Thermal, mechanical, and morphological analyses of poly(2,6-dimethyl-1,4-phenylene oxide)/styrene-butadiene-styrene copolymer blends
Thermal, mechanical, and morphological analyses of poly(2,6-dimethyl-1,4-phenylene oxide)/styrene-butadiene-styrene copolymer blends
复制标题
DOI：
10.1021/ma00184a026
复制
发表时间：
1988-11
期刊：
影响因子：
5.5
通讯作者：
P. S. Tucker;J. W. Barlow;D. R. Paul
中科院分区：
文献类型：
--
作者：
P. S. Tucker;J. W. Barlow;D. R. Paul
通过差示扫描量热仪和动态力学行为的观察，发现苯乙烯-丁二烯-苯乙烯(SBS)三嵌段共聚物与聚(2，6-二甲基-1，4-苯氧基)PPO的共混物在单一玻璃化转变的基础上形成了单一的混合硬相。这一相的玻璃化转变区域非常宽，这被认为是由于两种类型的聚合物链段跨域的浓度梯度造成的。扫描电子显微镜显示，硬磁区尺寸的增加与PPO的各向同性膨胀的方式一致。在很高的PPO水平下，似乎有少量未混合的PPO相，在所使用的技术范围内无法检测到热转变。对于许多共混物，橡胶和硬质相形成了相互连续的网络，其中玻璃相具有海绵状，而橡胶相具有骨架形式。在25℃下的模数随这些相的比例而变化，其方式与所看到的形态一致。
Blends of a styrene-butadiene-styrene, SBS, triblock copolymer with a poly (2, 6-dimethyl-1, 4-phenylene oxide), PPO, appear to form a single, mixed hard phase on the basis of the observation of a single, glass transition, by both differential scanning calorimetry and dynamic mechanical behavior, that varies with composition from that of polystyrenedomains to that of pure PPO. The glass transition region for this phase is unusually broad, and this is believed to be caused by concentration gradients of the two types of polymer segments across the domains. Scanning transmission electron microscopy shows that the dimensions of the hard domains increase in a manner consistent with their being isotropically swollen by the PPO added. At very high PPO levels, there appears to be small quantities of an unmixed PPO phase for which no thermal transition could be detected within the limits of the techniques used. For many of the blends, the rubber and the hard phases form co-continuous networks in which the glassy phase has a spongelike form and the rubbery phase has a skeletal form. The modulus at 25 C varies with the proportions of thesephases in a manner consistent with the morphologies seen.