Polypropylene: one of the most promising thermoplastics today

As a star product in the plastics industry, polypropylene has a high performance-price ratio, excellent mechanical properties, thermal properties, and processing properties, making it the most important polyolefin plastic product. Among the five synthetic resins used in plastics around the world, polypropylene production accounts for about a quarter of the total. Some of the mechanical properties of PP are comparable to engineering plastics and are one of the most promising thermoplastics today.

Disadvantages of PP: low melting point, low heat distortion temperature, poor creep resistance, poor dimensional stability, high temperature brittleness; PP dyeability, adhesion, antistatic, hydrophilic and polar polymer and The compatibility of inorganic fillers is poor; rigidity, strength, heat resistance and so on are still far from the needs of people. PP has poor photothermal stability and large molding shrinkage.

Therefore, the general direction of PP modification is focused on improving the impact strength and heat resistance temperature of PP. The mixed-modified polypropylene is mainly used for daily-use injection molding products, automobiles, home appliances, etc., which are required to withstand high temperature or low temperature impact, and can also be used for filling the masterbatch of the tendon sole while reducing the cost.

First, the use of high melt strength PP in automobile manufacturing

As a typical representative of high-performance general-purpose products, PP modified plastics have been well used in the automotive industry. In 2011, the average amount of plastic used in automobiles reached more than 300kg/unit, accounting for 20% of the whole vehicle's curb weight; it is expected that by 2020, the average amount of plastic used in automobiles will reach 500kg/unit. In the use of automotive plastics, polypropylene (PP) plastic is the largest amount of material, accounting for almost 55% of the total automotive plastics. In 2016, global vehicle production was 94.976 million units, a growth rate of 4.5%. It is estimated that by 2020, China's automobile production will reach 30 million units. According to this calculation, the annual demand for polypropylene modified materials in automobiles alone will reach 8.25 million tons, and the market prospect is very broad.

Second, transparent polypropylene products

(1) polymerizing a transparent PP using a metallocene catalyst;

(2) obtaining a transparent PP by random copolymerization;

(3) Adding a transparent modifier (mainly a nucleating agent) to ordinary polypropylene to improve its transparency.

Due to the obvious performance advantages of transparent PP, it has been rapidly developed all over the world in recent years. Applications range from household items to medical devices, from packaging supplies to heat-resistant utensils (for microwave heating).

Third, polypropylene microporous membrane

Through innovations in processing technology, polypropylene can be made into a microporous membrane with a circular hole of about 0.5 μm in diameter. Microporous membrane is a high-tech, high value-added product, which can be used as a diaphragm in the field of batteries. It can be used for artificial lung membranes and sterilization packaging materials because it is non-toxic and bacteria-resistant but ventilated. The membrane can also be used for the manufacture of sterile water, sterile air, wastewater filtration, soot separation, gas concentration, sanitary products, sapling cultivation, etc., and is very versatile.