HIGH PERFORMANCE POLYMERS
·
2020
·
IF 1.568
Xing-Hua Guan,He-Ran Nie,Hong-Hua Wang,Ji-Yong Zhao,Zhi-Peng Wang,Rui Wang,Bao-Feng Liu,Guang-Yuan Zhou,Qiang Gu
A series of aromatic polyesters bearing fluorene and phthalein groups were synthesized from commercially available 9,9-bis(4-hydroxyphenyl)fluorene (BPF), phenolphthalein, and terephthaloyl chloride through an interfacial polymerization method. The microstructure, molecular weight, morphology, thermal properties, and thermal decomposition mechanism of these aromatic polyesters were investigated. Their mechanical properties were also evaluated. The results suggested that the copolymer compositions were approximately equal to the feed compositions. Moreover, the increase in the BPF unit content increased the glass transition and weight loss temperatures of the aromatic polyesters, owing to the strong rigidity of the bulky fluorene group. All the polymers were amorphous and exhibited good solubility in common organic solvents. Hence, the synthesized polymers could be easily cast into flexible films. The copolymer film samples exhibited better mechanical properties than those of the homopolymers. The tensile strength, Young’s modulus, and elongation at break of the polymers first increased gradually, and then decreased with increasing BPF content. Notably, the copolymers exhibited the best mechanical properties at the BPF content range 30–50%. Owing to their characteristics, these synthesized polymers show great potential for application as high performance membrane materials.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
POLYMER INTERNATIONAL
·
2020
·Vol. 70
·期 3
·282-287
·
IF 2.574
Jiaxin Wei,Yingshuang Shang,Da Xu,Zhaoyang Wang,Zilong Jiang,Yanwei Gao,Haibo Zhang
A series of novel poly(ether ketone) copolymers with different contents of fluorene groups were synthesized. The effects of fluorene group content on the thermal and mechanical properties of poly(ether ketone) copolymers were investigated. The introduction of a low content of fluorene groups can lead to an increase in glass transition temperature, thermal stability and heat deflection temperature. Among them, the heat deflection temperature of 10% fluorene-containing poly(ether ketone) copolymers (PEK-FD10) increases from 178 °C (pure poly(ether ketone)) to 196 °C, which means that the material has a higher heat resistance rating. Compared with poly(ether ketone)s, these copolymers have excellent mechanical properties. When the content of fluorene groups is only 2% (PEK-FD2), the strength is significantly improved. And the flexural strength of PEK-FD2 is 149.3 MPa, which is 12% higher than that of poly(ether ketone). It is worth noting that the fracture toughness and impact toughness are also increased significantly. The strain at break of PEK-FD2 is up to 88% and the impact toughness of PEK-FD2 is 54.6 J m −1 . This suggests that the introduction of minute contents of fluorene groups can simultaneously increase the strength and toughness. © 2020 Society of Industrial Chemistry
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2018
·Vol. 36
·期 8
·970-978
·
IF 2.016
Meng Xiang-Li,Yu Gen-Hua,Ma Jian
Novel poly(aryl ether sulfone ketone)s (PAESK) were synthesized from bisphenol A (BPA), 9,9′-bis(4-hydroxyphenyl) fluorene (BHPF), 4,4′-dichlorodiphenylsulfone (DCS) and 4,4′-difluorobenzophenone (DFB) via nucleophilic substitution polymerization, which were subsequently used to fabricate ultrafiltration membrane by phase-inversion method for high temperature condensed water treatment. The obtained high molecular weight co-polymers with fluorene group with good solubility and good thermal stability, can be easily cast into flexible, white and non-transparent flat films. The influence of molar ratio of BPA and BHPF on the properties of the prepared co-polymers and membranes was investigated in detail. SEM study of the morphology of the membranes indicated that the prepared membranes possessed homogeneous pores on the top surface and were sponge-like or finger-like in cross-section. Pure water flux of the membranes increased from 71.87 L·m −2 ·h −1 to 247.65 L·m −2 ·h −1 , while the retention of BSA decreased slightly, and the water contact angle decreased from 82.1° to 55.6° with the PVP concentration from 0 wt% to 10 wt%. With increasing concentration of PVP, the mechanical properties of membranes decreased, while the thermal stability increased. The permeate flux measurement showed that the PAESK membrane had the potential for high temperature condensed water treatment.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER ENGINEERING AND SCIENCE
