THERMOCHIMICA ACTA
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2021
·
IF 3.115
Zhongying Ma,Dehai Meng,Zhihao Zhang,Yuhua Wang
A novel environment-friendly and efficient flame retardant (phytic acid [PA] - layered double hydroxide [LDH]) has been synthesized to enhance the flame retardancy of PVA. PA-LDH possesses better char formation ability with a high char residue of 68.7 wt% at 600 °C. Peak release rate (pHRR) and heat release capacity (HRC) values of PVA/PA-LDH15% are 180 W/g and 310 J/g-K, with the descent of 69.4% and 31.7%, respectively. The burning rate of PVA/PA-LDH decreased visibly, presented that higher fire retardancy can be obtained for PVA/PA-LDH. It is worth noting that PA-LDH could restrain the melt-dripping of PVA during the combustion process, which is of great significance in fire-spread control. Furthermore, the synergistic flame-retardant mechanism of phosphorus-contained PA and inorganic LDH is proposed based on microscopic analysis on char residues. In addition, PVA/PA-LDH composites exhibit good mechanical properties, the green flame retardant is of considerable significance to the flame-retardant treatment of polymers.
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Materials
·
2023
·Vol. 17
·期 1
·87
·
IF 3.4
Ying Lei,Feng Lin,Nengyu Hong,Jian Zhang,Yulin Wang,Haijie Ben,Jianguang Li,Liyong Ding,Liang Lv
Noble metal-free electrocatalysts have received widespread attention in a hydrogen evolution reaction (HER) due to the importance of renewable energy development. Herein, a Co2P/CoP heterojunction embedded on an N-doped carbon (Co2P/CoP/NC) electrocatalyst was prepared via an in situ pyrolysis method. The as-prepared electrocatalyst exhibited efficient electrocatalytic activity for HER in an acidic solution. The Co2P/CoP/NC catalyst displayed an overpotential of 184 mV at 10 mA cm−2and a low Tafel slope of 82 mV dec−1, which could be attributed to the tight Co2P/CoP heterojunction and the synergetic effect of Co2P/CoP and N-doped carbon. In addition, the electrochemical active surface area of Co2P/CoP/NC was 75.2 m2g−1, which indicated that more active regions can be applied for the HER process. This report may pave a new way for the design of efficient and low-cost N-doped-carbon-supported 3d transition metal phosphide electrocatalysts.
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PROGRESS IN ORGANIC COATINGS
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2023
·
IF 6.6
Hao Lu,Hanyu Feng,Yang Zhou,Huidong Qiu
As an important derivative of graphene, graphene oxide(GO) is widely applied in multiple fields due to the abundant active sites and large specific surface area. In this paper, phytic acid(PA) had been chosen to modify the simple aniline trimer(AT) integrate with GO for acquiring a significant improvement of marine corrosion protection . Moreover, waterborne polyurethane(WPU) was used as a coating substrate to prepare a novel kind of functional coating on metal with nontoxicity. An enhanced electrical performance had been discovered through the combination of PA-AT and GO, which could be attribute to the unique 2-dimensional structure and π-π* interactions between GO and PA-AT. Then, the results of electrochemical measurements performed in 3.5 wt% NaCl solution showed an excellent corrosion protection when the ratio of GO to PA-AT stood at 1:3. Meanwhile, the most significant protective effect was observed with a dosage of 0.8 g of GO/PA-AT compared with the pure WPU. Similarly, the hardness, adhesion and impact resistance, and contact angle of GO/PA-AT coating also obtained a significant improvement based on the performance measurement. As a result, GO/PA-AT composite could provide an efficient protective performance against electrolyte diffusive corrosion in this paper.
