ABSTRACT Partially bio‐based epoxy thermosets were developed using diglycidyl ether of bisphenol A (DGEBA) and two biobased amines hardeners. A novel tetra‐functional amine was synthesized from eugenol via oxidative coupling to form di‐eugenol, followed by thiol‐ene functionalization. Five formulations were prepared by varying the molar ratio of the two biobased amine hardeners to tailor the network architecture. Thermomechanical properties were evaluated by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Furthermore, Solid‐State 1H NMR provided a multiscale experimental approach into the relationship between cross‐link density, molecular chain dynamics, and macroscopic thermomechanical properties, leading to a straightforward structure‐property correlation.

The increasing demand for sustainable and fire-safe textiles has motivated the development of eco-friendly flame-retardant systems. Herein, a fully bio-based flame-retardant was used to improve the flame retardancy of natural cellulosic flax fabric. For this purpose, two coating aqueous solutions including phytic acid (PA) and a clove plant-derived diamine (DA) with 5 and 10

In this present investigation, epoxy polyether resins with tunable properties have been obtained. These epoxy polyether molecules were synthesized using resorcinol ( R ), a phenolic building block, as well as biobased polyols such as glycerol ( G ) and hexanediol ( H ). The obtained functional monomers were then cured with hexamethylenediamine ( HMDA ) to yield fully crosslinked epoxy polyether resins. The structures of such functional monomers were investigated by liquid‐state NMR 1 H, 13 C, and HSQC in order to better understand the structure. The epoxy equivalent weight (EEW) was also determined for resin formulation while the thermomechanical properties for cured resins were determined using different analytical methods such as dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), three‐point bending, and tenacity. Finally, Time Domain 1 H Double Quantum (DQ) NMR was used to yield a better insight into the network morphology of the epoxy polyether resins. It was found that these resins possess comparable thermomechanical properties with their industrial counterparts with flexural modulus reaching up to 3.5 GPa and flexural strength up to 134 MPa. The glass transition temperatures T g of these resins range from 40 to 70 °C, and it was found that the polyols work as “’spacers”’ rendering the material more flexible and therefore decreasing its T g when compared to industrial epoxy resins.

The goal of this study was to provide antioxidant and antibacterial properties to different types of fabrics via tannic acid (TA) covalent grafting. To that extent, TA was first methacrylated using glycidylmethacrylate. TA derivatives were characterized using infrared spectroscopy and 1H NMR to assess the degree of acrylation. Antioxidant and antibacterial properties of TA were preserved after chemical modification. The coating process was studied using infrared spectroscopy (IR), weight gain, and radical scavenging activity (RSA) measurements. To covalently bond TA to raw polypropylene (PP) and PP coated with chitosan, photoinduced grafting was performed. The process was optimized and resulted in fabrics with enough tannic acid to provide strong antioxidant activity, with RSA ranging at 95%. The antibacterial activity was assessed against E. coli and S. aureus, the main strains responsible for nosocomial infections. Results revealed a substantial reduction of bacterial contamination for PP samples coated with chitosan, with stronger activity against E. coli, attributed to hydrophobic repellence. This study highlights the benefits of using tannic acid to obtain antioxidant and antibacterial fabrics.

A straightforward and cost-effective way to coat polypropylene fibers, designed for healthcare textiles, was developed through chitosan crosslinking for antibacterial purposes. As polypropylene is an inert material, the goal was to physically trap the inert fibers through a network of crosslinked chitosan or a quaternized derivative (to enhance the antibacterial action). First, chitosan or its quaternized derivative was physically deposited by impregnation or spraying. Then, chitosan was crosslinked in glutaraldehyde solution followed by its quaternized derivative with a diisocyanate. Coated fabrics were characterized by infrared spectroscopy (IR), weight gain measurements, and scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX). This led us to conclude that spraying provides uniform deposition while maintaining the fabric's porosity. Acidic washing allowed us to prove that chitosan and its quaternized derivative were successfully immobilized on the fabric. Biological assays were conducted against two major strains of bacteria responsible for nosocomial infections: Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). Chitosan-crosslinked samples did not show significant antibacterial activity, but the quaternized derivative allowed a significant decrease in S. aureus colonization. This study presents a simple and scalable process to coat inert fabrics with a polymer containing reactive functions potentially available to graft various additional antimicrobial agents.

