Synthesis and characterization of porous Y 2 SiO 5 with low linear shrinkage, high porosity and high strength

2016 ◽  
Vol 42 (13) ◽  
pp. 14894-14902 ◽  
Author(s):  
Zhen Wu ◽  
Luchao Sun ◽  
Jingyang Wang
Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1342
Author(s):  
Hajer Radhouani ◽  
Susana Correia ◽  
Cristiana Gonçalves ◽  
Rui L. Reis ◽  
Joaquim M. Oliveira

Hydrogel application feasibility is still limited mainly due to their low mechanical strength and fragile nature. Therefore, several physical and chemical cross-linking modifications are being used to improve their properties. In this research, methacrylated Kefiran was synthesized by reacting Kefiran with methacrylic anhydride (MA). The developed MA-Kefiran was physicochemically characterized, and its biological properties evaluated by different techniques. Chemical modification of MA-Kefiran was confirmed by 1H-NMR and FTIR and GPC-SEC showed an average Mw of 793 kDa (PDI 1.3). The mechanical data obtained revealed MA-Kefiran to be a pseudoplastic fluid with an extrusion force of 11.21 ± 2.87 N. Moreover, MA-Kefiran 3D cryogels were successfully developed and fully characterized. Through micro-CT and SEM, the scaffolds revealed high porosity (85.53 ± 0.15%) and pore size (33.67 ± 3.13 μm), thick pore walls (11.92 ± 0.44 μm) and a homogeneous structure. Finally, MA-Kefiran revealed to be biocompatible by presenting no hemolytic activity and an improved cellular function of L929 cells observed through the AlamarBlue® assay. By incorporating methacrylate groups in the Kefiran polysaccharide chain, a MA-Kefiran product was developed with remarkable physical, mechanical, and biological properties, resulting in a promising hydrogel to be used in tissue engineering and regenerative medicine applications.


2015 ◽  
Vol 41 (10) ◽  
pp. 13294-13303 ◽  
Author(s):  
A.V. Gorokhovsky ◽  
J.I. Escalante-Garcia ◽  
E. Sanchez-Valdes ◽  
I.N. Burmistrov ◽  
D.V. Kuznetsov

2012 ◽  
Vol 549 ◽  
pp. 45-49
Author(s):  
Wei Hu ◽  
Guang Xian Zhang ◽  
Feng Xiu Zhang ◽  
Hui Zheng ◽  
Ming Lu

Aromatic polyamides are high performance materials, having outstanding thermal and mechanical properties. Poly(2,5-Diamino-terephthalic acid) (PATA) was designed as a novel aromatic polyamide with high strength and modulus. In this paper, 2,5-Diamino-terephthalic acid (DATA), as a monomer of PATA, was synthesized from 2,5-Dimetyl-1,4-phenyldiamine (DPA). First step was the amidation of DPA by reacting with acetic anhydride to protect amido group. Then N-(4–Acetylamino-2,5-dimethyl–phenyl)-acetamide (AMPA) was oxidized by potassium permanganate. Finally, AMPA was hydrolyzed by sodium hydroxide and the monomer DATA was precipitated by hydrochloric acid around PH 5. DATA and all the intermediate products were characterized and confirmed by 1HNMR and FT-IR spectra. They were all in great agreement with the proposed structure. The overall yield of DATA was about 40.0%.


1996 ◽  
Vol 61 (10) ◽  
pp. 3572-3572
Author(s):  
Lawrence T. Scott ◽  
Atena Necula

2018 ◽  
Vol 2 (1) ◽  
pp. 7
Author(s):  
S Chirino ◽  
Jaime Diaz ◽  
N Monteblanco ◽  
E Valderrama

The synthesis and characterization of Ti and TiN thin films of different thicknesses was carried out on a martensitic stainless steel AISI 410 substrate used for tool manufacturing. The mechanical parameters between the interacting surfaces such as thickness, adhesion and hardness were measured. By means of the scanning electron microscope (SEM) the superficial morphology of the Ti/TiN interface was observed, finding that the growth was of columnar grains and by means of EDAX the existence of titanium was verified.  Using X-ray diffraction (XRD) it was possible to observe the presence of residual stresses (~ -3.1 GPa) due to the different crystalline phases in the coating. Under X-ray photoemission spectroscopy (XPS) it was possible to observe the molecular chemical composition of the coating surface, being Ti-N, Ti-N-O and Ti-O the predominant ones.


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