Polymers
·
2019
·Vol. 11
·期 5
·803
·
IF 3.164
Feng Bao,Fengfeng Zhang,Chenghao Wang,Yuanyuan Song,Nan Li,Jinyan Wang,Xigao Jian
The application of poly(phthalazinone ether ketone)s (PPEKs) resin containing phthalazinone moiety is limited, due to its poor thermoforming processability. To investigate the effects of the phthalazinone’s side-group on the thermal stability and processability of the resin, a series of PPEKs resins with different side-group (–H/–CH3/–Ph) were prepared by nucleophilic aromatic substitution polymerization. The properties of the obtained resins were investigated by differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TGA), dynamic thermomechanical analysis (DMA), and rheogoniometer. The results show that the introduction of methyl or phenyl into the PPEKs resin, significantly reduced the melting viscosity of the resin, but resulted in a slight decrease in the thermal stability of it. This might be due to the presence of methyl or phenyl, which enhanced the free volume of the molecule and reduced the entanglement between the chains; the results of the computer simulation confirmed it. Moreover, the resin films displayed excellent tensile strength with the introduction of methyl or phenyl. In a word, a novel poly(phthalazinone ether ketone)s resin with thermal resistance, easy processing and excellent mechanical properties could be obtained by introducing appropriate bulk-rigid side-groups into the phthalazinone moiety.Keywords:phthalazinone;side-group;thermal properties;processability
研究领域:
材料科学
·
高分子化学
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产品关联
DOI
PubMed
高影响因子
POLYMER
·
2021
·
IF 4.43
Yadi Liu,Sheng Zhou,Ning Zhao,Jian Xu,Zhihao Shen,Xing-He Fan,Qi-Feng Zhou
A series of aramids containing hydroxyl side group (NOM-OH c , where c is the molar fraction of hydroxyl substitution in the polymer, and c = 0, 10, 20, 40, 60, 80, 100) were synthesized by direct high-temperature polycondensation . The synthesis employed a facile process. The monomer , 4,4'-(terephthaloylbis(azanediyl))bis(2-hydroxybenzoic acid), was prepared simply via an esterification reaction. The chemical structures of the soluble aramids were confirmed by 1 H NMR. And the molecular weight and mass dispersity of the aramids were obtained by size exclusion chromatography , instead of the traditional intrinsic viscosity method. The use of unsymmetrical monomers and the introduction of hydroxyl side group into the aramid structure decrease the conjugation of the polymer main chain, and thus the resulting aramid has excellent solubility in relatively polar solvents , such as N -methy-2-pyrrolidone, dimethylsulfoxide , N , N -dimethylacetamide, and N , N -dimethylformamide. As a result, the molding processability of the aramids and their composites is greatly improved. For example, films can be made by solution spinning and casting. The films have good mechanical strength , with tensile strength , tensile modulus , and elongation at break in the range of 68–95 MPa, 2.65–3.12 GPa, and 5–10%. The thermal resistance of the aramids is still quite good, with 5% weight loss temperatures in nitrogen and in air in the range of 360–430 °C.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
POLYMER INTERNATIONAL
·
2019
·Vol. 68
·期 6
·1186-1193
·
IF 2.433
Qi Wu,Xiaoru Ma,Feng Zheng,Xuemin Lu,Qinghua Lu
A new diamine with bulky pendant biphenyl and ortho -position dimethyl structures, 4,4′-((1,1′-biphenyl)-4-ylmethylene)bis(2,6-dimethylaniline), was synthesized via a one-pot reaction of 4-biphenyl carboxaldehyde and 2,6-dimethylaniline. The diamine was employed to polymerize with several dianhydrides via one-step condensation under high-temperature conditions. The light yellow or colorless polyimide (PI) films obtained were found to have cut-off wavelengths in the range 286–358 nm and transmittance over 80% in the visible region (400–780 nm). Meanwhile, these PIs possessed excellent solubility in common organic solvents, even in low-boiling-point solvents such as chloroform (CHCl 3 ), dichloromethane (CH 2 Cl 2 ) and tetrahydrofuran. The glass transition temperatures ( T g ) of the PIs were determined to exceed 343 °C, even to 456 °C. All PI films were flexible with a tensile strength of 78–119 MPa, a Young's modulus of 2.0–2.5 GPa and elongation at break of 4.0%–8.2%. Therefore, these colorless PIs can be used as candidate materials for flexible display substrates. © 2019 Society of Chemical Industry
