Huang Wei-Heng, Chen Pei-Hua, Chen Chin-Wen, Su Chie-Shaan, Tang Muoi, Tsai Jung-Chin, Chen Yan-Ping, Lin Feng-Huei
Department of Chemical and Materials Engineering, Chinese Culture University, Taipei 111396, Taiwan.
Department of Biomedical Engineering, National Taiwan University, Taipei 106319, Taiwan.
Molecules. 2024 Sep 6;29(17):4233. doi: 10.3390/molecules29174233.
Supercritical carbon dioxide (SCCO) is a non-toxic and environmentally friendly fluid and has been used in polymerization reactions, processing, foaming, and plasticizing of polymers. Exploring the behavior and data of SCCO sorption and dissolution in polymers provides essential information for polymer applications. This study investigated the sorption and diffusion of SCCO into polyetherimide (PEI). The sorption and desorption processes of SCCO in PEI samples were measured in the temperature range from 40 to 60 °C, the pressure range from 20 to 40 MPa, and the sorption time from 0.25 to 52 h. This study used the ex situ gravimetric method under different operating conditions and applied the Fickian diffusion model to determine the mass diffusivity of SCCO during sorption and desorption processes into and out of PEI. The equilibrium mass gain fraction of SCCO into PEI was reported from 9.0 wt% (at 60 °C and 20 MPa) to 12.8 wt% (at 40 °C and 40 MPa). The sorption amount increased with the increasing SCCO pressure and decreased with the increasing SCCO temperature. This study showed the crossover phenomenon of equilibrium mass gain fraction isotherms with respect to SCCO density. Changes in the sorption mechanism in PEI were observed when the SCCO density was at approximately 840 kg/m. This study qualitatively performed FTIR analysis during the SCCO desorption process. A CO antisymmetric stretching mode was observed near a wavenumber of 2340 cm. A comparison of loss modulus measurements of pure and SCCO-treated PEI specimens showed the shifting of loss maxima. This result showed that the plasticization of PEI was achieved through the sorption process of SCCO.
超临界二氧化碳（SCCO）是一种无毒且环保的流体，已被用于聚合物的聚合反应、加工、发泡和增塑。探索SCCO在聚合物中的吸附和溶解行为及数据，为聚合物应用提供了重要信息。本研究考察了SCCO在聚醚酰亚胺（PEI）中的吸附和扩散。在40至60°C的温度范围、20至40MPa的压力范围以及0.25至52h的吸附时间内，测量了SCCO在PEI样品中的吸附和解吸过程。本研究在不同操作条件下采用异位重量法，并应用菲克扩散模型来确定SCCO在进出PEI的吸附和解吸过程中的质量扩散率。报道了SCCO进入PEI的平衡质量增益分数从9.0 wt%（在60°C和20MPa下）到12.8 wt%（在40°C和40MPa下）。吸附量随SCCO压力的增加而增加，随SCCO温度的升高而降低。本研究表明，平衡质量增益分数等温线相对于SCCO密度存在交叉现象。当SCCO密度约为840 kg/m时，观察到PEI中吸附机制的变化。本研究在SCCO解吸过程中进行了定性的傅里叶变换红外光谱（FTIR）分析。在波数2340 cm附近观察到一个CO反对称拉伸模式。对纯PEI和经SCCO处理的PEI样品的损耗模量测量结果进行比较，显示出损耗最大值的偏移。该结果表明，通过SCCO的吸附过程实现了PEI的增塑。
