BIORESOURCE TECHNOLOGY
·
2019
·
IF 6.669
Yuan Zhang,Liping Kang,Hongmei Li,Xianzhang Huang,Xiaoyu Liu,Lanping Guo,Luqi Huang
The combustion of moxa floss was investigated by thermogravimetric/differential scanning calorimeter (TG/DSC), thermogravimetric/Fourier transform infrared spectroscopy (TG-FTIR) and an infrared radiation spectrum-detecting system. The average mass loss rate at the major stage of combustion was 1.08%/min with a peak at 7.86%/min. Moxa floss burning released the integral heat of 9188 mJ/mg from the temperature of 200 °C to 500 °C. The peak heat flow during char combustion stage was higher than those of other stages. The results indicated the combustion of moxa floss was a mild and slow process, releasing heat continuously and steadily. The infrared radiation spectra of burning moxa stick were in a range of 2.5–13.0 µm and showed double peaks at 3.75 µm and 8.75 µm. Thus, this study provided insight into why moxa floss biomass is the optimal material for thermal therapy and is beneficial for the development of electric thermal stimulation alternative.
研究领域:
热疗研究
·
生物医学工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2023
·
IF 5.2
Lei Dong,Yiwei Zhang,Yandong Guo,Xin Shu,Xuyan Shen,Qianping Ran,Pan Feng
The usage of chemical admixtures, such as starch-based materials, is a common approach to addressing the thermal cracking problem of cementitious materials. Capsule-based controlled release technique enables the adjustable action time of loaded chemical admixture and thus reveals the potential on inhibiting the exothermic process of cement hydration . Three types of silica-based nanocapsules loaded with 53–63% sucrose retarder are firstly prepared by interfacial polymerization in water-in-oil (W/O) emulsion. The release characteristics of three types of nanocapsules are precisely tuned by varied preparation conditions. The effects of nanocapsules on the exothermic process of cement hydration have been investigated through calorimetry measurements. All prepared nanocapsules not only delay the appearance of the main hydration peak as the retardation effect but also reduce the maximum heat flow of the main hydration peak, to some extent, as the depression effect. The depression and retardation effects are improved with the increased dosage and slower release rate of added nanocapsules. The relationship between the two effects and the action time of loaded sucrose suggests the importance of persistently inhibiting the cement hydration over the entire accelerating and decelerating processes, which can be estimated by the time window between the action of sucrose (50% release time) and occurrence of main hydration peak.
研究领域:
材料科学
·
化学工程
·
土木工程
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS & DESIGN
·
2018
·
IF 4.525
Yajie Chen,Wenchao Zhang,Chunpei Yu,Debin Ni,Kefeng Ma,Jiahai Ye
NiCo 2 O 4 has been selected as an oxidizer to realize the nanothermite film for the first time in this study. The NiCo 2 O 4 /Al core-shell nanowires (NWs) thermite film has been fabricated using a facile hydrothermal-annealing synthesis method and a controllable magnetron sputtering process. The as-obtained NiCo 2 O 4 /Al NWs thermite film shows a uniform structure and distribution on the substrate, with a favorable interfacial contact between the bimetallic oxide and the fuel at the nanoscale . It is found that the quantity of Al plays a key role in the total heat release magnitude. The maximal heat release of the NiCo 2 O 4 /Al nanothermite film has reached 2076.0 J/g at the optimal Al deposited thickness of 450 nm with the obtained optimum Al/NiCo 2 O 4 molar ratio of 4.9. Moreover, this design strategy is highly compatible with microelectromechanical systems (MEMs) and it can be applied to realize other nanothermites composed by bimetallic oxide and fuel.
