EUROPEAN POLYMER JOURNAL
·
2021
·
IF 4.598
Zhenghui Yang,Pingchuan Ma,Furong Li,Haiquan Guo,Chuanqing Kang,Lianxun Gao
The flexibility of organic light-emitting diode (OLED) displays highly depends on the properties of the flexible substrates. In this paper, a series of aromatic polyimides have been fabricated via the copolycondensation of pyromellitic dianhydride (PMDA), the two different rigid heterocyclic diamines, 2,5-bis(4-aminophenyl)pyrimidine (PRM) or 2,5-bis(4-aminophenyl)pyridine (PRD), and another flexible diamine, 4,4′-oxydianiline (ODA). The performance of the polyimide films could be systematically tailored by means of adjusting the main-chain rigidity, as well as the close packing and orientation of polymer chains by the formation of the intermolecular hydrogen bonds between poly(amic acid)s. The optimal results (PIb-4, PIb-5, PIc-2) showed that the polyimides were endowed with ultra-high glass transition temperature (T g ) exceeding 450 °C, low coefficient of thermal expansion (CTE) at 0–5 ppm K −1 and excellent thermal stability (T d5% = 570–590 °C). Meanwhile, all of them exhibited sufficient flexibility, the elongation at break at of 40–60%, extremely high tensile strength of 250–380 MPa and modulus of 4.1–6.1 GPa. Hence, the polyimide films should be the promising candidates for application as the polymer substrates for flexible OLED displays.
研究领域:
材料科学
·
显示技术
✓ 已验证
产品关联
DOI
高影响因子
Polymer Chemistry
·
2021
·Vol. 12
·期 37
·5364-5376
·
IF 5.582
Zhenghui Yang,Haiquan Guo,Chuanqing Kang,Lianxun Gao
Three novel dianhydride monomers involving amide groups were synthesized and further polymerized with various diamines to afford a series of colorless polyimides (cPI). The resultant cPI films present outstanding optical performance, exceedingly good dimensional stability at high temperature, great film ductility and solution-processability. In particular, chemically imidized AMDA/TFDB has an ultra-low coefficient of thermal expansion value of 5.2 ppm K−A, a relatively high Tg value of 333 °C and large elongation at break of 29%, resulting from its rigid-rod backbone and the formation of hydrogen bonding (–CO⋯NH–) between adjacent molecular chains. Concurrently, it exhibits a high optical transmittance of 87% at a wavelength of 550 nm, a small haze value of 0.71 and low yellow index of 4.29 by reason that the incorporation of bulky trifluoromethyl and cyclohexyl preclude the formation of a charge transfer complex effectively. The high overall performance of the amide-containing cPI films suggests its potential application in the field of flexible OLED displays.
研究领域:
材料科学
·
显示技术
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Polymer Materials
·
2026
·
IF 5.2
Zeyu Li,Desheng Kong,Shun Shi,Tong Yuan,Jianfeng Qian,Jiaojiao Ma,Haiquan Guo
To address the current challenge in advanced packaging technology where it is difficult to simultaneously achieve multiple outstanding properties in photosensitive polyimide (PSPI) structural designs. This work designed a low dielectric constant (Dk), low coefficient of thermal expansion (CTE) negative-photosensitive polyimide with water-based development capable of low-temperature curing. The method achieves low Dk (minimum ε < 3.0 at 10 GHz) and low CTE (minimum CTE as low as −3.23 ppm/K) by introducing a fluorinated rigid backbone structure into the polyamide ester (PAE, PSPI precursor) main chain. Simultaneously, photosensitive groups and water-soluble quaternary ammonium groups were incorporated into the side chains to enable high-resolution aqueous development (up to 4 μm). Quaternary ammonium salts degrade into tertiary ammonium during the imidization stage, which can further catalyze the low-temperature thermal imidization of PAE. Side chains degrade and vanish during imidization while preserving the polyimide backbone’s superior properties. This method achieves the synthesis of PSPI with multiple outstanding properties through sophisticated molecular structure design. This passage tackles the existing bottlenecks in PSPI performance stemming from structural limitations, aligns with the evolving requirements of cutting-edge packaging technologies, and showcases remarkable promise for future applications.
