Скачать или смотреть polymethacrylate (PMA) and polymethyl methacrylate (PMMA)

The synthesis of polymethacrylate (PMA) and polymethyl methacrylate (PMMA) is mainly completed by free radical polymerization, and the specific process has certain differences in monomers, initiators, solvents and reaction conditions. The following introduces the synthesis process of these two polymers:

1. Synthesis process of polymethacrylate (PMA)
PMA is a copolymer of methacrylate monomers (such as methyl methacrylate, ethyl methacrylate, etc.), which is often used as a viscosity index improver and pour point depressant.

Reaction raw materials
Monomer:
Methyl methacrylate (MMA)
Octyl methacrylate (OMA) or other long-chain alkyl esters
Initiator: peroxide (such as ammonium persulfate), azo compounds (such as AIBN, 2,2'-azobisisobutyronitrile)
Solvent: toluene, xylene, isopropanol, etc.
Chain transfer agent (optional): thiols (such as n-dodecyl mercaptan) to control molecular weight
Synthesis steps
Solution preparation: Mix the monomers and solvents evenly, and the proportion is designed according to the molecular structure of the target copolymer.
Initiator addition: Add an appropriate amount of initiator, usually controlled within the range of 0.1% - 1% of the total weight of the monomer.
Polymerization reaction:
Heat and stir at 80 - 120°C to start the free radical polymerization reaction.
The reaction time is controlled at 4 - 8 hours, and the chain transfer agent is gradually added to regulate the molecular weight.
Termination reaction: Add a small amount of inhibitor (such as hydroquinone) to terminate the polymerization reaction.
Purification: Remove unreacted monomers and solvents by precipitation or vacuum distillation to obtain the target polymer.
Reaction mechanism
Free radicals initiate monomers to form active centers, and the monomers grow in a chain through addition reactions to generate linear or branched polymethacrylates.

2. Synthesis process of polymethyl methacrylate (PMMA)
PMMA is a homopolymer of methyl methacrylate (MMA) and is widely used in optical materials and coatings.

Reaction materials
Monomer: methyl methacrylate (MMA)
Initiator: commonly used dibenzoyl peroxide (BPO) or AIBN
Solvent (optional): benzene, toluene, xylene, etc.
Chain transfer agent (optional): n-dodecyl mercaptan
Synthesis steps
Monomer pretreatment: Add MMA monomer to the solvent, stir evenly, and add an appropriate amount of stabilizer (such as hydroquinone) to prevent early polymerization.
Initiator dissolution: Dissolve the initiator in a small amount of solvent and slowly add it to the reactor.
Polymerization reaction:
Heat the reaction system to 60-80°C to initiate free radical polymerization.
The reaction time is usually 6-10 hours, and the monomer conversion rate is gradually controlled.
Polymerization termination: Add a small amount of antioxidant to terminate the reaction and avoid chain growth.
Product post-processing:
Precipitation method: Pour the polymer solution into a non-solvent (such as methanol) for precipitation.
Drying: Dry to constant weight in a vacuum drying oven to obtain PMMA powder or granules.
Reaction Mechanism
Free radical polymerization is completed through three stages: initiation, growth and termination. The structure of PMMA is relatively simple and is usually a linear homopolymer.

Main differences between PMA and PMMA
Parameters PMA (copolymer) PMMA (homopolymer)
Monomer composition Various methacrylates Single methyl methacrylate (MMA)
Applications Pour point depressant, viscosity index improver Optical materials, coatings
Molecular weight control Usually low (tens of thousands) Usually high (millions)
Chain structure May be linear or branched depending on the monomer ratio Mainly linear structure
Optimization suggestions
Solvent selection: Non-polar solvents help to generate linear polymers, while polar solvents may increase branching.
Initiator control: Reasonably select the initiator concentration and addition speed to avoid gelation caused by too fast reaction.
Amount of chain transfer agent: Control the molecular weight distribution and improve the solubility and functionality of the product.
If you have specific production goals or need more detailed process conditions, you can further explore the adjustment plan!