Chemistry Department, Faculty of Science, Alexandria University, Alexandria 21321, Egypt.
Department of Engineering Mathematics and Physics, Faculty of Engineering, Alexandria University, Alexandria 21544, Egypt.
Molecules. 2022 Aug 24;27(17):5409. doi: 10.3390/molecules27175409.
A series of novolac phenolic polymeric networks (NPPN) were prepared via an acid-catalyzed polycondensation reaction of formaldehyde with chalcones possessing a -phenolic OH group. When -hydroxybenzaldehyde was treated with formaldehyde under the same conditions, a phenolic polymer (PP) was obtained. The resulting polymers were isolated in excellent yields (83-98%). Isolated polymers (NPPN, PP) were characterized using FTIR, TGA, and XRD. The results obtained from the TGA revealed that all prepared phenolic polymers have high thermal stability at high temperatures and can act as thermosetting materials. XRD data analysis showed a high degree of amorphousness for all polymers (78.8-89.2%). The electrical conductivities and resistivities of all chalcone-based phenolic networks (NPPN) and p-hydroxybenzaldehyde polymer (PP) were also determined. The physical characteristics obtained from the I-V curve showed that the conductivity of phenolic polymers has a wide range from ultimately negligible values of 0.09 µS/cm up to 2.97 μS/cm. The degree of polarization of the conjugated system's carbonyl group was attributed to high, low, or even no conductivity for all phenolic polymers since the electronic effects (inductive and mesomeric) could impact the polarization of the carbonyl group and, consequently, change the degree of the charge separation to show varied conductivity values.
通过酸催化缩合反应，将具有 - 酚羟基的查尔酮与甲醛反应制备了一系列 novolac 酚醛聚合物网络（NPPN）。当 - 羟基苯甲醛在相同条件下与甲醛反应时，得到酚醛聚合物（PP）。所得聚合物以优异的产率（83-98%）分离。使用 FTIR、TGA 和 XRD 对分离得到的聚合物（NPPN、PP）进行了表征。TGA 结果表明，所有制备的酚醛聚合物在高温下具有很高的热稳定性，可用作热固性材料。XRD 数据分析表明，所有聚合物都具有很高的非晶度（78.8-89.2%）。还测定了所有基于查尔酮的酚醛网络（NPPN）和对羟基苯甲醛聚合物（PP）的电导率和电阻率。从 I-V 曲线获得的物理特性表明，酚醛聚合物的电导率从 0.09 µS/cm 的最终可忽略值到 2.97 µS/cm 的宽范围。共轭体系羰基的极化程度归因于所有酚醛聚合物的高、低甚至无导电性，因为电子效应（诱导和介电）可能会影响羰基的极化，从而改变电荷分离的程度，显示出不同的电导率值。
