Chemical properties of aldehyde PMMA

First, it needs to be made clear that acetals and PMMA(polymethyl methacrylate) are two different chemicals that each have unique chemical properties. I will introduce the chemical properties of acetal and PMMA respectively.

Chemical properties of acetals

Acetal is a class of organic compounds, its chemical properties mainly include the following points:

Stability: Acetals are less stable than other ethers and tend to polymerize when placed. It is stable to bases, but warm in dilute acids will undergo hydrolysis reaction to form the original aldehyde. Therefore, acetals are often used as a method to protect the aldehyde group from destruction in a multi-step reaction.

Reactivity: acetals are easily hydrolyzed to the original aldehydes and alcohols under the catalysis of acids. In addition, it can react with hydrogen iodide gas to form iodoethane and acetaldehyde, and when oxidized to form acetic acid. However, many reagents that can react with aldehydes, such as Grignard's reagent and metal hydride, do not react with acetals.

Use: Because of its stability and aromatic smell, acetal is often used in the fragrance industry as an additive in food and cosmetics. At the same time, it is also an important raw material for organic synthesis.

Chemical properties of PMMA

PMMA(polymethyl methacrylate) is a polymer, commonly known as plexiglass, its chemical properties mainly include the following points:

Transparency and optical performance: PMMA has extremely high transparency, with light transmittance of up to 90%-92% or even higher. It provides good optical clarity and can be used to manufacture lenses and other optical components.

Mechanical properties: PMMA has good toughness and mechanical strength, although compared to some engineering plastics its impact resistance is slightly weaker, but it is still much tougher than glass.

Weather resistance and chemical stability: PMMA has strong resistance to ultraviolet light and atmospheric environment, and can be exposed outdoors for a long time without easy degradation. It has good tolerance to weak acids, bases and salts, but is easily eroded by strong acids (such as concentrated sulfuric acid), strong bases and some organic solvents (such as ketones and esters).

Processing performance: PMMA is easy to process, can be processed by injection molding, extrusion and other ways, but also can be cut, drilling, bending and bonding and other secondary processing.

Thermal performance: The heat resistance of PMMA is not high, although the glass transition temperature reaches 104 ° C, the maximum continuous use temperature varies between 65 ° C and 95 ° C with different working conditions. The thermal decomposition temperature is slightly higher than 270 ° C, and its flow temperature is about 160 ° C.

Sum up

Acetals and PMMA are two different chemicals that differ significantly in their chemical properties. Acetals are mainly used to protect aldehyde groups and as raw materials for organic synthesis, while PMMA is widely used in many fields because of its excellent transparency, mechanical properties, weather resistance and processing properties.