Chain Aggregation Process of Poly(methyl methacrylate) in the Mixed Solvent tert-Butyl Alcohol + Water
Chain Aggregation Process of Poly(methyl methacrylate) in the Mixed Solvent tert-Butyl Alcohol + Water
复制标题
聚甲基丙烯酸甲酯在叔丁醇-水混合溶剂中的链聚集过程
DOI：
10.1021/ma011225c
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发表时间：
2002
期刊：
影响因子：
5.5
通讯作者：
M. Nakata
中科院分区：
文献类型：
--
作者：
Yoshiki Nakamura;N. Sasaki;M. Nakata
为了研究链聚集过程，将分子量m = 1.57 × 106的聚（甲基丙烯酸甲酯）在叔丁醇+水（2.5体积%）的混合溶剂中的稀溶液淬灭至低于相分离温度，并测量散射强度。在1.5 × 10-4至5.6 × 10-4 g/cm 3的浓度范围内进行光散射测量，持续数小时。通过使用Guinier图，作为时间t（min）和浓度c（g/cm 3）的函数，确定聚合物链簇的重均分子量<$M <$w和z均平方半径<$R2 <$z。链聚集过程表现出还原形式的指数增长，其中g = 34.8 cm 3/（g min），其中M（0）是外推到t = 0的值。双对数曲线图中，当Δ M Δ w较小时，Δ M Δ w与Δ R 2 Δ z 1/2之间的关系为略微弯曲的曲线，接近于Δ M Δ w Δ R 2 Δ z 3/2。这些特点所观察到的链聚集过程是C…
To study a chain aggregation process, dilute solutions of poly(methyl methacrylate) in the mixed solvent tert-butyl alcohol + water (2.5 vol %) with the molecular weight m = 1.57 × 106 were quenched to below the phase-separation temperature and scattered intensities were measured. The light-scattering measurement was carried out in the concentration range from 1.5 × 10-4 to 5.6 × 10-4 g/cm3 for a time period of several hours. By using the Guinier plot, the weight-average molecular weight 〈M〉w and z-average square radius 〈R2〉z of clusters of polymer chains were determined as a function of time t (min) and concentration c (g/cm3). The chain aggregation process exhibited an exponential growth of the reduced form 〈M〉w = M(0) exp(gct) with g = 34.8 cm3/(g min), where M(0) is the value extrapolated to t = 0. A double-logarithmic plot of 〈M〉w vs 〈R2〉z1/2 yielded a slightly curved line at small 〈M〉w and approached the relation 〈M〉w ∼ 〈R2〉z3/2. These characteristics of the observed chain aggregation process were c...