Poly(acrylates) are widely used as superabsorbent polymers (SAPs) because they absorb more than 100 times their weight in water but are petro-sourced and non-biodegradable. To reduce their carbon footprint, we copolymerized acrylic acid (AA) and acrylamide (AM) with bio-based itaconic (IA) and fumaric (FA) acids via free-radical copolymerization. Two families of N,N '-methylenebis(acrylamide)-crosslinked networks were synthesized: p(AA-co-AM-co-FA) and p(IA-co-AM-co-FA), with varied parameters. Formulations were characterized by FTIR and TGA; physicochemical tests (rheology G '/G '' and compression, SEM, zeta potential, pH, conductivity, density, moisture, and biodegradation); and absorption performance in 0.9 wt% NaCl and deionized water using standardized hygiene-SAP procedures. A commercial Poly(acrylates) based SAP was used as control. The key outcome of this work is that the combined incorporation of itaconic and fumaric acids enabled partially biobased SAP networks to reach up to 52 % of the saline AUL performance of a commercial hygienic poly(acrylate) superabsorbent. The best materials, p(AA-co-AM-co-FA)-1 and p(IA-co-AM-co-FA)-3, showed competitive uptake versus the commercial control. In deionized water, FSC (g/g) = 205 and 54, CRC (g/g) = 139 and 32, with AUL (0.7 psi, g/g) = 25 and 27, respectively (control: 246, 139, 43 g/g). In saline solution, FSC = 54 and 26, CRC = 38 and 15, with AUL = 14 and 17 (control: 62, 34, 33 g/g). Materials exhibited low yet non-negligible biodegradation (9-12 % at 42 days; control = 0 %). IA/FA-based networks provide eco-friendly SAP alternatives, combining strong performance with lower carbon footprint and cost.

Superabsorbent polymers (SAPs) are versatile materials, indispensable in the design of various products (98 % of SAPs in the hygiene sector, and 2 % of SAPs in agriculture, biomedical, water treatment and civil engineering) due to their ability to absorb massive quantities of fluids. SAPs are mainly made from polyacrylate derivatives despite their high ecological footprint, because of their high absorption capacities and their low cost. This reality forces some players in the field to envisage a more sustainable future through the development of eco-friendly SAPs. However, the notion of SAPs is often generalized independently of their field of application, and the procedures used to evaluate their performance are sometimes far removed from the standardized procedures essential to their industrial applications. This review attempts to give readers clear definitions of SAPs depending on their applications. It aims also to take stock of existing standardized and normalized procedures for qualifying them. It highlights the cruel reality in this field, distinguishing eco-friendly “SAP” materials from those that are not. Finally, it recontextualizes the subject proposing a clear approach to adopt and showing that the industrial application potential of “eco-friendly and biodegradable SAP” is poorly understood when it is not evaluated according to industrial requirements.

This work valorizes rejects from Tenebrio Molitor TM breeding through the production of chitin and chitosan. Two processes are proposed for extracting chitin from larval exuviae and adult. The first process P1 provides chitin with high contents compared to literature data but the characterization shows the presence of impurities in the exuviae chitin responsible for the shifts in the values of the physicochemical characteristics towards those presented by γ chitin. These impurities are removed by delipidation and pure α chitin is obtained. The effective delipidation of this chitin would be linked to its fibrous surface structure. The analysis of the results of P1 led us to develop a second extraction process P2 which provides pure chitin with improved yields using delipidation followed by deproteinization. The N-deacetylation of chitin according to Kurita or Broussignac process makes possible the preparation of pure, highly deacetylated chitosan samples (2 % < DA < 12 %) with high yields and controlled molar masses (Mv). A kinetic study of molecular degradation during deacetylation is carried out. A comparison with Hermetia illucens allows to extend the use of insects as a potential source of chitin and chitosan and confirms the role of the source and the processes in the determination of their characteristics.