✓ 已验证
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2024
·
IF 5.8
Junji Wei,Hao Wang,Zongwu Zhang,Zexing Zhang,Runlin Lu
High-temperature thermosetting resin with low dielectric constant ( κ ), low thermal expansion coefficient (CTE), and high modulus are drawing more and more attention from scientists and engineers in the field of the high-frequency circuit, 5G and 6G communication networks to improve the signal transmission speed. Epoxy resin, as one of the important thermosetting resin members, possesses excellent properties such as heat resistance, cohesiveness, and reactivity. However, Epoxy resin was usually mixed with different inorganic fillers to meet the above requirements, especially to decrease the κ and CTE. In this work, a new class of spirobisindane epoxy resin monomer (TSDEP) was synthesized by a classic two-step method based on 3,3,3′,3′-tetramethyl-1,1′-spirobisindane-6,6′-diol (TSD). Due to the highly distorted rigid structure of TSD, the movement of the TSDEP molecular segment is subject to more restrictions after being cured, and the free volume will increase. After cured by 4,4′-diamino diphenyl sulfone (DDS), the TSDEP/DDS resin exhibited many desirable physical properties, e.g., low dielectric constant (∼3.45, 1 MHz), low dielectric loss (∼0.025, 1 MHz), low coefficient of thermal expansion (CTE, 72 ppm/ °C, 35–150 °C), high glass transition temperature ( T g > 241 °C) and high thermal stability ( T d5% ∼400 °C). Furthermore, TSDEP/DDS exhibited excellent mechanical rigidity with a storage modulus of ∼ 3.1 GPa. Compared with TSDEP/DDS, 4-methylhexahydrophthalic anhydride (MHHPA) cured TSDEP system showed lower κ (∼3.09) and dielectric loss (0.015) due to weaker polar ester groups instead of more polar hydroxy groups.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2023
·
IF 6
Yuan-Yuan Liu,Jian-Hua Cao,Yue Li,Ya-Kun Wang,Da-Yong Wu
In this work, we use 2-aminobenzimidazole and 2-aminobenzoxazole to end-cap colorless polymer, PAI TFDB-TPC-6FDA, in order to investigate methods for reducing the CTE value of products and their effects on other properties. Results show that, as the ratio of 2-aminobenzimidazole to the raw material, diamine TFDB, increases from 0:100 to 2:99, the CTE value of products gradually decreases from 20.0 to 12.9 ppm/K (a decrease of 36%). Nevertheless, the CTE value of products rebounds as the dosage of the end-capped groups exceeds this ratio. Among all the products obtained, PAI-1M film has the best overall properties: its CTE is 12.9 ppm/K, T d 5 is 518 ℃, T g is 366 ℃, T S is 191 MPa, T 430 is 85.1%, W A is 85.4% and C A is 0.8%. The two end-capped groups are of highly linear and rigid structures. They also help to enhance the hydrogen bonding between molecules, resulting in a decrease in d -spacing values. The results of molecular configuration simulation and calculation indicate that, using 2-aminobenzimidazole to end-cap the chains of PAI molecules is beneficial for suppressing the formation of the charge-transfer complexes (CTCs), and thereby offsetting impacts of the reduced molecular chain spacing on the transparency of films. Based on these two influencing factors, we confidently conclude that linear and rigid end-capped groups can effectively improve the dimensional stability and mechanical properties of PAI films without damaging their optical properties.
