scholarly journals Homogeneous grafting of cellulose with polycaprolactone using quaternary ammonium salt systems and its application for ultraviolet-shielding composite films

RSC Advances ◽  
2018 ◽  
Vol 8 (20) ◽  
pp. 10865-10872 ◽  
Author(s):  
Yongqi Yu ◽  
Xin Gao ◽  
Zeming Jiang ◽  
Wentao Zhang ◽  
Jiwei Ma ◽  
...  

Microcrystalline cellulose graft polycaprolactone (MCC-g-PCL) was successfully synthesized by ring-opening copolymerization catalyzed by 4-dimethylaminopyridine in a dual tetrabutylammonium acetate/dimethyl sulfoxide solvent system.

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Shuqiang Zhao ◽  
Pibo Ma ◽  
Ailan Wan ◽  
Jiwei Huang ◽  
Houyong Yu ◽  
...  

AbstractA novel and excellent composite film was fabricated by simply casting cassava silk fibroin (CSF), chitosan quaternary ammonium salt (HACC), and graphene oxide (GO) in an aqueous solution. Scanning electron microscope images showed that when GO was dispersed in the composite films, the surface of CSF-based composite film became rough, and a wrinkled GO structure could be found. When the content of GO was 0.8%, the film displayed a higher change with respect to the breaking strength and elongation, respectively, up to 97.69 ± 3.69 and 79.11 ± 1.48 MPa, keeping good thermal properties because of the incorporation of GO and HACC. Furthermore, the novel CSF/HACC/GO composite film demonstrates a lower degradation rate, implying the improvement of the resistance to the enzyme solution. Especially in the film with 0.8 wt% GO, the residual mass arrived at 64.35 ± 1.1% of the primary mass after 21 days compared with the CSF/HACC film. This would reclaim the application of silk-based composite films in the biomaterial field.


2020 ◽  
Vol 22 (19) ◽  
pp. 6437-6443
Author(s):  
Cheng-Kou Liu ◽  
Meng-Yi Chen ◽  
Xin-Xin Lin ◽  
Zheng Fang ◽  
Kai Guo

A catalyst-, oxidant-, acidic solvent- and quaternary ammonium salt-free electrochemical para-selective hydroxylation of N-arylamides at rt in batch and continuous-flow was developed.


2013 ◽  
Vol 50 (1) ◽  
pp. 9-13 ◽  
Author(s):  
Yong-Qiang Sun ◽  
Wen-Jing Li ◽  
Wan-Xu Wang ◽  
Qiu-Xiao Li ◽  
Wieslaw Hreczuch ◽  
...  

1997 ◽  
Vol 62 (6) ◽  
pp. 849-854 ◽  
Author(s):  
Vladislav Holba ◽  
Renata Košická

The paper deals with instability of solutions of quaternary ammonium permanganates, QMnO4 (Q = tetraethyl-, tetra-1-propyl-, tetra-1-butyl-, tetra-1-pentyl-, tetra-1-octyl-, and cetyltrimethylammonium), in dichloromethane and presents the rate constants and activation parameters of the reduction of permanganate. Attention was paid to the properties of colloidal Mn(IV) intermediate. The stability of the solutions depends markedly on the quaternary ammonium salt used.


2021 ◽  
Vol 19 (1) ◽  
pp. 273-278
Author(s):  
Göran Schulz ◽  
Andreas Kirschning

The oxidative radical decarboxylation of carboxylic acids with TEMPO as radical scavenger in a biphasic solvent system is reported which is successfully used in a new synthetic approach for the antidepressants indatraline.


2011 ◽  
Vol 695 ◽  
pp. 170-173 ◽  
Author(s):  
Voravadee Suchaiya ◽  
Duangdao Aht-Ong

This work focused on the preparation of the biocomposite films of polylactic acid (PLA) reinforced with microcrystalline cellulose (MCC) prepared from agricultural waste, banana stem fiber, and commercial microcrystalline cellulose, Avicel PH 101. Banana stem microcrystalline cellulose (BS MCC) was prepared by three steps, delignification, bleaching, and acid hydrolysis. PLA and two types of MCC were processed using twin screw extruder and fabricated into film by a compression molding. The mechanical and crystalline behaviors of the biocomopsite films were investigated as a function of type and amount of MCC. The tensile strength and Young’s modulus of PLA composites were increased when concentration of MCC increased. Particularly, banana stem (BS MCC) can enhance tensile strength and Young’s modulus of PLA composites than the commercial MCC (Avicel PH 101) because BS MCC had better dispersion in PLA matrix than Avicel PH 101. This result was confirmed by SEM image of fractured surface of PLA composites. In addition, XRD patterns of BS MCC/PLA composites exhibited higher crystalline peak than that of Avicel PH 101/PLA composites


Fuel ◽  
2021 ◽  
Vol 287 ◽  
pp. 119434
Author(s):  
Jun Chen ◽  
Hongliang Li ◽  
Chunfu Liu ◽  
Lingyun Liu ◽  
Yu Sun ◽  
...  

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