2ND INTL SYMP ON GREEN CHEMISTRY AND POLYMERS AND THEIR APPLICATION FOR SUSTAINABLE DEVELOPMENT

Actuality of the research is determined by needs of modern optics and electronics, because it is well known that modern technologies for the vast majority of electronic and optoelectronic devices, both for household and special purpose, are based on materials harmful to humans and environment. Further development of heterostructures based on traditional materials is limited by the need to harmonize the properties of individual components at the interface. Such limitations are not principal for hybrid composites, where the matrix and its filling components (fillers) interact relatively "weakly" with each other. Then, "strong" interactions within the components provide their stability, while "weak" - allow to find the combinations of components providing necessary properties of a composite as a whole [1].
We described here hybrid composite materials based on natural polymer matrix (micro/nanosized cellulose, MC/NC) incorporated with three types of fillers: microcrystalline cellulose (MCC), graphene oxide (GO), and nanosized dielectric oxides (DO). The fillers should improve or modify, each in its own direction, the properties of the matrix, and they should bring to the composite their own properties uncharacteristic to matrix. Short review about background of this science direction was given (see, e.g. [2, 3]).
New data obtained in our R&D team about cellulose composites are described. Simple oxides (ZnO, ZrO2 nanopaticles co-doped with europium and fluorine ions) as well as complex oxides (bismuth and lanthanum phosphates doped with luminescent RE ions) were incorporated into MC/NC matrix. Morphology, moisture resistance, conductivity, dielectric, optical absorption and luminescence properties of the composites have been studied and analyzed together with data about of starting components properties [4].
Obtained results confirmed the perspectives of practical use of the composites under study.

Biomass is a sustainable and renewable source of valuable monomers. However, the number of monomers that can be obtained from biomass processing is rather limited. In addition, the recycling of used polymeric materials is still challenging.
Here, a sustainable strategy of bio-based polymers recycling was described. First, a series of vinyl ethers was obtained from selected terpenols according to the well-established procedure for vinylation with calcium carbide [1-4]. Further, from the obtained monomers, the corresponding polymers were synthesized by standard procedures. Polymers possessed a certain plasticity and thermal stability, which made it possible to melt them repeatedly without decomposition and changes in properties. After cooling, the polymers became solid again and retained their shape.
The obtained polymeric materials were heated under inert atmosphere at different temperatures (pyrolysis) [5]. It was found that the pyrolysis products under certain conditions were only the starting alcohols (terpenols) and the corresponding aldehydes or ketones. It should be noted that all pyrolysis products are natural compounds.
After pyrolysis, the resulting liquid mixtures were collected and reduced with sodium borohydride. Thus, the corresponding ketones and aldehydes were again converted into the starting alcohols. The yields of these processes were quantitative. Thus, the mixture after the pyrolysis and reduction consisted the starting alcohol. The alcohol was again vinylated with calcium carbide, and then vinyl ethers and corresponding polymers were again obtained. The properties of the re-obtained polymers were found to be the same as initially. Thus, the resulting polymer materials can be recycled many times after the end of life.
In presentation, the synthetic and analytical data will be presented (TGA, DSC, NMR, etc.), characterizing the properties of the obtained compounds and polymers.
This work was supported by the Russian Science Foundation (21-73-20003).

In Europe, construction including heating & coaling of buildings amounts for 40
% of total CO2 emission and hence presents by far the largest source of CO2
release. Globally, a similar situation exists. The paper presents current steps in
the construction industry to dramatically reduce its CO2 footprint which include:
1) Migrate to low or zero carbon binders by replacing Portland cement clinker
with calcined clay, slag etc. Currently, cement manufacture accounts for ~ 8
% of total global CO2 emission, just behind coal, oil and gas.
2) Capture CO2 released in cement plants and utilize for concrete hardening
or dispose on CCS wells.
3) Identify CO2 stable new cements which can be used on CCS wells
4) Make highly effective thermal insulation materials mandatory on buildings.
5) Introduce concepts for mega cities to avoid unnecessary heat-up by having
plants on facades, roofs, etc. to provide a sun shelter and absorb CO2.
6) Switch from heating using fossil fuel to “green” energy including solar,
geothermal and wind energy.
7) Discourage the use of wood in construction, as we need more trees as a
natural sink for CO2.
These measures require a complete reset of our current construction processes
and will result in a huge transformation of this industry.

Cell imaging carriers with good biocompatibility have aroused wide attention.[1] Carbon quantum dots (CQDs) have attracted a great deal of attention due to their excellent properties, which is need to capsulated with non-toxic materials because of its biological toxicity.[2, 3] Gelatin has been widely used as a delivery vehicle on account of its good biocompatibility and biodegradability.[4] In this work, fluorescent gelatin nanoparticles (GNPs) were successfully fabricated by simple-cocervation and UV-crosslinking method with carbon quantum dots (CQDs) and fluorescein isothiocyanate (FITC) as fluorescence factors. The morphology and size were characterized by TEM and particle size analyzer. The average diameter of the gelatin nanoparticles (GNPs) is estimated at 390±50 nm. Meantime, the CQDs/GNPs have fluorescent properties with maximum emission at 416nm, with a slight 6±1nm blue-shift compared with CQDs. In vitro cytotoxicity test suggested that CQDs/GNPs and FITC/GNPs had not obvious toxic effect on L929 cells compared to that of individual CQDs and FITC. By confocal microscope observation, CQDs/GNPs and FITC/GNPs could bind to L929 cells for labeling. The results showed that gelatin nanoparticles have excellent fluorescence luminescence performance, including gelatin particles could be an ideal carriers for fluorescence factors. This work provided a new pathway for fabricating gelatin-based carriers for cell labeling and imaging.