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Nanomaterials
·
2023
·Vol. 14
·期 1
·76
·
IF 5.3
Ziqi Lv,Kai Ren,Tao Liu,Yunyan Zhao,Zhonghua Zhang,Guicun Li
The rupture of a micro/nano container can trigger the release of repair agents and provides the coating with a self-healing and anti-corrosion effect. However, the defect and inhomogeneity of the coating, produced by the rupture of the micro/nano container, may weaken its anti-corrosion performance. This study reports a rare protection mechanism, which optimizes the space occupying of zirconium phosphate, and the de-doping peculiarity of polyaniline without the rupture of the micro/nano container. Polyaniline/α-zirconium phosphate composites were constructed through in situ oxidation polymerization. Repair agents were added in the form of doped acids. According to the different repair agents in polyaniline/α-zirconium phosphate composites (citric ion, tartaric ion and phytic ion), the performance and protection mechanism of the composites were researched. Polyaniline/α-zirconium phosphate coating (with phytic ion) shows an excellent self-healing anti-corrosive effect, due to the large spatial structure and abundant chelating groups of the precipitation inhibitor. Considering the anti-corrosive application, the developed polyaniline/α-zirconium phosphate composite has a far-reaching influence on marine development.Keywords:polyaniline;α-zirconium phosphate;phytic acid;anti-corrosion;self-healing
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MATERIALS CHEMISTRY AND PHYSICS
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2023
·
IF 4.6
Guangyan Chen,Zai-Yin Hu,Nuo Chen,Zongjiang Zhao,Chao Li,Yi Xie
The development of environmentally benign flame retardant technology is crucial for flexible polyurethane foam (FPUF). Herein, a hybrid organic-inorganic coating (CNT–NH 2 –PA) was prepared through a facile salt formation reaction between biomass phytic acid (PA) and aminated carbon nanotubes (CNT-NH 2 ) on FPUF. The obtained flame retardant foam (FPUF@CNT–NH 2 –PA) passed the UL-94 rate of V-0, with a high limiting oxygen index (LOI) of 27.6 ± 0.3 %. More importantly, the cone calorimeter (CC) results demonstrated that the peak heat release rate (PHRR) of FPUF@CNT–NH 2 –PA was reduced by 39.7 % compared with that of neat foam. The mechanism analysis confirmed that a dense and compact char layer was formed during the combustion, which can effectively prevent the massive diffusion of heat and oxygen from the FPUF. Besides, the compression tests have clearly shown that the FPUF@CNT–NH 2 –PA retained the excellent mechanical nature of FPUF. Therefore, this easy and efficient process provided a powerful basis for technology and potential industrial applications.
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COMPOSITES PART B-ENGINEERING
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2023
·
IF 13.1
Yongqian Shi,Ruizhe Huang,Miao Liu,Junqiang Han,Peihui Xu,Yuezhan Feng,Libi Fu,Fuqiang Yang,Bin Yu
Impact injuries and fire risks generally coexist simultaneously in extreme environments. In this context, it is of great necessity to design impact resistant materials with both flame retardant performance and thermal stability. Here, a multi-functional flame retardant coating was prepared from the combination of silica sol (Si-sol), phytic acid (PA) and expandable graphite (EG) by graft modification with γ-propyl-trimethoxysilane (KH550). Subsequently, hierarchical composites were fabricated using one-pot foaming and brush coating method, where the carbon fiber cloth and coating served as the surface layer, while rigid polyurethane foams (RPUF) acted as the interlayer . The hierarchical structure endowed the RPUF composites with high compression resistance and impact resistance properties. Furthermore, the flame retardant coating could effectively reduce the values of peak heat release rate and peak smoke production rate of RPUF composites by 77.5% and 81.8%, respectively. Therefore, these RPUF composites can effectively prevent impact damage and achieve excellent flame retardancy , making them promising candidates as safety protective materials.
