JOURNAL OF ELECTRONIC MATERIALS
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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
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
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
MACROMOLECULAR RESEARCH
·
2022
·Vol. 30
·期 8
·579-586
·
IF 2.127
Deng Bo,Luo Xueqin,Jiang Feng,Liu Wei,Gu Jianwei,Liu Chao,Song Yanan
In the petroleum industry, water-soluble polymers can be used as oil displacement agents. However, the use of water-soluble polymers is limited because of poor temperature and salt resistance. To improve temperature and salt resistance, a weakly cationic polymer with large side groups (PAM/AMPS/VI) was prepared by copolymerizing acrylamide (AM) with 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and 1-vinylimidazole (VI). The viscosity of PAM/AMPS/VI water solutions can be increased more than 20 mPa·s compared with PAM/AMPS. In addition, the viscosity of the solution increased continuously after aging at 80 °C, showing good temperature and salt stability. The protonated tertiary amine in the imidazole ring electrostatically interacts with the sulfonic group, increasing the viscosity and salt resistance of the polymer. The five-membered ring of imidazole also enhances the rigidity of the polymer chain and improves the temperature tolerance. As a confirm of the result, a complete spatial network of PAM/AMPS/VI was observed in scanning electron microscopy (SEM) micrographs. Using weak cationic polymers with large side groups can provide a reference for the design of new temperature tolerance and salt resistant polymer.
研究领域:
石油工程
·
高分子化学
✓ 已验证
DOI
高影响因子
Geoenergy Science and Engineering
·
2023
·
IF 0
He Li,Xianbin Huang,Jinsheng Sun,Kaihe Lv
The control of filtration loss under high temperature and high salinity conditions has been a challenge in drilling fluid industry. In this study, a novel tetra-copolymer with multi-ring side groups was prepared with free radical polymerization as a filtration control additive. The copolymer consisting of N, N-dimethylacrylamide (DMAM) 2-acrylamide-2-methylpropanesulfonic acid (AMPS), N-acryloylmorpholine (ACMO), and sodium p-styrenesulfonate (SSS) was named DAAS. DAAS was analyzed for chemical structure and thermal stability, respectively. The rheological behavior and filtration performance of bentonite-based mud (BM) with DAAS addition was investigated under various temperatures and salt contamination (NaCl) conditions. The effect of DAAS on the dynamical stability of BM was analyzed by a multi-light scattering method. The relationship of DAAS absorption capacity on bentonite surface with concentration, absorption time, temperature and NaCl content was investigated in detail. The effect of DAAS on the chemical group, electrical properties, particle size of bentonite was studied to illuminate the mechanism. Based on the results, the DAAS maintained thermally stable up to 306 °C. DAAS enabled the BM to resist saturated salt contamination after aging at 200 °C with a filtration loss of 7.6 ml. DAAS with multiple ring groups absorbed on the bentonite by forming of hydrogen bond with bentonite. Even under saturated salt and high temperature conditions, the adsorption capacity of DAAS remained at a good level. The dispersion properties of BM were enhanced through decreasing the zeta potential and changing particle size of bentonite. One compact and low permeability filter cake was formed. The filtration loss of BM was finally controlled to a low volume.
研究领域:
石油工程
·
材料科学
✓ 已验证
DOI
PROGRESS IN ORGANIC COATINGS
·
2018
·
IF 2.955
Junhua Chen,Kaimei Peng,Ziyi Deng,Chengcheng Tang,Teng Yuan,Feng Wang,Jianqing Hu,Weiping Tu
A series of UV-curable waterborne cathodic electrophoretic deposition (CED) coatings with various structures were successfully developed by introducing modified acrylic monomer with different molecular chain lengths and side groups. The length of linear chain of the modified monomer had little effect on phase separation of acrylic polymer and easily formed homogeneous structure. Owing to the longer molecular chains, the pencil hardness decreased from 2H to H and the glass transition temperature reduced to 77.7 °C. The hard side groups of the modified monomer in CED coatings exhibited opposite characteristics resulting from the steric hindrance of the rigid groups and the crosslinking network, which were more likely to exhibit partial phase separation. Therefore, the stronger rigidity of the molecular structure improved the particle size to 122.42 nm, the smoothness of the CED cured film and surface contact angle decreased. And the morphology of the films became rough and surface contact angle decreased. Besides, the adhesive force and flexibility of the films could be excellent. The surface rust of the modified CED film is not remarkable under salt spray test. The photopolymerization rate (R p ) and the double bond conversion were evaluated. It was found that the R p and the conversion obviously decreased with increasing rigid groups in acrylate molecular chains. However, the maximum decomposition temperature of it was higher than the other samples. The residue char yield (Y c ) was 5.24 wt%. The stronger rigidity of the molecular structure had better thermal stability and mechanical properties.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Xiaorong Dou,Zheqi Chen,Fuhao Ren,Lijun He,Jianxiong Chen,Li-Juan Yin,Yingwu Luo,Zhi-Min Dang,Jie Mao
Dielectric elastomer actuators (DEAs) face an acknowledged challenge: On the one hand, the majority of elastomers only achieve small electroactive deformation (<20%) in the absence of prestretch; on the other hand, rare elastomers capable of showing large electroactive deformation require relatively complicated processing and chemistry. This work addresses this challenge by fabricating an elastomer with a network of large side groups, which achieves a very large electroactive deformation (218%) without pre-stretch. This elastomer can be rapidly and massively fabricated within a few min, by polymerizing a commercial monomer with a large alkyl side group. The large side groups in the polymer network repel each other and extend the load-bearing strands, which results in a pronounced strain-hardening behavior. This behavior helps the elastomer to get rid of electromechanical instability during actuation and hence to exhibit a large electro-active deformation, a high energy density (>> human muscle), and a large output force (≈500 times self-weight). the elastomer capable of manufacturing a soft electroactive gripper is demonstrated with large deformation, large force, and rapid response, which enables grasping fragile objects of various complex shapes in an agile away.
研究领域:
材料科学
·
软体机器人技术
✓ 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）