PP material is polypropylene, polypropylene is non-toxic, odorless, tasteless milky white highly crystalline polymer, density 0. 90-0. 91g/cm3, which is one of the lightest varieties of all plastics. It is particularly stable to water, with a water absorption rate of 0.01% and a molecular weight of about 80,000 to 150,000. Good formability, but due to the large shrinkage rate (1% ~ 2.5%), thick-walled products are easy to dent, for some parts with high dimensional accuracy, it is difficult to meet the requirements, and the surface gloss of the products is good.
Polypropylene is a high-density, side-chain-free, high-crystalline linear polymer with excellent comprehensive properties. Common products: basins, barrels, furniture, films, woven bags, bottle caps, car bumpers, etc.
pp plastic, chemical name: polypropylene, English name: Polypropylene (abbreviated as pp) specific gravity: 0.9-0.91 g/cm3, molding shrinkage: 1.0-2.5%, molding temperature: 160-220 °CPP is a crystalline polymer, and the comprehensive performance of PP is better than that of PE material. PP products are lightweight, tough and chemically resistant. The disadvantages of PP: low dimensional accuracy, insufficient rigidity, poor weather resistance, it has the phenomenon of post-shrinkage, and after demoulding, it is easy to age, become brittle and easy to deform. In engineering projects, the commonly used air duct is made of PP material.
In the PP material inside the high-purity propylene as the main material, including a small amount of ethylene copolymer, after drying, mixing, extrusion, granulation, screening and homogenization into polypropylene particles, this particle is cylindrical particles, the particles are very smooth, without any mechanical impurities, it has good mechanical properties and heat resistance, in the temperature range of minus 30 degrees Celsius to 140 degrees Celsius is not toxic.
Mechanical properties PP has high crystallinity and regular structure, so it has excellent mechanical properties. However, at room temperature and low temperature, the impact strength is poor due to the high regularity of its molecular structure. The most outstanding performance of PP is its resistance to flexural fatigue.
Chemical stability PP has good chemical stability, in addition to being eroded 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 polypropylene, and its chemical stability is improved with the increase of crystallinity, so PP is suitable for making various chemical pipes and fittings, and the anti-corrosion effect is good.
Electrical properties PP has excellent high-frequency insulation properties, and since it hardly absorbs water, the insulation properties are not affected by humidity. It has a high dielectric coefficient, and with the increase of temperature, it can be used to make heated electrical insulation products. It also has a high breakdown voltage, making it suitable for use as an electrical accessory, etc. It has good voltage resistance and arc resistance, but has a high degree of electrostatic electricity. Due to the presence of the side methyl group in PP, tertiary carbon atoms alternately appear on the molecular chain, and the tertiary carbon atoms are very easy to oxidize when in contact with copper ions, resulting in poor oxidation resistance and radiation resistance of polypropylene. Therefore, copper inhibitors must be added in applications that come into contact with copper.
The performance can be changed through additives: PP can change its performance by adding various fillers, plasticizers, antistatic agents, etc., so that it has the characteristics of flame retardant, antistatic, antibacterial, and reinforcing. For example, adding glass fiber can enhance the rigidity and strength of PP, adding carbon black can make PP have anti-ultraviolet and antistatic properties, adding antioxidants can extend the service life of PP, etc.