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AAPS PHARMSCITECH
·
2019
·Vol. 20
·期 1
·1-14
·
IF 2.608
Wang Xingqi,Zhang Yong,Huang Jie,Tian Chunling,Xia Mengqiu,Liu Liu,Li Zhengguang,Cao Jiaojiao,Gui Shuangying,Chu Xiaoqin
The purpose of this paper was to investigate the potential of liquid crystalline (LC) gels for ophthalmic delivery, so as to enhance the bioavailability of pilocarpine nitrate (PN). The gels were prepared by a vortex method using phytantriol and water (in the ratio of 73:27 w / w ). Their inner structures were confirmed by crossed polarized light microscopy, small-angle X-ray scattering, attenuated total reflectance-Fourier transform infrared spectrum, and rheology. The in vitro release studies revealed that PN could keep sustained release from the gels over a period of 12 h. The ex vivo apparent permeability coefficient of the gels demonstrated a 3.83-folds ( P < 0.05) increase compared with that of eye drops. The corneal hydration levels of the gel maintained in the normal range of 79.46 ± 2.82%, hinting that the gel could be considered non-damaging and safe to the eyes. Furthermore, in vivo residence time evaluation suggested that a better retention performance of LC gel was observed in rabbit’s eyes compared to eye drops. In vivo ocular irritation study indicated that LC gel was nonirritant and might be suitable for various eye applications. In conclusion, LC gels might represent a potential ophthalmic delivery strategy to overcome the limitations of eye drops.
研究领域:
药剂学
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药物递送系统
·
眼科学
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Jierui Ye,Yuebing Gao,Qingtian Xu,Zhenfu Jin,Guomin Wu,Siqun Wang,Zengkun Cai,Ke Yang,Qiang Wu,Qian Li
Cellulose nanofibrils (CNFs) have widely attracted significant attention due to the excellent mechanical performance, biodegradability, and high surface functionality. However, the high flammability of CNFs commonly restricts their wider application. In this study, the intrinsically flame-resistant holocellulose nanofibrils (HCNFs, which is rich in both cellulose and hemicellulose) were obtained from bamboo under pretreatment using a highly efficient ternary deep eutectic solvent (TDES) and subsequential mechanical homogenization. The phytates and sulfate-containing HCNFs (PHCNFs) displayed nanofibril diameter of 3–5 nm and high aspect ratio of (∼500), and the aqueous suspension exhibited colloidal stability and high transmittance. The PHCNF films exhibited excellent fire resistance, mechanical and optical properties. Compared with raw HCNF, the limiting oxygen index (LOI) of PHCNF-120 film was up to 52.5 %, and the total heat release (THR) and peak heat release rate (PHRR) of PHCNF-120 films were significantly reduced by 92.2 % and 82.4 %, respectively. The flame retardant mechanism was attributed to the synergistic effect of P/N/S in both condensed phase and gaseous phases during the burning process. This work provides a novel, efficient strategy for developing eco-friendly flame-resistant and fireproof holocellulose-based nanomaterials.
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POLYMER DEGRADATION AND STABILITY
·
2023
·
IF 5.9
Song Li,Feng Zhao,Xueya Wang,Zhihua Liu,Jingze Guo,Yutong Li,Shuangmei Tan,Zhenxiang Xin,Shuai Zhao,Lin Li
Green flame retardants have drawn much attention because of their environmental friendliness. But for the high flame retardancy of flammable polymers, most existing green flame retardants are unsatisfactory, even the flame-retardant process can not achieve high efficiency and environmental protection. In this work, flame retardants and flame-retardant process are addressed in a two-pronged approach. An eco-friendly bio-based synergistic flame retardant (PAU) was synthesized based on phytic acid (PA) and urea (U) through simple complexation assembly in water. The designed flame retardant coating can be directly coated on the surface of any topological shape with polydopamine as an adhesive. Flame retardant expandable polystyrene (EPS-PAU) with light weight and high toughness is prepared with the designed PAU flame-retardant coating. The coated EPS plates exhibit V-0 UL-94 rating and 42.0 % of limited oxygen index and excellent smoke suppression. Moreover, the density of EPS-PAU is slightly increased only by 2.27 % on the basis of the neat EPS, and the hard shell formed using PDA as an adhesive layer is beneficial for the improvement of impact strength. This novel biomass-based PAU system provides a promising strategy for manufacturing polymer products with excellent flame retardancy, smoke inhibition and light weight.
