Fibers
·
2024
·Vol. 12
·期 8
·61
·
IF 4
Wissam Bessa,Djalal Trache,Sid-Ali Moulai,Ahmed Fouzi Tarchoun,Amir Abdelaziz,Tuan Sherwyn Hamidon,Mohd Hazwan Hussin
This study aims to explore new flame-retardant composites based on a phosphorus-functionalized cellulose derivative and epoxy/benzoxazine thermosetting resins in order to broaden the use of natural fibers in advanced applications. The study involved the phosphorylation of microcrystalline cellulose followed by its characterization through employing various analytical methods to corroborate the accomplishment of its functionalization. The curing behavior of composites based on the polybenzoxazine/epoxy copolymer reinforced with (1 and 5 wt.%) modified microcrystalline cellulose was hereafter considered. The thermal behavior of these composites was correspondingly investigated using thermogravimetric analysis, where improved thermal stability and the limiting oxygen index were stressed. Flame retardancy tests using the vertical burning test UL 94 and heat of combustion analysis utilizing an oxygen bomb calorimeter were also carried out to deeply examine the possible flame retardancy ability of the considered composites.
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
HIGH PERFORMANCE POLYMERS
·
2023
·
IF 2.1
Xuhai Xiong,Donghui Liu,Rong Ren,Jing Wang
Four novel phthalonitrile-capped polyarylene ether nitrile oligomers containing trifluoromethyl groups (FPEN-Ph) with different molecular weight were designed and synthesized by adjusting the ratio of bisphenol AF (BPAF) and 2,6-dicholorobenzonitrile (DCBN). The molecular structure of FPEN-Ph oligomers were characterized and analyzed by FTIR, 1HNMR and Gel permeation chromatography. Their curing behaviors were studied by Differential scanning calorimetry and rheological tests, and curing kinetics were also discussed by gel method in detail. The glass fiber cloth reinforced FPEN-Ph composites (FPEN-Ph/GF) had flexural strengths of 415.9–497.5 MPa, shear strengths of 34.5–50.5 MPa, and glass transition temperatures (Tgs) in the range of 211.3°C–416.6°C. The initial thermal decomposition temperatures (T5%) of various FPEN-Ph cured products were higher than 500°C under nitrogen. Meanwhile, Fracture morphologies showed that the GF/FPEN-Ph composites had excellent interfacial adhesion between FPEN-Ph matrix and GF reinforcement. Herein, the FPEN-Ph resin could be a good candidate for high-performance polymeric composites and the advanced FPEN-Ph/GF composites can be used under high temperature environment.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2018
·
IF 2.975
Abdul Qadeer Dayo,An-ran Wang,Mehdi Derradji,Sadia Kiran,Abdeldjalil Zegaoui,Jun Wang,Wen-bin Liu
The eugenol based phthalonitrile (EPN) monomer was successfully copolymerized with mono and difunctional benzoxazine (P-a and BA-a) monomers via concerted catalysis polymerization . The loading of EPN in benzoxazine monomers was varied from 10 to 40 wt% and impacts of loading on thermal, thermomechanical and mechanical properties were studied. The FTIR analysis confirmed that both poly(P-a/EPN) and poly(BA-a/EPN) copolymers can be completely cured without the addition of curing additive. The addition of the bio-based EPN monomer enhanced the curing peak temperatures and reduced the curing reaction enthalpies . Initially, OH groups were produced from the oxazine ring opening polymerization of benzoxazine and they enhanced the curing of EPN. The thermal stabilities, as well as the stiffness and T g of the copolymers, were much higher as compared to the neat polymers. Highest values were seen on the 40 wt% loading of EPN monomer in the copolymers. Moreover, the difunctional benzoxazine based copolymer showed higher enhancements in the properties as compared to the mono-functional benzoxazine based copolymer. The decline was seen in the flexural properties as EPN monomer contains the flexible chain in the structure. The morphological changes supported all the claims for the copolymers. The prepared copolymers can be used as a high performance thermosetting resin .