Breeding of the black soldier fly is carried out to produce proteins. It is accompanied by releases during the life cycle of this insect. This work is a study of the valorization of these rejects through the production of chitins and chitosans with controlled characteristics. An extraction process is developed with an order of treatments and reaction conditions that provide chitins with high contents. These contents increase as the stages of the life cycle progress and drop for the adult. However, the exuviae chitins present organic impurities which will be eliminated at the N-deacetylation reaction for pupe and after a purification treatment for chitosan from larval stages. All these chitins have an α structure although certain physicochemical characteristics of the larval exuviae chitins are close to those presented by γ chitin. The observed shifts are linked to the effect of impurities rather than to a difference in structure. N-deacetylation of chitins makes possible the valorization of all rejects by the production of pure chitosans with high yields which retain a porous structure for the exuviae and fibrous for the adult which allow complementary applications. These chitosans are highly to completely deacetylated and their molar masses can vary depending on the process and life stage.

In this work, chitin was extracted using a single step of deproteinization from the whole locust and its different morphological parts (thorax, legs, abdomen, head and wings). All chitins present an α structure with contents of 10 to 12

Chitin is a natural polysaccharide produced abundantly by biosynthesis in algae and fungi of the plant kingdom, as well as arthropods, mollusks, and other taxonomic groups of the animal kingdom. It consists of a sequence of monomers of N-acetylglucosamine and is found in three forms (α, β, and γ) which differ according to the arrangement of the chains in the crystalline region. Chitosan is the main high-value derivative of chitin. It is obtained by N-deacetylation reactions. Chitin and chitosan are copolymers consisting of units of N-acetylglucosamine and D-glucosamines linked by β- (1 → 4) glycosidic linkages. The major structural parameter is the degree of acetylation (DA), defined as the molar fraction of acetylglucosamine units. When the DA exceeds 50%, the copolymer is substantially insoluble in dilute acid solutions and corresponds to chitin. The chitosan name applies when DA is below 50%; the smaller the DA, the more soluble the copolymer is in acidic solutions. Methods for chitin and chitosan extraction from biomass are considered (Kurita, Broussignac, and laboratory processes) and compared to prepare samples with definite characteristics relative to the intended applications. The roles of the source (and the type of chitin) and the process will be discussed. Structural analysis will be presented to determine the DA using different techniques (spectroscopic, potentiometric, or conductimetric), which will be compared. The techniques to characterize the pattern of acetylation are discussed relative to the properties depending on this pattern. Finally, solution properties are addressed. Concerning these determinations and solution properties, special care must be taken to avoid macromolecular aggregates; this can be achieved by choosing appropriate solvents and solution concentration domains.

In 2020, Coronavirus disease (COVID-19), a new viral respiratory disease caused by a virus that belongs to Coronaviridae family, has been identified. It is a very severe flu that negatively affects the functions of the lung and other respiratory organs. COVID-19 virus can be transmitted between people either by touching an infected person or by direct contact with their respiratory droplets. Therefore, the COVID-19 virus has become a global concern due to its rapid spread and severity. Based on the World Health Organization report from 2 March 2020 to 24 October 2022, the total infected cases and deaths in Morocco are around 1,265,389 (3.46%) and 16,280 (0.04%), respectively. Recently, some scientists have found that chitosan, a polymer existed in nature, can inhibit COVID-19 infection and repair damaged tissue. Therefore, understanding chitosan mechanisms in controlling COVID-19, might lead to innovative strategies in the medical field, such as developing drugs against SARS-CoV-2, and replacing vaccines, which have negative side effects. This review aims to show the evolution of the COVID-19 pandemic worldwide, specifically in Morocco, its pathophysiology, and its ability to silence the immune system. This review also provides an overview of the treatments and measures applied to protect human beings and how chitosan acts and controls COVID-19.

