Use of ultrasonic degradation to study the molecular weight influence of polymeric admixtures for mortars

International audienceThe aim of this paper is to provide a methodology to study the influence of the molecular weight of polysaccharidic admixtures on mortar properties. A wide range of admixtures with different molecular weight and constant structure was prepared. This has been made possible by the use of ultrasonic treatment, a simple, effective, and without additive method. It appears that cellulose and guar gum derivatives, used as water retention agents, exhibit a significant molecular weight reduction according to the ultrasonic treatment duration. The water retention capacity of the mortars mixed with ultrasonically degraded admixture solutions increases with molecular weight for a same admixture. However, comparing water retention values obtained with similar molecular weight of a same family shows that effectiveness of polysaccharides as water retention agent is not linearly linked to their molecular weight

Chemical specificity in REDOX-responsive materials:the diverse effects of different Reactive Oxygen Species (ROS) on polysulfide nanoparticles

REDOX responsive (nano)materials typically exhibit chemical changes in response to the presence and concentration of oxidants/reductants. Due to the complexity of biological environments, it is critical to ascertain whether the chemical response may depend on the chemical details of the stimulus, in addition to its REDOX potential, and whether chemically different responses can determine a different overall performance of the material. Here, we have used oxidation-sensitive materials, although these considerations can be extended also to reducible ones. In particular, we have used poly(propylene sulfide) (PPS) nanoparticles coated with a PEGylated emulsifier (Pluronic F127); inter alia, we here present also an improved preparative method. The nanoparticles were exposed to two Reactive Oxygen Species (ROS) typically encountered in inflammatory reactions, hydrogen peroxide (H2O2) and hypochlorite (ClO−); their response was evaluated with a variety of techniques, including diffusion NMR spectroscopy that allowed to separately characterize the chemically different colloidal species produced. The two oxidants triggered a different chemical response: H2O2 converted sulfides to sulfoxides, while ClO− partially oxidized them further to sulfones. The different chemistry correlated to a different material response: H2O2 increased the polarity of the nanoparticles, causing them to swell in water and to release the surface PEGylated emulsifier; the uncoated oxidized particles still exhibited very low toxicity. On the contrary, ClO− rapidly converted the nanoparticles into water-soluble, depolymerized fragments with a significantly higher toxicity. The take-home message is that it is more correct to discuss ‘smart’ materials in terms of an environmentally specific response to (REDOX) stimuli. Far from being a problem, this could open the way to more sophisticated and precisely targeted applications

Open-source games for health, multiplayer and gamepads. Co-creating fun care with children with asthma, young adults with cystic fibrosis, elders with COPD

Without air pollution, our life expectancy would increase by 34 months. With a commons-based economy, each and every human could afford medical care (vs one in two today). How not to produce risks? How to foster mutual care? We, people across regions and disciplines, get engaged to value pluralism and collective wisdom. We embrace play as a natural way to experiment, socialize, learn. We document and share our work so that everyone can freely use, study, improve, adapt it. In traditional medtech, corporate experts build a technical tool to manage a disease. Sealed in a black box, its price make it unaffordable to some. At Breathing Games, volunteer, diverse contributors co-create an evolving, rewarding, immersive story to promote holistic health. Free to use, study, improve, its gratuity helps develop solidarity. We present here our games (Asthma Heroes, Asthmonautes, Rise); controllers (Spirotroller enhanced, Spirotroller gaming, Breathing gamepad); creation as research (game testing, controller testing, games co-creation, translations); our next steps (international study, game accessibility via Raspberry Pi, link to air pollution sensor); and our advocacy activities for health as commons

Mutual care taking: collectively creating our respiratory wellbeing with open sciences

Background: Worldwide, 6 people out of 10 have no access to treatment, or are not encouraged to follow it. Air pollution alone kills 7 million people yearly, reduces our life expectancy by 20 months, and costs 6% the gross world product. Devices to assess lung capacity remain often unavailable in low / middle income countries. Actions: We co-create inclusive, open science knowledge: open source breath and air quality controllers, and libre / gratis education to reduce risks and make care fun. Learnings: Awareness: breath as a way to feel life, from childhood. Universal health: mutualizing resources to end poverty. Partnership: reducing barriers with remote participation

Synthèse et polymérisation de méthacrylates phosphones. Application à l'anticorrosion

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Analyse coût-efficacité des stratégies de gestion du risque de cancer pulmonaire induit par le radon en Franche-Comté