研究领域:
材料科学
·
化学工程
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产品关联
DOI
高影响因子
MACROMOLECULES
·
2022
·
IF 6.057
Hui Jie Zhang,Xinyi Wang,Yuxi Yang,Tao Lin Sun,Aokai Zhang,Xiangyu You
Hydrogen bonds stabilized by hydrophobic side groups have been widely applied to realize high toughness of hydrogels. Herein, we studied the effect of the content of the hydrophobic methyl side group on the structure and mechanical properties of tough hydrogen-bonded gelatin/poly (methacrylic acid–co-acrylic acid) (G/Mx-Ay) hydrogels by alternating the content of methacrylic acid (MAA) in the methacrylic acid–acrylic acid copolymer (MAA-co-AA). The content of MAA did not affect the hydrogen-bond formation between the MAA-co-AA and gelatin but affected the phase-separated structure. With an increase in the MAA content, the local structure of the hydrogels with similar water content transformed from a “network” structure to a “bicontinuous” phase-separated structure and to a phase-separated structure with wide size distribution. The hydrogels with the same structure exhibited similar viscoelastic behaviors, and the G/Mx-Ay hydrogels with “bicontinuous” phase separation exhibited the best mechanical properties with an optimal Young’s modulus of ∼7.5 MPa and fracture tensile stress of ∼10 MPa.
研究领域:
材料科学
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生物材料
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2017
·Vol. 55
·期 13
·2227-2233
·
IF 2.952
Zhi-Peng Yu,Na Liu,Ya-Lan Lin,Jian Huang,Hui-Qing Wang,Zong-Quan Wu
A cholesteryloxyallene (1) bearing chiral cholesteryl pendant group was designed and synthesized. Living polymerization of this monomer with an allylnickel complex as a catalyst give poly(cholesteryloxyallene)s (poly- 1 m s) in high yields with controllable molecular weights and narrow molecular weight distributions. These polymers were found to possess a dynamic helical conformation with a preferred handedness in n -hexane as confirmed by circular dichroism and absorption spectra as well as optical ratios. The helical conformation of the polymers was revealed to stabilize as the number of repeat units increased until the degree of polymerization reached 100. The helical conformation of poly- 1 100 could be controlled by altering the temperature of solutions. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2227–2233
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF ELECTRONIC MATERIALS
·
2016
·Vol. 46
·期 2
·982-991
·
IF 1.491
Guo Huilong,Lu Mangeng,Liang Liyan,Wu Kun,Ma Dong,Xue Wei
In this work, liquid crystalline epoxies with lateral substituents were synthesized and cured with aromatic amines or anhydride. The liquid crystalline phase structure of liquid crystalline epoxies with lateral substituents was determined by polarized optical microscopy. The relationship between thermal conductivity and dielectric properties and liquid crystalline domain structure was discussed in the paper. The samples show high thermal conductivity up to 0.29 W/(m × K), due to the orientation of mesogenic units in epoxies. The sample's low dielectric constant of 2.29 is associated with the oriented mesogenic units and long nonpolar lateral substituents. This indicates a new way to obtain materials with high thermal conductivity and a low dielectric constant by introducing oriented mesogenic units into cross-linked epoxy systems. The water repellency is reflected in the contact angles of 92–98°, which are apparently higher than that of conventional epoxy systems. It was also found that the better toughness of liquid crystalline epoxies with lateral substituents was attributed to the existence of long flexible alkyl lateral substituents.
