Figure - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
Source publication
To the best of our knowledge, this is the very first time that a thorough study of the synthetic procedures, molecular and thermal characterization, followed by structure/properties relationship for symmetric and non-symmetric second generation (2-G) dendritic terpolymers is reported. Actually, the synthesis of the non-symmetric materials is report...
Context in source publication
Context 1
... should be mentioned that the obtained morphologies were examined for unannealed samples, and after thermal annealing at 120 • C for five days. In Table 3, the estimated values for the Flory-Huggins interaction parameters of all possible combinations are presented at 20 • C and 120 • C based on specific calculated equations reported already in the literature [68]. ...Similar publications
Increasing the energy density of lithium-sulfur batteries necessitates the maximization of their areal capacity, calling for thick electrodes with high sulfur loading and content. However, traditional thick electrodes often lead to sluggish ion transfer kinetics as well as decreased electronic conductivity and mechanical stability, leading to their...
Citations
... Specifically, for the case of PI 1,4 -b-P(o-Bn-L-Tyr), the PI microstructure consisting of 90% PI 1,4 and 10% PI 3,4 , two distinctive peaks are evident at 839 cm −1 and 890 cm −1 (redcolor spectrum), respectively, whereas in the case of PI 3,4/1,2 -b-P(o-Bn-L-Tyr), the absence of the 1,4 microstructure indicated that the reaction took place in a polar environment leading to 3,4/1,2 microstructures predominantly (blue-color spectrum) [44,45]. Coherent results were also acquired for the PB segment both in the case of nonpolar PB 1,4 -b-P(o-Bn-L-Tyr) and polar PB 1,2 -b-P(o-Bn-L-Tyr) depicted in green-and purple-color spectra in Figure 2, respectively. ...
... In Figure 3, 1 H-NMR spectra for the four synthesized samples are presented, indicating the different chemical shifts due to the various polydiene conformations, which is in accordance with the results obtained from the IR spectroscopy. The characteristic chemical shifts in the monomeric unit of both PB and PI have already been thoroughly reported in the literature and are in good agreement with the results presented in this study [44,45]. The -NH-groups in the main polypeptide chain are usually evident at 7.5 ppm [3,14], but due to the overlapping of the shift attributed to the deuterated solvent (CDCl 3 ), a precise calculation of the contributing protons is not possible. ...
... In Figure 6b The glass transition temperatures (T g s) of the components, as well as the potential mixing between the chemically dissimilar blocks, were identified from DSC experiments. In the samples PI 3,4/1,2 -b-P(o-Bn-L-Tyr) and PB 1,2 -b-P(o-Bn-L-Tyr), the T g s are expected at temperatures equal to −30 • for the PI 3,4 (~55-60%) segment while for PB 1,2 at approximately 0 • C, as already thoroughly reported in the literature [44,45,49,50]. The remaining polydienes, namely PI 1,4 (in PI 1,4 -b-P(o-Bn-L-Tyr)) and PB 1,4 )in PB 1,4 -b-P(o-Bn-L-Tyr)) display lower T g s, at approximately −70 • and −90 • , respectively [51][52][53]. ...
Citation: Politakos, N.; Moutsios, I.; Manesi, G.-M.; Moschovas, D.; Abukaev, A.F.; Nikitina, E.A.; Kortaberria, G.; Ivanov, D.A.; Avgeropoulos, A. Synthesis, Characterization and Structure Properties of Biobased Hybrid Copolymers Consisting of Polydiene and Polypeptide Segments. Polymers 2021, 13, 3818. https://doi. Abstract: Novel hybrid materials of the PB-b-P(o-Bn-L-Tyr) and PI-b-P(o-Bn-L-Tyr) type (where PB: 1,4/1,2-poly(butadiene), PI: 3,4/1,2/1,4-poly(isoprene) and P(o-Bn-L-Tyr): poly(ortho-benzyl-L-tyrosine)) were synthesized through anionic and ring-opening polymerization under high-vacuum techniques. All final materials were molecularly characterized through infrared spectroscopy (IR) and proton and carbon nuclear magnetic resonance (1 H-NMR, 13 C-NMR) in order to confirm the successful synthesis and the polydiene microstructure content. The stereochemical behavior of secondary structures (α-helices and β-sheets) of the polypeptide segments combined with the different polydiene microstructures was also studied. The influence of the α-helices and β-sheets, as well as the polydiene chain conformations on the thermal properties (glass transition temperatures, thermal stability, α-and β-relaxation) of the present biobased hybrid copolymers, was investigated through differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dielectric spectroscopy (DS). The obtained morphologies in thin films for all the synthesized materials via atomic force microscopy (AFM) indicated the formation of polypeptide fibrils in the polydiene matrix.
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.
A pioneering synthetic approach for the design of novel composite materials is reported. The final products are consisting of high number average molecular weight diblock copolymers which are surface initiated (“grafting from” approach) from either single or multi-wall carbon nanotubes (SWCNTs or MWCNTs respectively). In-situ anionic polymerization results in nanocomposites, exhibiting narrow dispersity indices which are in accordance with anionic polymerization standards, able to self-assemble when studied in bulk. The polymer matrices are diblock copolymers of the PS-b-PI type [PS: polystyrene and PI: poly(isoprene)]. The successful “grafting from” the corresponding CNTs is verified by Raman and Χ-Ray Photoelectron spectroscopy, while the structure/properties relationship of the composites is determined employing High Resolution Transmission Electron Microscopy (HR-TEM). HR-TEM characterization is very important for the successful identification of the MWCNTs as well as for the justified conformation of the polymeric chains grafted from the CNTs.
Linear and non-linear copolymers of the PB-b-PI sequence [PB: polybutadiene of high 1,4-microstructure (~ 92%) and PI: polyisoprene of high 3,4-microstructure (~ 55-60%)] and their corresponding miktoarm star copolymers of...
