Tuning Molecular Composition for Better Cross-section Homogeneity of Thermal Oxidative Stabilized Polyacrylonitrile for Carbon Materials

Shiyu Liu,Yuan Ge,Baijun Liu,Zhongyu Fu,Xiaoyu Yu,Ming Yao Zhang,Hui Xuan Zhang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.6

A strategy to improve the cross-section homogeneity of thermal oxidative stabilized polyacrylonitrile for carbonmaterials was provided in the present work. A kind of comonomer, dimethyl itaconate (DMI), which possesses two bulkyside groups was introduced into poly(acrylonitrile-co-itaconic acid). The efficiency of DMI in improving the cross-sectionhomogeneity of polyacrylonitrile films during thermal oxidative stabilization (TOS) processes and the properties of resultedPAN-based carbon materials were investigated in detail. It was found that DMI facilitated the formation of longer cyclicstructures, higher oxygen content, more homogeneous cross-section fracture morphology and denser structure during TOSprocess. DMI was also benefit for easing heat release. The presence of DMI also facilitated a smaller ID/IG value of thecarbonized PAN film and a bigger in-plane size of graphite crystals La.

Synthesis of Novel Poly(aryl ether sulfone)s Bearing Bulky Pendants for Gas Separation Membranes

Zhuang Liu,Baijun Liu,Long Li,Yinan Zhang,Zhenhua Jiang 한국고분자학회 2013 Macromolecular Research Vol.21 No.6

A hydroxylated poly(aryl ether sulfone) (PES-OH) was synthesized by a demethylation reaction of a methoxy-functionalized PES (PES-OCH3) using the HCl/pyridine system. Derived from this hydroxylated PES precursor,bulky (2-trifluoromethyl-4-nitro) phenyl (TFN) and benzophenone (BZP) were introduced to the PES backbones as side groups via aromatic nucleophilic substitution reactions. A direct property comparison of PES-OH,PES-OCH3, PES-TFN and PES-BZP has been made, and these analogues exhibited different solubility, thermal properties and gas permeability. PES grafted with the trifluoromethyl side group (PES-TFN) demonstrated more attractive permeabilities and permselectivities for O2/N2 separation compared to the others, and it exhibited the best P(O2)/P(N2) value of 8.44.

Synthesis of Sulfonated Fluorenyl-Containing Poly(ether ether ketone ketone)s and Their Blends with an Amino-Functionalized Poly(ether ether ketone) for Fuel Cell Applications

Long Li,Baijun Liu,Siyuan Liu,Zhuang Liu,Yunwu Yu,Liwei Jing,Zhenhua Jiang 한국고분자학회 2013 Macromolecular Research Vol.21 No.7

A new family of sulfonated fluorenyl-containing poly(ether ether ketone ketone)s (SFPEEKKs) were successfully synthesized through a mild postsulfonation in concentrated sulfuric acid at room temperature. Further, a series of “molecule-enhanced” blend membranes were prepared based on SFPEEKKs and an amino-functionalized poly(ether ether ketone) by the solution casting method. These blend membranes generally showed higher thermal stability, lower swelling ratio and methanol permeability and superior mechanical properties in comparison with pristine SFPEEKK membranes. The results showed that some blend membranes may be promising proton exchange membranes for fuel cell applications.

Fluorinated/Non-Fluorinated Sulfonated Polynaphthalimides as Proton Exchange Membranes

Yang Song,Chang Liu,Dianfu Ren,Liwei Jing,Zhenhua Jiang,Baijun Liu 한국고분자학회 2013 Macromolecular Research Vol.21 No.5

Two -SO3H containing diamine monomers, 2,5-bis(4-amino-2-trifluoromethylphenoxy)benzenesulfonic acid and 2,5-bis(4-aminophenoxy)benzenesulfonic acid were successfully synthesized through a typical aromatic nucleophilic substitution reaction followed by a reduction reaction, respectively. Derived from the diamine monomers,two series of sulfonated naphthalic polyimides (polynaphthalimides) containing ether and ketone linkages were synthesized through a “one pot” polymerization reaction. Some properties including thermal stability, mechanical properties, water uptake, swelling dimensional ratio, methanol permeability, and proton conductivity were thoroughly investigated. Some exhibited attractive properties as proton exchange membranes. It was found that the fluorinated series (CF3-SPI-X) exhibited higher dimensional stability and lower methanol permeability in comparison with non-fluorinated ones (SPI-X) at the same -SO3H group content.

