scholarly journals Ionic Conductivity and Structure of Chitosan Films Modified with Lactic Acid-Choline Chloride NADES

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 350 ◽  
Author(s):  
Mikhail A. Smirnov ◽  
Alexandra L. Nikolaeva ◽  
Vitaly K. Vorobiov ◽  
Natalia V. Bobrova ◽  
Ivan V. Abalov ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Choline Chloride ◽  
Composite Films ◽  
Deep Eutectic Solvent ◽  
Thermomechanical Analysis ◽  
X Ray Scattering ◽  
Composition And Structure ◽  
Solution Casting Method ◽  
Natural Deep Eutectic Solvent ◽  
The Impact

The natural deep eutectic solvent (NADES) based on choline chloride (ChCl) and lactic acid (LA) was used for the preparation of chitosan (CS) films by the solution casting method. The content of NADES in films was from 0 to 82 wt%. The impact of NADES on the morphology and crystalline structure of films was investigated using scanning electron microscopy as well as wide-angle and small-angle X-ray scattering. The experimental results allow to propose CS chains swelling in NADES. FTIR spectroscopy confirms the interactions between CS and NADES components via the formation of hydrogen and ion bonds. The thermal properties of the composite films were studied by simultaneous thermogravimetric and differential thermal analysis. Thermomechanical analysis demonstrated appearance of two transitions at temperatures between −23 and −5 °C and 54–102 °C depending on NADES content. It was found that electrical conductivity of film with 82 wt% of NADES reaches 1.7 mS/cm. The influence of the composition and structure of films on the charge carriers concentration and their mobility is discussed.

scholarly journals Delignification of Low-Energy Mechanical Pulp (Asplund Fibers) in a Deep Eutectic Solvent System of Choline Chloride and Lactic Acid

2021 ◽  
Vol 9 ◽  
Author(s):  
Alan D. Pérez ◽  
Juha Fiskari ◽  
Boelo Schuur
Keyword(s):  
Mass Transfer ◽  
Lactic Acid ◽  
Fiber Length ◽  
Lignin Content ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Low Energy ◽  
Pulp Yield ◽  
Operational Conditions ◽  
The Impact

Deep eutectic solvents (DESs) are considered as a green and environmentally benign solvent class for various applications, including delignification of biomass. One of the major challenges in the delignification of biomass by DES is attributed to the limitations in mass transfer. By subjecting wood chips to a low-energy mechanical refining, i.e., the Asplund process, the accessible surface area increases greatly, which in turn improves the mass transfer and increases the reaction rate. In this research, the DES delignification of Asplund fibers made of Norway spruce was studied as a strategy to produce papermaking fibers under mild conditions. A DES consisting of lactic acid and choline chloride was used due to its proven performance in delignification. Various operational conditions, such as temperature, time, DES-to-wood ratio, and the type of stirring were studied. A novel parameter, Q, allowed to evaluate the impact of the operational conditions on the quality of the pulp in terms of delignification degree and fiber length. The results showed that cooking temperature had the most significant effect on the pulp quality. Additionally, it was observed that cooking times between 30 and 45 min result in a pulp yield of about 50%, while fibers have a lignin content of about 14% and a fiber length of 0.6 mm. These results demonstrate that it is possible to obtain fibers of relatively good quality from DES delignification using Asplund fibers as the starting material.

scholarly journals Esterification of Lignin Isolated by Deep Eutectic Solvent Using Fatty Acid Chloride, and Its Composite Film with Poly(lactic acid)

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2149
Author(s):  
Chan-Woo Park ◽  
Song-Yi Han ◽  
Rajkumar Bandi ◽  
Ramakrishna Dadigala ◽  
Eun-Ah Lee ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Fatty Acid ◽  
Composite Film ◽  
Acid Chloride ◽  
Pinus Densiflora ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Morphological Characteristics ◽  
Poly Lactic Acid ◽  
Fatty Acid Chloride