Bài báo trình bày kết quả phát triển vật liệu composite mới nguồn gốc tự nhiên trên cơ sở nhựa epoxy resorcinol sinh học – diatomite bằng quy trình xanh hai giai đoạn dựa trên đặc tính “sống” của sự trùng hợp cation. Bao gồm sự khởi đầu phản ứng bằng ánh sáng và sau đó là sự hóa rắn không cần ánh sáng dưới tác dụng nhiệt, quy trình này cho phép thu được các composite epoxy-diatomite dày và không trong suốt mà không cần dùng bất cứ dung môi hay chất hóa rắn gốc amine nguy hại nào. Các ảnh hưởng của hàm lượng diatomite đối với các tính chất cơ học và phản ứng với lửa của những composite này đã được khảo sát. Trên cơ sở đánh giá các tính chất này, composite thu được với diatomite chiếm 40% khối lượng được xem như composite tối ưu. Composite này có mô đun uốn là 3,6 MPa và ứng xử làm chậm cháy đáng chú ý với đỉnh tốc độ tỏa nhiệt (peak of Heat Release Rate - pHRR) 132 W/g và tổng lượng tỏa nhiệt 6 kJ/g ghi nhận được trong phân tích nhiệt lượng kế dòng đốt cháy nhiệt phân (Pyrolysis Combustion Flow Calorimetry - PCFC).

To avoid disturbing membrane functioning while preventing biofilm formation, antibacterial agents were incorporated in membrane spacers that are currently inert elements in the membrane processes. 3D-printed PA11 membrane spacers with different wt. % of magnesium oxide (MgO) were shaped and characterized Several extrusions allowed to increase the percentage of MgO incorporated up to 10 wt. %. Scanning electron microscope equipped with Energy-dispersive X-ray confirmed the presence of MgO and showed the morphology and distribution of those particles. Thermo-mechanical properties were evaluated using dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, and mechanical assays. No significant difference, in melting and glass transition as well as tensile properties, was found due to the addition of MgO, except a slight decrease in degradation temperature. The addition of MgO decreased the water contact angle of the materials. Biological assays against E. coli and S. aureus showed that increasing MgO wt. % up to 7.5 lead to a significant decrease in bacterial colonization of both strains. This study points out the potential of a simple and efficient way to provide antibacterial properties to membrane spacers to overcome biofouling in wastewater treatment applications.

The polyhydroxyalkanoates (PHAs) are biobased, biocompatible and biodegradable polyesters. To enhance their biodegradability and flexibility, we develop low density PHAs by an emulsion-templated method without organic solvent. Polycaprolactone (PCL) and castor oil are required to improve the flexibility and to generate the porosity, respectively. To overcome the well-known lack of compatibility between PHA and PCL, pluronic is introduced to improve the miscibility of these polyesters The densities of native PHA and PCL are 1.2 g.cm−3 and the densities decreased to 0.49 g.cm−3 in presence of castor oil (40 wt%). Different PHAs were studied: polyhydroxybutyrate (PHB), polyhydroxybutyrate-co-hydroxyvalerate (PHBHV) and polyhydroxybutyrate-co-hydroxyhexanoate (PHBHHx). The porous PHBHHx based material showed the best colonization by Pseudomonas, followed by the PHBHV and PHB. This colonization only occurred in the surface and no bacterial diffusion was observed inside the material. The biodegradability study in presence of lipase showed that after 8 days, the weight losses are, respectively, 20% and 75% when the densities decreased from 0.82 g.cm−3 to 0.49 g.cm−3. These results showed the importance of the porosity on the biodegradation of PHAs.

This work aims at studying the mechanical and acoustic behaviours of a new bio-based porous epoxy resin obtained by a "green" adapted combination of the cationic photopolymerization and the porogen leaching technique. This new kind of material generally possesses interconnected complex morphology and it would be useful to consider this feature in a model. In this study, the effective properties of the material were estimated by using the asymptotic homogenization method. Four types of ordered pore arrangements together with systematic variations of the porosity and the pore size have been studied. Based on the results of these investigations, a subtle relation between the microstructure and mechanical/acoustic properties has been established. The estimated equivalent dynamic density and equivalent dynamic bulk modulus were compared with experimental results obtained by conducting the three-microphone impedance tube testing. The processing parameters of material elaboration could be adjusted so that the obtained porous material would possess the best sound absorption performance.