研究领域:
高分子科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2025
·Vol. 36
·期 14
·831
·
IF 2.8
Zhao Tianqun,Zeng Tianrui,Jin Shilei,Li Xiaohui,Yu Zhiqiang
BNT (BaO–Nd 2 O 3 –TiO 2 ) system was modified via doping using sol–gel method, and BNST-Mn/PTFE microwave dielectric composite was prepared by mechanical blending. Scanning electron microscopy (SEM), thermal dilatometer, and split post-dielectric resonator (SPDR) were used to characterize the microstructure, dielectric properties, and thermal properties of the composite materials. The results indicate that as the amount of ceramic filler supplied grows, the agglomeration of fillers becomes more pronounced. At a filler content of 10 wt%, the dispersion of the filler in the matrix resin is relatively uniform. The dielectric constant and dielectric loss of the composites increased, and the bonding ability between the two phases diminished with the increase in filler content. When the mass fraction of the ceramic was increased to 70 wt%, the dielectric constant of the composite was 10.92 and the Q·f value was measured at 3584 GHz. At the same time, the coefficient of thermal expansion (CTE) of the composites reached 23 ppm/°C, which was a good compatibility with the copper foil. Lichtenecker equation, Maxwell–Wagner equation, Jayasundere–Smith equation, and effective medium theory equation (EMT) were used to predict the dielectric constant of the composites. In comparison, the dielectric constant values calculated using the EMT equation were in good agreement with the experimental values, especially at low filling volumes. Also, the simulation results of the thermal expansion coefficient of composite materials using the Lichtenecker equation and its improved form are in good agreement with the experimental values.
研究领域:
材料科学
·
陶瓷与复合材料
·
介电材料
·
微波技术
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2021
·Vol. 222
·期 23
·2100284
·
IF 2.527
Da Zhang,Jinxin Zheng,Pengfei Zhang,Ronghui Zhao,Zhuo Chen,Meng Wang,Kuilin Deng
In the synthesis of traditional AIE-active polymers with conjugate or multi-benzene system, the troublesome process is still faced such as consuming time, high temperature, catalysis, no water or vacuum, and so on. In this study, the polydihydropyrimidone derivatives (PDPMDs) with AIE properties are facilely synthesized by the introduction of 4-dihydropyrimidone rings onto non-AIE-active intermediate polyureas (PUs) in Biginelli reaction. It is found that the unsymmetrical L- lysine ethyl diisocyanate and butylenediamine played a very important role in the smooth preparation and fluorescence enhancement of PDPMDs. Compared with the intermediate PUs, the fluorescence of PDPMDs is significantly enhanced (35-fold increase), which is mainly due to the intramolecular aggregation of dihydropyrimidone rings on PUs chains. At the same time, with the increase of the content of dihydropyrimidone rings, the fluorescence intensity of PDPMDs also increases, and the emission wavelength shows an obvious red shift. The fluorescence of PDPMDs also showed obvious dependence on excitation wavelength, which further reveals the clusterization-triggering emission (CTE) mechanism. In summary, the strategy of endowing AIE properties to non-AIE active polymer by introducing heterocycles into the backbone through multi-component reaction provides useful guidance for AIE functionalization of other non-AIE materials.
研究领域:
材料科学
·
化学
·
高分子科学
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE
·
2024
·
IF 3.9
Lei Yang,Jinglei Xing,Minghui Bai,Xingzhong Fang,Guofei Chen
Transparent polyimides were expected to be an alternative to glass substrates. To meet the requirements of high transparency, high heat resistance, and low coefficients of thermal expansion (CTE) for substrate materials, a series of poly(amide-imide)s (PAIs) were synthesized from 2,2′-bis(trifluoromethyl)benzidine (TFDB), (hexafluoroisopropylidene)diphthalic anhydride (6FDA), cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA), terephthaloyl chloride (TPC) and 9,9-bis(4-aminophenyl)fluorene (FDA) with different substituents. And the corresponding films were prepared by adding 0 or 2 pph lithium chloride (LiCl). Through the adjustment of monomer ratio, regulation of the amino ortho -position of diamine monomer, and coordination of Li ions, all PAIs exhibited high glass transition temperatures ( T g ) of 390°C–436°C, low CTE of 12.5–60.9 ppm K −1 , excellent optical transmittances of 71%–84% at 400 nm, high tensile strengths of 140–204 MPa, and high tensile moduli of 4.4–7.2 GPa. In particular, PAI-M-1-2-2Li showed the best comprehensive properties with the transmittance of 83% at 400 nm, T g of 432°C, CTE of 18.7 ppm K −1 , tensile modulus of 6.9 GPa and tensile strength of 204 MPa, which made it competitive in flexible display applications. Graphical
