Polymers
·
2023
·Vol. 15
·期 7
·1673
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IF 5
Zhenzhen Pi,Changyu Deng,Hongmei Pan,Kemei Pei
Polyethylene glycol 1000 (PEG1000) and epoxy resin E20 were used to synthesize the E20/PEG1000 polymer (EP1K), which was later transformed into a self-emulsifying water-based epoxy curing agent by reacting with m-Xylylenediamine (MXDA). The effects of molecular weight, the molar ratio of the raw materials, the catalyst dosage, and the different co-solvents on the properties of the prepared curing agent were systematically explored. The infrared absorption spectra of E20, EP1K, and the water-based epoxy curing agent were compared and analyzed. The coating properties of the waterborne epoxy varnish, which was based on water-based epoxy curing agents to emulsify and cure the resin E44, were systematically tested. The results demonstrated that with a molar ratio of 1:1:4 of PEG1000, E20, and MXDA, the boron trifluoride etherate (BF3·Et2O) as catalyst accounts for 0.3% of the total mass of E20 and PEG1000, and an applicable period of 3 h for the prepared varnish, the anti-corrosion performance, and mechanical properties of the coatings were excellent.Keywords:epoxy resin;curing agent;polyethylene glycol;self-emulsifying
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材料科学
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化学工程
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PubMed
高影响因子
Polymers
·
2022
·Vol. 14
·期 2
·245
·
IF 4.967
Yong Sun,Yongli Peng,Yajiao Zhang
In this work, a flame retardant curing agent (DOPO-MAC) composed of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide DOPO and methyl acrylamide (MAC) was synthesized successfully, and the structure of the compound was characterized by FT-IR and1H-NMR. The non-isothermal kinetics of the epoxy resin/DOPO-MAC system with 1% phosphorus was studied by non-isothermal DSC method. The activation energy of the reaction (Ea), about 46 kJ/mol, was calculated by Kissinger and Ozawa method, indicating that the curing reaction was easy to carry out. The flame retardancy of the epoxy resin system was analyzed by vertical combustion test (UL94) and limiting oxygen index (LOI) test. The results showed that epoxy resin (EP) with 1% phosphorus successfully passed a UL-94 V-0 rating, and the LOI value increased along with the increasing of phosphorus content. It confirmed that DOPO-MAC possessed excellent flame retardance and higher curing reactivity. Moreover, the thermal stability of EP materials was also investigated by TGA. With the DOPO-MAC added, the residual mass of EP materials increased remarkably although the initial decomposition temperature decreased slightly.Keywords:DOPO;flame retardant;curing agent;epoxy resin
研究领域:
材料科学
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化学工程
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PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2017
·Vol. 134
·期 17
·
IF 1.86
Hui Zhang,Liting Yang,Yantao Li,Zijian Tang,Zhihuan Zheng,Li Zhang
In order to improve the flexibility properties of conventional epoxy resin, two novel soybean oil–based curing agents were synthesized. The curing agent obtained from the reaction between epoxy soybean oil and ethylene diamine was named EEDA, and another curing agent derived from epoxy soybean oil and isophorone diamine was named EIPDA. Several techniques were used to systematically investigate the effects of the structure and content of the two curing agents on the properties of the cured products. The Fourier transform infrared analysis demonstrated that epoxy resin reacted with soybean oil–based curing agents. The differential scanning calorimetry analysis showed that the curing process between diglycidyl ether of bisphenol-A (DGEBA) and soybean oil–based curing agents only had an exothermic peak. Thermogravimetric analysis indicated that the cured DGEBA/EIPDA system was more stable than the DGEBA/EEDA system below 300 °C. Mechanical tests and Shore D hardness tests suggested that excessive EEDA greatly enhanced the toughness of cured products because of the introduction of aliphatic chains.© 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44754.
