Preparation of Styrene–Maleic Anhydride Random Copolymer by Stabilizer-Free Dispersion Polymerization

Abstract

In this paper, random copolymer of styrene (St) and maleic anhydride (MAH) were prepared by stabilizer-free dispersion polymerization, with dicumyl peroxide (DCP) as initiator and ethyl butyrate as solvent at 120 • C. The microsphere morphology and sequential structure of the copolymers were characterized by SEM and 13 C-NMR, respectively. When the molar feed ratio of MAH to St (MAH/St) was 20/80, the overall MAH content in the copolymer was about 26% (molar) from the 13 C-NMR spectrum, and the three St-centred triads SSS, MSS+SSM, and MSM were about 41%, 44%, and 15%, respectively. The variation of sequential structure of the copolymer on the changes of the polymerization time is marginal. When the feed ratio of MAH/St was less than 15/85, it was observed that the obtained copolymer could be partially dissolved in the solvent. The molecular weight of the soluble fraction was smaller than that of the precipitation part. The effects of feed ratios of MAH to St, the initiator concentrations, and monomer concentrations on polymerization yields and compositions of the copolymer were investigated in detail. The results showed that a stable dispersion of SMA random copolymer particles was formed when the feed ratio MAH/St≥20/80.

Preparation of Styrene–Maleic Anhydride–Acrylamide Terpolymer Particles of Uniform Size and Controlled Composition via Self-Stabilized Precipitation Polymerization

“…Moreover, the high monomer concentration and particle yield provide this method with intensive potential for broad industrial applications. Therefore, many functional polymer particles with a well-defined morphology have been prepared via 2SP since the first report of 2SP of MAH and vinyl acetate by Xing. ,,− So far, the monomers for 2SP are mainly composed of electron-donating monomers (olefinic compounds) and electron-accepting monomers (MAH and its derivatives). Though AM is also an electron-accepting monomer, the 2SP of AM is not that simple due to the poor solubility of PAMs in common solvents.…”

Stabilizer-free Dispersion Copolymerization of Styrene and Maleic Anhydride: Mathematical Model for Nucleation

“…Another relevant fact regarding the copolymer is that the copolymerization between ST/MAH is widely known as an alternating copolymerization, − which points to the solvent as the most significant factor for the system stability and final particle diameter. Some authors suggest that particle stabilization in the stabilizer-free case may result from the affinity between the polymer particles and the ester groups in the reaction medium. − Also, the soluble polymer formed in situ may act as the stabilizer, preventing complete coagulation of the system. − Therefore, a particle formation model would help in understanding the nucleation in stabilizer-free polymerization systems, especially for the IBA and IPA case.…”

“…Dispersion polymerization can also be carried out in the absence of a stabilizing agent and, in this case, it is called stabilizer-free dispersion polymerization. − The literature shows that only some organic solvents lead to the formation of uniform, monodisperse particles, for instance, alkyls esters. Moreover, all of the stabilizer-free systems that allowed particle formation were copolymerization reactions between maleic anhydride (MAH) and another monomer, such as styrene (ST) or vinyl acetate (VA). − …”

“…Some authors suggest that particle stabilization may result from the affinity between the polymer particles and the ester groups in the reaction medium. In addition, the polymer formed in situ may act as the particle stabilizer, preventing complete system coagulation. − …”

Self-stabilized precipitation polymerization: principle, method and application

“…郝国亮等 [19] 将2SP体系用于苯乙烯/马来酸酐(St/ MAn)的交替共聚合, 考察了聚合过程中单体转化率、 微球尺寸以及共聚物相对分子质量随反应时间的变 化, 成功制备了粒径为290~640 nm的单分散苯乙烯-马 来酸酐交替共聚物(PMS)微球. 郭晓月等 [20] 通过溶剂…”