Controlled Synthesis and Ti-O Bond Stability of Star-Shaped Biodegradable Polyesters via Titanate-Initiated ROP of Cyclic Esters at Ambient Temperature

2012 ◽  
Vol 213 (14) ◽  
pp. 1499-1508 ◽  
Author(s):  
Jun-Bing Fan ◽  
Feng Long ◽  
Matthew P. Aldred ◽  
Ya-Jing Li ◽  
Zhi-Wu Liang ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Controlled Synthesis ◽  
Cyclic Esters ◽  
Biodegradable Polyesters ◽  
Bond Stability

Controlling polymer stereochemistry in ring-opening polymerization: a decade of advances shaping the future of biodegradable polyesters

2021 ◽  
Author(s):  
Mathieu J.-L. Tschan ◽  
Régis M. Gauvin ◽  
Christophe M. Thomas
Keyword(s):  
Biodegradable Polymer ◽  
Ring Opening ◽  
Polymer Synthesis ◽  
Ring Opening Polymerization ◽  
Cyclic Esters ◽  
Biodegradable Polyesters ◽  
The Future ◽  
Recent Developments

In this review, we describe recent developments in biodegradable polymer synthesis with a focus on the use of discrete complexes and organocatalysts as active initiators for the stereocontrolled ring-opening polymerization of cyclic esters.

scholarly journals A controlled synthesis method of alkyl methacrylate block copolymers via living anionic polymerization at ambient temperature

RSC Advances ◽  
2019 ◽  
Vol 9 (28) ◽  
pp. 16049-16056 ◽  
Author(s):  
Zheng Li ◽  
Jianding Chen ◽  
Guijin Zou ◽  
Tongyuan Zhang ◽  
Dafu Wei ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Ambient Temperature ◽  
Anionic Polymerization ◽  
Diblock Copolymers ◽  
Synthesis Method ◽  
Controlled Synthesis ◽  
Living Anionic Polymerization ◽  
Alkyl Methacrylate ◽  
High Yields

A series of well-defined diblock copolymers containing PMMA, PEMA and PBMA blocks were synthesized with narrow MWDs and high yields via anionic polymerization, while t-BuOK was selected as initiator in THF at 0 °C. .

Nanosilver rainbow: a rapid and facile method to tune different colours of nanosilver through the controlled synthesis of stable spherical silver nanoparticles

RSC Advances ◽  
2016 ◽  
Vol 6 (54) ◽  
pp. 48792-48799 ◽  
Author(s):  
Pramujitha Mendis ◽  
Rohini M. de Silva ◽  
K. M. Nalin de Silva ◽  
Lahiru A. Wijenayaka ◽  
Kalana Jayawardana ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Silver Nanoparticles ◽  
Optical Properties ◽  
Ambient Temperature ◽  
Controlled Synthesis ◽  
One Pot

A rapid and simple one-pot reaction to synthesize stable, spherically shaped silver nanoparticles of different sizes producing distinct optical properties in aqueous solution at ambient temperature has been developed.

Controlled Synthesis of Biodegradable Polyesters

2001 ◽  
pp. 179-194 ◽  
Author(s):  
Pieter J. Dijkstra ◽  
Zhiyuan Zhong ◽  
Wim M. Stevels ◽  
Jan Feijen
Keyword(s):  
Controlled Synthesis ◽  
Biodegradable Polyesters

SEM of non-coated hepatocellular cytoskeleton of perfused livers

1984 ◽  
Vol 42 ◽  
pp. 306-307
Author(s):  
S.W. French ◽  
N.C. Benson ◽  
C. Davis-Scibienski
Keyword(s):  
Ambient Temperature ◽  
Critical Point ◽  
Protease Inhibitors ◽  
Metal Deposition ◽  
Heat Damage ◽  
Detergent Extraction ◽  
Cytoskeletal Elements ◽  
Triton X ◽  
Excised Tissue