研究领域:
材料科学
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化学工程
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高影响因子
ACS Sustainable Chemistry & Engineering
·
2024
·
IF 7.1
Chang-An Xu,Wenzi Liang,Shaoheng Yang,Yang Hu,Zhuohong Yang,Hao Pang
At present, the dielectric constant of anticorrosion coatings is relatively high, which limits its application in electronic devices, and the epoxy curing agent currently used is mostly from fossil resources, which is not conducive to sustainable development. Therefore, a vanillin-based active ester curing agent (VAEI) containing an imine bond was prepared by the esterification reaction and amine aldehyde condensation reaction. Subsequently, VAEI and amino curing agents cured the epoxy resin to prepare a coating with antibacterial properties, low dielectric, and corrosion resistance. The results showed that when the content of VAEI was 5 wt %, its anticorrosion properties were basically equivalent to that of the coating prepared by the pure amino curing agent. When the content of VAEI was 14 wt %, the impedance modulus of the coating was as high as 1.00 × 109 Ω cm2 after soaking in salt water for 150 days, which was 2 orders of magnitude higher than that of the control group. In addition, the dielectric constant of the coating at 10 MHz decreased from 4.16 to 3.64, and it also exhibited excellent antibacterial properties against Escherichia coli (7.0%) and Staphylococcus aureus (19.6%). This work expands the added value of vanillin and provides a reference for the preparation of various performance coatings.
研究领域:
材料科学
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化学工程
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生物学
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高影响因子
CHEMOSPHERE
·
2021
·
IF 7.086
Pufang Zhao,Wei Zeng,Zhiwang Yang,Yaoxia Yang,Ju Li,Jianping Shi,Na Wen,Hongtao Li,Jie Guan,Ziqiang Lei,Denglong Chen
In this study, a novel organic-inorganic hybrid flame retardant 10-(1,4-dicarboxylic acid magnesium salt)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DMMH) was synthesized via neutralization and addition reaction of maleic acid, magnesium hydroxide and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), and subsequently used in an intrinsic flame retardant epoxy resin . The chemical structure and morphology of DMMH were analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Further, the prepared DMMH was combined with ammonium polyphosphate (APP) to form an intumescent flame retardant system. The thermal stability and flame retardance were evaluated by thermogravimetric analysis (TG), UL-94 vertical burning test, limiting oxygen index (LOI) and cone calorimetry. It was observed that the addition of 1.7% DMMH and 5.3% APP led EP-7 to acquire UL-94 V-0 rating, with the limiting oxygen index of 26.0%. As compared with pure EP, the peak heat release rate, total heat release, smoke production rate and total smoke production of the sample was noted to decrease by 54.5%, 35.1%, 43.6% and 38.1%, respectively. In addition, the introduction of DMMH did not negatively impact the mechanical properties of the epoxy resin.
研究领域:
材料科学
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化学工程
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PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 138
·期 23
·50523
·
IF 3.125
Bing Chen,Qiang Zhang,Mangeng Lu,Huifa Meng,Zhencai Qu,Chang'an Xu,Enxiang Jiao
In this contribution, first of all, the methoxy groups of organic solvent lignin (OSL) was converted to phenolic hydroxyl groups through demethylation reaction for the purpose of fabricating demethylated organic solvent lignin (DOSL). In addition, the resulting DOSL was utilized as a renewable material to synthesize a novel esterified lignin (EDOSL) by reacting with isobutyryl chloride for curing of epoxy resin. Finally, commercial liquid diglycidyl ether of bisphenol A was cured by EDOSL in the presence of 4-dimethylaminopyridine (DMAP) used as a catalyst based on dual-curing mechanism. Dual curing is a processing methodology based upon the alliance of two diverse and compatible polymerization reactions occurring sequentially or simultaneously. According to the FTIR spectra and 1 H-NMR analyses, the demethylation of OSL, esterification of DOSL, and the curing reaction of epoxy resin with EDOSL were successfully conducted. The value of the phenolic hydrogen in the DOSL was approximately 4.89 mmol/g, which increased by 12.64% after demethylation. The thermal and mechanical performances of these cured epoxy samples were measured by DSC, DMA, TGA, and tensile testing. The epoxy system cured by 10%wt esterified lignin with 1%wt DMAP possessed the tensile strength of 71.54 ± 7.50 MPa and the initial degradation temperature ( T 5% ) of 370°C, which can compete fairly with commercial aromatic curing agents or other lignin-based agents studied currently for the curing of epoxy systems.
