Comprehensive insight of crosslinking agent concentration influence on starch‐based aerogels porous structure

2021 ◽  
pp. 50863
Author(s):  
Paulo H. Camani ◽  
Maria G. M. Gonçalo ◽  
Rennan F. S. Barbosa ◽  
Derval S. Rosa
1990 ◽  
Vol 32 (4) ◽  
pp. 666-670
Author(s):  
A.A. Tager ◽  
M.V. Tsilipotkina ◽  
L.C. Kolmakova ◽  
E.V. Morozov ◽  
V.M. Balakin ◽  
...  

1987 ◽  
Vol 29 (5) ◽  
pp. 1064-1069 ◽  
Author(s):  
Ye.I. Mal'ko ◽  
A.A. Tager ◽  
V.P. Vorob'ev ◽  
K.S. Pozhivilko ◽  
Yu.Ya. Dumpis ◽  
...  

2016 ◽  
Author(s):  
Cigdem Kilicarislan Ozkan ◽  
Hasan Ozgunay ◽  
Stefania Marin ◽  
Madalina Georgiana Albu Kaya

2017 ◽  
Author(s):  
Christoph Engwer ◽  
Ronja Loy ◽  
Ioannis S. Chronakis ◽  
Ana C. Mendes ◽  
Francisco M. Goycoolea

Genipin is increasingly used as a crosslinking agent for chitosans due to its low cytotoxicity as a naturally occurring extract of the plant <i>Gardenia jasminoides</i>. Genipin reacts with the primary amino groups of chitosan to form blue hydrogels. We studied the gelation kinetics of different chitosans varying in their properties (molar mass 34 000-213 000 g mol<sup>-1</sup>, degree of acetylation 9-20%) and genipin in detail. We found that critical sol-gel transition times obtained from dynamic light scattering were in good agreement with the results obtained by small deformation oscillatory rheometry and microviscosimetry at high concentrations of chitosan. However, at below critical concentrations, we found a second regime of gelation that followed the same Ross-Murphy's gelation kinetics. The macroscopic appearance of these samples was a suspension of weak gel-like particles that were sensitive to mechanical forces. We believe that the material is a mesoscopic gel, as described for other polymers. To the best of our knowledge, this is the first time that this phenomenon has been described for the gelling system of chitosan and genipin.


Arena Tekstil ◽  
2013 ◽  
Vol 28 (1) ◽  
Author(s):  
Maya Komalasari ◽  
Bambang Sunendar

Partikel nano TiO2 berbasis air dengan pH basa telah berhasil disintesis dengan menggunakan metode sol-gel dan diimobilisasi pada kain kapas dengan menggunakan kitosan sebagai zat pengikat silang. Sintesis dilakukan  dengan prekursor TiCl4 pada konsentrasi 0,3 M, 0,5 M dan 1 M, dan menggunakan templat kanji dengan proses kalsinasi pada suhu 500˚C selama 2 jam. Partikel nano TiO2 diaplikasikan ke kain kapas dengan metoda pad-dry-cure dan menggunakan kitosan sebagai crosslinking agent. Berdasarkan hasil Scanning Electron Microscope (SEM),diketahui bahwa morfologi partikel TiO2 berbentuk spherical dengan ukuran nano (kurang dari 100 nm). Karakterisasi X-Ray Diffraction (XRD) menunjukkan adanya tiga tipe struktur kristal utama, yaitu (100), (101) dan (102) dengan fasa kristal yang terbentuk adalah anatase dan rutile. Pada karakterisasi menggunakan SEM terhadap serbuk dari TiO2 yang telah diaplikasikan ke permukaan kain kapas, terlihat adanya imobilisasi partikel nano TiO2 melalui ikatan hidrogen silang dengan kitosan pada kain kapas. Hasil analisa tersebut kemudian dikonfirmasi dengan FTIR (Fourier Transform Infra Red) yang hasilnya memperlihatkan puncak serapan pada bilangan gelombang 3495 cm-1, 2546 cm-1, dan 511 cm-1,  yang masing-masing diasumsikan sebagai adanya vibrasi gugus fungsi O-H, N-H dan Ti-O-Ti. Hasil SEM menunjukkan pula bahwa kristal nano yang terbentuk diantaranya adalah fasa rutile , yang berdasarkan literatur terbukti dapatberfungsi sebagai anti UV.


2012 ◽  
Vol 27 (4) ◽  
pp. 798-805 ◽  
Author(s):  
Collin Hii ◽  
Øyvind W. Gregersen ◽  
Gary Chinga-Carrasco ◽  
Øyvind Eriksen ◽  
Kai Toven

Abstract This study shows that wet-pressing TMP and DIP with a shoe press pulse may yield similar afterpress solids, provided that an adequate shoe pulse length with similar pressure profile is applied. A wet web with more porous structure in the sheet dewatering (felt) layer seems to contribute to the increased dewatering during wet pressing. In addition, a shoe press pulse with high peak pressure at the end yields higher solids content after wet-pressing and higher bulk compared to a pulse with a peak pressure in the beginning. The increased dewatering during wet-pressing implies a reduction of steam consumption in the dryer.


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