Application of barium sulfate in general plastics and engineering plastics

Barium sulfate has the advantages of strong chemical inertness, good stability, acid and alkali resistance, moderate hardness, high specific gravity, high whiteness, and ability to absorb harmful rays, so it is widely used in various plastics, rubber, coatings, medium and high-grade inks, chemical industry , papermaking, ceramics, pigments and other fields. It can increase the hardness, strength, heat resistance and wear resistance of products, and is one of the most promising functional fillers. The following will introduce the application of barium sulfate in the modification of general plastics and engineering plastics.

1. Filling modification of barium sulfate in general plastics

General-purpose plastics have the advantages of good formability and low price, but their disadvantages such as easy aging and easy deformation bring many inconveniences to use. In order to overcome these shortcomings, it can be improved by modification and addition of auxiliaries to meet its needs in practical applications. The application of barium sulfate in general plastics is one of the research hotspots in recent years.

By applying uniform design method, high-gloss PP composite material was prepared with ultra-fine modified barium sulfate and nucleating agent. The properties such as tensile strength, flexural strength, flexural modulus, and Izod impact strength of the product were investigated. The results show that when the content of nucleating agent is 2.0‰ and the filling amount of modified ultrafine barium sulfate is 28.0%, high gloss PP is obtained. Compared with imported similar products, the performances are equivalent.

The PVC/MBS/nanobarium sulfate ternary composites were prepared by melt blending method, and their mechanical properties and thermal stability were investigated. The results show that MBS and nano barium sulfate can synergistically toughen PVC; when the content of MBS and nano barium sulfate are 10% and 1%, respectively, the toughness and rigidity of the material can be improved at the same time, and the impact section shows typical ductile fracture. Features: Thermogravimetric analysis shows that adding 1% nano-barium sulfate can significantly improve the thermal stability of PVC/MBS.

Using the method of wet reaction modification, the long carbon chain molecules of stearic acid are embedded in the surface of barium sulfate in the precipitation reaction stage, so that the surface of barium sulfate is changed from hydrophilic to lipophilic. Therefore, the dispersibility of barium sulfate in the polyvinyl alcohol solution is improved, and the mechanical properties of PP can be improved by using it as the filler of PP.

2. Filling modification of barium sulfate in engineering plastics

With the increasing progress of modern science and technology, society has put forward extensive and multi-functional requirements for engineering plastics. For example, engineering plastics are required to have both good toughness and good hardness; both good rigidity and excellent impact strength; both good comprehensive performance and low price. For diverse requirements, it is difficult for a single resin to meet the diverse and high-quality requirements, and plastic modification can turn this limited single resin into a multifunctional new material to meet the needs of different fields.

There are many ways to modify engineering plastics, such as blending modification, filling modification and so on. Among them, filling modification is the most commonly used method for enterprises, not only because the filling and modification properties give plastics new functions (such as aging resistance, electrical conductivity, heat resistance, etc.) and new properties (improving impact strength, tensile strength, elastic modulus, etc.) and other mechanical properties), but also because filling and modifying properties can reduce product costs and enhance market competitiveness on the premise of ensuring quality.

Using natural exposure and thermal oven aging experiments, the aging performance of ABS/barium sulfate system and the effects of stearic acid, titanate coupling agent, rare earth coupling agent and other treatment agents on the aging performance of the system were studied. The experimental results show that: sulfuric acid The addition of barium has a retarding effect on the photo-oxygen and thermal-oxidative aging process of the ABS system, which can improve the aging resistance of ABS.

Morphological structure and mechanical properties of polyamide 66 (PA66)/barium sulfate composites, and the effect of surface treatment of barium sulfate on the mechanical properties of composites was discussed.

The results show that in the PA66 composite system of 20% activated barium sulfate and 5% ethylene-octene copolymer melt-grafted maleic anhydride, a small amount of barium sulfate has anomalous nucleation effect on PA66, and a large amount of barium sulfate can nucleate PA66. Part of barium sulfate has a toughening effect on PA66. Compared with the unactivated barium sulfate, the tensile strength of the material is increased by 10MPa, the bending strength is increased by 11MPa, and the notched impact strength of the simply supported beam is increased by 9kJ/m2.