Hydrogels based on poly(3-hydroxyalkanoate) (PHA) sulfonate and poly(ethylene glycol) diacrylate, PEGDA, are prepared. First, PHA sulfonate is synthesized from unsaturated PHA by a thiol-ene reaction in the presence of sodium-3-mercapto-1-ethanesulfonate. The hydrophilicity of PHAs is considerably increased by adding sulfonate functions, and three amphiphilic PHAs are synthesized, containing 10, 22, or 29% sulfonate functions. Then, hydrogels are formed in the presence of PEGDA having different molar masses, that is, 575 or 2000 g mol-1. The hydrogels show fibrillar and porous structures observed in cryo-MEB with pore sizes that vary according to the content of sulfonated groups (10 to 29 mol %) ranging from 50 to more than 150 nm. Furthermore, depending on the proportions of the two polymers, a variable rigidity is observed from 2 to 40 Pa. In fact, the evaluation of the dynamic mechanical properties of the hydrogel determined by DMA reveals that the less rigid hydrogels hinder the adhesion of Pseudomonas aeruginosa PaO1 bacteria. Finally, these hydrogels swelling up to 5000% are noncytotoxic, allowing the adhesion and amplification of immortalized C2C12 cells, and they are therefore seen as promising materials both for repelling PaO1 bacteria and for amplifying myogenic cells.

A green cross-linking and straightforward method to physically trap inert fibers in a network of chitosan was implemented. The cross-linking reaction involved a biosourced and biocompatible cross-linker [tannic acid (TA)] and mild conditions in water (pH = 8.5, O2 bubbling, 60 °C, 3 h). The steric hindrance of TA led to a low but effective cross-linking rate leaving parts of primary amines of chitosan available for postmodification such as the grafting of quaternary ammoniums for antibacterial purposes. Fabric's coatings were characterized by scanning electron microscopy coupled with energy-dispersive X-ray, infrared spectroscopy, and weight gain measurements. This allowed the optimization of process conditions. No significant antioxidant activity was observed on fabrics coated with chitosan cross-linked with TA, confirming the low cross-linking rate. This low cross-linking rate allowed grafting of quaternary ammoniums for antibacterial purposes, but it is possible to consider grafting other active molecules. Biological assays were conducted on this coating to assess its antibacterial properties. Reduction of bacterial colonization on both Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative), two of the major strains responsible for nosocomial infections, confirmed the potential of the coating for antibacterial purposes. This study displays a simple and ecofriendly process to coat inert fabrics with a chitosan network containing reactive functions (primary amines) available for grafting active molecules for various purposes.

Phenolic resins are an attractive family of thermosetmaterials.However, there are some concerns related to the high toxic natureof formaldehyde and phenol, i.e., the main buildingblocks for phenolic resins. Herein, a sustainable alternative methodis proposed to synthesize fully biobased and nonharmful resoles basedon the condensation of resorcinol (R) with 4-four differentaldehydes under alkaline conditions. Two aldehyde-based building blocksincluding 5-methylfurfural (MFu) and cinnamaldehyde (C) obtained from biobased renewable and abundant resourceswere successfully formulated with resorcinol, providing more sustainableand environmental-friendly alternatives to current commercially availableand hazardous phenol-formaldehyde resins. Two molar ratios of basiccatalyst (HO-)/(R) were consideredto study their effect on the prepolymerization reaction and on thethermo-mechanical properties of the final materials. The thermal decompositionbehavior of the cured resoles was investigated by thermogravimetricanalysis (TGA), showing high degradation temperatures and high charyields (up to 60%). Furthermore, the resoles also exhibited high chemicalresistance with insoluble fractions (IFs) up to 80%. Finally, to studythe mechanical properties of the obtained resoles, the fully cross-linkedresoles were consolidated using the spark plasma sintering (SPS) technique.The microstructures of the sintered resoles were investigated by scanningelectron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS).Compression tests were also conducted to evaluate the mechanical resistanceof cured resoles with compression moduli and strength values rangingup to 1.25 GPa and 74 MPa, respectively. Pyrolysis-combustionflow calorimetry analysis (PCFC) revealed that MFu hasa very low flammability behavior, demonstrated with a peak of heatrelease (pHRR) of around 16 W/g and the total heat release (THR) of2.5 kJ/g. Overall, it was demonstrated that MFu as anontoxic, biobased, and inexpensive aldehyde can be advantageouslyused in the preparation of more sustainable phenolic resins. The mechanical properties of biobasedphenolic resins basedon resorcinol with furfural derivatives were obtained and showed promisingmechanical properties.

