What is the difference between polyoxymethylene and methyl acetal?

Polyformaldehyde and methyl acetal are not the same substance; their properties differ greatly. Polyformaldehyde (English: polyformaldehyde) is a thermoplastic crystalline polymer, known as \"super steel\" or \"steel substitute\", and is also referred to as polyoxymethylene, abbreviated as POM； Polyoxymethylene is a linear polymer without side chains, featuring high density and high crystallinity, as well as excellent overall properties. Polyoxymethylene is a hard and dense material with a smooth, shiny surface; it is pale yellow or white in color, and can be used over long periods at temperatures ranging from -40 to 100°C. Its wear resistance and self-lubricating properties are also superior to those of the vast majority of engineering plastics, in addition to having good oil resistance and peroxide resistance. It is very sensitive to acids, strong alkalis, and ultraviolet radiation from moonlight. Polyoxymethylene has a tensile strength of 70 MPa, low water absorption, dimensional stability, and a glossy finish – properties that are all better than those of nylon. It is a highly crystalline resin and the toughest among thermoplastic resins. It possesses high heat resistance, high bending strength, and high fatigue resistance, as well as excellent wear resistance and electrical properties. Methylal (English: Methylal ； dimethoxymethane ； formal）Chinese name: methyl acetal ； Formaldehyde dimethyl acetal ； Dimethoxymethane. 　　 Methyl acetal is a colorless, clear, volatile, flammable liquid with a chloroform-like odor and an irritating taste. Soluble in 3 times its weight of water (solubility in water at 20°C is 32% (by mass)). This product is irritating to mucous membranes and has **effects**. Inhaling vapors can cause irritation of the nose and throat ； Inhalation of high concentrations can cause dizziness and other symptoms. It causes damage to the eyes, and the damage can last for several days. Prolonged skin contact can cause dry skin.