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
EUROPEAN POLYMER JOURNAL
·
2019
·
IF 3.621
Qi Wu,Xiaoru Ma,Feng Zheng,Xuemin Lu,Qinghua Lu
Highly transparent polyimides (PIs) with excellent combined properties are in great demand for flexible optical devices. In this work, transparent PIs were synthesized by fluorinated aromatic dianhydride ( 6FDA ) and three aromatic diamines containing methyl side groups with different amount and position. These PIs possessed moderate to great optical transparency and excellent solubility. With four methyl groups at 2,2′,5,5′-position in diamine, 2255TMB–PI exhibited the best transmittance up to 82% at 400 nm. In all cases, PIs were determined to have low dielectric constants (2.84–2.99) and high glass transition temperature (above 390 °C, even up to 407 °C for 2255TMB–PI ). In addition, the toughness of these PI films was also proven by a tensile strength of 130 – 156 MPa. In spite of the electron donating character of methyl groups, their steric hindrance was found to have significant effect on the combination properties of PIs. Spatial structures and packing morphology are thought to be the main contribution. Therefore, this work provided an easy way to prepare highly transparent polyimides with excellent combined properties by controlling steric hindrance through methyl side groups.
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
POLYMER COMPOSITES
·
2016
·Vol. 39
·期 1
·126-134
·
IF 2.004
Chunhua Lai,Junjie Li,Xiongzhi Xiang,Lei Wang,Danqing Liu
A series of conjugated poly(3,4-ethylenedioxythiophene methine)s (PEDOT-Ms) with different side groups (e.g., electron-withdrawing, electron-donating, and electron-neutralizing groups) containing 3,4-ethylenedioxythiophene (EDOT) units was synthesized and characterized, showing low optical bandgaps. Then, the PEDOT-M polymers were blended with graphite (G) to prepare polymer–inorganic composites to compare their thermoelectric (TE) properties. The optical absorption study indicated direct bandgaps ranging from 1.72 to 1.79 eV. The results showed that PEDOT-M polymers with strongly electron-withdrawing and electron-donating groups exhibited lower bandgap values and higher Seebeck coefficients, and their composites exhibited better TE properties than PEDOT-M with an electron-neutralizing side group. The highest figure of merit (ZT) value for the (poly[{3,4-ethylenedioxythiophene-2,5-diyl} { p -nitrobenzylidene}{3,4-ethylenedioxythiophenequinodimethane-2,5-diyl}])(PEDOT-NBQ)/80 wt% G composite was 6.75 × 10 −3 at 120°C, which was higher than the ZT value of the other PEDOT-M/G composites. These results reveal a novel approach using the structural modifications of polymers to improve the understanding of TE performance and confirm that the conjugated PEDOT-M samples studied are low-bandgap conducting polymers that can be used as TE materials. POLYM. COMPOS., 39:126–134, 2018. © 2016 Society of Plastics Engineers
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
INDUSTRIAL CROPS AND PRODUCTS
·
2022
·
IF 6.449
Juan He,Lingzhi Song,Zhongkai Wang
The design of functional polyamides for specialized applications has attracted increasing attention during recent years. Herein, a facile and efficient method towards mechanical strong functional polyamides with varied side groups is developed. An α , ω -diene functional amide monomer was prepared through the amidation reaction of methyl 10-undecenoate (a kind of castor oil derivative) and 1,3-diamino-2-propanol. The pendant hydroxyl group was converted to ester groups to afford six other monomers. High molecular weight functional polyamides with varied pendant groups, including hydroxyl, acetate, butyrate , isobutyrate, benzoate, acrylate, and imidazole, were prepared via thiol-ene addition polymerization. Differential scanning calorimetry (DSC) and atomic force microscopy (AFM) results indicate that the melting temperature, degree of crystallization, and crystalline size depend on the pendant groups. Inspired by natural silk proteins , functional polyamides with controllable mechanical properties can be achieved by copolymerizing of these monomers.