Biocompatible gels based on poly(3-hydroxyalkanoate)s (PHAs) were developed by radical polymerization in the presence of poly(ethylene glycol) diacrylate (PEGDA). In order to elaborate cross-linked networks based on PEGDA and PHAs, several PHAs were tested; saturated PHAs, such as poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) or poly(3-hydroxyoctanoate) (PHO), and an unsaturated PHA, poly(3-hydroxyoctanoate-co-3-hydroxyundecenoate) PHOU. The PHAxPEGDA1−x networks obtained in this work were studied by FTIR, Raman spectroscopy, DSC, TGA and NMR. The microscopic structure varied according to the mass proportions between the two polymers. Time Domain 1H DQ NMR measurements demonstrated that in the case of the unsaturated PHA, it was chemically crosslinked with PEGDA, due to the presence of double bonds in the lateral groups. The organogels were able to swell in organic solvents, such as THF, up to 2000% and in water up to 86%. It was observed by rheological analysis that the stiffness of the networks was dependent on the content of PHA and on the degree of cross-linking. The biocompatible characters of PHOU and PEGDA were not affected by the formation of the networks and these networks had the advantage of being non-cytotoxic to immortalized C2C12 myoblast cells.

Poly(3-hydroxybutyrate), PHB, has gathered a lot of attention for its promising properties—in particular its biobased nature and high biodegradability. Although PHB is prime candidate for the packaging industry, the applications are still limited by a narrow processing window and thermal degradation during melt processing. In this work, three novel additives based on ferulic acid esterified with butanediol, pentanediol, and glycerol (BDF, PDF, and GTF, respectively) were used as plasticizers and antioxidative additives to improve mechanical properties of PHB. Elongation at break up to 270% was obtained in presence of BDF and the processing window was improved nearly 10-fold. The Pawley method was used to identify the monoclinic space group P2 of the BDF. The estimated crystallite size (71 nm) agrees with a crystalline additive. With PHB70BDF30 blends, even higher elongations at break were obtained though dwindled with time. However, these properties could be recovered after thermal treatment. The high thermal stability of this additive leads to an increase in the fire retardancy property of the material, and the phenolic structure induced antioxidant properties to the samples as demonstrated by radical scavenging tests, further highlighting the possibilities of the PHB/additive blends for packaging applications.

By successive enzymatic and chemical modifications, novel fluorinated polyhydroxyalkanoates were synthesized and characterized. Unsaturated polyhydroxyalkanoate, PHAU, was first produced by fermentation using marine bacteria Pseudomonas raguenesii, and a graft copolymer PHAU-g-C8F17 was further prepared by controlled thiol-ene reaction in the presence of perfluorodecanethiol (PFDT). The PFDT grafting is realized by two different processes. In the first method, PHAU was previously solubilized in toluene. The grafting in solution is more efficient than the direct heterogeneous grafting onto a PHAU film. The degrees of grafting were determined by 1H NMR. The characterization of the microstructure by SEM-EDX and modulated and conventional DSC showed the formation of microdomains due to the organization of the hydrophobic segments of graft PFDT. Biomaterials prepared by 3D printing and coated by PHAU-g-C8F17 have the potential to be used as novel contrast agents as shown by Hahn echo experiments.

