POLYMERS FOR ADVANCED TECHNOLOGIES
·
2020
·Vol. 31
·期 4
·635-644
·
IF 2.578
Fengfeng Zhang,Lishuai Zong,Feng Bao,Zhihuan Weng,Chenghao Wang,Jinyan Wang,Xigao Jian
A novel tetrafunctional epoxy (TEPZ) was synthesized by “one spot two steps” method, and the effects of solvents, reaction temperature, and mole ratios of reactants on the reaction conversion were systematically investigated. The results demonstrated that the solvents participating in the reaction were the most crucial factor for high conversions. After curing, TEPZ/4,4′-diaminodiphenyl sulfone (DDS) system exhibited better thermal stability compared with famous N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenyl methane (TGDDM)/DDS analog. When TEPZ is blended with TGDDM/DDS, the initial decomposition temperature of TGDDM/TEPZ/DDS hybrid elevated from 348°C to 362°C. The storage modulus and the glass transition temperature were sensitive to curing procedure and concentration of DDS. While the system consisted of 100 phr TGDDM, 30 phr TEPZ, and 40 phr DDS, the storage modulus and glass transition temperature increased significantly compared with those of TGDDM/DDS, and the impact strength increased by 31.6% simultaneously. Such enhancement could be ascribed to the structural feature of phthalazinone in TEPZ, which formed stable interpenetrating networks during thermal cure procedure.
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
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 31
·e52718
·
IF 3.057
Zhihang Ma,Xiao Wang,Junru Li,Xinlin Li,Chuanwei Zhang,Ruyi Zhang,Yan Gu,Pengfei Zhang
The reaction process and curing mechanism of self-healable epoxy resin TGDDM and curing agent TA are complicated. In this paper, the curing reaction kinetic mechanism of the system is studied from the perspective of isoconversional models. The n th-order model and autocatalysis model are established for observations of heat flow versus temperature and time during real-time curing obtained by non-isothermal differential scanning calorimetry (DSC), and evaluated under the standards of MSE, RMSE, and R -square. Under the guidance of least squares fitting, the pre-exponential factor ( A ), the activation energy ( E α ), the order of models ( n, m ) and other parameters in f α of the model are mainly estimated by Kissinger method, Ozawa method, Malek method, and other methods. The correlation between the activation energy ( E α ) of the reaction and the degree of conversion α also analyzed by the Flynn-Wall-Ozawa method. The chemical reaction of the system is studied by Fourier transform infrared (FTIR) and the self-healing property of the system is characterized by scanning electron microscope (SEM). It was found that the esterification reaction occurred in the system, and the realization of the self-healing property was also due to the transesterification reaction. In addition, the effect of the accelerator on the system is analyzed by the established autocatalysis model and dynamic mechanical analysis (DMA). The result shows that the addition of the accelerator does not change the curing reaction mechanism of the system, but accelerated the reaction process and increased the glass transition temperature.
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
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2014
·Vol. 117
·期 2
·603-610
·
IF 2.206
Liu Jialin,Li Jingrui,Fan Mengjin,Zhang Junying,Cheng Jue
Aromatic amine curing agent with flexible unit in backbone, 1,4-bis (4-diaminobenzene-1-oxygen) n -butane (DDBE), was synthesized, and the structure was confirmed by FT-IR and 1 H NMR. The curing kinetics of tetraglycidyl methylene dianiline (TGDDM, or AG80) using DDBE and 4,4′-bis-(diaminodiphenyl) methane (DDM) as curing agents, respectively, were comparatively studied by non-isothermal DSC with a model-fitting Málek approach and a model-free advanced isoconversional method of Vyazovkin. The dynamic mechanical properties and thermal stabilities of the cured materials were investigated by DMTA and TG, respectively. The results showed that the activation energy of AG80/DDBE system was slightly higher than that of AG80/DDM system. Šesták-Berggren model can generally simulate well the reaction rates of these two systems. DMTA measurements showed that the storage modulus of cured AG80/DDBE is similar to that of cured AG80/DDM at the temperature below glass transition temperature ( T
g ) and lower than that of cured AG80/DDM at the temperature above glass transition temperature, while T
g of cured AG80/DDBE is lower than that of cured AG80/DDM. TG showed that the thermal stabilities of these two cured systems are similar.
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
CHINESE JOURNAL OF POLYMER SCIENCE
·
2020
·Vol. 38
·期 8
·867-876
·
IF 3.154
Chen Qi,Wang Shun,Qin Feng,Liu Kuan,Liu Qian,Zhao Qing,Wang Xing-Yi,Hu Yan-Hong
Polyimide (PI) synthesized from aromatic diamine and dianhydrides via two-step poly-condensation method was highly soluble in TGDDM (MY-720) and DGEBA (E-51) at desirable temperature. TGDDM-PI (M-PI) and DGEBA-PI (E-PI) composites within 0.5%-3% PI loading could be prepared without organic solvent. On the cryogenically fractured surfaces of M-PI and E-PI composites, no obvious heterogeneous phase was observed by SEM. The mechanical properties were promoted significantly by PI, especially for impact strength. Adding 2% PI-2W into MY-720 and E-51 composites, the impact strength increased to 21 and 51 kJ/m 2 , the tensile strength increased by 62% and 19%, and the flexural strength by 18% and 13%, respectively, with slight increases in tensile modulus. These results were related to the promotion in plasticity of composites and changes in fragile→ductile fracture mode. Moreover, T g and thermal stability of M-PI and E-PI were increased effectively.
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 DEGRADATION AND STABILITY
·
2013
·
IF 2.77
Hua Yan,Chunxiang Lu,Deqi Jing,Xianglin Hou
Chemical decomposition of an epoxy system made of tetraglycidyl 4,4′-diaminodiphenylmethane (TGDDM) and 4,4′-diaminodiphenylsulfone (DDS) in supercritical 1-propanol was investigated under different reaction temperature and time. The GC–MS results suggested that the epoxy system was decomposed to the products including aniline, N-propylbenzenamine, and 4,4′-diaminodiphenylsulfone. The change of the products' yield with time was measured by GC . In addition, the formed chars were characterized by SEM, elemental analysis , Raman and XRD . The results implied the presence of some graphite microcrystals and disordered structure in the solid residue. Upon the addition of KOH, the Guerbet reaction of 1-propanol was promoted to generate more hydrogen. A possible free-radical reaction mechanism was proposed for the depolymerization of TGDDM/DDS epoxy resin . Hydrogenation of radicals had a promotion effect on thermolysis of TGDDM/DDS epoxy resin.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）