is poor, and the combination of silane and titanate is also ideal, which may be related to the synergistic effect of the two.
The influence of stone powder particle size on the enhanced performance of PP: talc particle size is a very important factor in the preparation of filled PP composite materials, with the decrease of talc particle size, the increase of surface area, and the improvement of the strengthening performance of powder, this is mainly because the surface defects of small particles are relatively few, the possibility of physical and chemical combination with PP is large, and the interface bonding performance is good. The powder is prone to agglomeration, which affects the dispersibility in PP.
When the amount is less than 15%, the strength of the composite material increases with the increase of talcum powder dosage, and decreases when it is greater than 15%. This is mainly due to the fact that the filling amount of talcum powder is too small, the dispersion concentration is too low, and the main body that absorbs external stress is PP matrix, which cannot play an obvious role in enhancing and toughening. When the filling amount is large, the particles are too close to each other, because the limited matrix is not enough to wrap all the particles, the interface bonding condition decreases, the bonding defects appear, and the micro-cracks and plastic deformation of the material are too large when the material is impacted, almost becoming macroscopic cracking, resulting in a decrease in strength.
Adhesion function between talc and PP extrusion line: the dynamic viscosity of the ultrafine talc filled PP system modified with different coupling agents is quite different, and the effect of silane coupling agent is ideal, and the dynamic viscosity of the modified talc filled PP system is significantly reduced, which improves the compatibility with PP. The adhesion work between talc and PP has a good correspondence with the tensile strength of the composite material, and the greater the adhesion work, the better the mechanical properties of the material.
The tensile strength of the composite increases when the talcum powder mass fraction is 20%, while decreases at higher mass fractions. With 10% talc and no MAPP, the maximum strength increases by about 5%.
Post time: May-20-2024