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ACS Applied Nano Materials
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2023
·
IF 5.9
Meiqin Wu,Yunhui Chen,Hou-Yong Yu,Xiaosong Liu,Yanjuan Dong,Peng-Cheng Qian,Xiaohua Wang
Traditional halogenated flame retardants (FRs) have been severely hindered because they are toxic and hazardous carcinogenic byproducts during their application. In this study, we present a biobased FR composite consisting of cellulose nanocrystals (CNCs) modified with melamine (MEL) and phytic acid (PA) through successive grafting and electrostatic adsorption processes. It was found that the CNC/MEL/PA nanocomposite had a noticeable highly improved thermal blocking performance of the cellulose nanofibril aerogel, excellent carbon layer formation, and high thermal insulation ability because of a synergistic FR effect between the components in both the condensed and gas phases. These findings highlight the potential of nanoscale engineering in producing structural foams with excellent fire-retardant properties using cellulose and other nanosized fibrous biomaterials.
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CELLULOSE
·
2023
·Vol. 30
·期 7
·4713-4733
·
IF 5.7
Chen Maoshuang,Ayaz Pirah,Xiao Yuanxiang,Li Yong,Wang Pei,Huang Wenjia,Zhao Shujun,Fu Feiya,Liu Xiangdong,Xiang Shuangfei
Versatile cotton fabrics can be used in a variety of special environments and offer unparalleled advantages in textile products. In this work, bio-based phytic acid (PA), octadecylamine (ODA) and TiO 2 (NPs) were used as raw materials to prepare multifunctional cotton fabrics with excellent flame retardant (LOI = 48.5%), hydrophobic (WCA = 152°), UV-blocking (UPF = 2000) and antibacterial (BR = 100%) properties through a facile and scalable dip coating and spraying process. Firstly, the phytic acid was grafted onto the surface of cotton fabric by esterification reaction between its phosphoric acid group and the hydroxyl group of cellulose molecules. Then ODA reacted with the residual phosphoric acid group of phytic acid to form an ODA layer, for further immobilizing TiO 2 (NPs) particles on the surface of cotton fabric. The resulting cotton fabric possessed excellent flame resistance (LOI > 36.2%), hydrophobicity (WCA > 138°), UV-blocking (UPF = 2000) and antibacterial abilities (BR > 96.0%) even after 20 washing cycles. Moreover, this modification process did not sacrifice the desired cotton properties, including water vapor permeability, flexibility and tensile strength. This work proposed a simple and scalable pad-dry curing method to construct stable and multifunctional cotton textiles, which have broadened application prospects in many fields. Graphical abstract
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Xiaoyun Zhang,Fan Yang,Siyuan Sun,Kexin Wei,Hongchen Liu,Guohua Li,Yang Sun,Xi Li,Jinxiu Qian,Shaoxiong Du,Mingjie Li,Yi Lu,Chuangui Xia,Sai Che,Yongfeng Li
An electrocatalyst of single-atomic Mn sites with MnP nanoparticles (NPs) on N, P co-doped carbon substrate was constructed to enhance the catalytic activity of oxygen reduction reaction (ORR) through one-pot in situ doping-phosphatization strategy. The optimized MnSA-MnP-980℃ catalyst exhibits an excellent ORR activity in KOH electrolyte with a half-wave potential (E 1/2 ) of 0.88 V (vs. RHE), and the ORR current density of MnSA-MnP-980℃ maintained 97.9 % for over 25000 s chronoamperometric i-t measurement. When using as the cathode, the MnSA-MnP-980℃ displays a peak power density of 51 mW cm −2 in Zinc-Air batteries, which observably outperformed commercial Pt/C (20 wt%). The X-ray photoelectron spectroscopy reveal that the doped P atoms with a strong electron-donating effectively enhances electron cloud density of Mn SAs sites, facilitating the adsorption of O 2 molecules. Meanwhile, the introduction of MnP NPs can regulate the electronic structure of Mn SAs sites, making Mn SAs active sites exist in a low oxidation state and are less positively charged, which can supply electrons for ORR process to narrow the adsorption energy barrier of ORR intermediates. This work constructs novel active sites with excellent ORR properties and provides valuable reference for the development of practical application.
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