Rational design of tetrahydrogeraniol-based hydrophobically modified poly(acrylic acid) as emulsifier of terpene-in-water transparent nanoemulsions

Abstract

Amphiphilic copolymers based on renewable resources were involved as emulsifiers to prepare transparent terpene-in-water nanoemulsions. The amphiphilic copolymers are composed of hydrophobically modified poly(acrylic acid) (HMPAA) grafted with different fractions of hydrophobic bio-based tetrahydrogeraniol (THG) side chains. The well-defined PAA were synthesized by reversible addition fragmentation transfer (RAFT) polymerization in order to tune the number-average molar mass of the initial PAA. The self-assembly in aqueous solution of the HMPAA copolymers was investigated through the measurement of their critical aggregation concentration by viscometry, tensiometry, dynamic light scattering and the determination of their aggregation number by static light scattering. Series of oil-in-water nanoemulsions using dihydromyrcenol (DHM) terpene as dispersed phase and PAA-THG as emulsifier were prepared with different PAA-THG/DHM weight ratios and DHM/water weight ratios. The level of transparency of the emulsions was monitored though the transmittance value measured at 600 nm and the measurements of the hydrodynamic diameter of droplets by dynamic light scattering. This study highlights that the structure of the PAAx-THGy is a key parameter to prepare terpene-inwater nanoemulsions with the required high level of transparency. The optimised structure of the emulsifier consists in a moderate degree of polymerization of PAA backbone (DP n ̅̅̅̅̅ ,PAA  180) 2 along with an intermediate average degree of substitution in hydrophobic THG side chains (13  DS ̅̅̅̅  32).

Biosourced Polymeric Emulsifiers for Miniemulsion Copolymerization of Myrcene and Styrene: Toward Biobased Waterborne Latex as Pickering Emulsion Stabilizer

“…The copolymers were synthesized according to the procedure described in our previous work. 58 Poly(acrylic acid) was synthesized by reversible addition−fragmentation transfer (RAFT) polymerization and PAA-THG was prepared by esterification of PAA with tetrahydrogeraniol.…”

“…The methylated PAA precursor of PAA-THG was characterized by the SEC THF system, which was described along with their synthesis in our previous work. 58 Fourier Transform Infrared Spectroscopy (FTIR). The polymers were analyzed as a powder with a spectrometer Nicolet IS50 FT-IR (Thermo Scientific, USA) in attenuated total reflectance mode.…”

Comonomer effect: Switching the lower critical solution temperature to upper critical solution temperature in thermo‐pH sensitive binary graft copolymers

“…The pendant carboxylic group of PAAc has a pKa ≈ 4.6 . In deprotonate state, PAAc chains undergo electrostatic repulsions causing a phase transition among 4.5–5 pH . PVim is a pH‐sensitive polymer with antimicrobial activity, this derivatives present good biocompatibility with human body; therefore, it present potential biomedical applications .…”

Biobased latexes from natural oil derivatives

“…The dimensions of latex free films were evaluated before each measurement. [12][13][14] Biobased latex coatings performance was characterized by measuring the hardness, flexibility, and adhesion to the metal substrate of each selected coating. The hardness of the latex coatings was evaluated using pencil and pendulum hardness tests according to ASTM D3363-05 and ASTM D4366-16 standards respectively.…”

“…9,10 Nevertheless, synthesizing latexes with high biobased content becomes an attractive alternative approach for replacing petroleumbased counterparts in commercial polymeric materials. [11][12][13][14] In this regard, Kaya et al reported synthesis of latexes with varying amounts of soybean oilbased macromonomers in copolymerization with methyl methacrylate. 15 Moreno et al used miniemulsion polymerization to polymerize monomer synthesized by incorporation of methacrylic functionality into linoleic acid.…”