A novel unique arch-bridge-like stator, after the rigidification of rotor 1 by intramolecular H-bonding, afforded two classes of solution and solid dual photoluminescence (PL) molecules.
Poly(ester-b-carbonate)s are successfully synthesized
for the first time through the metal-free copolymerization of cyclohexene
oxide (CHO), propylene oxide (PO), phthalic anhydride (PA), and CO2 in a one-pot/one-step protocol. Catalyzed by triethyl borane
(TEB) and bis(triphenylphosphine)iminium chloride (PPNCl) Lewis pair,
the diblock and triblock copolymers with little tapering are synthesized
from the initiation of PPNCl and phthalic acid, respectively. Copolymers
with a high molecular weight of up to 50 kDa can be readily obtained
under mild conditions. By changing the content of chain components
in quadripolymers, glass transition temperature (T
g) values are adjusted between 86 and 115 °C. Moreover,
the products appear extremely transparent with transparency of above
85% in the range of 600–1000 nm. This work first focuses on
the synthesis of quadripolymers with high T
gs (>90 °C) and tensile strength (up to 54.8 MPa), which have
similar thermal, mechanical properties, and transparency as those
of commercial polystyrene and thus may be candidate green materials
to replace the nondegradable polystyrene in extensive application
areas.
A new
one-pot synthesis method of dimethyl hexane-1,6-diyldicarbamate
(HDC), a potential intermediate compound in the synthesis of polyurethanes,
from CO2, methanol, and 1,6-hexanediamine (HDA) is disclosed.
The starting materials are renewable, stable, easily available, and
cheap. The process was implemented in 1-methyl-2-pyrrolidinone (NMP)
solvent over CeO2 catalysts. Three different CeO2 catalysts (commercial nanospheres, CeO2(c) obtained by direct calcination of (NH4)2Ce(NO3)6, and CeO2 nanorods) were tested in
this reaction and their micromorphology and physical–chemical
properties were characterized by transmission electron microscopy
(TEM), X-ray diffraction (XRD), and N2 adsorption. CeO2 nanorods proved to be the most active catalytic material.
The influence of different parameters on reaction outcome was studied.
The yield of HDC was about 80% under optimized reaction conditions.
Experiments for better understanding of reaction mechanism were also
performed.
The objective of this study is to develop a nonisocyanate route to prepare a biodegradable CO 2 -based poly(ester-co-urethane) (PEU), which has some improved performances when compared with commercial poly(butylene adipate-co-terephthalate) (PBAT). These performances include mechanical properties, biodegradability, and melt processability. Specifically, five bis-alkylcarbamates were synthesized from diamines, methanol, and CO 2 . Subsequently, 1,4-butanediol (BDO) and dimethyl terephthalate (DMT) reacted with five kinds of CO 2 -based bisalkylcarbamates to study the influence of methylene group number on the performances of PEUs. Moreover, the effect of various ratios of aromatic to aliphatic blocks in PEUs on their properties was systematically investigated. Additionally, the hydrolytic stability of synthesized PEUs was evaluated upon the degradation percentage in phosphate-buffered saline. The semicrystalline PEUs with tunable properties exhibit an initial thermal decomposition temperature of over 273.7 °C and a T g above 12.4 °C. Due to the presence of hydrogen bonding, the tensile strength is as high as 49 MPa. The designed and synthesized PEUs are promising as a potential biodegradable thermoplastic with superior performances when compared with commercial PBAT.
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