Both polyethylene and polypropylene are flammable products, and both are classified as severe hazards in the fire hazard level.

1. Polyethylene: Polyethylene is flammable with an oxygen index of 17.4. It produces low smoke when burning, with a small amount of molten dripping. The upper part of the flame is yellow and the lower part is blue, and there is a paraffin smell. Polyethylene is prone to photo-oxidation, thermal oxidation, ozone decomposition, and degradation under the action of ultraviolet rays. Carbon black has an excellent light-shielding effect on polyethylene. After exposure to radiation, reactions such as cross-linking, chain scission, and the formation of unsaturated groups may occur.

2. Polypropylene: It is easy to burn, and the products are susceptible to aging due to the effects of light, heat and oxygen during use. Non-toxic, odorless, low density, strength, stiffness, hardness and heat resistance are better than low-pressure polyethylene, and can be used at around 100℃.

It has good dielectric properties and high-frequency insulation and is not affected by humidity, but it becomes brittle at low temperatures, is not wear-resistant, and is prone to aging. Suitable for making general mechanical parts, corrosion-resistant parts and insulating parts. Common organic solvents such as acids and alkalis have little effect on it and can be used in tableware.

Extended information:

Fire danger level:

1. Light danger level: hotels and office buildings with a building height of 24m and below. Buildings with closed systems only in walkways, etc.

2. Medium risk level: high-rise civil buildings: hotels, office buildings, complex buildings, postal buildings, financial telecommunications buildings, command and dispatch buildings, radio and television buildings (towers), etc.

(1) Public buildings (including single and multi-story buildings): hospitals, sanatoriums, libraries (except bookstores), archives, exhibition halls (halls), theaters, concert halls and auditoriums ( (except stages) and other entertainment venues, buildings in railway stations, airports and docks, shopping malls with a total construction area of ??less than 5,000 square meters, underground shopping malls with a total construction area of ??less than 1,000 square meters, etc.

(2) Cultural heritage buildings: ancient wooden structures, national cultural relics protection units, etc.

(3) Industrial buildings: material preparation and production workshops for food, household appliances, glass products and other factories, cold storage, steel roof trusses and other building components.

(4) Civil buildings: bookstores, stages (except grape trellises), car parking lots, shopping malls with a total construction area of ??5,000 square meters or more, underground shopping malls with a total construction area of ??1,000 square meters or more, etc.

(5) Industrial buildings: cotton, wool, linen, silk and chemical fiber textiles, fabrics and products, wood, wood and plywood, grain processing, tobacco and products, drinking alcohol (except beer), leather and products, paper and Material preparation and production workshops of paper products, pharmaceutical and other factories.

3. Severe hazard level: material preparation and workshops of printing plants, alcohol products, flammable liquid products and other factories. Flammable liquid spray operation area, solid flammable items, flammable aerosol products, solvents, paints, asphalt products and other factories' material preparation and production workshops, photo studios, and the lower part of the stage "grape rack".

4. Warehouse hazard level: food, tobacco and alcohol, non-combustible and retardant items packaged in wooden boxes and cartons, shelf areas of warehouse-type shopping malls, etc.

(1) Wood, paper, leather, grains and products, cotton, wool, linen, silk, chemical fibers and products, household appliances, cables, Group B plastics and rubber and their products, steel-plastic mixed material products, various plastics Warehouses for mixed storage of non-combustible items packaged in bottles and boxes and various items.

(2) Group A plastics and rubber and their products, asphalt products, etc.

Baidu Encyclopedia - Polyethylene

Baidu Encyclopedia - Polypropylene

Baidu Encyclopedia - Fire Hazard Level