聚丙烯酸-b-聚丙烯酸甲酯的制备及其在丙烯酸丁酯乳液聚合中的应用

Synthesis of Ploy( acrylic acid)-b-Poly( methyl acrylate) and Its Application in Emulsion Polymerization of Butyl Acrylate

采用三硫代碳酸S-1-十二烷基-S'-(a,a'-二甲基-a″-乙酸)酯(MTTCD)作为链转移剂,偶氮二异丁腈(AIBN)为引发剂,丙烯酸(AA)为第一单体,通过可逆加成-断裂链转移(RAFT)自由基聚合合成大分子链转移剂PAA-MTTCD,以丙烯酸甲酯(MA)为第二单体,合成5种不同嵌段比的两亲性嵌段共聚物聚丙烯酸-b-聚丙烯酸甲酯(PAA-b-PMA)。采用FT IR和1H NMR确定了PAA-MTTCD和PAA-b-PMA的结构,用GPC测定了PAA-MTTCD和PAA-b-PMA的分子量及分子量分布。分析了聚合反应动力学,发现该聚合具有活性可控聚合的特征,聚合动力学呈一级线性关系。测定了PAA-b-PMA的乳化性能,并将其作为乳化剂用于丙烯酸丁酯(BA)的乳液聚合中,同时考察了不同嵌段长度共聚物对乳液聚合的影响。结果表明,具有21个AA单元和18个MA单元的两亲性嵌段共聚物具有较好的乳化性能,其作为乳化剂时乳液聚合效果相对最好。

Amphiphilic block copolymers ploy( acrylic acid)-b-poly( methyl acrylate)( PAA-b-PMA) with different block ratios were synthesized by reversible addition-fragmentation chain transfer( RAFT) living free radical polymerization,in which S-1-dodecyl-S'-( a,a'-dimethyl-a″-acetic acid) trithiocarbonate( MTTCD) as chain transfer agent,azodiisobutyronitrile( AIBN) as initiator,acrylic acid as the first monomer,methyl acrylate as the second monomer. The structure of the macro-chain transfer agent MTTCD-MAA and the block copolymers PAA-b-PMA were confirmed by FT IR and1 H NMR,and the molecular weight and polydispersity indexes were determined by GPC. The results showed that the polymerization possesses 'living '/ controlled and first order linear reaction kinetics characteristics. The PAA-b-PMA was employed as an emulsifier in butyl acrylate( BA) emulsion polymerization. The effect of the copolymers with different length of block on emulsion polymerization was investigated and it was found that the emulsifying performance and the effect of the emulsion polymerization are relatively better while using PAA21-b-PMA18 as emulsifier.