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
POLYMER BULLETIN
·
2015
·Vol. 72
·期 8
·2105-2125
·
IF 1.438
Liu Yuhong,Wang Yichao,Jiang Xue,Zhang Xiying
Abstract In the study, we investigated the influence of degree of branching (DB) of isocyanate-functionalized hyperbranched polyurethanes (HPU –NCOX ) on the cure and thermal property of phenol-terminated benzoxazine oligomer (BZ –OH ). The structure of the as-synthesized HPU –NCOX was confirmed by proton nuclear magnetic resonance ( 1 H NMR and 13 C NMR), gel permeation chromatography (GPC) and Fourier transform infrared spectra (FT-IR). Thermally activated cross-linking behavior as well as the thermal stability of HPU –NCOX /BZ –OH blend was investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). HPU –NCOX can covalently incorporate into BZ –OH via urethane reaction. Both the cure kinetics and the weight residue of HPU –NCOX /BZ –OH copolymer reveal a gradual increase with the improvement of DB of HPU –NCOX . Graphical abstract A novel isocyanate-functionalized hyperbranched polyurethanes (HPU –NCOX ) with degree of branching (DB) ranging from 25.1 to 51.1 % were successfully synthesized. The HPU –NCOX and benzoxazine copolymers exhibit enhanced cure kinetics with the increase of DB of HPU –NCOX .
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
JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 53
·期 11
·8221-8231
·
IF 2.993
Chen Pengpeng,Liang Xiao,Zhou Yifeng,Nie Wangyan
The effects of amino-functionalized molybdenum disulfide (f-MoS 2 ) on the curing activity and mechanical properties of epoxy-based composites were evaluated. The f-MoS 2 was prepared through the mild reaction between mercapto-ethylamine and the exfoliated MoS 2 . Benefiting from the universal binding ability of amino groups, good dispersion of f-MoS 2 in epoxy matrix was achieved. Studies of the curing behavior of epoxy composites showed that the curing temperature and heat release during the curing process of epoxy composites with MoS 2 was lower than that of neat epoxy and composites with MoS 2 , indicating a decreased activation energy. The f-MoS 2 containing amino groups on its surface was revealed can react with epoxy matrix and enhance the curing reactions like a co-curing agent of amine-type curing agent. The mechanical properties and thermal stability of the epoxy were both enhanced by f-MoS 2 . The storage modulus of the EP/f-MoS 2 composites was about 60% higher than that of EP/MoS 2 composites, which was attributed to the improved dispersion of f-MoS 2 in matrix and the strengthened interfacial interactions between f-MoS 2 with epoxy than that of the neat MoS 2 .
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
MACROMOLECULAR RESEARCH
·
2018
·Vol. 26
·期 6
·529-538
·
IF 1.767
Wei Jingjing,Ma Songqi,Yue Hong,Wang Sheng,Zhu Jin
Hydrogenated bisphenol A epoxy resin was cured using different kind of curing agents, resulting in epoxy networks with better shape memory properties than bisphenol A epoxy networks. The non-isothermal curing kinetics investigated by differential scanning calorimetry (DSC) demonstrated that hydrogenated bisphenol A epoxy showed lower curing reactivity than bisphenol A epoxy, while it still could be cured well. The thermal and mechanical properties as well as shape memory properties were studied by dynamic mechanical analysis (DMA), DSC, thermogravimetric analysis (TGA), three-point bending test and U-type shape memory test and cyclic stretch test using DMA. Results manifested that hydrogenated bisphenol A epoxy systems exhibited lower shape transition temperature (lower T
g
), slightly higher modulus, better toughness, much faster shape recovery rate, and better elongating ability at temperature above T
g
than bisphenol A epoxy systems, which was due to the rigidity of cyclohexane ring from its steric hindrance and favorable segmental mobility when absorbing external energy such as heating or bending. Moreover, the shape fixity and shape recovery ratio of all the samples were as high as 96.3~98.5% and 100% and their cycling stability during shape memory test was excellent. Although lower than bisphenol A epoxy networks, hydrogenated bisphenol A epoxy networks possessed high thermal stability with initial degradation temperature ( T d 5% ) of >305 °C.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
Frontiers of Chemical Science and Engineering
·
2021
·Vol. 15
·期 5
·1281-1295
·
IF 4.204
Yang Jinian,Xu Yuxuan,Su Chang,Nie Shibin,Li Zhenyu
Poor interfacial adhesion and dispersity severely obstruct the continued development of carbon nanotube (CNT)-reinforced epoxy (EP) for potential applications. Herein, hierarchical CNT nanohybrids using nickel phyllosilicate (Ni-PS) as surface decorations (CNT@Ni-PS) were synthesized, and the nanocomposites derived from varied mass fractions of EP and CNT@Ni-PS were prepared. The morphological structures, tribological performances, curing behaviors and thermal properties of EP/CNT@Ni-PS nanocomposites were carefully investigated. Results show that hierarchical CNT nanohybrids with homogeneous dispersion and well-bonded interfacial adhesion in the matrix are successfully obtained, presenting significantly improved thermal and tribological properties. Moreover, analysis on cure kinetics proves the excellent promotion of CNT@Ni-PS on the non-isothermal curing process, lowering the curing energy barrier steadily.