BESANCON-BU Médecine pharmacie (250562102) / SudocSudocFranceF

Synthèse de matériaux biodégradables par modification chimique de l'amidon

Ce travail comporte une partie consacrée à la synthèse d'amidon greffés poly -caprolactone (PCL) et une partie réservée à l'étude de la biodégradabilité de ces matériaux. Nous avons synthétisé une famille d'amidon greffé par polymérisation de CL Grafting from et greffage de PCL Grafting Onto . La synthèse Grafting from est effectuée avec un nouveau catalyseur organique, la N méthyl-Imidazole (NMI). Ce catalyseur permet d'obtenir des amidons porteurs de courtes chaînes de PCL (DPn 2~3) sans formation d'homopolymère. Les produits obtenus sont bien caractérisés par de nombreuses méthodes (NMR, HR-MAS NMR, IR, MEB, RX...). Une étude cinétique est faite avec des alcools mono (alcool benzylique) et hexafonctionnels (mannitol) afin de mieux cerner le rôle d'un tel catalyseur nucléophile. La technique Grafting Onto emploie le carbodiimidazole (CDI) comme agent de couplage. Cette méthode permet de synthétiser des amidons greffés PCL de taille contrôlée, réticulés (PCL difonctionnelle) ou non (PCL monofonctionnelle). Dans une dernière partie, nous présentons l'étude de la biodégradation par respirométrie de ces différents amidons greffés PCL dans un sol naturel. L'activité spécifique des microorganismes (actinomycètes et bactéries) isolés du sol naturel est aussi détailléeThis work includes one part of the synthesis pf poly ( -caprolactone) (PCL) graft starch and a second part dedicated to the evaluation of biodegrability of the various synthesized materials. A family of polyester-graft-starch has been synthesized through CL polymerization Grafting from and the grafting of PCL Grafting Onto . A new organic catalyst, N methyl-Imidazole (NMI), is employed in Grafting from technique leading to short polyester graft (Dpn 2~3) without homopolymer formation. These derivatives have been well characterized by several methods (NMR, HR-MAS NMR, IR, MEB, RX...). Kinetic studies have been achieved with mono functional alcohol (benzyl alcohol) and hexa functional alcohol (mannitol) to understand the sole of such nucleophilic catalyst. Grafting Onto technique uses carbodiimidazole (CDI) as coupling agent. This method permits to synthesize PCL-graft starch bearing controlled polyester length, reticulated (difunctional PCL) or not (mono functional PCL). In a last part, the biodegradation of these starches is studied using respirometry under natural soil conditions. Specific microorganisms activities (actinomycetes and bacteria) from this soil is also describedST ETIENNE-BU Sciences (422182103) / SudocSudocFranceF

New Phosphonated Methacrylate Monomers with C2/C3 Spacers

International audienceSyntheses of new phosphonated methacrylates with 2 or 3 hydrocarbon methylene spacers were investigated in order to avoid the conventional methacrylation of hydroxyphosphonate compounds with methacryloyl chloride. The first possibility concerns the esterification of methacrylic anhydride in the presence of either 2-hydroxyethylphosphonate or 3-hydroxypropylphosphonate. This reaction was proved to be quantitative when a basic catalyst, i.e. n-methylimidazole, was used at 60°C. However, this reaction also generates a side product, i.e. methacrylic acid, which was difficult to remove due to it having similar solubility to both dimethyl(2-methacryloyloxyethyl)phosphonate and dimethyl(2-methacryloyloxypropyl)phosphonate. The second process was based on the alcoholysis of MMA in the presence of the above hydroxy compounds. This reaction also proceeded quantitatively with Zr(AcAc)4 as acid catalyst. Unlike esterification of methacrylic anhydride, this second process did not require any solvent. The final phosphonated methacrylates were obtained with high purity, as the side product of the reaction (i.e., methanol) could be easily removed due to the azeotropic behavior of MMA/Methanol

Synthesis of poly(ε-caprolactone)-block-poly(n-butyl acrylate) by combining ring-opening polymerization and atom transfer radical polymerization with Ti[OCH2CCl3]4 as difunctional initiator: I. Kinetic study of Ti[OCH2CCl3]4 initiated ring-opening polymerization of ε-caprolactone

International audienceA new titanium alkoxide, Ti[OCH2CCl3]4, designed to combine the ring-opening polymerization (ROP) of 3-caprolactone and atom transfer radical polymerization (ATRP) of n-butyl acrylate, was synthesized through the ester-exchange reaction of titanium n-propoxide and 2,2,2-trichloroethanol. The mechanism and kinetics of Ti[OCH2CCl3]4 initiated bulk polymerization of 3-caprolactone were studied. The results demonstrate that the polymerization proceeds through the coordination-insertion mechanism and all the four alkoxide groups in Ti[OCH2CCl3]4 share a similar activity in the initiation. The determined polymerization activation energy is 70 kJ/mol. The polymerization process can be well predicted by the obtained kinetic parameters. Furthermore, PCL synthesized with Ti[OCH2CCl3]4 can be used as the macroinitiator in ATRP of n-butyl acrylate to synthesize poly(3-caprolactone)-block-poly(n-butyl acrylate) (PCL-b-PBA) copolymer