A novel sulfated xylogalactan (JASX) was extracted and purified from the rhodophyceae Jania adhaerens. JASX was characterized by chromatography (GC/MS-EI and SEC/MALLS) and spectroscopy (ATR-FTIR and 1H/13C NMR) techniques. Results showed that JASX was constituted by repeating units of (→3)-β-d-Galp-(1,4)-3,6-α-l-AnGalp-(1→)n and (→3)-β-d-Galp-(1,4)-α-l-Galp-(1→)n substituted on O-2 and O-3 of the α-(1,4)-l-Galp units by methoxy and/or sulfate groups but also on O-6 of the β-(1,3)-d-Galp mainly by β-xylosyl side chains and less by methoxy and/or sulfate groups. The Mw, Mn, Đ, [η] and C* of JASX were respectively 600 and 160 kDa, 3.7, 102 mL.g−1 and 7.0 g.L−1. JASX exhibited pseudoplastic behavior influenced by temperature and monovalent salts and highly correlated to the power-law model and the Arrhenius relationship. JASX presented thixotropic characteristics, a gel-like viscoelastic behavior and a great viscoelasticity character. JASX showed important antioxidant activities, outlining its potential as a natural additive to produce functional foods.

Alginic acids and alginates have important applications in food, medicine, pharmaceutical industry, dentistry and textile. The sodium alginate from Nizimuddinia zanardini (an Iranian brown seaweed) was extracted with high voltage electrical discharge to investigate the influence of this extraction method on its structural and physico-chemical characteristics. The extracted alginate had a M/G ratio of 1.22, a molecular weight of 119 kDa, a polydispersity index of 2.7 and an intrinsic viscosity of 170.8 mL/g. The rheological properties of an alginate solution (2% w/v) indicated a Newtonian fluid type of behavior. The influence of pH on the flow behavior of this solution was investigated. The solution had a Newtonian behavior at pH 7.0, an intermediary behavior between Newtonian and non-Newtonian shear thinning at pH 6.0 and 5.0 and a clearly shear thinning behavior at lower pH values (4.5 and 3.0). Its antioxidant activity was tested by diphenyl picrylhydrazyl radical scavenging and hydroxyl radical-scavenging activity showing its potential for food preservation. High voltage electrical discharge improved the antioxidant properties explained by the co-extraction of phenolic compounds. The stability of emulsion increased with concentration of alginate and was reported at 94.7% +/- 0.1 at 2% (w/v) concentration. The stability of emulsions was not affected by temperatures up to 55 degrees C and was resistant to pH changes.

Dentistry, as a branch of medicine, has undergone continuous evolution over time. The scientific world has focused its attention on the development of new methods and materials with improved properties that meet the needs of patients. For this purpose, the replacement of so-called “passive” dental materials that do not interact with the oral environment with “smart/intelligent” materials that have the capability to change their shape, color, or size in response to an externally stimulus, such as the temperature, pH, light, moisture, stress, electric or magnetic fields, and chemical compounds, has received much attention in recent years. A strong trend in dental applications is to apply nanotechnology and smart nanomaterials such as nanoclays, nanofibers, nanocomposites, nanobubbles, nanocapsules, solid-lipid nanoparticles, nanospheres, metallic nanoparticles, nanotubes, and nanocrystals. Among the nanomaterials, the smart nanoparticles present several advantages compared to other materials, creating the possibility to use them in various dental applications, including preventive dentistry, endodontics, restoration, and periodontal diseases. This review is focused on the recent developments and dental applications (drug delivery systems and restoration materials) of smart nanoparticles.

New polymer-bioactive compound systems were obtained by immobilization of triazole derivatives onto grafted copolymers and grafted copolymers carrying betaine units based on gellan and N-vinylimidazole. For preparation of bioactive compound, two new types of heterocyclic thio-derivatives with different substituents were combined in a single molecule to increase the selectivity of the biological action. The 5-aryl-amino-1,3,4 thiadiazole and 5-mercapto-1,2,4-triazole derivatives, each containing 2-mercapto-benzoxazole nucleus, were prepared by an intramolecular cyclization of thiosemicarbazides-1,4 disubstituted in acidic and basic medium. The structures of the new bioactive compounds were confirmed by elemental and spectral analysis (FT-IR and 1H-NMR). The antimicrobial activity of 1,3,4 thiadiazoles and 1,2,4 triazoles was tested on gram-positive and gram-negative bacteria. The triazole compound was chosen to be immobilized onto polymeric particles by adsorption. The Langmuir, Freundlich, and Dubinin–Radushkevich adsorption isotherm were used to describe the adsorption equilibrium. Also, the pseudo-first and pseudo-second models were used to elucidate the adsorption mechanism of triazole onto grafted copolymer based on N-vinylimidazole and gellan (PG copolymer) and grafted copolymers carrying betaine units (PGB1 copolymer). In vitro release studies have shown that the release mechanism of triazole from PG and PGB1 copolymers is characteristic of an anomalous transport mechanism.

