scholarly journals Addition of Al(OH)3 versus AlO(OH) nanoparticles on the optical, thermo-mechanical and heat/oxygen transmission properties of microfibrillated cellulose films

Cellulose ◽  
2021 ◽  
Author(s):  
Tjaša Kolar ◽  
Branka Mušič ◽  
Romana Cerc Korošec ◽  
Vanja Kokol
Keyword(s):  
Thermal Management ◽  
Oxygen Permeability ◽  
Hydrophobic Surface ◽  
Exothermic Peak ◽  
Microfibrillated Cellulose ◽  
Low Oxygen ◽  
Cellulose Films ◽  
One Step ◽  
Thermal Stability Of ◽  
Oxygen Transmission

AbstractDifferently structured aluminum (tri/mono) hydroxide (Al(OH)3 /AlO(OH)) nanoparticles were prepared and used as thermal-management additives to microfibrillated cellulose (MFC), cast-dried in thin-layer films. Both particles increased the thermal stability of the MFC film, yielding 20–23% residue at 600 °C, and up to 57% lowered enthalpy (to 5.5–7.5 kJ/g) at 0.15 wt% of loading, while transforming to alumina (Al2O3). However, the film containing 40 nm large Al(OH)3 particles decomposed in a one-step process, and released up to 20% more energy between 300 and 400 °C as compared to the films prepared from smaller (21 nm) and meta-stable AlO(OH), which decomposed gradually with an exothermic peak shifted to 480 °C. The latter resulted in a highly flexible, optically transparent (95%), and mechanically stronger (5.7 GPa) film with a much lower specific heat capacity (0.31–0.28 J/gK compared to 0.68–0.89 J/gK for MFC-Al(OH)3 and 0.87–1.26 for MFC films), which rendered it as an effective heat-dissipating material to be used in flexible opto-electronics. Low oxygen permeability (2192.8 cm3/m2day) and a hydrophobic surface (> 60°) also rendered such a film useful in ecologically-benign and thermosensitive packaging.

scholarly journals Addition of Al(OH)3 vs. AlO(OH) nanoparticles on the optical, thermo-mechanical and heat/oxygen transmission properties of microfibrillated cellulose films

2021 ◽  
Author(s):  
Tjaša Kolar ◽  
Branka Mušič ◽  
Romana Cerc Korošec ◽  
Vanja Kokol
Keyword(s):  
Thermal Management ◽  
Oxygen Permeability ◽  
Hydrophobic Surface ◽  
Exothermic Peak ◽  
Microfibrillated Cellulose ◽  
Low Oxygen ◽  
Cellulose Films ◽  
One Step ◽  
Thermal Stability Of ◽  
Oxygen Transmission

Abstract Differently structured aluminum (tri/mono) hydroxide (Al(OH)3 / AlO(OH)) nanoparticles were prepared and used as thermal-management additives to microfibrillated cellulose (MFC), cast-dried in thin-layer films. Both particles increased the thermal stability of the MFC film, yielding 20–23% residue at 600 °C, and up to 57% lowered enthalpy (to 5.5–7.5 kJ/g) at 0.15 wt% of loading, while transforming to Al2O3. However, the film containing 40 nm large Al(OH)3 particles decomposed in a one-step process, and released up to 20 % more energy between 300–400°C as compared to the films prepared from smaller (21 nm) and meta-stable AlO(OH), which decomposed gradually with an exothermic peak shifted to 480 °C. The latter resulted in a highly flexible, optically transparent (95%), and mechanically stronger (5.7 GPa) film with a much lower specific heat capacity (0.31 − 0.28 J/gK compared to 0.68–0.89 J/gK for MFC-Al(OH)3 and 0.87–1.26 for MFC films), which render it as an effective heat-dissipating material to be used in flexible opto-electronics. Low oxygen permeability (2192.8 cm3/m2day) and a hydrophobic surface (>60°) rendered such a film also useful in ecologically-benign and thermosensitive packaging.

scholarly journals Modification of polyvinyl alcohol/microfibrillated-cellulose films by ethylene triethoxysilane

