The main physical and chemical properties of polypropylene

1. Shape The longitudinal plane of polypropylene fiber is straight and smooth, and the cross-section is circular.

2. The advantage of density polypropylene is its light texture, its density is only 0.91g/cm3, which is the lightest variety of common chemical fibers, so the same weight of polypropylene can get a higher coverage area than other fibers.

3. Strong elongation Polypropylene has high strength, long elongation, high initial modulus and excellent elasticity. So polypropylene has good abrasion resistance. In addition, the wet strength of polypropylene is basically equal to the dry strength, so it is an ideal material for making fishing nets and cables.

4. Hygroscopicity and dyeability Polypropylene has very little hygroscopicity, almost no moisture absorption, and the moisture regain under general atmospheric conditions is close to zero. But it has a wicking effect, passing water vapour through the capillaries in the fabric, but does not have any absorption effect on its own. Polypropylene has poor dyeability and incomplete chromatogram, but it can be compensated by the method of dope dyeing.

5. Acid and alkali resistance Polypropylene has good chemical resistance. Except for concentrated nitric acid and concentrated caustic soda, polypropylene has good resistance to acid and alkali, so it is suitable for use as filter material and packaging material.

6. Lightfastness, etc. Polypropylene has poor lightfastness, poor thermal stability, easy aging, and is not resistant to ironing. But it can improve its anti-aging performance by adding anti-aging agent during spinning. In addition, polypropylene has good electrical insulation, but it is easy to generate static electricity during processing.