研究领域:
材料科学
·
有机化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2025
·
IF 4.5
Yu Zhang,Guang-ming Yan,Jie Yang,Gang Zhang
Low dielectric polymers are urgently needed in wireless communication. Compared with porous structure, the introduction of free volume can reduce the dielectric constant without damage the mechanical properties. Therefore, a new kind of low dielectric constant polyarylates with furan as the reactive pendent groups (PAFRs) were innovatively designed and synthesized based on furfural. The introduction of pendent furan groups was found to increase the free volume and molecular chain space that further affect the dielectric properties. The dielectric constant and dielectric loss of PAFRs decreased down to 2.57–2.92 and 0.005–0.0091 at 1 MHz, respectively, with excellent thermal (T g > 209 °C) and mechanical properties (Tensile strength >73 MPa). Furthermore, reversible crosslinked low dielectric constant polyarylates (C-PAFR) were designed and prepared by dynamic covalent based on pendent furan groups. The crosslinked structure further reduced the dielectric constant as the dielectric constant of crosslinked PAFR films (C-PAFR23) could even decrease down to 2.17. In addition, the dynamic crosslinked structure endowed C-PAFRs with excellent solvent resistance and good re-processability with the on/off Diels-Alder reaction. We believe such recyclable dynamic crosslinked low dielectric materials are interesting and would be applicable in the field of wireless communication.
研究领域:
材料科学
·
无线通信材料
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Wenran Gao,Yiling Wan,Shanhui Zhao,Muhammad Asif Akhtar,Kuan Ding,Bin Li,Yinlong Wu,Shoujun Zhang,Shu Zhang
Ketonization of biomass-derived oxygenates is promising for sustainable production of platform chemicals, but the catalyst activity will be severely inhibited by furanic compounds. To investigate the mechanism of the inhibition effect, furanic compounds with different side functional groups were chosen for co-ketonization with propanoic acid over CeO 2 . Results from 12 h continuous reaction showed that conversion of propanoic acid changed slightly when furan was co-fed with propanoic acid, while decreased significantly from 100 % for sole propanoic acid feeding to <55 % when co-feeding with furfural and furfuralcohol. Therefore, the inhibition ability followed the order of furfural ≈ furfuralcohol ≫ furan, which agreed well with the coke yield on the spent catalysts (51 %, 47 %, and 22 %, respectively). DFT calculation indicated that furfural and furfuralcohol, with the adsorption energy of 17–19 kJ·mol −1 , were much easier to adsorb on the catalyst than furan (11 kJ·mol −1 ). However, the lack of α-H of these furanic compounds led to their conversion into aromatic coke components. It is evidenced that the oxygenated side groups, rather than the furan ring, are responsible for the inhibition effect. Successive ketonization-combustion-ketonization tests revealed that simple air calcination can hardly recover the activity of the spent CeO 2 . This investigation gives new insights into the inhibitory impact of furans on the ketonization activity.
研究领域:
化学工程
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2023
·
IF 9.5
Junhao Xin,Xiaowei Zhou,Guolong Huo,Zhiguang Zhang,Yuchen Zhang,Shuanyan Kang,Zhongde Dai,Nanwen Li
In the current study, three 6FDA 1 /BPDA 1 -based polyimides (PIs) containing different diamine moieties (DMB, TCDB, TFDB) were selected to prepare CMS membranes (CMSMs), providing a systematic study of PIs with different side group functionalization. The resultant CMSMs were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, and CO 2 absorption measurements. Pure gas (N 2 , O 2 , CH 4 , CO 2 ) and mixed gas (CO 2 /CH 4 ) permeability tests were also conducted. The resultant CMSMs exhibited attractive gas separation performance. Compared to DMB-based PI, TFDB-based with trifluoromethyl (-CF 3 ) side groups exhibited ultra-high permeability (P CO2 = 14938 Barrer, P O2 = 3146 Barrer) and moderate selectivity (α CO2/CH4 = 20.3, α O2/N2 = 4.5), while CMSMs prepared from PI with chlorine functionalization showed higher gas permeability (P CO2 = 6031 Barrer, P O2 = 1311 Barrer) and selectivity (α CO2/CH4 = 46.2, α O2/N2 = 6.5). The results indicated that side group functionalization on PIs exerts a considerable influence on the gas permeation properties of CMSMs.
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
危险品化学品经营许可证（带存储）