研究领域:
材料科学
·
纳米技术
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2012
·Vol. 126
·期 1
·205-215
·
IF 1.289
Jiang-tao Hu,Aijuan Gu,Guozheng Liang,Dongxian Zhuo,Li Yuan
A new hyperbranched polysiloxane containing maleimide (HPMA) was synthesized through the reaction between N -(4-hydroxyphenyl) maleimide and 3-glycidoxypropyltrimethoxysilane, which was then used to prepare cyanate ester (CE) resin-based hybrids (coded as HPMA x /CE, where x is the weight fraction of HPMA in the hybrid). The curing behavior of uncured hybrids and the typical properties (impact strength and dielectric properties) of cured hybrids were systemically investigated. Results show that the performance of hybrids is greatly related with the content of HPMA. Hybrids have obviously lower curing temperature than CE, overcoming the poor curing characteristics (higher curing temperature and longer curing time) of neat CE, for example, the curing peak temperature of HPMA20/CE is about 65°C lower than that of CE. In the case of cured resin and hybrids, the hybrids exhibit decreased dielectric constant and loss than CE resin; moreover, the former also exhibits lower water absorption than the latter. Specifically, the dielectric loss of HPMA15/CE hybrid is only about 27% of that of neat CE resin. In addition, the hybrids with suitable contents of HPMA have significantly improved impact strengths. The overall improved properties suggest that HPMA x /CE hybrids have great potential in applications needing harsh requirements of curing feature, dielectric properties, and toughness. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
研究领域:
材料科学
·
高分子化学
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 22
·52263
·
IF 3.057
Jie Zhang,Zongwei Guo,Jinpeng Ma,Lingxiao Song,Guorui Yang,Yuhui Ao,Lei Shang,Ming Li
As an important thermosetting resin, epoxy resin (EP) is widely used in the field of composite materials. Long storage time, rapid curing and low viscosity of one-component EP is ideal for preparing composite materials by vacuum assisted resin transfer molding (VARTM). For this sake, we developed and synthesized a new imidazole thermal latent curing agent, 4,7-diimidazol-2,1,3-benzothiadiazole (BTD-MZ 2 ) with a yield of about 75%. The curing behavior, thermal stability and storage time of the prepared EP system was studied by differential scanning calorimeter (DSC), thermal gravimetric analyzer (TGA), modular compact rheometer (MCR), respectively. DSC results showed that EP/17.5 wt% BTD-MZ 2 had a good latent period at low temperature, and can rapidly cure EP when heated to 150°C. TGA results show that BTD-MZ 2 promoted the formation of carbon residue and the residual carbon rate of EP/17.5 wt% BTD-MZ 2 is as high as 37.9%. MCR results show that the storage time of EP/17.5 wt% BTD-MZ 2 at 60°C can reach 850 min. In addition, it could play a role of catalyst used as co-curing agents with aromatic amines for EP. DSC test showed that the addition of 5 wt% BTD-MZ 2 reduced the activation energy of EP/4,4′-diaminodiphenylmethane (DDM) and promoted the curing reaction.