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
ACS Applied Polymer Materials
·
2022
·
IF 4.855
Yuan-Yuan Liu,Jian-Hua Cao,Ying Wang,Shao-Gang Shen,Wei-Hua Liang,Da-Yong Wu
In this study, we intend to solve the problem of the low glass transition temperature (Tg) and the high coefficient of thermal expansion (CTE) that colorless polyimide (PI) films always exhibit. First, we copolymerized 2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diamine (TFDB) with 4,4′-(hexafluoroisopropene) diphthalic anhydride (6FDA) and p-phthaloyl chloride (TPC) and obtained a series of transparent and colorless films (PAI-10). These PAI films showed a high Tg of 346–362 °C and a low CTE of 25.2–62.9 ppm/K, which were better than those of PI6FDA-TFDB. Subsequently, three rigid diamines, p-phenylenediamine (p-PDA), 5-amino-2-(4-aminophenyl)benzoxazole (DAPBO) and 5-amino-2-(4-aminophenyl)benzimidazole (DAPBI), were used to replace 10% of the TFDB (PAI-9P-5, PAI-9O-5, and PAI-9I-5, respectively) to investigate the effect of the rigid structure on the thermal and optical properties. The results showed that rigid structures can greatly improve the thermal properties but impair transparency to some extent. Among these, PAI-9O-5 possessed the best performance with T430 of 81.9%, Tg of 364 °C, and CTE of 19.8 ppm/K. Furthermore, we fabricated an organic light-emitting diode (OLED) with PAI-9O-5 as the substrate. The flexible and bendable OLED@PAI-9O-5 showed typical green emission at 520 nm, a turn-on voltage of 2.9 V, a luminance of 1000 cd/m2 at 5 V, a current efficiency (CE) of 2.53 cd/A, and an external quantum efficiency (EQE) of 0.81%, which were comparable to those of devices fabricated on conventional glass substrates.
研究领域:
材料科学
·
高分子化学
·
光电学
·
柔性电子学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Polymer Materials
·
2020
·
IF 0
Ke Jin,Yuhui Huang,Yudi Feng,Jia Guo,Jiangtao Xu,Changchun Wang
Soluble, thermally, and dimensionally stable polyarylamides have been a long-standing challenge for polymer chemists and materials scientists. Herein, we designed and synthesized a series of polyarylamides with various contents of the seven-membered carbocycle unit of 1,2:4,5-dibenzocycloheptadiene (DBCHD) as the linkage in the polymer backbones. In comparison to their analog with an ether linkage, these advanced polyarylamides showed improved thermal stability (5% weight loss temperature, 413–480 °C) and elevated glass transition temperatures (218–243 °C) depending on the content of the DBCHD unit. Given the good solubility in polar aprotic solvents, the polyarylamide films were prepared by simple and straightforward solution casting, which presented excellent optical transparency and low coefficient of thermal expansion (CTE). The polyarylamide with the highest content of DBCHD (43.5 wt %) showed a CTE value of 41.0 ppm/K in the temperature range of 0–150 °C, which is 43% lower than that of the corresponding ether-linked polyarylamide film. Variable-temperature 1H NMR demonstrated that the nonplanar and moderately rigid structural features of DBCHD units in polymer backbones are the key influence factors that contribute to thermal stability and reduced thermal expansion.
研究领域:
聚合物化学
·
材料科学
✓ 已验证
产品关联
DOI
BIOMACROMOLECULES
·
2022
·
IF 6.978
Jun Hu,Kunyan Lu,Chuan Gu,Xingyu Heng,Fangjian Shan,Gaojian Chen
The search for novel fluorescent materials has attracted the attention of many researchers. Numerous bioimaging materials based on the aggregation-induced emission (AIE) units have been surging and could be employed in wide areas during the past two decades. In recent few years, the appearance of nonconventional fluorescence emitters without aromatic conjugated structures provides another bioimaging candidate which has the advantage of enhanced biodegradability and relatively low cost, and their luminescent mechanism can be explained by clustering-triggered emission (CTE) like AIE. In our contribution, we utilize nonaromatic sugar as a monomer to prepare a series of glycopolymers with designed components through sunlight-induced reversible addition fragmentation chain transfer polymerization; these glycopolymers can be employed in bioimaging fields due to the bioactivity coming from sugar and CTE capacity.
研究领域:
材料科学
·
生物医学工程
·
化学
·
生物学
✓ 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）