2020 ◽  
Vol 15 ◽  
pp. 155892502091087
Author(s):  
Pei-wei Bian ◽  
Bin-qing Sun ◽  
Li-qiang Huang
Keyword(s):  
Polyvinyl Alcohol ◽  
Composite Films ◽  
Film Surface ◽  
Barrier Properties ◽  
Microfibrillated Cellulose ◽  
Hydrophobic Property ◽  
Water Contact ◽  
Cellulose Films ◽  
Cellulose Composite ◽  
Thermal Stability Of

This study aimed to improve the strength and hydrophobic properties of polyvinyl alcohol/microfibrillated-cellulose composite films and thereby solve problems such as the poor water resistance of polyvinyl alcohol films and defects in the packaging. Polyvinyl alcohol/microfibrillated-cellulose composite films were prepared with the silane coupling agent KH151. The mechanical, optical, crystalline, and other properties of the composite films were tested. After the modification of the polyvinyl alcohol/microfibrillated-cellulose films, their strength and hydrophobic and barrier property were greatly improved. Moreover, their oxygen transmittance decreased by 85.9%, and the water contact angle of the film surface increased by 44%. The internal structure of a polyvinyl alcohol/microfibrillated-cellulose film is formed by KH151, which improves the strength and barrier properties of the film, forms an alkane-based layer on the film surface, and improves the hydrophobic property of the film. Thermogravimetric analysis shows that the thermal stability of composite materials has been greatly improved.

scholarly journals HYDROGELS FROM POLYACRYLIC ACID FOR REDUCTION OF BIOADHESION ON SILICONE CONTACT LENSES

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Zahida Ademović ◽  
Snježana Marić ◽  
Peter Kingshott ◽  
Zoran Iličković
Keyword(s):  
Surface Modification ◽  
Oxygen Permeability ◽  
Contact Lenses ◽  
Low Oxygen ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Lysozyme Adsorption ◽  
Tof Ms

Contact lenses suffer from two limitations: low oxygen permeability and deposition of protein and lipids. In order to prevent bioadhesion, surface must be completely inert to all biological reactions. To achieve this, surface properties must be tailored. Also, to improve comfort, surface must be highly wettable and lubricous. In this paper the surface of silicone contact lenses was modified by plasma induced copolymerization of acrylic acid. A wettable surface was generated and in addition carboxyl groups that were created on the surface provided an ideal reactive platform for subsequent grafting of polyethylene glycol. Each surface modification step was analysed by XPS and contact angle measurements. Lysozyme adsorption on modified silicone contact lenses was analysed by surface-MALDI-ToF-MS and XPS. After incubation with lysozyme, surface-MALDI-TOF-MS and XPS analysis showed a reduction of adsorbed lysozyme on hydrogel modified contact lenses. Surface modification of silicone with PEG is a method for reduction of protein adsorption on contact lenses.

High-consistency milling of oxidized cellulose for preparing microfibrillated cellulose films

Cellulose ◽  
2015 ◽  
Vol 22 (5) ◽  
pp. 3151-3160 ◽  
Author(s):  
Henrikki Liimatainen ◽  
Juho Antti Sirviö ◽  
Kaarina Kekäläinen ◽  
Osmo Hormi
Keyword(s):  
Microfibrillated Cellulose ◽  
Oxidized Cellulose ◽  
Cellulose Films ◽  
High Consistency

scholarly journals One-Step Preparation of Durable Super-Hydrophobic MSR/SiO2 Coatings by Suspension Air Spraying

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 677 ◽  
Author(s):  
Zhengyong Huang ◽  
Wenjie Xu ◽  
Yu Wang ◽  
Haohuan Wang ◽  
Ruiqi Zhang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Adhesion Strength ◽  
Contact Angle Hysteresis ◽  
Surface Hardness ◽  
Hierarchical Structures ◽  
Hydrophobic Surface ◽  
Water Contact ◽  
Hydrophobic Coating ◽  
Mechanical Durability ◽  
One Step