·
2012
·Vol. 52
·期 11
·2473-2481
·
IF 1.302
Zien Fu,Huan Liu,Hualun Cai,Xin Liu,Guo Ying,Kai Xu,Mingcai Chen
Three difunctional fluorene-based benzoxazine compounds were synthesized via Mannich condensation and were characterized by proton nuclear magnetic resonance spectroscopy ( 1 H NMR), Fourier transform infrared spectroscopy (FTIR), and elementary analysis (EA). The polymerization of benzoxazine monomers were investigated with differential scanning calorimeter (DSC) method. Thermal properties of the polybenzoxazines were studied by thermogravimetric analysis (TGA) and DSC. Water absorption of the polybenzoxazines was tested. Contact angle measurement was employed to characterize the surface property of materials. The glass transition temperatures ( T g s) and thermal stability were improved significantly in comparison with bisphenol-A-based analogue because of the incorporation of rigid fluorenyl group. The fluorenyl-based polybenzoxazines showed hydrophobic characteristics, which was ascribed to the low polarity of fluorenyl and pi–pi stacking interaction of fluorenyl on the surface. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2024
·Vol. 48
·期 23
·10497-10506
·
IF 2.7
Zhoufeng Wang,Yingying Liu,Bolin Wang,Xiubo Long,Wenlong Yao
Random and block polyarylates were synthesized using bisphenol A (BPA), bisphenol fluorene (BHPF), terephthaloyl chloride (TPC), and isophthaloyl chloride (IPC) as raw materials. The synthesis strategies of one-step and stepwise interfacial polymerization methods were adopted. Both types of polyarylates exhibited similar solubility, with block polyarylates showing slightly broader solvent selectivity. The presence of large sterically hindered fluorene groups in BHPF monomers rendered both block and random polyarylates amorphous by restricting the movement of macromolecular segments. The polyarylates demonstrated excellent thermal stability (T5% = around 490 °C) and a high glass transition temperature (Tg > 210 °C). As the covalent bonds of the monomer linkage showed no significant difference, the thermal stability of both types of products was similar. The glass transition temperature increased with an increase in TPC and diefluorene monomer content. The tensile strengths of the random and block polyarylate films ranged from 45.77–69.89 MPa and 49.49–55.29 MPa, respectively, indicating the high tensile strength of the resulting polyarylates. While the block polyarylates did not show significant differences from the conventional properties of random polyarylates, the synthesis of block polyarylates in this study represents a novel attempt, further highlighting the significant influence of the large pendant group of the main chain on the ordered arrangement of molecular segments.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2014
·
IF 4.908
Guang Lu Han,Pei Yu Xu,Ke Zhou,Qiu Gen Zhang,Ai Mei Zhu,Qing Lin Liu
A series of poly (arylene ether sulfone) block copolymers with hydrophilic segments containing fluorene groups were successfully synthesized as confirmed by 1 H NMR. The molecular weights were measured in the range 115–140 kDa by gel permeation chromatography (GPC). The hydrophilic segment showed a helical structure due to fluorene with butterfly-shaped framework in the main chain. With incorporating imidazolium groups, the microphase separation can also be achieved between the hydrophilic and the hydrophobic moieties. The membrane structure was characterized by positron annihilation lifetime spectroscopy (PALS) and small angle X-ray scattering (SAXS). The block copolymers were used to prepare membranes successfully for pervaporation separation of methanol (MeOH)/methyl tert-butyl ether (MTBE) mixture. The correlation between the membrane microstructure and the separation performance was discussed thoroughly. By increasing the hydrophilic segment proportion, the permeation flux increased while the separation factor declined. The membranes have the highest permeation flux (0.334 kg m −2 h −1 ) and the lowest separation factor (287) for a 15 wt% MeOH feed mixture at 40 °C, and the mass fraction of MeOH in the permeate is higher than 98 wt%.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
HIGH PERFORMANCE POLYMERS
·
2017
·
IF 1.179
Tengyang Zhu,Xing Yang,Xiaoqi He,Yayun Zheng,Jujie Luo