研究领域:
材料科学
·
化学工程
·
高分子科学
✓ 已验证
产品关联
DOI
高影响因子
Applied Sciences-Basel
·
2019
·Vol. 9
·期 11
·2365
·
IF 2.217
Hongtao Cao,Beijun Liu,Yiwen Ye,Yunfang Liu,Peng Li
Featured ApplicationThe addition of the BADCy resin nanoparticles can accelerate the formation of the microgels in the BADCy resin prepolymer. The kinetic paraments of systems with different BADCy resin nanoparticles contents were obtained using the Avrami equation and Arrhenius equation and explained the formation and growth of the microgels.AbstractBisphenol A dicyanate (BADCy) resin nanoparticles were synthesized by precipitation polymerization and used to modulate the microstructure of the BADCy resin matrix. A microscopic mechanism model was used to characterize the curing process of BADCy resin systems with different contents of the prepared nanoparticles. Due to the curing process of the thermosetting resin being analogous to the crystallization process of the polymer, the Avrami equation was used to analyze the microscopic mechanism of the curing process. The reactive functional groups, structure, and size of the prepared BADCy resin nanoparticles were characterized by FT-IR, SEM, and TEM, respectively. The kinetic parameters of different systems were then obtained using the Avrami equation, and they adequately explained the microscopic mechanism of the curing process. The results showed that the Avrami equation effectively described the formation and growth of gel particles during the curing process of the BADCy resins. The addition of nanoparticles can affect the curing behavior and curing rate. Since the reaction between the BADCy resin nanoparticles and the matrix is dominant, the formation process of the gel particles was neglected. This phenomenon can be understood as the added BADCy resin nanoparticles replacing the formation of gel particles. The reasons for accelerated curing were analyzed from the perspective of thermodynamics and kinetics. Besides this, the Arrhenius equation for non-isothermal conditions correctly accounted for the change in the cross-linked mechanism in the late-stage curing process. A comparison of the theoretical prediction with the experimental data shows that the Avrami theory of phase change can simulate the curing kinetics of different BADCy resin systems well and explain the effects of BADCy resin nanoparticles on the formation of the microstructure.Keywords:bisphenol a dicyanate resin;Avrami equation;Arrhenius equation;curing behavior
研究领域:
材料科学
·
高分子化学
·
热固性树脂
✓ 已验证
产品关联
DOI
高影响因子
IRANIAN POLYMER JOURNAL
·
2021
·Vol. 30
·期 7
·643-654
·
IF 1.899
Zhang Haibo,Li Wanbing,Xu Jiali,Shang Shibin,Song Zhanqian
Acrylicpimaric acid-based epoxy (APA-based epoxy) and tung oil maleic anhydride (TMA), as a curing agent, were synthesized and used to prepare fully bio-based cured epoxies. The chemical structure was characterized by FTIR and 1 H NMR spectroscopy techniques. The effects of using APA-based epoxy to replace DER332 epoxy were investigated. The curing behavior, dynamic mechanical properties, mechanical properties, thermal stability and fracture surface were studied using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), a universal testing machine, thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The activation energy ( E a ) of the curing process of the APA-based epoxy with TMA was 69.45 kJ/mol, which was almost the same as the E a of the curing of DER332 process with TMA. Because of the rigidity of the hydrogen phenanthrene ring structure in the APA-based epoxy was higher than that of bisphenol A structure in DER332, the glass transition temperature ( T g ) of the cured APA-based epoxy was 21 °C higher than that of the cured DER332 epoxy. The tensile strength, Young’s modulus and the peak temperature of the weight loss rate ( T max ) of cured APA-based epoxy were higher than those of the cured DER332 epoxy. With a decrease in the APA-based epoxy content, the fracture surfaces of the cured APA-epoxy were much rougher. The cured APA-based epoxy exhibited higher storage modulus and Young’s modulus than the cured resins that were formed from flexible monomers. Therefore, the APA-based epoxy showed great potential to replace DER322 epoxy in preparing cured epoxies.
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
CERAMICS INTERNATIONAL
·
2016
·
IF 2.758
Kehang Li,Zhe Zhao
Stereolithography (SLA) has been regarded as the most promising rapid prototype (RP) production method for ceramic parts recently because of its better precision in size and site control. The rheological behavior and curing behavior of suspensions are controlling factors for ceramic stereolithography. In this work, oleic acid (OA), stearic acid (SA) and Poly(Acrylate Ammonium) (PAA-NH 4 ) were studied as the surfactant for HDDA-based suspension formulation. Modified alumina particles exhibit different wettability with HDDA monomer and thus the different rheology behavior and stability between the formulated suspensions. OA shows the best performance among all three dispersants . 40 vol% alumina suspensions with a viscosity ˂3 Pa s at 30 s −1 shear rate were successfully formulated with OA and SA. A sintering density of 95% can be reached for the OA- and SA-modified alumina UV-curable resins.
研究领域:
材料科学
·
陶瓷
·
三维打印
·
高分子化学
·
表面化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）