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我们用自制的扭辫分析仪对结构不同的五种可熔性聚酰亚胺(见表1)按照程序控温进行了扭辫分析。 (1)对聚(酮-酰亚胺)的热力谱进行了分析,能比较明确区别出玻璃化转变(T_9)及其经闭环、交联反应后的改变(T_(91)、T_(92)),玻璃态中的次级转变(T_β),以及环化反应(T_(r1)),交联反应(T_(r2))与分解反应(T_d)等化学转化。 (2)对五种聚酰亚胺经300℃热处理后的热力谱进行了比较,考察化学结构对T_(91)的影响,T_(91)之值随高分子链刚性的增高而增高。其中四种试样的Tβ(°K)/T_(91)(°K)比值的平均值为0.70。 (3)聚(双酯-酰亚胺)及聚(脂环-酰亚胺)在热力谱上显现特殊性。X-衍射表示聚(双酯-酞亚胺)能形成高度有序的结构;热重分析表示所测样品中聚(脂环-酰亚胺)热稳定性最差。观察到振动曲线的基线飘移,在化学转化时的飘移程度比物理转变时的大。
We used a twist-braided analyzer made of our own twist-pigtailed analysis of five structurally different types of fusible polyimide (see Table 1) according to programmed temperature control. (1) The thermal spectra of poly (keto-imide) were analyzed and the changes of the glass transition (T9) and its ring-closure and cross-linking reaction were clearly distinguished ), The secondary transition in the glassy state (T_β), the cyclization reaction (T_ (r1)), the crosslinking reaction (T_ (r2)) and the decomposition reaction (T_d) (2) The thermodynamic spectra of five polyimides after heat treatment at 300 ℃ were compared. The effect of chemical structure on T 91 was investigated. The value of T 91 increased with the increase of polymer chain rigidity. The average Tβ (° K) / T 91 (° K) ratio of the four samples was 0.70. (3) Poly (dioleate - imide) and poly (alicyclic - imide) in the thermal spectrum showed particularity. X-ray diffraction shows that poly (diester-phthalimide) can form a highly ordered structure; thermogravimetric analysis shows that the poly (alicyclic-imide) in the tested samples has the worst thermal stability. The baseline drift of the vibration curve was observed, and the shift in chemical conversion was greater than that at physical transition.