A novel generation of gels based on medium chain length poly(3-hydroxyalkanoate)s, mcl-PHAs, were developed by using ionic interactions. First, water soluble mcl-PHAs containing sulfonate groups were obtained by thiol-ene reaction in the presence of sodium-3-mercapto-1-ethanesulfonate. Anionic PHAs were physically crosslinked by divalent inorganic cations Ca2+, Ba2+, Mg2+ or by ammonium derivatives of gallic acid GA-N(CH3)3+ or tannic acid TA-N(CH3)3+. The ammonium derivatives were designed through the chemical modification of gallic acid GA or tannic acid TA with glycidyl trimethyl ammonium chloride (GTMA). The results clearly demonstrated that the formation of the networks depends on the nature of the cations. A low viscoelastic network having an elastic around 40 Pa is formed in the presence of Ca2+. Although the gel formation is not possible in the presence of GA-N(CH3)3+, the mechanical properties increased in the presence of TA-N(CH3)3+ with an elastic modulus G’ around 4200 Pa. The PHOSO3−/TA-N(CH3)3+ gels having antioxidant activity, due to the presence of tannic acid, remained stable for at least 5 months. Thus, the stability of these novel networks based on PHA encourage their use in the development of active biomaterials.

Ion-exchange membranes (IEMs) are increasingly used in dialysis and electrodialysis processes for the extraction, fractionation and concentration of valuable components, as well as reagent-free control of liquid media pH in the food industry. Fouling of IEMs is specific compared to that observed in the case of reverse or direct osmosis, ultrafiltration, microfiltration, and other membrane processes. This specificity is determined by the high concentration of fixed groups in IEMs, as well as by the phenomena inherent only in electromembrane processes, i.e., induced by an electric field. This review analyzes modern scientific publications on the effect of foulants (mainly typical for the dairy, wine and fruit juice industries) on the structural, transport, mass transfer, and electrochemical characteristics of cation-exchange and anion-exchange membranes. The relationship between the nature of the foulant and the structure, physicochemical, transport properties and behavior of ion-exchange membranes in an electric field is analyzed using experimental data (ion exchange capacity, water content, conductivity, diffusion permeability, limiting current density, water splitting, electroconvection, etc.) and modern mathematical models. The implications of traditional chemical cleaning are taken into account in this analysis and modern non-destructive membrane cleaning methods are discussed. Finally, challenges for the near future were identified.

The development of biofouling is a major problem for marine industries. The conception of antifouling and fouling release coatings, with controlled physical-chemical properties is a promising strategy. Among them, amphiphilic systems, such as those composed of a hydrophobic polydimethylsiloxane matrix and a hydrophilic polyethyleneglycol additive are the most efficient and up to date. Despite their effectiveness, these systems are questioned due to the petrochemical origin of PDMS. The aim of this project was to substitute the PDMS matrix with a biopolymer, poly(3-hydroxybuyrate-co-3-hydroxyvalerate) and to improve its anti-adhesion properties through the elaboration of an amphiphilic system, via the addition of PEG or PHBHHx-b-PEG copolymer. The results, including the physico-chemical properties of PHBHV based coatings and static adhesion tests on a marine bacterium, Bacillus 4J6 and a diatom, Phaeodactylum tricornutum are compared with those of PDMS and PEG-modified PDMS coatings. Real antiadhesion activity was obtained for the PHBHV/PHBHHx-b-PEG system for a promising eco-friendly strategy.

This study has developed novel fully bio-based resorcinol epoxy resin–diatomite composites by a green two-stage process based on the living character of the cationic polymerization. This process comprises the photoinitiation and subsequently the thermal dark curing, enabling the obtaining of thick and non-transparent epoxy-diatomite composites without any solvent and amine-based hardeners. The effects of the diatomite content and the compacting pressure on microstructural, thermal, mechanical, acoustic properties, as well as the flame behavior of such composites have been thoroughly investigated. Towards the development of sound absorbing and flame-retardant construction materials, a compromise among mechanical, acoustic and flame-retardant properties was considered. Consequently, the composite obtained with 50 wt.% diatomite and 3.9 MPa compacting pressure is considered the optimal composite in the present work. Such composite exhibits the enhanced flexural modulus of 2.9 MPa, a satisfying sound absorption performance at low frequencies with Modified Sound Absorption Average (MSAA) of 0.08 (for a sample thickness of only 5 mm), and an outstanding flame retardancy behavior with the peak of heat release rate (pHRR) of 109 W/g and the total heat release of 5 kJ/g in the pyrolysis combustion flow calorimeter (PCFC) analysis.