CELLULOSE
·
2022
·Vol. 29
·期 17
·9089-9104
·
IF 6.123
Zhao Yang,Jin Bo,Zheng Tian,Peng Rufang
A novel natural macromolecule stabilizer, tea polyphenol, was developed based on the scavenging effect of nitroxide radical to enhance the thermal stability of nitrocellulose. The structural of tea polyphenols was confirmed by infrared spectroscopy, and their good thermal stability of tea polyphenols in nitrocellulose was confirmed by methyl violet paper test and vacuum stability test. The iso-thermogravimetric test showed that tea polyphenols could prolong the safe storage life of nitrocellulose. The inhibition of tea polyphenols on the autocatalytic thermal decomposition of nitrocellulose in the early stage of nitrocellulose thermal decomposition was confirmed by SEM images at different stages of nitrocellulose thermal decomposition. The thermal interaction between tea polyphenols and nitrocellulose was further analyzed by non-isothermal thermal analysis. Experiments confirmed that tea polyphenols can enhance the thermal stability of nitrocellulose. Their addition increased the T 0 of nitrocellulose by 2.0–9.4 ℃, the T bp 0 by 1.4–9.6 ℃, and the activation energy of nitrocellulose by 5.38–9.77 kJ·mol –1 .
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Journal of Bioresources and Bioproducts
·
2025
·Vol. 10
·期 4
·660-675
·
IF 13
Hao Jia,Wenhui Su,Bin Huang,Xianxian He,Shaohui Fan,Zhoubin Huang,Chuanxia Pan,Chenye Liu
The fluctuations of storage temperature and humidity detrimentally affect the bamboo quality and longevity, making it crucial to investigate. Herein, we explored the physical and mechanical properties of moso bamboo ( Phyllostachys edulis ) subjected to 100-day moist heat cycling aging (MHCA-1: transitioning from low-temperature/high-humidity to high-temperature/low-humidity; MHCA-2: transitioning from low-temperature/low-humidity to high-temperature/high-humidity; CHT: 25 °C-constant temperature and 60% relative humidity) alongside a control group. Employing a multiscale characterization and Random Forest (RF) modeling, we evaluated the impacts of temperature and humidity fluctuations on the bamboo quality, and the influence mechanism of storage conditions on its physical and mechanical properties were elucidated. Results indicated that elevated temperature and humidity led to remarkable fluctuation in bamboo moisture (from −20.36% to 32.99%), weight gain (from −32.69% to 6.19%), and dimensional expansion (from −5.37% to 2.38%). Conversely, high-temperature and low-humidity drying conditions resulted in moisture loss and dimensional shrinkage. Total color difference (TCD) of bamboo cortex followed the order: MHCA-2 (7.46) < CHT (12.24) < MHCA-1 (20.10) < control (22.63). The TCD of bamboo pith positively was related with storage temperature. Periodic moist heat aging induced the permanent deformation in bamboo, reducing its elastic modulus by 30.05%–43.79%. Under moist heat aging conditions, the characteristic hemicellulose functional groups, including hydroxyl (−OH), carbonyl ( C = O ), ether (C–O–C), and aromatic C = C moieties exhibited remarkable structural modifications, i.e., peak weakening, shifting, or morphological alterations in Fourier transform infrared (FT-IR) spectra. Additionally, these conditions elevated the thermal decomposition onset temperature of cellulose while decreasing its peak intensity. Overall, the RF modeling approach demonstrated a high accuracy in predicting bamboo behavior under varying moisture-heat conditions. It improved bamboo storage and recycling by supporting sorting and grading with reliable long-term data.
研究领域:
材料科学
·
林产化工
·
高分子材料
·
环境因素影响
·
生物基材料耐久性
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2024
·
IF 5.1
Falin Li,Yi Wang,Qiu Wang,Binbo Wang,Shuai Du,Fengyuan Zhang,Songqi Ma
This work discloses a new strategy based on dynamic cross-linking chemistry to achieve advanced one-component thermosets combining ultralong storage life and fast cross-linking. One-component thermosets containing resin and cross-linker in one pot have the features of simple operation, stable quality, and low waste; however, an urgently needed one with long storage life at room temperature and fast cross-linking at medium–low temperatures (≤130 °C) remains an enormous challenge. Herein, we innovatively propose a strategy of dynamic cross-linking and controlled dissolution to address this issue. As an example, a dynamic cross-linked cross-linker (DCC) is synthesized via Diels–Alder reaction to hide the high activity of a commercial amine-type cross-linker. A one-component thermoset from a DCC and a commercial diepoxy monomer can be stored for an ultralong time at room temperature and cross-linked rapidly below 130 °C. Moreover, the DCC can also serve as a latent accelerator for epoxy/anhydride thermosets with the same storage life as the control system with no accelerator at room temperature and fast cross-linking at elevated temperatures. This work is beneficial for promoting the application of dynamic cross-linking chemistry and meeting the urgent need for advanced one-component thermosets in the fields of advanced composites, coatings, electronic packaging materials, automotive and electronic adhesives, etc.
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
FOOD RESEARCH INTERNATIONAL
·
2022
·
IF 7.425
Yuanfei Ge,Jinyong Wu,Min Pang,Dan Hu,Zhongkui Li,Xiangqin Wang,Lijie Sun,Xiangsong Chen,Jianming Yao
In this study, carboxymethyl chitosan (CMCS) and N - acetylneuraminic acid (NeuAc) were used to develop C-NeuAc hydrogels to encapsulate Pediococcus pentosaceus QK-1. The mechanical properties, thermal stability, in vitro degradation, and pH sensitivity of the hydrogel were evaluated. The C-NeuAc concentration required for optimal hydrogel performance was 3% (w/v). Hydrogel swelling behaviour was effectively assessed by Fickian diffusion and Schott’s second-order kinetic models. The hydrogel demonstrated excellent biocompatibility and low in vitro cytotoxicity. An in vitro assay revealed that the viability of Pediococcus pentosaceus QK-1 in C-NeuAc had decreased by only 1.41 log (CFU/ mL) after exposure to simulated acidic gastric fluid. Moreover, the survival rate of the encapsulated and free Pediococcus pentosaceus QK-1 cells were 80.1% and virtually zero, respectively, after passage through the gastrointestinal tract. It was empirically determined that low temperature and freeze-drying were the ideal condition and method to ensure storage longevity of the hydrogel-encapsulated probiotic. Hence, C-NeuAc hydrogel is highly desirable as a food-grade probiotic delivery vehicle.
研究领域:
生物技术
·
食品科学
·
材料科学
✓ 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）