In this study, the effect of lignin esterification with fatty acid chloride on the properties of lignin and lignin/poly(lactic acid) (PLA) composites was investigated. Lignocellulose (Pinus densiflora S. et Z.) was treated using a deep eutectic solvent (DES) with choline chloride (ChCl)/lactic acid (LA). From the DES-soluble fraction, DES-lignin (DL) was isolated by a regeneration process. Lignin esterification was conducted with palmitoyl chloride (PC). As the PC loading increased for DL esterification, the Mw of esterified DL (EDL) was increased, and the glass transition temperature (Tg) was decreased. In DL or EDL/PLA composite films, it was observed that EDL/PLA had cleaner and smoother morphological characteristics than DL/PLA. The addition of DL or EDL in a PLA matrix resulted in a deterioration of tensile properties as compared with neat PLA. The EDL/PLA composite film had a higher tensile strength and elastic modulus than the DL/PLA composite film. DL esterification decreased water absorption with lower water diffusion coefficients. The effect of lignin esterification on improving the compatibility of lignin and PLA was demonstrated. These results are expected to contribute to the development of high-strength lignin composites.

Deep eutectic solvent delignification: Impact of initial lignin

BioResources ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. 7301-7310
Author(s):  
Veronika Majová ◽  
Silvia Horanová ◽  
Andrea Škulcová ◽  
Jozef Šima ◽  
Michal Jablonský
Keyword(s):  
Lactic Acid ◽  
Oxalic Acid ◽  
Lignin Content ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Deep Eutectic Solvents ◽  
Kappa Number ◽  
Kraft Pulps ◽  
Oxygen Delignification ◽  
Detailed Understanding

This study aimed to resolve the issue of the lack of detailed understanding of the effect of initial lignin content in hardwood kraft pulps on pulp delignification by deep eutectic solvents. The authors used Kappa number of the concerned pulp, intrinsic viscosity, and selectivity and efficiency of delignification as the parameters of the effect. The pulp (50 g oven dry pulp) was treated with four different DESs systems based on choline chloride with lactic acid (1:9), oxalic acid (1:1), malic acid (1:1), and system alanine:lactic acid (1:9); the results were compared to those reached by oxygen delignification. The results showed that the pulp with a higher initial lignin content had a greater fraction of easily removed lignin fragments.

scholarly journals Assessment of Natural Deep Eutectic Solvent Pretreatment on Sugar Production from Lignocellulosic Biomass

2018 ◽  
Vol 152 ◽  
pp. 01014 ◽  
Author(s):  
Yoon Li Wan ◽  
Yuen Jun Mun
Keyword(s):  
Enzymatic Hydrolysis ◽  
Lignocellulosic Biomass ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Economic Feasibility ◽  
Effect Of Temperature ◽  
Sago Waste ◽  
Natural Deep Eutectic Solvent ◽  
Hydrolysis Of ◽  
Sugar Loss

Before the conversion of lignocellulosic biomass into fuel such as ethanol, the biomass needs to be pretreated and the yield of ethanol is highly dependent on the pretreatment efficiency. This study investigate the performance of deep eutectic solvent (DES) in pretreating sago waste which is a type of starchy biomass. The suitable type of DES in sago waste pretreatment was selected based on three criteria, which is the structural characteristic, the sugar yield during enzymatic hydrolysis and the amount of sugar loss during pretreatment. In this study, three types of DES namely Choline Chloride-Urea (ChCl-Urea), Choline Chloride-Citric acid (ChCl-CA) and Choline Chloride-Glycerol (ChCl-Glycerol) was investigated. The effect of temperature and duration on DES pretreatment was also investigated. All DES reagents were able to disrupt the structure and increase the porosity of sago waste during pretreatment. ChCl-Urea was selected in this study as it shows apparent structural disruption as examined under Scanning Electron Microscope (SEM). The highest glucose yield of 5.2 mg/mL was derived from enzymatic hydrolysis of ChCl-Urea pretreated sago waste. Moreover, reducing sugar loss during ChCl-Urea pretreatment was low, with only 0.8 mg/mL recorded. The most suitable temperature and duration for ChCl-Urea pretreatment is at 110°C and 3 hr. In a nutshell, the application of DES in pretreatment is feasible and other aspects such as the biodegradability and recyclability of DES is worth investigating to improve the economic feasibility of this pretreatment technique.

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