β-chitins are extracted from two different parts of cuttlefish (Sepia officinalis officinalis) bone; the shell and the thin layer. They are then subjected to N-deacetylation reactions to prepare chitosans using the Broussignac or the Kurita process. The physicochemical characteristics of chitins and chitosans are compared to those obtained in the case of squid (Loligo vulgaris) β-chitin. In this work, the role of the source in determining the reaction behavior, during the extraction of chitin and the preparation of chitosan, is confirmed, although it is a β-chitin of two taxonomically close species. In particular, we show that the differences observed can be related to the differences in molar masses of the starting chitins, their crystallinity index and the rates of molecular degradation which accompany the N-deacetylation reactions. Finally, it was demonstrated that the huge quantities of bones rejected each year by the cuttlefish processing units from Dakhla city, alone, can be valorized by the production of about 77 tons of β-chitin that can be transformed into 60 tons of chitosan (presenting low degree of acetylation and molar masses ranging from 78,000 to 340,000 g/mol).

A water-soluble polysaccharide (PSPC) was extracted from the seeds of Plantago ciliata Desf., a spontaneous Algerian Saharan plant by a hot aqueous extraction then purified by successive ethanolic precipitations. The final extraction yield for PSPC was close to 18.6% (w/v). PSPC was then investigated regarding its global composition, structural features and rheological properties. PSPC is a neutral arabinoxylan, composed of a beta-(1,3)/beta(1,4)-D-xylan backbone with side chains of Xylp, and Araf residues attached in O-2 and O-3 positions. The macromolecular characteristics of PSPC in water was determined by SEC/MALLS, with a high molecular weight (Mw) of 700 kDa, a low polydispersity index (PDI) of 1.47 and an intrinsic viscosity [eta] close to 157 mL/g. PSPC showed a pseudoplastic behavior in semi-dilutemedia and the critical overlay concentration (C*) was estimated around 0.32-0.37% (w/v). This current research has supplied original structural information on a new arabinoxylan which could be particularly useful as a novel source of soluble fiber belonging to psyllium. (C) 2019 Elsevier B.V. All rights reserved.

New grafted copolymers possessing structural units of 1-vinyl-3-(1-carboxymethyl) imidazolium betaine were obtained by graft copolymerization of N-vinylimidazole onto gellan gum followed by the polymer-analogous reactions on grafted polymer with the highest grafting percentage using sodium chloroacetate as the betainization agent. The grafted copolymers were prepared using ammonium persulfate/N,N,N′,N′ tetramethylethylenediamine in a nitrogen atmosphere. The grafting reaction conditions were optimized by changing one of the following reaction parameters: initiator concentration, monomer concentration, polymer concentration, reaction time or temperature, while the other parameters remained constant. The highest grafting yield was obtained under the following reaction conditions: ci = 0.08 mol/L, cm = 0.8 mol/L, cp = 8 g/L, tr = 4 h and T = 50 °C. The kinetics of the graft copolymerization of N-vinylimidazole onto gellan was discussed and a suitable reaction mechanism was proposed. The evidence of the grafting reaction was confirmed through FTIR spectroscopy, X-ray diffraction, 1H-NMR spectroscopy and scanning electron microscopy. The grafted copolymer with betaine structure was obtained by a nucleophilic substitution reaction where the betainization agent was sodium chloroacetate. Preliminary results prove the ability of the grafted copolymers to bind amphoteric drugs (cefotaxime) and, therefore, the possibility of developing the new sustained drug release systems.

