CO2-Induced stereocomplex formation of stereoregular poly(methyl methacrylate) and microcellular foams
CO2-Induced stereocomplex formation of stereoregular poly(methyl methacrylate) and microcellular foams
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DOI：
10.1021/ma000443n
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发表时间：
2000-08
期刊：
影响因子：
5.5
通讯作者：
T. Mizumoto;Norio Sugimura;M. Moritani;Yoshiyuki Sato;H. Masuoka
中科院分区：
文献类型：
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作者：
T. Mizumoto;Norio Sugimura;M. Moritani;Yoshiyuki Sato;H. Masuoka
采用差示扫描量热法（DSC）和广角x射线散射（WAXS）研究了高压co2在压力为5-35 MPa、温度为30-110℃范围内诱导的等规聚甲基丙烯酸甲酯（it-PMMA）和间规聚甲基丙烯酸甲酯（st-PMMA）晶体立体配合物的形成与处理压力、温度和it-PMMA/st-PMMA之比的关系。在一定的it-PMMA/st-PMMA比例下，随着处理压力和温度的升高，立体配合物的熔化温度也随之升高。结果表明，用高压co2法合成的立体配合物的数量要高于用原位热退火法合成的立体配合物的数量。在1/2-1/1 it-PMMA/st-PMMA比例下，立体配合物的熔融热最高。与无定形PMMA相比，高压co2诱导的结晶立体配合物有助于获得优异的微孔泡沫形貌。对于CO 2处理的聚合物，随着形成的立体络合物的数量增加，平均细胞尺寸减小，平均细胞密度增加。
Crystalline stereocomplex formation of isotactic poly(methyl methacrylate) (it-PMMA) and syndiotactic poly(methyl methacrylate) (st-PMMA) induced by high-pressure CO 2 at pressures in the 5-35 MPa range and at temperatures in the 30-110 °C range was demonstrated by means of differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS) investigations as a function of treatment pressure, temperature, and the it-PMMA/st-PMMA ratio. At a constant it-PMMA/st-PMMA ratio, the melting temperature of the stereocomplexes was shown to increase with increasing treatment pressure and temperature. The amount of the stereocomplex formed by high-pressure CO 2 was found to be higher than that by thermal annealing in bulk. The heat of melting of the stereocomplex was the highest for the 1/2-1/1 it-PMMA/st-PMMA ratio. Compared with amorphous PMMA, the crystalline stereocomplex induced by high-pressure CO 2 contributes to the superior morphology of the microcellular foams obtained. For the CO 2 -treated polymer, the average cell size decreases and the average cell density increases as the amount of the stereocomplex that was formed increases.