Polymerization of Myrcene in Both Conventional and Renewable Solvents: Postpolymerization Modification via Regioselective Photoinduced Thiol-Ene Chemistry for Use as Carbon Renewable Dispersants

Amphiphilic Poly(β-Myrcene-co-Acrylic Acid) Copolymers Synthesized by Nitroxide-Mediated Copolymerization as Stabilizers of Terpene-Based Waterborne Latex

Terpene-based amphiphilic copolymers have been designed as biobased stabilizers for waterborne latex synthesized by miniemulsion or emulsion polymerization of 1,3-diene terpene monomers. The pH-responsive P(AA-co-My) amphiphilic copolymers were synthesized by nitroxide-mediated radical copolymerization of β-myrcene (My) and acrylic acid (AA) with reactivity ratios of rMy = 0.24 ± 0.06 and rAA = 0.05 ± 0.10. Polymerization was controlled for My-rich monomer feed ratios (fMy,0 > 0.3). Though AA NMP exhibited reasonable control, a low fraction of My (fMy,0 ≤ 0.3) produced branched structures with higher molar masses. P(AA0.80-co-My0.20) was the most efficient copolymer to stabilize monomodal PMy latexes (Dh ∼ 150-350 nm) synthesized by miniemulsion or emulsion polymerization. P(AA-co-My) copolymers with a higher hydrophobic PMy fraction (>35 mol %) were less efficient stabilizers. The more hydrophobic β-farnesene monomer was successfully polymerized by miniemulsion polymerization, whereas emulsion polymerization failed. The biobased waterborne latexes are pH-responsive with pH-triggered flocculation at low pH.

Terpene polymerization via a binary neodymium-based catalytic system with di-n-butylmagnesium as a co-catalyst

The development of materials from renewable resources has been increasing, intending to reduce the consumption of fossil sources, with terpenes being one of the main families that reduce the consumption of isoprene. The study of the binary catalytic system neodymium versatate/dibutyl magnesium (NdV3/Mg(n-Bu)2), for the coordination homopolymerization of β-myrcene and β-farnesene, was carried out analysing different [Nd] : [Mg] ratios (between 4 and 10). Reporting conversions of 92% and 83% at an [Nd] : [Mg] ratio of 8 for polymyrcene (PMy) and polyfarnesene (PFa), respectively, and microstructures comprising 1,4 content above 80% for both polymers (PMy, cis-59% and PFa, cis-83%). It was observed that PFa samples presented a higher 1,4-cis content in relation to PMy samples, presumably due to the size of the side group present in the monomer structure and due to steric hindrance; similarly, a 3,4 content of 14% (PMy) and 10% (PFa) was observed. The glass transition temperature of the PMy samples ranged from -63.7 °C to -66.5 °C, while for the PFa samples, it was between -75.4 °C and -75.5 °C. The binary [Nd] : [Mg] system used in the study predominantly exhibited a 1,4-cis content at [Nd] : [Mg] ratios of 8.

Highly selective fluorescence turn-on sensor for·thiol compounds detection

As a kind of commonly-used synthetic materials for many pesticides, thiol compounds, once being leaked, can cause serious harm to the environment and humans. Therefore, the efficient detection of thiol compounds is essential. In this study developed a turn-on fluorescent probe (Cu@Zn-CP) for the highly sensitive fluorescence detection of thiol compounds. The probe was constructed based on a zinc coordination polymer (Zn-CP), whose fluorescence was quenched through the effective doping of Cu2+ ions. After the introduction of methyl thioglycolate (MTC), a rapid fluorescence turn-on response was generated within 90 s with a low detection limit of 23 ppb. Even after being reused for five cycles, the sensor maintains excellent detection performance and demonstrates good recyclability. It can also detect MTC in river water, with a spike recovery rate between 98-103 %. Furthermore, the designed Cu@Zn-CP exhibits good universality for detecting multifarious thiol compounds, including L-cysteine, glutathione, monothioglycerol, and 2-hydroxy-1-ethanethiol. This result provides a potential recyclable fluorescent sensor for thiol compounds.

