Biosourced terpenoids for the development of sustainable acrylic pressure-sensitive adhesivesviaemulsion polymerisation

The increasing regulations and restrictions in favour of a biobased and sustainable community could potentially harm the strong economic position of the polymer industry, which still heavily relyies on crude oil. The adhesive industry, in particular, is looking for more renewable alternatives and more environmentally friendly synthesis routes. In this work, (meth)acrylate derivatives of terpenoids, namely tetrahydrogeraniol, citronellol, menthol and isoborneol are introduced in the synthesis of waterborne pressure-sensitive adhesives (PSA) based on acrylic latexesviaemulsion polymerisation. This industrially implemented setting enables the preparation of five different formulations with high biobased content with a renewable carbon content ranging from 70 to 100%. The biobased PSAs are found to be comparable in terms of tack, peel strength and shear resistance to a benchmark petroleum-derived commercial product. They show good adhesion properties on steel, glass and polyethylene surfaces. Moreover, the various formulations displayed different mechanical and adhesion properties, which make them attractive for a wide range of applications

Modeling and characterization of the morphology of multiphase polymeric nanoparticles

Multiphase polymeric nanoparticles that synergistically combine the properties of their constituents present enhanced properties and display new functionalities. Therefore, they are used in a wide range of applications including anticorrosive, superhydrophobic and anti-molding coatings; switchable adhesives; photoswitchable fluorescent particles; energy storage; gene and drug delivery; anticounterfeiting and LEDs. Although it is recognized that application properties strongly depend on the morphology of the nanoparticles, there is a surprising lack of progress towards the knowledge-based synthesis of these materials with well controlled morphologies. There are two main reasons for this. Firstly, the difficulties associated to the accurate characterization of the morphology of the polymeric nanoparticles, and secondly, the lack of quantitative understanding of the processes controlling the morphology. Please click Additional Files below to see the full abstrac

Complement component 3 (C3) expression in the hippocampus after excitotoxic injury: role of C/EBPβ

[Background] The CCAAT/enhancer-binding protein β (C/EBPβ) is a transcription factor implicated in the control of proliferation, differentiation, and inflammatory processes mainly in adipose tissue and liver; although more recent results have revealed an important role for this transcription factor in the brain. Previous studies from our laboratory indicated that CCAAT/enhancer-binding protein β is implicated in inflammatory process and brain injury, since mice lacking this gene were less susceptible to kainic acid-induced injury. More recently, we have shown that the complement component 3 gene (C3) is a downstream target of CCAAT/enhancer-binding protein β and it could be a mediator of the proinflammatory effects of this transcription factor in neural cells.[Methods] Adult male Wistar rats (8–12 weeks old) were used throughout the study. C/EBPβ+/+ and C/EBPβ–/– mice were generated from heterozygous breeding pairs. Animals were injected or not with kainic acid, brains removed, and brain slices containing the hippocampus analyzed for the expression of both CCAAT/enhancer-binding protein β and C3.[Results] In the present work, we have further extended these studies and show that CCAAT/enhancer-binding protein β and C3 co-express in the CA1 and CA3 regions of the hippocampus after an excitotoxic injury. Studies using CCAAT/enhancer-binding protein β knockout mice demonstrate a marked reduction in C3 expression after kainic acid injection in these animals, suggesting that indeed this protein is regulated by C/EBPβ in the hippocampus in vivo.[Conclusions] Altogether these results suggest that CCAAT/enhancer-binding protein β could regulate brain disorders, in which excitotoxic and inflammatory processes are involved, at least in part through the direct regulation of C3.This work was supported by MINECO, Grant SAF2014-52940-R and partially financed with FEDER funds. CIBERNED is funded by the Instituto de Salud Carlos III. JAM-G was supported by CIBERNED. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).Peer reviewe

Control of Molecular Weight Distribution in Emulsion Polymerization Using On-Line Reaction Calorimetry

The molecular weight distribution (MWD) of linear polymers was controlled based on on-line reaction calorimetry. A method to estimate the MWD from reaction calorimetry when chain transfer to a chain-transfer agent is the main termination event was developed and its robustness assessed by simulation. Following this method, the desired final MWD was decomposed in a series of instantaneous MWDs to be produced at different stages of the process. An optimization algorithm was used to calculate the set-point trajectories to produce the desired MWD in a minimum time. A nonlinear model based controller was used to track these trajectories. The control scheme was validated by preparing polystyrene latexes of widely different predefined MWD.Fil: Vicente, Matias. Universidad del País Vasco; EspañaFil: BenAmor, Selwa. Universidad del País Vasco; EspañaFil: Gugliotta, Luis Marcelino. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Leiza, Jose R.. Universidad del País Vasco; EspañaFil: Asua, Jose M.. Universidad del País Vasco; Españ

Synthesis of High Solids Content Low Surfactant/Polymer Ratio Nanolatexes

A new two-stage strategy for the synthesis of high-solids-content low-surfactant/polymer ratio nanolatexes was developed. In the first stage, the knowledge-based strategy is used to obtain 18 wt % nanolatexes with the maximum number of particles and using a fraction of the surfactant. In the second stage, the rest of the surfactant is employed to stabilize these particles while they are growing to reach the target solids content. The final particle size results from the interplay between limited particle coagulation and secondary homogeneous nucleation during the second stage. Smaller particle sizes were obtained for surfactants able to desorb from the existing particles and diffuse quickly to the newly formed particles. Waterborne nanoparticles as small as 32 nm in diameter were obtained with 36 wt % solids content and solids content/(surfactant/polymer) ratio higher than 26. This represents a substantial improvement with respect to the best results reported in the literature (dp = 32 nm; 23 wt % solids, and solids content/(surfactant/polymer) = 21)