Early Plasma Circulating Tumor DNA as a Potential Biomarker of Disease Recurrence in Non-metastatic Prostate Cancer

Xiaochen Fei,Xinxing Du,Yiming Gong,Jiazhou Liu,Liancheng Fan,Jiayi Wang,Yanqing Wang,Yinjie Zhu,Jiahua Pan,Baijun Dong,Wei Xue 대한암학회 2023 Cancer Research and Treatment Vol.55 No.3

Purpose In non-metastatic prostate cancer (nmPCa) setting, it is important to early identify the patients at risk of biochemical recurrence (BCR) for immediate postoperative intervention. Our study aimed to evaluate the potential clinical utility of circulating tumor DNA (ctDNA) for predicting disease recurrence.Materials and Methods This real-world observational study evaluated 161 cases of nmPCa undergoing next-generation sequencing at our institution. A total of 139 ctDNA samples and 31 biopsied tumor tissue underwent genomic profiling. The study endpoint was BCR after radical prostatectomy. Relationships between the ctDNA status and the biochemical progression-free survival (bPFS) were analyzed by log-rank test and multivariate Cox regression.Results Of 161 enrolled patients, 19 (11.8%) harbored deleterious alterations in <i>NCOR2</i>, followed by <i>BRCA2</i> (3.7%), <i>ATR</i> (2.5%), and <i>CDK12</i> (2.5%). Of available pre-operative blood samples (n=139), ctDNA was detectable in 91 (65.5%). Until last follow-up, 56 of 68 patients (85.3%) with detectable ctDNA had achieved BCR, whereas only eight of 39 patients (20.5%) with undetectable ctDNA had achieved BCR. Patients who had undetectable ctDNA experienced significantly longer bPFS compared with those who had detectable ctDNA (not available vs. 8.2 months; hazard ratio, 0.14; p < 0.01). Pre-operative ctDNA status was a significant prognostic factor of disease recurrence.Conclusion Pre-operative ctDNA detection could identify patients at high risk of recurrence and has the potential to inform immediate postoperative interventions, but these approaches remain to be validated in prospective studies. ctDNA studies can provide insights into accurate monitoring and precise treatment rather than simply following routine clinical care.

Lignin Based Flexible Electromagnetic Shielding PU Synergized with Graphite

Jia Zhang,Yunxia Qi,Yumei Zhang,Jinchi Duan,Bairun Liu,Baijun Liu,Zhaoyan Sun,Yiquan Xu,Wei Hu,Niaona Zhang 한국섬유공학회 2021 Fibers and polymers Vol.22 No.1

In this paper, lignin (L)-based polyurethane (FeGLPU) with excellent electromagnetic shielding properties wasprepared and studied. The modified reduced iron powder was modified with KH550, and then the obtained modified reducediron powder (Fe) was mixed with lignin, polyethylene glycol 200 (PEG200), hexamethylene diisocyanate (HDI) and graphite(G) to in-situ synthesize the FeGLPU. The thermal stability, mechanical properties, electronic conductivity, and morphologyof the composite FeGLPU were characterized in detail. The electromagnetic interference shielding effectiveness (EMI SE) ofFeGLPU was tested in the frequency range of 8.2-26.5 GHz. When the content of Fe and G was fixed at 10 % and the lignincontent was 5 %, the maximum EMI SE was 21.6 dB, and the frequency width of EMI SE greater than 10 dB was 18.3 GHz. The conductivity was 4.27×10-4 S/m, and the tensile strength of Fe10G10L5PU reached 11.7 MPa. When the lignin contentincreased to be 20 %, the maximum EMI SE was 22.5 dB, and the frequency width of EMI SE greater than 10 dB was18.3 GHz. The conductivity was 1.06×10-2 S/m, and the thermal decomposition temperature T5 (5 % weight loss) reached234 °C. The obtained excellent EMI SE should be due to the synergistic effect of Fe, G and lignin. It can be observed fromthe SEM observation that the G and Fe are uniformly dispersed in PU matrix with strong interfacial interaction. It wasillustrated that the prepared FeGLPU was with efficient electromagnetic shielding properties, good mechanical properties,and high thermal stability. This lignin based electromagnetic shielding PU was proposed to have broad application prospectsdue to its low expenses and ecology friendliness.