The main features of plastic honeycomb panels are waterproof and moisture-proof. Due to their honeycomb structure, they are lightweight and have the advantages of being shockproof, heat-insulating, thermal-insulating, and sound-insulating. What are the properties of the raw material polypropylene that give plastic honeycomb panels so many advantages?
(1) Physical properties: Polypropylene is a non-toxic, odourless, milky white, highly crystalline polymer with a density of only 0.90-.091g/cm3, making it one of the lightest plastics currently available. It is particularly stable in water, with a water absorption rate of only 0.01% in water for 24 hours and a molecular weight of about 80,000 to 150,000. It has good formability, but due to its large shrinkage, thick-walled products are prone to dents. The product has a good surface gloss and is easy to colour.
(2) Mechanical properties: Due to its high crystallinity and regular structure, polypropylene has excellent mechanical properties. Its strength, hardness, and elasticity are higher than those of HDPE. However, due to its high regularity of molecular structure, its impact strength is poor at room temperature and low temperature. When the molecular weight increases, the impact strength also increases, but the molding and processing performance deteriorates. PP's most outstanding performance is its resistance to bending fatigue.
(3) Thermal properties: PP has good heat resistance, with a melting point of 164~170"C. The product can be sterilized at a temperature above 100"C. Without external force, it will not deform at 150"C. The brittle temperature is -35°C. It will become brittle at temperatures below -35°C. Its cold resistance is not as good as that of polyethene.
(4) Chemical stability: Polypropylene has good chemical stability. Except for being corroded by concentrated sulfuric acid and concentrated nitric acid, it is relatively stable to various other chemical reagents. However, low molecular weight aliphatic hydrocarbons, aromatic hydrocarbons and chlorinated hydrocarbons can soften and swell PP. At the same time, its chemical stability increases with the increase in crystallinity. Therefore, polypropylene is suitable for the production of various chemical pipelines and accessories and has a good anti-corrosion effect.
(5) Electrical properties: Polypropylene has excellent high-frequency insulation properties. Since it hardly absorbs water, its insulation properties are not affected by humidity. It has a high dielectric constant and can be used to make heated electrical insulation products as the temperature rises. Its breakdown voltage is also high, making it suitable for use as electrical accessories. It has good voltage resistance and arc resistance, but it has high static electricity and is prone to ageing when in contact with copper.
(6) Weather resistance: Polypropylene is very sensitive to ultraviolet rays. Adding zinc oxide, Dilauryl thiodipropionate, carbon black or similar milky white fillers can improve its ageing resistance.