研究领域:
材料科学
·
纳米技术
·
化学工程
·
能源材料
✓ 已验证
产品关联
DOI
高影响因子
Soft Matter
·
2023
·Vol. 19
·期 32
·6097-6107
·
IF 3.4
Xiaodong Qian,Nire Mu,Xiaojiong Zhao,Congling Shi,Saihua Jiang,Mei Wan,Bin Yu
Rigid polyurethane foam (RPUF) has attracted great attention as an insulation material, but its inherent flammability restricts its practical application. Developing a sustainable fire-retardant strategy that can improve its fire safety is particularly desirable and challenging. Herein, novel fire-retardant hydrogel coatings based on polyvinyl alcohol (PVA) and borax are proposed and applied in RPUF, and the self-healing, recyclability and flame retardant properties of the coatings are investigated. The dynamic and reversible cross-linked networks based on the borate ester bonds and hydrogen bonds endow the hydrogels with excellent repairability, recyclability, and elasticity. Compared with a neat RUPF, the coated RPUF exhibited improved fire-retardant properties without the inherent advantages being influenced and can be reflected by the 8% increase in the limiting oxygen index (LOI), 20% reduction in total heat release (THR), and 25% decrease in total smoke production (TSP) with the coatings, along with a rapid self-quenching behavior. The novel hydrogel coatings provide a new strategy for the development of flame-retardant coatings, demonstrating the potential of the next generation of self-healing hydrogel coatings to reduce the fire risk of the RPUF.
研究领域:
材料科学
·
消防安全
·
高分子化学
·
涂层技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2024
·
IF 7.4
Jia-Xiang Yang,Yu Sun,Wan-Meng Song,Yun Liu
As a kind of plant fiber, ramie fibers (RFs) are widely used in fiber reinforced resin matrix composites, however, both of RFs and resin matrix are flammable. Enhancing the flame retardancy of ramie fiber reinforced epoxy composites is important. In this study, a highly efficient flame retardant, PBXY, was synthesized from phytic acid, boric acid, and xylitol to improve the flame retardancy of ramie fibers, and flame-retardant ramie fiber reinforced epoxy composites (EP/RF-PBXYs) with different weight gain were prepared by coating PBXY on the surface of ramie fibers. The effects of different weight gain of PBXY on the thermal stability, flame retardancy, and mechanical properties of EP/RF-PBXYs were investigated. Compared with that of EP/RF, the limiting oxygen index value of EP/RF-PBXY2 was increased from 23.0 % to 31.4 % and a UL-94 V-0 rating was obtained, the total heat release and total smoke production were reduced by 33.2 % and 31.0 %. However, the presence of PBXY had a negative effect on the mechanical properties of EP/RF when the weight gain of PBXY was more than 10 wt% (related to RFs). This study offers a promising avenue to improve the flame-retardant resistance of EP/RF.
研究领域:
材料科学
·
化学工程
·
高分子科学
·
消防安全工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Leilei Cheng,Yuyuan Zhang,Yazhuo Wang,Jing Gu,Haoran Yuan,Yong Chen
Converting plastic wastes into value-added products through energy-efficient pyrolysis is essential, and it requires lower pyrolysis temperatures and shorter processing times than that of other processes. An exothermic phenomenon was observed during the process high-pressure polyethylene pyrolysis. It was proven for the first time that the exotherm is caused by a pressure-induced phase transition, in which colossal heat release can be driven by relatively small pressures. A large temperature change (> 100 °C) leads to the deep cracking of polyethylene, although the set temperature is far lower than the required temperature for thermal cracking. Importantly, the heat input stops immediately when the set temperature is reached; thus, the external heating time is short. Polyethylene can be completely converted into liquid products in ~90 wt% yield and with a small number of gases. The self-exothermic phase transition only occurs within a certain range of material thickness, which is related to the corresponding phase behavior. In the self-exothermic pyrolysis process, with an increase in the thickness of polyethylene, the proportion of low-value olefins in oil products decreases gradually, while alkanes, isoalkanes and aromatics show an increasing trend, making the product composition closer to the fuel standard. This work provides a viable approach for plastic recycling at low pyrolysis temperatures and short external heating times with the help of a self-exothermic phase transition in the absence of a catalyst.
研究领域:
化学工程
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）