This chapter describes mainly the methods to prepare water-soluble chitosan derivatives and to characterize the different products. Chitosan is the fully deacetylated chitin, i.e., a pure d-glucosamine polymer, but also polymers with low degree of acetylation such as to become soluble in acidic conditions. For grafting hydrophobic alkyl chains, reductive alkylation is chosen as an easy and versatile method to form a covalent bond between an alkyl substituent and the amine function of chitosan. One of the most important chitin derivatives results from the carboxymethylation of chitosan. This reaction allows to get a water-soluble polymer in a large range of pH and especially over pH 6 where chitosan is no longer soluble. The acetylation degree can also be determined from conductimetric titration: the chitosan sample is dissolved in water with a known quantity of HCl and titrated using a sodium hydroxide solution.

Gellan and xanthan are extracellular polysaccharides with very interesting rheological or gelling properties. They are esterified with acrylic acid, acryloyl chloride or maleic anhydride. Consequently, due to the presence of carbon double bonds, hydrogels are obtained using a grafting-crosslinking process with N-isopropylacrylamide and N '-bisacrylamide. Such hydrogels, due to the presence of poly(N-isopropylacrylamide), are thermosensitive and present drug release properties which can be adjusted through the reaction conditions. This concept was demonstrated for ophthalmic applications. (c) 2019 Society of Chemical Industry

A novel sulfated xylogalactan-rich fraction (JSP for J. adhaerens Sulfated Polysaccharide) was extracted from the red Tunisian seaweed Jania adhaerens. JSP was purified using an alcoholic precipitation process and characterized by Attenuated Total Reflectance-Fourier-transform infrared spectroscopy (ATR-FTIR), high-pressure size exclusion chromatography (HPSEC) with a multi-angle laser light scattering (MALLS), gas chromatography coupled to mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR, 1D and 2D). JSP was then evaluated regarding its physicochemical and rheological properties. Results showed that JSP was mainly composed of an agar-like xylogalactan sharing the general characteristics of corallinans. The structure of JSP was mainly composed of agaran disaccharidic repeating units (→3)-β-d-Galp-(1,4)-α-l-Galp-(1→)n and (→3)-β-d-Galp-(1,4)-3,6-α-l-AnGalp-(1→)n, mainly substituted on O-6 of (1,3)-β-d-Galp residues by β-xylosyl side chains, and less with sulfate or methoxy groups. (1,4)-α-l-Galp residues were also substituted by methoxy and/or sulfate groups in the O-2 and O-3 positions. Mass-average and number-average molecular masses (Mw) and (Mn), intrinsic viscosity ([η]) and hydrodynamic radius (Rh) for JSP were, respectively, 8.0 × 105 g/mol, 1.0 × 105 g/mol, 76 mL/g and 16.8 nm, showing a flexible random coil conformation in solution. The critical overlap concentration C* of JSP was evaluated at 7.5 g/L using the Williamson model. In the semi-diluted regime, JSP solutions displayed a shear-thinning behavior with a great viscoelasticity character influenced by temperature and monovalent salts. The flow characteristics of JSP were described by the Ostwald model.

Chitosan has very specific and interesting properties, either structural or physico-chemical, which make chitosan a raw material for drug delivery formulations. Chitosan is a natural, biodegradable, biocompatible, cationic, non-toxic, and mucoadhesive polysaccharide that can be modified with chemical and biological molecules. Chitosan can be formulated in various solid pharmaceutical forms, liquids and gels. For instance, mucoadhesive formulations, liposomes and micro- and nanoparticulate systems provide the premises for achieving the intended therapeutic goals. This chapter presents the preparation methods for obtaining capsules, spheres and hydrogels. Then we discuss applications of chitosan-based formulations in controlled delivery sytems. These systems include digestive, respiratory, cardiovascular, renal, vaginal, bone or immune sytems, thus demonstrating the diversity of the domains and the interest in using chitosan based formulations. Among the most interesting properties allowing the development of chitosan in this domain are its cationic nature, mucoadhesiveness, biocompatibility and antibacterial activity.