老虎机永利

search for:
The team of Professor Huang Jin and Associate Professor Gan Lin of Southwest University has made new progress in regulating the elasticity of cellulose nanocrystalline aerogels
2019-12-27 Source: Polymer Technology

Cellulose nanocrystal (CNC) -based aerogel is a three-dimensional porous solid material with low density, high porosity, high specific surface area, and chemical modifiability. It is widely used for adsorption, catalysis, and storage due to its excellent properties. Energy and Sensing. However, the high strength and high modulus of CNC-based aerogels are accompanied by insufficient toughness, which limits their application as flexible materials and increases the difficulty of processing and post-processing. The main reason is that the uncontrolled hydrogen bonding network between CNCs restricts the movement of CNC particles. Therefore, there is an urgent need for a strategy to regulate the hydrogen bonding network of aerogels to solve their rigidity and brittleness problems.

Inspired by sea cucumber skin, when its collagen fiber cross-linking network was weakened by stiparin inhibitors, sea cucumber skin changed from rigid to flexible. Professor Huang Jin and Associate Professor Gan Lin's team chemically cross-linked the CNC with a flexible polymer polyethylene glycol (PEG) that can form hydrogen bonds, and prepared a CNC-based chemically cross-linked aerogel containing a hydrogen bond network (as shown in the figure) 1).

Figure 1 a) Rigid-flexible transition of sea cucumber skin. b) Schematic illustration of CNC-based aerogel chemical crosslinking. c) Schematic diagram of aerogel rigid-flexible transition.

At this time, the solvation based on hydrogen bonding can reversibly destroy the hydrogen bonding network between CNC and PEG, and the movement of the CNC particles and PEG segments has thus obtained a controllable limit switch, making CNC-based aerogel Realize a reversible transition from rigid to flexible, plastic deformation to elastic deformation (as shown in Figure 2).

Figure 2 Stress-strain curves of aerogels with different molecular weight PEG in (a) air and (b) water; c) compression modulus in air and water; d) shape recovery in air and e) water .

Finally, after adjusting the molecular weight of PEG, CNC-based aerogels have a modulus in the air of nearly MPa level, and in the wet state, the modulus will drop to the kPa level. This reversible transformation allows this aerogel to take into account the height Machinability and use of mechanical properties (as shown in Figure 3).

Figure 3 Stress-strain curves of aerogels with different molecular weight PEG in a) in DMF, b) ethanol, and c) petroleum ether; d) Compression modulus of aerogels in DMF, ethanol, and petroleum ether. The aerogel shape recovery is related to the e) polarity and f) solubility parameters of the solvent.

The research results were recently published in ACS Applied Materials & Interfaces (DOI: 10.1021 / acsami.9b18569). The first author of the thesis is Li Dong , a graduate student in the School of Chemistry and Chemical Engineering of Southwest University, and the corresponding authors are Professor Huang Jin and Associate Professor Gan Lin .

Paper link: http://pubs.acs.org/doi/abs/10.1021/acsami.9b18569

Copyright and Disclaimer: Original article from China Polymer Network. For reprinting of publications or media, please contact the email address : info@chevronsz.com , and please indicate the source.
(Responsible editor: xu)

Invited to pay attention to polymer technology

最新资讯 More >> Latest News
科教新闻 More >> Science and Education News
永利娱乐资讯 ag体育 球探体育平台登录 葡京app官网 足球平台 ag平台游戏老虎机永利 亚博登录网站 皇冠体育网站 188体育 沙巴体育平台官方投注