研究领域:
材料科学
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化学工程
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高影响因子
POLYMER DEGRADATION AND STABILITY
·
2019
·
IF 3.78
Siqi Huo,Zhitian Liu,Chuan Li,Xiaolei Wang,Haopeng Cai,Jun Wang
A flame-retardant curing agent (DTA) for epoxy resin (EP), which was constructed by phosphaphenanthrene and benzimidazole groups, was successfully synthesized via one-pot reaction between 2-aminobenzimidazole, terephthalaldehyde, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). DTA induced the decomposition of EP matrix and promoted the carbonization at high temperature. As expected, DTA endowed EP thermoset with excellent flame retardancy and smoke suppression. For instance, EP/DDS/DTA-0.5 sample containing only 0.5 wt% phosphorus passed UL94 V-1 rating and its LOI value increased to 34.2%. In addition, the pk-HRR, av-HRR, THR, TSR, and TSP of EP/DDS/DTA-1.0 sample were decreased by 56.6%, 31.6%, 34.4%, 24.6% and 24.6% in comparison to those of EP/DDS sample. The flame retardant mechanism showed that the decomposition products of DTA played an important role in the formation of a compact and intumescent char layer in condensed phase. Meanwhile, the phosphorus-containing and nitrogen-containing fragments, which was generated by the pyrolysis of DTA, quenched the active free radicals and diluted the fuels in gaseous phase. Therefore, DTA exerted flame retardant effect in condensed and gaseous phases during combustion.
研究领域:
材料科学
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化学工程
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高影响因子
RSC Advances
·
2015
·Vol. 5
·期 25
·19048-19057
·
IF 3.84
JiaQin Sun,Wei Wei,YaZhen Xu,JieHao Qu,XiangDong Liu,Takeshi Endo
Five commercially available amines: m-phenylenediamine (A1), m-xylylenediamine (A2), isophorone diamine (A3), trimethylhexamethylenediamine (A4), and 4,4′-diaminodiphenyl sulfone (A5), were examined as nucleophilic hardeners for bis-benzoxazine monomers based on aniline paired with bisphenol-A (BA-a) or bisphenol-F (BF-a). The reactivities and reaction mechanisms of their mixtures with BA-a were investigated using FTIR and NMR spectroscopy, DSC, and HPLC techniques. It was found that BA-a rapidly cured with the amines upon heating at 120 °C or 150 °C. The cure rate was similar to the amine/epoxy curing process in practical uses, and significantly faster than the ring-opening polymerization of bulk BA-a. The possible reaction mechanism was supported by the experimental results and includes three successive steps: (i) nucleophilic substitution at the carbon atom (O–C–N) in the oxazine ring by the amine, (ii) thermal decomposition of the resulting aminomethanaminium structure, and (iii) electrophilic addition of the newly formed iminium ion with the aromatic ring to form stable aminomethylphenol structures. These findings are helpful to improve the thermosetting resins in terms of their chemical structure, material properties, and processability.
研究领域:
材料科学
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化学工程
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高影响因子
Materials Chemistry Frontiers
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2021
·Vol. 5
·期 24
·8387-8396
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IF 6.482
Ying Ge,Xueqin Zhang,You Shi,Yuanbo Cai,Shengtai Zhou,Mei Liang,Huawei Zou
In this work, a modified curing agent (MCA) with a flexible long chain and semi-aromatic amide units was synthesized using M-benzoyl chloride and polyether amine (D-230 and D-400), and then innovatively incorporated into epoxy to prepare a multifunctional epoxy structural adhesive with superior flexibility, damping and durability. It was shown that the strength of the MCA modified epoxy thermosets was 18 MPa, and the elongation at break was significantly improved to 17.9 times higher than that of the control blending samples (D-230, D-230&D-400 and D-400). Meanwhile, the MCA modified epoxy resin exhibited great damping behavior; its damping temperature range was from 24.3 °C to 81.6 °C, suggesting that it was a good damping material. After three stretch–recovery cycles, over 97% of the tensile strength of the MCA modified epoxy was still maintained, indicating that it has good stress fatigue durability. This new multifunctional epoxy adhesive significantly broadened the usage of epoxy and has the potential for use as a high damping adhesive in the automotive and aerospace fields.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2024
·
IF 5.9
Yang Luo,Lewen Huang,Jingyu Cai,Qing Jiang,Xiafeng Liao,Haowen Zhang,Yunhong Lan,Xiangyu Yin,Linxi Hou,Longqiang Xiao
