Search

The Oseberg Viking ship burial is one of the most extensive collections of Viking wooden artefacts ever excavated in Norway. In the early twentieth century, many of these artefacts were treated with alum in order to preserve them, inadvertently leading to their current degraded state. It is therefore crucial to develop new bioinspired polymers which could be used to conserve these artefacts and prevent further disintegration. Two hydroxylated polymers were synthesised (TPA6 and TPA7), using α-pinene- and oleic acid-derived monomers functionalised with an acrylate moiety. Characterisation using biomolecular hydrodynamics (analytical ultracentrifugation and high precision viscometry) has shown that these polymers have properties which would potentially make them good wood consolidants. Conformation analyses with the viscosity increment (ν) universal hydrodynamic parameter and ELLIPS1 software showed that both polymers had extended conformations, facilitating in situ networking when applied to wood. SEDFIT-MSTAR analyses of sedimentation equilibrium data indicates a weight average molar mass Mw of (3.9 ± 0.8) kDa and (4.2 ± 0.2) kDa for TPA6 and TPA7 respectively. Analyses with SEDFIT (sedimentation velocity) and MultiSig however revealed that TPA7 had a much greater homogeneity and a lower proportion of aggregation. These studies suggest that both these polymers—particularly TPA7—have characteristics suitable for wood consolidation, such as an optimal molar mass, conformation and a hydroxylated nature, making them interesting leads for further research. [ABSTRACT FROM AUTHOR]

Poly(vinyl pivalate) (PVPi) nanoparticles obtained via miniemulsion have particular properties useful for several applications. Thus, the present study aims to synthesize and characterize PVPi nanoparticles through the miniemulsion polymerization process, studying the effects of water‐soluble and oil‐soluble initiators, polymerization temperature, and the co‐stabilizer concentration on the final properties of the polymer, nanoparticle size, and conversion. The polymeric nanoparticles are characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance (1H and 13C NMR), thermogravimetric analysis, differential scanning calorimetry, gel permeation chromatography, dynamic light scattering, and transmission electron microscopy. The miniemulsion polymerization process ensures the formation of a polymeric fluid with high colloidal and thermal stability, with maximum conversions of ≈85% and average particle diameter of 97.2 ± 21.8 nm. The polymeric properties, such as molar mass and glass transition temperature (Tg), are influenced by process variables such as synthesis temperature and the type of initiator. The use of potassium persulfate and 2,2‐azobisisobutyronitrile (AIBN) initiators favors the homogeneous nucleation mechanism, resulting in a decrease in the average particle diameter and in the growth of the chains, result in greater average molar masses and, consequently, greater Tg. [ABSTRACT FROM AUTHOR]

This work presents experimental results on the synthesis of soybean oil-based polymers through emulsion polymerization process. It was shown that polymeric materials can be successfully synthesized with high monomers conversion close to 100% and very high stability, displaying relatively high shelf-life time. Polymeric nanoparticles showing narrow particle size distribution, with average diameter around 80 nm (PdI = 0.213), determined via dynamic light scattering measurements were obtained. It was also observed by calorimetric analysis, that the final polymeric material presents two exothermic transitions and two glass transition temperatures. This complex thermal behavior probably takes place due to the nature of the monomeric mixture (AFFAM—acrylated linolenic, linoleic, and oleic acids in combination with methyl methacrylate), indicating that the final polymer presents a complex macromolecular arrangement. The glass transition temperature of the polymer lattices was reduced because of the AFFAM incorporation into the growing polymer chains, and additionally the thermal stability was improved. Regarding the average molar masses, it was observed that AFFAM comonomer plays an important role, leading to a decreasing in the mass-average molar mass when the AFFAM concentration is increased in the reaction medium. Depending on the AFFAM amount, the mass-average molar masses were found within the range from 70,000 g mol −1 to 890,000 g mol −1 with molar-mass dispersity lying in the interval from 1.7 to 2.4. [ABSTRACT FROM AUTHOR]