In this study, we develop a facial one-step approach to prepare durable super-hydrophobic coatings on glass surfaces. The hydrophobic characteristics, corrosive liquid resistance, and mechanical durability of the super-hydrophobic surface are presented. The as-prepared super-hydrophobic surface exhibits a water contact angle (WCA) of 157.2° and contact angle hysteresis of 2.3°. Mico/nano hierarchical structures and elements of silicon and fluorine is observed on super-hydrophobic surfaces. The adhesion strength and hardness of the surface are determined to be 1st level and 4H, respectively. The coating is, thus, capable of maintaining super-hydrophobic state after sand grinding with a load of 200 g and wear distances of 700 mm. The rough surface retained after severe mechanical abrasion observed by atomic force microscope (AFM) microscopically proves the durable origin of the super-hydrophobic coating. Results demonstrate the feasibility of production of the durable super-hydrophobic coating via enhancing its adhesion strength and surface hardness.

scholarly journals Yerba Mate Extract in Microfibrillated Cellulose and Corn Starch Films as a Potential Wound Healing Bandage

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2807
Author(s):  
Meysam Aliabadi ◽  
Bor Shin Chee ◽  
Mailson Matos ◽  
Yvonne J. Cortese ◽  
Michael J. D. Nugent ◽  
...  
Keyword(s):  
Wound Healing ◽  
Bioactive Compounds ◽  
Corn Starch ◽  
Microfibrillated Cellulose ◽  
Ilex Paraguariensis ◽  
Mechanical And Thermal Properties ◽  
Yerba Mate ◽  
Cellulose Films ◽  
Ultrafine Grinding

Microfibrillated cellulose films have been gathering considerable attention due to their high mechanical properties and cheap cost. Additionally, it is possible to include compounds within the fibrillated structure in order to confer desirable properties. Ilex paraguariensis A. St.-Hil, yerba mate leaf extract has been reported to possess a high quantity of caffeoylquinic acids that may be beneficial for other applications instead of its conventional use as a hot beverage. Therefore, we investigate the effect of blending yerba mate extract during and after defibrillation of Eucalyptus sp. bleached kraft paper by ultrafine grinding. Blending the extract during defibrillation increased the mechanical and thermal properties, besides being able to use the whole extract. Afterwards, this material was also investigated with high content loadings of starch and glycerine. The results present that yerba mate extract increases film resistance, and the defibrillated cellulose is able to protect the bioactive compounds from the extract. Additionally, the films present antibacterial activity against two known pathogens S. aureus and E. coli, with high antioxidant activity and increased cell proliferation. This was attributed to the bioactive compounds that presented faster in vitro wound healing, suggesting that microfibrillated cellulose (MFC) films containing extract of yerba mate can be a potential alternative as wound healing bandages.

Novel Thermally Stable Epoxy-polyurethane Composites: Preparation, Characterization

2011 ◽  
Vol 239-242 ◽  
pp. 2742-2747
Author(s):  
Jing Lin ◽  
Qiu Zhuan Yang ◽  
Xiu Fang Wen ◽  
Zhi Qi Cai ◽  
Pi Hui Pi ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ring Opening ◽  
Thermal Characteristics ◽  
Ring Opening Reaction ◽  
Tetramethylammonium Bromide ◽  
One Step ◽  
Novolac Epoxy ◽  
Polyurethane Composites ◽  
Novolac Epoxy Resins ◽  
Thermal Stability Of

A novel series of hydroxyl terminated bisphenol-A type novolac epoxy resins modified with propionic acid (MEP) were prepared by one-step ring-opening reaction process in the presence of tetramethylammonium bromide catalyst. The obtained MEP was characterized using FTIR,1HNMR analyses. In addition, Intercross-linked epoxy-polyurethane composites networks were also obtained by curing reaction among MEP, cross linker polyisocyanate IL1351 and phthalic anhydride. The thermal characteristics of the epoxy-polyurethane composites were determined by thermogravimetric analysis (TGA). The thermal stability of the cured MEP with different ring-opening rate and cured alkyd polyol A450 were compared. The results showed that the obtained epoxy-polyurethane composites had much better thermal stability than the conventional polyurethane system A450/IL1351, and the thermal stability of them was correlated to the content of MEP.

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