Herein, we present the synthesis and characterization of a novel phosphorus-containing epoxy co-curing agent, ANVD, fabricated via a one-pot method utilizing vanillin, 1,5-diaminonaphthalene, and DOPO as raw materials. Structural analysis conducted through FTIR and NMR spectroscopy confirmed the composition of ANVD. Differential scanning calorimetry (DSC) results indicated ANVD has significant contribution to the curing crosslinking of DGEBA, resulting in a slightly decreased T g value for EP/ANVD compared to EP/DOPO, albeit still notably higher. Thermogravimetric analysis (TGA) revealed a reduction in the T 5% and T max values of EP/ANVD, yet ANVD’s superior char-forming ability increased char residue mass at elevated temperatures. Combustion tests showcased the outstanding flame retardancy of EP/ANVD, with EP/ANVD-5 exhibiting a limiting oxygen index (LOI) value of 33.2 % and achieving a V-0 rating in the UL-94 test. Furthermore, EP/ANVD-5 displayed a notable decrease of 38.6 % and 32.1 % in pHRR and av-HRR, respectively, compared to pure EP, surpassing EP/DOPO with equivalent phosphorus content. Analysis of decomposition products in both condensed and gas phases revealed ANVD’s role in forming dense and continuous expanded char layers during combustion, releasing phosphorus radicals and non-combustible gases, thus exhibiting dual-phase flame retardant effects. Additionally, EP/ANVD-3 exhibited enhanced mechanical properties, with tensile strength and modulus increasing from 68.5 MPa and 0.75 GPa to 76.5 MPa and 0.86 GPa, respectively, compared to pure EP. Overall, the introduction of the bio-based flame retardant ANVD presents promising opportunities for the utilization of bio-based materials in flame retardancy applications.
研究领域:
材料科学
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化学工程
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高影响因子
Materials
·
2024
·Vol. 17
·期 17
·4411
·
IF 3.1
Cong Peng,Tao Luo,Zhanjun Wu,Shichao Li
The bisphenol A-type phthalonitrile (BAPH) was blended with the classic epoxy system E51/DDS to prepare the epoxy/phthalonitrile thermoset. The curing kinetics were investigated by differential scanning calorimetry (DSC) using the isoconversional principle, and the average activation energy (Eα) of the E51/DDS curing reaction was found to decrease from 87 kJ/mol to 68.6 kJ/mol. Combining the results of the rheological study, the promoting effect of phthalonitrile on the crosslink of epoxy/amine is confirmed. The curing reaction of the blended resin was characterized using FTIR, and the results showed that BAPH could react with DDS. The thermal behaviors of the thermosets were investigated via DMA and TGA. The glass transition temperature (Tg) is found to increase from 181 °C to 195 °C. The char yield increases from 16% to 59.6% at 800 °C in a N2atmosphere, which is higher than the calculated value based on the proportional principle. The AFM phase images show that there is no phase separation in the cured thermoset. The results imply that the cured epoxy/amine/phthalonitrile blend is probably a kind of copolymer. The real-time TG-MS indicated that the pyrolysis of the thermoset can be divided into two relatively independent stages, which can be assigned to the cleavage of the E51/DDS network, and the phthalocyanine/triazine/isoindoline, respectively.
研究领域:
材料科学
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化学工程
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PubMed
高影响因子
POLYMER ENGINEERING AND SCIENCE
·
2016
·Vol. 56
·期 4
·441-447
·
IF 1.719
Cong Xie,Jifu Du,Zhen Dong,Shaofa Sun,Long Zhao,Lizong Dai
A new reactive phosphorus-containing curing agent with imine linkage called 4, 4′-[1, 3-phenyl-bis(9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-yl)dimethyneimino)]diphenol (2) was synthesized both via two-pot and one-pot procedure. The chemical structure of this curing agent was confirmed by FTIR, 1 H, 13 C, and 31 P NMR spectra. A series of thermosetting systems were prepared by using conventional epoxy resins (E51), 4, 4′-diaminodiphenyl methane (DDM) and (2). Resins with different phosphorus contents were obtained by changing the DDM/(2) molar ratios. Their dynamic mechanical thermal, thermal and flame-retardant properties were evaluated by dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), and limiting oxygen index (LOI), respectively. All samples had a single T g , which showed that these epoxy resins were homogeneous phase. Both the two char yields under nitrogen and air atmospheres increased with increasing content of (2) and the LOI values increased from 24.5 for standard resin to 37.5 for phosphorus-containing resin, which indicated that incorporation of (2) could impart good thermal stability and excellent flame retardancy to the conventional epoxy thermosets. POLYM. ENG. SCI., 56:441–447, 2016. © 2016 Society of Plastics Engineers
研究领域:
材料科学
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化学工程
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DOI
高影响因子
危险品化学品经营许可证（带存储）