Styrene with Methyl Acrylate Internal Plasticization

Example 3.42 Copolymerization of Styrene with Methyl Acrylate (Internal Plasticization) 

Safety precautions Before this experiment is carried out, Sect. 2.2.5 must be read as well as the material safety data sheets (MSDS) for all chemicals and products used. 

Samples 1 and 2 are precipitated by adding 50 ml of methanol containing 3 drops of concentrated hydrochloric acid. All other samples are precipitated by the addition of n-hexane. All of the precipitants should be cooled with an ice/water mixture. The yields have to be calculated. 

To investigate the internal plasticization of polystyrene (Tg = 105°C) by insertion of methyl acrylate (Tg = 4°C), the samples are run on a DSC. Therefore, approximately 15 mg of each of the well dried polymers are weighed into small aluminum pans and measured by two heat-cool runs in a DSC apparatus. The glass transition is found as a characteristic jump in the heat capacity in the system. The glass transition temperature is evaluated after the second heating from the DSC plot. 

Example 3.43 Three-Step Synthesis of Core/Double Shell Particles of Methyl Methacrylate/Butyl/Acrylate/Methyl Methacrylate 

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Emulsions can be formulated with only hard monomer and plasticized at a later stage, but it is normal to internally plasticize the emulsion by copolymerizing some soft monomer. Vinyl acetate plasticized with an acrylate such as butyl or ethylhexyl acrylate, or a dialkyl maleate, are common combinations. Other hard (high Tg) monomers include methyl methacrylate, styrene, and vinyl chloride. Soft monomers include Vinyl Versatate (Shell Chemicals), ethylene, and vinylidene chloride (Figure 1). 

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