scholarly journals Effect of A Limited Amount of D-Sorbitol on Pitch and Mechanical Properties of Cellulose Nanocrystal Films

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1324
Author(s):  
Xiao-Yao Wei ◽  
Tao Lin ◽  
Le Wang ◽  
Xue-Feng Yin

A cellulose nanocrystal (CNC) suspension can form liquid crystal films with unique self-assembly behaviors. This gives CNC films a special iridescence, which has potential in many aspects, but the brittleness of pure CNC films limits their application. In this work, we propose a simple physical mixing method to obtain CNC film by adding D-sorbitol as a plasticizer. We first found that low D-sorbitol content (less than 6 wt% in CNC/DS composite solution) did not make a significant difference compared with pure CNC films in optical performance and, at the same time, the mechanical properties of the CNC films were improved. The various low contents of D-sorbitol can be well dispersed in CNC aqueous suspension, and the wavelength of the selectively reflected phenomenon is relatively stable and slightly decreased at 5 nm for concentrations from 0 to 6%. This phenomenon is opposite to that generally reported, where the wavelength of the selective reflected phenomenon increases obviously with the increase in plastic content. The pitch of the chiral structure decreased from 406 to 362 nm with an increase in D-sorbitol concentration. When the content of D-sorbitol reached 4%, the tensile strength, elongation at break, and Young modulus increased to 39.9 Mpa, 3.00%, and 2.99 GPa, respectively.

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3419 ◽  
Author(s):  
Beata Kaczmarek ◽  
Katarzyna Lewandowska ◽  
Alina Sionkowska

Collagen materials are widely used in biomedicine and in cosmetics. However, their properties require improvement for several reasons. In this work, collagen solution as well as collagen films were modified by the addition of ferulic acid (FA). Thin collagen films containing FA were obtained by solvent evaporation. The properties of collagen solution have been studied by steady shear tests. The structure and surface properties of collagen thin films were studied. It was found that for collagen solution with 5% addition of FA, the apparent viscosity was the highest, whereas the collagen solutions with other additions of FA (1%, 2%, and 10%), no significant difference in the apparent viscosity was observed. Thin films prepared from collagen with 1 and 2% FA addition were homogeneous, whereas films with 5% and 10% FA showed irregularity in the surface properties. Mechanical properties, such as maximum tensile strength and elongation at break, were significantly higher for films with 10% FA than for films with smaller amount of FA. Young modulus was similar for films with 1% and 10% FA addition, but bigger than for 2% and 5% of FA in collagen films. The cross-linking of collagen with ferulic acid meant that prepared thin films were elastic with better mechanical properties than collagen films.


2020 ◽  
Vol 12 (1) ◽  
pp. 386-394
Author(s):  
E.C. Agwamba

The major setback with most bioplastics is their inherent inability to compete with Petro-plastics in terms of high production cost, and there poor mechanical properties like low tensile strength and percentage extension. This study explore the availability and affordability of mango starch as raw material for bioplastic production and compared some of its mechanical properties with High density Polyethylene (HDPE), Low density polyethylene (LDPE), polyvinyl chloride (PVC), and Polyurethane (PU). Mango starch was used to synthesize bioplastic derivatives, with variable levels of sucrose as plasticiser, aqueous HCl concentration and Carboxymethyl cellulose (CMC) as additive and the mechanical properties of the derived biofilms was measured and compared with the selected Petro-plastics films. It was observed that B1 thermoplastic derivatives have the higher young modulus of 5.658 GPa than that obtained for PVC (4.682 GPa), and PU (3.771 GPa) but show no significant difference and significantly higher than that of HDPE (0.049 GPa), and LDPE (0.063 GPa) (p < 0.05). B2 and B3 indicated a young modulus that is significantly lower than PU and PVC, but showed a young modulus that is higher than LDPE and HDPE with no significant difference (p < 0.05). The FTIR spectra indicate that hydrogen bond was formed in the bulk matrix of the bioplastic derivatives at a band region of 3600 -600 cm-1 wavenumber with broad discrete peaks. Keywords: Petro-plastics; Bioplastics; Mechanical Properties; Plasticization; Mango Starch


Author(s):  
Aline Olivier ◽  
Tadeusz Pakula ◽  
Bernd Ewen ◽  
Xavier Coqueret ◽  
Mustapha Benmouna ◽  
...  

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4389
Author(s):  
Xiao Xiao ◽  
Jie Chen ◽  
Zhe Ling ◽  
Jiaqi Guo ◽  
Jianbin Huang ◽  
...  

The exploration of functional materials relies greatly on the understanding of material structures and nanotechnologies. In the present work, chiral nematic cellulose nanocrystal (CNC) films were prepared by incorporation with four types of amino acids (AAs, glycine, histidine, phenylalanine, and serine) via evaporation-induced self-assembly. The films present ideal iridescence and birefringence that can be tuned by the amount of AAs added. The intercalation of AAs enlarged the pitch values, contributing to the red-shift trend of the reflective wavelength. Among the AAs, serine presented the most compatible intercalation into cellulose crystals. Interestingly, histidine and phenylalanine composite films showed high shielding capabilities of UV light in diverse wavelength regions, exhibiting multi-optical functions. The sustainable preparation of chiral nematic CNC films may provide new strategies for materials production from biocompatible lignocellulose.


2014 ◽  
Vol 15 (11) ◽  
pp. 4343-4350 ◽  
Author(s):  
Qi Chen ◽  
Ping Liu ◽  
Fuchun Nan ◽  
Lijuan Zhou ◽  
Jianming Zhang

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