Chain transfer polymerization agents Methacrylic acid

In a preparation of triblock polyions, a radical polymerization of methacrylic acid was carried out in ethanol solution, at 30 C, with Z w(isopropylxanthogen) disulfide acting as initiator, chain transfer agent, and chain terminator, under uv-irradiation. The purified product was then used as a uv-initiator for the block polymerization of sodium styrene-p-sulfonate [72]. 

Emulsion polymerization with the chain transfer agent l-benzyl-2,5-cyclohexadiene-1-carboxylic acid was also used to prepare poly(ethyl acrylate-co-methacrylic acid). Poly(N-vinylpyrrolidone) was prepared using the chain transfer agent l-i-propyl-2,5-cyclohexadiene-1 -carboxylic acid. 

Poly(methacrylic acid) and poly(acrylic acid) (PAA) were prepared by AIBN initiated polymerization of the freshly distilled monomer in deoxygenated methyl ethyl ketone at 60°C. The incorporation of 9,10-dimethylanthracene (9,10-DMA) end-groups in the polymer was achieved by the addition of the chain transfer agent (1% by weight) to the polymerization mixture. Unreacted 9,10-DMA was separated from the polymer by gel permeation chromatography using a column packed with Sephadex LH-20 and methanol as the eluent. Analysis of the PMA sample by NMR indicates that the polymer produced under these conditions consists of 57% syndiotactic, 33% heterotactic and 10% isotactic triads (15). Solution concentrations were 0.02 M in repeating units of the polymer. 

Other examples of peroxy inisurfs can also be found in Russian scientific papers. As for instance in Ref. [41] Voronov et al. describe a polymeric surfactant with peroxy side chains for application as inisurfs in emulsion polymerization. They obtained the polymeric inisurf (Inisurf 2) by copolymerization of a peroxide containing monomer (dimethyl-vinylethinyl-methyl-tm-butyl-peroxide) with acrylic or methacrylic acid or 2-methyl-5-vinyl pyridine with benzoyl peroxide as initiator in the presence of dodecylmercaptan as chain transfer agent. The resulting copolymers are water soluble at appropriate pH-values, surface active, and exhibit a critical micelle concentratioiL... 

Table 6.1 presents a typical formulation for emulsion polymerization. The polymer is mainly made out of a mixture of hard monomers (leading to polymers with a high glass transition temperature, Tg for example, styrene) and soft" monomers (low Tgi for example, butyl acrylate) of low solubility in water. In addition, small amounts of functional monomers such as acrylic and methacrylic acids are included in the formulation as they provide some special characteristics, such as improved adhesion. Crosslinking agents and chain-transfer agents (CTAs) are used to control the molecular weight distribution of the polymer. 

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