Nopadiene: A Pinene-Derived Cyclic Diene as a Styrene Substitute for Fully Biobased Thermoplastic Elastomers

The bicyclic 1,2-substituted, 1,3-diene monomer nopadiene (1R,5S)-2-ethenyl-6,6-dimethylbicyclo[3.1.1]hept-2-ene was successfully polymerized by anionic and catalytic polymerization. Nopadiene is produced either through a facile one-step synthesis from myrtenal via Wittig-olefination or via a scalable two-step reaction from nopol (10-hydroxymethylene-2-pinene). Both terpenoids originate from the renewable β-pinene. The living anionic polymerization of nopadiene in apolar and polar solvents at 25 °C using organolithium initiators resulted in homopolymers with well-controlled molar masses in the range of 5.6-103.4 kg·mol-1 (SEC, PS calibration) and low dispersities (Đ) between 1.06 and 1.18. By means of catalytic polymerization with Me4CpSi(Me)2NtBuTiCl2 and (Flu)(Pyr)CH2Lu(CH2TMS)2(THF), the 1,4 and 3,4- microstructures of nopadiene are accessible in excellent selectivity. In pronounced contrast to other 1,3-dienes, the rigid polymers of the sterically demanding nopadiene showed an elevated glass temperature, Tg,∞ = 160 °C (in the limit of very high molar mass, Mn). ABA triblock copolymers with a central polymyrcene block and myrcene content of 60-75 mol %, with molar masses of 100-200 kg/mol were prepared by living anionic polymerization of the pinene-derivable monomers nopadiene and myrcene. This diene copolymerization resulted in thermoplastic elastomers displaying nanophase separation at different molar ratios (DSC, SAXS) and an upper service temperature about 30 K higher than that for traditional petroleum-derived styrenic thermoplastic elastomers due to the high glass temperature of polynopadiene. The materials showed good thermal stability at elevated temperatures under nitrogen (TGA), promising tensile strength and ultimate elongation of up to 1600%.

Structure-Property Relationships of CO2 Absorbing Core-Shell Microparticles with Encapsulated Ionic Liquid

The demand for new ionic liquid (IL)-based systems to selectively sequester carbon dioxide from gas mixtures has prompted the development of individual components involving the tailored design of IL themselves or solid-supported materials that provide excellent gas permeability of the overall material as well as the ability to incorporate large amounts of ionic liquid. In this work, novel IL-encapsulated microparticles comprising a cross-linked copolymer shell of β-myrcene and styrene and a hydrophilic core of the ionic liquid 1-ethyl-3-methylimidazolium dicyanamide ([EMIM][DCA]) are proposed as viable materials for CO2 capture. Water-in-oil (w/o) emulsion polymerization of different mass ratios of β-myrcene to styrene (i.e. 100/0, 70/30, 50/50, 0/100) yielded IL-encapsulated microparticles, where the encapsulation efficiency of [EMIM][DCA] was dependent on the copolymer shell composition. Thermal analysis using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) revealed that both thermal stability and glass transition temperatures depend on the mass ratio of β-myrcene to styrene. Images from scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the microparticle shell morphology as well as measure the particle size perimeter. Particle sizes were found to be between 5 and 44 μm. CO2 sorption experiments were conducted gravimetrically using TGA instrumentation. Interestingly, a trade-off between CO2 absorption capacity and ionic liquid encapsulation was observed. While increasing the β-myrcene content within the microparticle shell increases the amount of encapsulated [EMIM][DCA], the observed CO2 absorption capacity did not increase as expected due to reduced porosity compared to microparticles with higher styrene content in the microparticle shell. [EMIM][DCA] microcapsules with a 50/50 weight ratio of β-myrcene/styrene showed the best synergistic effect between spherical particle diameter (32.2 μm), pore size (0.75 μm), and high CO2 sorption capacity of ∼0.5 mmol CO2/g sample within a short absorption period of 20 min. Therefore, core-shell microcapsules composed of β-myrcene and styrene are envisioned as a promising material for CO2 sequestration applications.

Quo Vadis Carbanionic Polymerization?

Living anionic polymerization will soon celebrate 70 years of existence. This living polymerization is considered the mother of all living and controlled/living polymerizations since it paved the way for their discovery. It provides methodologies for synthesizing polymers with absolute control of the essential parameters that affect polymer properties, including molecular weight, molecular weight distribution, composition and microstructure, chain-end/in-chain functionality, and architecture. This precise control of living anionic polymerization generated tremendous fundamental and industrial research activities, developing numerous important commodity and specialty polymers. In this Perspective, we present the high importance of living anionic polymerization of vinyl monomers by providing some examples of its significant achievements, presenting its current status, giving several insights into where it is going (Quo Vadis) and what the future holds for this powerful synthetic method. Furthermore, we attempt to explore its advantages and disadvantages compared to controlled/living radical polymerizations, the main competitors of living carbanionic polymerization.