Gas sensing materials fabricated from graphene based materials have been shown to provide good sensing properties: high surface area providing low limit of detection; facilitating gas interaction owing to the oxygen species functionalized on their structure promoting energy and gas adsorptions [1]. Different types of graphene materials namely; the commercial graphene (cm-G), the commercial graphene oxide (cm-GO), reduced graphene oxide (rGO), and the synthesized graphene oxide (OIHM-GO), and their composites with polyindole (PIn) were used as methanol sensing materials. The synthesized graphene oxide was synthesized by the optimized improved Hummers method because of its non-toxic method, fast preparation and low cost [2]. Herein, the synthesized GO was called OIHM-GO. The reduced graphene oxide was prepared by two different methods, the thermally mild reduction at 120˚C to yield the in situ T-rGO and the chemically reduction by ascorbic acid to yield the in situ C-rGO, in which the cm-GO was used as a raw material.
The different types of graphene materials presented different behavior responses toward methanol. The hydrophilicity of graphene materials related to oxygen content was the key factor for the methanol response.
The sensing responses were evaluated from the relative electrical conductivity at room temperature by a custom-built two point probe.
The element content of materials was clarified by X-ray photoelectron spectroscopy in which GO showed a higher oxygen content than rGO, and G, respectively. The functional groups were also confirmed by Fourier-transform infrared spectroscopy. The morphology was checked by Emission Scanning Electron Microscope.

Among the widely used soft materials, hydrogels have been investigated because of their biocompatibility, water absorption, softness, and flexibility to convert the external stimuli into the mechanical actuation by changing volume through shrinking, swelling or bending [1]. Agarose (AG), a non-ionic linear polysaccharide extracted from red seaweeds, is one of two main components of agar in addition to agaropectin. It has been widely used to study the thermo-reversible gelation. Generally, the gelation mechanism of agarose hydrogel occurs via the hydrogen bonding of helical structure, called physically cross-linked hydrogel [2].
In the present work, the agarose hydrogels (AG HyGels) were fabricated by a solvent casting method. The electromechanical properties, namely the storage modulus (G') and the storage modulus relative response (ΔG'/G'0) under various agarose contents, electric field strengths, and operation temperature were investigated by a rheometer. The electro-induced bending responses, namely the deflection angle and the dielectrophoresis force (Fd) were examined under various agarose contents and electric field strengths by immersing the sample in a silicone oil chamber between two parallel copper electrodes.
In the electromechanical properties under applied electric field strength of 800 V/mm, the highest storage modulus (G') and storage modulus relative response (ΔG'/G'0) of 4.48 x 106 Pa and 1.07 were obtained from the AG HyGel_12.0%v/v due to the electrostriction effect [3]. With increasing operating temperature, the intermolecular hydrogen bonding interaction between the agarose chains were disturbed, leading to the decrease in the G' [4]. For the electro-induced bending response, the free ends of the AG HyGels bended toward the positively charged electrode depending on the electric field strength, implying the attractive interaction between the polarizations of the AG HyGel and the electrode [5]. The highest deflection angle of 74° was obtained from the AG HyGel_2.0%v/v due to its initial lower rigidity.
Comparing the performances with other bio-based hydrogels, the AG HyGels are possible candidates to use as electro-responsive hydrogels for soft actuator applications.

Stimuli responsive polymeric materials are materials that can convert external stimuli such as electric field, heat, light, and magnetic field into mechanical work [1]. They have been utilized in various applications, including medical devices, switches, artificial muscle, and shape memory materials [2]. In recent decades, biopolymers are promising materials to replace the petroleum-based polymers in which poly (lactic acid) (PLA) has attracted a great deal of attention. PLA can respond under applied electric field due to the carbonyl group in main chain that can rotate in the presence of electric field [3].
In this work, the PLA composites consisting of MWCNT as a nanofiller and DBP as a plasticizer were prepared by solvent casting. The electromechanical properties were investigated in the terms of the MWCNT concentration and electric field strength.
The PLA composites showed good recoverability during the time sweep test. The storage modulus response (∆Gꞌ) increases with increasing MWCNT content from 0 to 0.5%v/v and then decreases and become negative values after the MWCNT content higher than 0.8%v/v. 0.1%v/v MWCNT/PLA/DBP composite provided the highest storage modulus sensitivity of 1.56 at the electric filed strength of 1.5 kV/mm. Moreover, the 0.1%v/v MWCNT/PLA/DBP showed higher bending distances and dielectrophoresis forces at the electric filed strength below 300 V/mm.

SIPS is the flagship event of FLOGEN STARS OUTREACH, a not-for-profit, non-political and all-inclusive science organization. SIPS as well as FLOGEN STARS OUTREACH takes no sides in political, scientific or technological debates. We equally welcome, without reservations, all spectrum of ideas, theories, technologies and related debates. Statements and opinions expressed are those of individuals and/or groups only and do not necessary reflect the opinions of FLOGEN, its sponsors or supporters.

FLOGEN Stars OUTREACH | Home | Contact Us | Privacy Policy | Cancellations/Refund Policy
© Copyright of FLOGEN Stars Outreach Organization: The content of this page including all texts and photos are copyright of FLOGEN Stars Outreach and none can be used in their original or in any modified or combined form in any publication, web site or in any other medium whatsoever without prior written permission from FLOGEN Stars Outreach.