Novel design, facile synthesis and low infrared emissivity properties of single-handed helical polysilanes

J of Applied Polymer Sci

Zhou

et al. 2018

Self Cite

Left and right single-handed helical polysilane (L-HPS and D-HPS) and racemic helical polysilane (R-HPS) were synthesized by the Wurtz-type coupling reaction. The chiral dichloro(methoxycarbonyl ethyl propyl ether)methylsilane monomers applied in copolymerization were derived from methyl D/L-lactate. The obtained polymers were characterized by 1 H and 13 C nuclear magnetic resonance, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, circular dichroism spectroscopy, gel permeation chromatography and X-ray diffraction. Infrared emissivity (IRE) values were also investigated. Compared to R-HPS, L-HPS, and D-HPS, a pair of mirror image, showed higher crystallinity, better thermal stability, and lower IRE (8-14 mm) at the values of 0.592 and 0.576, respectively. The higher regular secondary structure of HPSs was attributed to the formation of intermolecular hydrogen bonds. To further study the configurations of L-HPS, D-HPS, and R-HPS, rotational isomeric state scheme with molecular dynamics simulation have been utilized.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Infrared emissivity property study and conformational analysis of helical polysilane

J of Applied Polymer Sci

Zhou

et al. 2018

Self Cite

“…DCMMS monomer derived from the methyl 2-(allyloxy)propanoate was synthesized according to previous literature. 28 Copolymerization of DCMMS and DCDHS were carried out under the inert gas environment. In a glovebox, 1.035 g (45 mmol, 2.5 equiv.)…”

Section: Synthesis Of Hps Copolymermentioning

confidence: 99%

“…HPS copolymerized by DCDHS and DCMMS are utilized to reduce infrared emission. 28 The incorporation of chiral methyl lactate provides both the single-handed helical conformation and methoxycarbonyl functional group, which ultimately contributed to low infrared emissivity. Helical polymer/inorganic composites are proved to be a common complexes pattern to reduce infrared emissivity.…”

Section: Introductionmentioning

confidence: 99%

Helical polysilane wrapping onto carbon nanotube: preparation, characterization and infrared emissivity property study

Zhou

et al. 2016

RSC Adv.

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“…Recently, in order to achieve tunable infrared emission properties, considerable effort has been devoted to the design of numerous synthetic helical polymers including polysilane, polyurethane, and polyacetylene . According to previous works, one‐handed helical conformation with compact accumulation of fragments in organic polymers can accelerate thermal restraining in backbones.…”

Section: Introductionmentioning

confidence: 99%

Optically active tyrosine‐containing poly(N‐propargylamides): Synthesis, helical conformation, and infrared emissivity study

J of Applied Polymer Sci

Hang

et al. 2017

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Novel optically active and racemic poly(N-propargylamides) bearing tyrosine pendants (LPT, DPT, and RPT) were synthesized and characterized. The polymers possessed moderate molecular weights and were thoroughly soluble in common organic solvents. The secondary structure of these three polymers in chloroform was studied and the results indicated that LPT and DPT could adopt helical structures with predominantly one-handed screw sense according to their intense Cotton effect and large specific rotation values, while RPT adopted random coiled polymer chain. The amide groups could form amide-amide hydrogen bonds to engender the twist of dihedral angle and the strong steric repulsion of phenol groups might have the opposite effect on the helix. The helical structure of the optically active polymers were conclusively constructed and stabilized by the optimization of intra-and intermolecular hydrogen bonding and steric repulsion of the side chains. Moreover, the infrared emissivity values of LPT and DPT at 30 8C were 0.682 and 0.671, which were much lower than RPT. LPT and DPT also showed superior heat resistance due to their unique helical conformation.