A series of new aromatic polyamides (PAs) and copolyamides (CPAs) containing fluorene group have been synthesized through polycondensation reaction. The chemical structure was confirmed by Fourier transform infrared and proton nuclear magnetic resonance (1H NMR). PAs and CPAs exhibited the higher thermal stability (Td15 > 378°C in nitrogen), the higher glass transition temperature (Tg > 345°C), and excellent solubility in polar solvent. Gas transport properties of the PA and CPA membranes were investigated using different single gases (hydrogen (H2), carbon dioxide (CO2), oxygen (O2), methane (CH4), and nitrogen (N2)). We discussed the effect of chemical structure and operating temperature on gas transport properties. The results show that PA-1 containing a hexafluoroisopropylidene moiety exhibited the highest gas permeability (PH2 = 12.71 Barrer, PCO2 = 12.26 Barrer, and PO2 = 2.62 Barrer) and reasonably good selectivity (α(H2/N2) = 27.63, α(CO2/N2) = 26.65, and α(O2/N2) = 5.70) at 25°C and 1 atm. For all the membranes, gas permeability gradually increased with the increase in operating temperature, while the selectivity gradually decreased. These gas permeation results were well correlated with fractional free volume, interchain d-spacing (dsp), and intermolecular interaction.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2024
·Vol. 14
·期 25
·17771-17779
·
IF 3.9
Tao Lu,Wei Fang,Qian Zhou,Mengjuan Liu,Guozhang Wu
This study aims to synthesize a specific type of polycarbonate with high refractive index, low birefringence, and resistance to hygrothermal aging by copolymerizing 2,2′-bis(2-hydroxyethoxy)-1,1′-binaphthyl (BNE) with 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene (BPEF). Comparative analysis revealed that the copolymer synthesized from BNE and BPEF demonstrated superior hydrolytic stability relative to the bisphenol A-based polycarbonate. This augmented stability can be attributed to the monomers' higher pKa values, rendering acidic substances less capable of dissociating and thereby mitigating ester hydrolysis under hygrothermal conditions. Furthermore, the investigation probed into the phenomenon of physical aging in copolymerized polycarbonate when exposed to hygrothermal environments. It was discerned that the enthalpy loss, observable under both dry and hygrothermal conditions, could be linearly correlated with the difference between the aging temperature and the glass transition temperature (Tg), signifying a close correlation between the magnitude of physical aging and Tg. A lower Tg in the copolymerized polycarbonate led to more pronounced physical aging within the same timeframe, resulting in an augmentation of tensile strength and modulus, while higher Tg effectively mitigated the physical aging phenomenon.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Polymers
·
2024
·Vol. 16
·期 6
·767
·
IF 4.7
Changhai Zhang,Ziyang Liu,Chao Tang,Tiandong Zhang,Yue Zhang,Yongquan Zhang,Qingguo Chi
With the policy tilt and increased investment in research and development in the world, new energy vehicle technology continues to progress and the drive motor power density continues to improve, which puts forward higher requirements for the comprehensive performance of the core insulating material enameled wire enamel for drive motors. Polyimide (PI) has excellent electrical insulation properties, and heat resistance is often used to drive the motor winding insulation. To further improve the corona resistance and insulating properties of PI wire enamel varnish, in this paper, firstly, fluorene groups with a rigid conjugated structure were introduced into the molecular chain of the PI film by molecular structure modulation, and then uniformly dispersed alumina nanoclusters (AOCs) were introduced into the PI matrix by using an in situ growth process to inhibit the migration of high-energy electrons. The quantum size effect of the alumina nanoclusters was exploited to synergistically enhance the suppression and scattering of energetic moving electrons by PI-based composite films. The results show that the breakdown field strength of the PI-based composite film (MPI/1.0 vol% AOC) reaches 672.2 kV/mm, and the corona resistance life reaches 7.9 min, which are, respectively, 1.55 and 2.19 times higher than those of the initial PI film. A PI-based composite film with excellent insulating and corona resistance properties was obtained.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）