Preparation Of Calcium Carbonate And Its Effect On The Mechanical Properties Of Pvc Films

PVC is widely used in building materials, toys, packaging, decorative materials, etc. due to its wide source of raw materials, corrosion resistance, and light and thin products. However, due to the overall poor mechanical properties of PVC film materials, it is easy to break under the action of external forces. In order to improve its mechanics Performance, the PVC film material is modified.

Calcium carbonate is the most commonly used filling modification material for PVC materials. Dong Dongdong and others selected ammonium metavanadate, polyethylene glycol, cetyltrimethylammonium bromide, sodium pyrophosphate decahydrate and polyvinylpyrrolidone as calcium carbonate. Morphology control agent, calcium chloride and sodium carbonate are used as raw materials, and calcium carbonate particles with different morphologies are prepared by the chlorination method. Influence.

1. Preparation Of Calcium Carbonate With Different Morphologies

The structure of calcium carbonate prepared with ammonium metavanadate as the morphology control agent is irregular flakes, poor dispersion, serious agglomeration, unclear interface between particles, and particle size between 1 and 5 μm;

The structure of calcium carbonate prepared with polyethylene glycol as the morphology control agent is rhombus, the dispersibility is improved compared with ammonium metavanadate, the particle surface is clear, the crystal is developed intact, the particle surface is regular, and the average particle size is 4μm ；

The structure of calcium carbonate prepared with cetyltrimethylammonium bromide as the morphology control agent is rod-shaped, the particles have a disjointed structure, agglomeration, different particle sizes, irregular particle surfaces, defective structures, and contours. Vague;

The structure of calcium carbonate prepared with sodium pyrophosphate decahydrate as the morphology control agent is spherical, the surface of the particles is relatively regular, and the outline is clear. Among the five calcium carbonates with different morphologies, the particles are the smallest and the dispersibility is the best. Under the action of the morphology control agent, a spherical morphology is obtained, and the average particle size of the particles is as large as 2 µm;

The structure of calcium carbonate prepared with polyvinylpyrrolidone as the morphology control agent is cubic micron particles, with poor dispersibility, showing parallel development. The growth degree of each crystal surface is slightly different, resulting in two structures of cube and cube, and the surface is relatively smooth. And there are edges and corners.

2. The Influence Of Different Morphology Calcium Carbonate On The Mechanical Properties Of Pvc Film

The results show that calcium carbonate with different morphologies improves the mechanical properties of PVC film, and the tensile strength and elongation at break of PVC film are increased significantly. Among them, calcium carbonate with rod shape has the best effect on improving the mechanical properties of PVC film. The tensile strength reached 27.11MPa; the elongation at break of the rhombic calcium carbonate modified PVC film was the highest, 98.23%.

Calcium carbonate is filled in the PVC material. During the stretching process, the calcium carbonate particles in the composite material transfer surface tension to the surrounding matrix, causing the surrounding matrix to yield and form a "water wave" pattern, which makes the PVC material tough and rigid The increase in toughness leads to an increase in the elongation at break of the PVC material; the increase in rigidity leads to an increase in the tensile strength of the PVC material.