Yuan Lei tells you | Talcum powder 5 major surface modification examples

Release time:

2024-01-29 09:35


Yuan Lei tells you | Talcum powder 5 major surface modification examples


The surface modification of talcum powder can improve the interfacial affinity between talcum powder and polymer, improve the dispersion state of talcum powder filler in high polymer base material, so that talcum powder not only has an incremental effect in the composite material, but also can enhance the effect of modification, so as to improve the physical and mechanical properties of the composite material, so that talc can get better application effect and wider application field.


1, Talcum powder modified by titanate coupling agent


The function of the titanate coupling agent is to form a monomolecular covering film on the surface of the filler. Change its original hydrophilic properties, so that the surface properties of the filler has a fundamental change.


Because the titanate coupling agent has a unique structure, it has a good coupling effect on the polymer and filler, which can improve the dispersion and fluidity of the filler, improve the elongation at break, impact and flame retardant properties of the composite material.


(1) Modification method


Dry modification:Talc powder is stirred and dried in a high-speed mixer preheated to 100 ℃-110 ℃, then a measured amount of titanate coupling agent (diluted with an appropriate amount of 15# white oil) is evenly added, and stirred for several minutes to obtain a modified talcum powder filler.


Wet modification:After the measured titanate coupling agent is diluted with a certain amount of solvent, a certain amount of talcum powder is added, stirred at 95 ℃ for 30min, filtered and dried to obtain a modified talcum powder product.


(2) Application characteristics


The talc filler modified by titanate coupling agent can improve the compatibility with polypropylene (PP), reduce the viscosity of the system, increase the fluidity of the system, improve the processing performance of the system, reduce the deformation, improve the dimensional stability, and expand the application range of PP.


2, Talcum powder modified by aluminate coupling agent


(1) Modification method


An appropriate amount of aluminate (such as L2 type) is dissolved in a solvent (such as liquid paraffin), dried fine talcum powder of 1250 purpose is added for grinding and modification for 30min, and the modified product is obtained after cooling at 100 ℃ for a period of time.


(2) Application characteristics


Compared with ordinary talc, the viscosity of talc modified by aluminate in liquid paraffin is significantly reduced, the water penetration time is increased, and the effect of organic hydrophobic modification is obvious. The tensile strength, elongation and other mechanical properties of the semi-reinforced carbon black filled rubber were improved by the talc powder modified by aluminate. At the same time, the amount of substitution is large. Can achieve the effect of reducing costs and reducing environmental pollution.


3, Talcum powder organic polymer modification


The talcum powder was modified by toluene diisocyanate (TDI) and hydroxypropyl acrylate (HPA), and then grafted with polymethyl methacrylate (PMMA) layer and methyl methacrylate-butyl acrylate copolymer (PMMA-Co-PBA) layer, respectively, to form composite particles.


(1) Preparation method of composite particles


The organic talc particles, toluene, initiator, butyl acrylate (BA) and divinylbenzene (DVB) treated by TDI and HPA surface treatment and further purification are placed in a reaction kettle and stirred evenly. Under the condition of maintaining the temperature at 75±5 ℃, the following solutions mixed in appropriate proportion are continuously dropped: methyl methacrylate (MMA), BA, DVB, toluene and azobisisobutyronitrile. After completion of the dropwise addition, the reaction was maintained at 80±5°C for 2.5h. Then, the solvent and unreacted substance are distilled off under reduced pressure (absolute pressure is about 8kPa, temperature is not less than 85 ℃), and then extracted with isopropanol for 24h by Soxhlet extractor, and then washed, dried and sieved to obtain surface organic polymer composite talc particles.


(2) Application characteristics


The tensile and impact strength of the material mixed with the talc powder composite particles coated with the polymer is significantly higher than that of the talc powder directly filled, and the impact and tensile strength of the coated particles are approximately increased by (119±4)%, while the tensile strength of the random copolymer flexible polymer coated is increased by 136, and the impact strength is increased by 162. The flexible polymer coated talcum powder composite particle mixed material has obvious reinforcing and toughening effect, and can continuously and effectively increase the strength and toughness under a large range of filling (particle filling mass fraction 5%-35%) (tensile strength is increased by 1/3, impact strength is increased by nearly 2/3). This composite particle is a new type of filling material which can effectively improve the comprehensive performance of the product and reduce the material cost, and has good comprehensive performance when used in cable materials.


4, Talcum powder modified by silane coupling agent


Talcum powder is a polar water-insoluble substance. When they are dispersed in organic polymer resins with minimal polarity, the compatibility of the two is not good due to the difference in polarity. Direct or excessive filling often leads to the decline of some mechanical properties of the material and the disadvantages of easy embrittlement, which has a negative impact on the processing performance and use performance of the product. A silane coupling agent can be used to modify the surface of the talc filler.


(1) Modification method


The silane coupling agent (such as KH-570) into a solution, stirring evenly. The solution is dripped into the dried talcum powder, stirred for 40-60min, so that the treatment agent is fully coated with filler 4, and then heated and dried to obtain the modified talcum powder.


(2) Application characteristics


The talcum powder modified by silane coupling agent as the filler of polymer materials can obviously improve the strength and modulus of the filling system, and the modification effect is good, which has good practical application value.


5, talc phosphate modification


(1) Modification method


First, the talc powder is pre-coated in the aqueous solution of phosphoric acid ester at 80 ° C. under stirring for 1h, and then dried at about 95 ° C. Finally, the temperature is increased to 125 ° C., and the heat treatment is performed for 1h. The amount of phosphate ester is 0.5-8% of the talc.


(2) Application characteristics


Phosphate ester can react with the surface of talc by chemical adsorption and physical adsorption to form surface coating. Increasing the amount of surface coating can improve the dispersion state of talc, and can significantly change the morphology and mechanical properties of the filling system.

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