Previous SEM studies of liver cytoskeletal elements have encountered technical difficulties such as variable metal coating and heat damage which occurs during metal deposition. The majority of studies involving evaluation of the cell cytoskeleton have been limited to cells which could be isolated, maintained in culture as a monolayer and thus easily extracted. Detergent extraction of excised tissue by immersion has often been unsatisfactory beyond the depth of several cells. These disadvantages have been avoided in the present study. Whole C3H mouse livers were perfused in situ with 0.5% Triton X-100 in a modified Jahn's buffer including protease inhibitors. Perfusion was continued for 1 to 2 hours at ambient temperature. The liver was then perfused with a 2% buffered gluteraldehyde solution. Liver samples including spontaneous tumors were then maintained in buffered gluteraldehyde for 2 hours. Samples were processed for SEM and TEM using the modified thicarbohydrazide procedure of Malich and Wilson, cryofractured, and critical point dried (CPD). Some samples were mechanically fractured after CPD.

Formation of Dislocation Channels in Neutron Irradiated Molybdenum

1972 ◽  
Vol 30 ◽  
pp. 672-673
Author(s):  
S. Mahajan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ambient Temperature ◽  
Room Temperature ◽  
Channel Formation ◽  
Early Stages ◽  
Transmission Electron ◽  
Three Stages ◽  
Two Stages ◽  
Polycrystalline Molybdenum

The evolution of dislocation channels in irradiated metals during deformation can be envisaged to occur in three stages: (i) formation of embryonic cluster free regions, (ii) growth of these regions into microscopically observable channels and (iii) termination of their growth due to the accumulation of dislocation damage. The first two stages are particularly intriguing, and we have attempted to follow the early stages of channel formation in polycrystalline molybdenum, irradiated to 5×1019 n. cm−2 (E > 1 Mev) at the reactor ambient temperature (∼ 60°C), using transmission electron microscopy. The irradiated samples were strained, at room temperature, up to the macroscopic yield point.Figure 1 illustrates the early stages of channel formation. The observations suggest that the cluster free regions, such as A, B and C, form in isolated packets, which could subsequently link-up to evolve a channel.

Crystallographic Characterization of Dislocation Loops in Irradiated Tungsten

1968 ◽  
Vol 26 ◽  
pp. 290-291
Author(s):  
Robert C. Rau
Keyword(s):  
Electron Microscope ◽  
Ambient Temperature ◽  
Dislocation Loops ◽  
Polycrystalline Specimen ◽  
Post Irradiation ◽  
Neutron Fluences

Previous work has shown that post-irradiation annealing, at temperatures near 1100°C, produces resolvable dislocation loops in tungsten irradiated to fast (E > 1 MeV) neutron fluences of about 4 x 1019 n/cm2 or greater. To crystallographically characterize these loops, tilting experiments were carried out in the electron microscope on a polycrystalline specimen which had been irradiated to 1.5 × 1021 n/cm2 at reactor ambient temperature (∼ 70°C), and subseouently annealed for 315 hours at 1100°C. This treatment produced large loops averaging 1000 Å in diameter, as shown in the micrographs of Fig. 1. The orientation of this grain was near (001), and tilting was carried out about axes near [100], [10] and [110].

Voids in Quenched Nickel

1968 ◽  
Vol 26 ◽  
pp. 266-267
Author(s):  
J. J. Laidler
Keyword(s):  
Electron Beam ◽  
Ambient Temperature ◽  
Cooling Rate ◽  
Three Dimensional ◽  
Cooling Curve ◽  
Polycrystalline Nickel ◽  
Quenching Temperature ◽  
Long Tail ◽  
Diffusion Pump

The presence of three-dimensional voids in quenched metals has long been suspected, and voids have indeed been observed directly in a number of metals. These include aluminum, platinum, and copper, silver and gold. Attempts at the production of observable quenched-in defects in nickel have been generally unsuccessful, so the present work was initiated in order to establish the conditions under which such defects may be formed.Electron beam zone-melted polycrystalline nickel foils, 99.997% pure, were quenched from 1420°C in an evacuated chamber into a bath containing a silicone diffusion pump fluid . The pressure in the chamber at the quenching temperature was less than 10-5 Torr . With an oil quench such as this, the cooling rate is approximately 5,000°C/second above 400°C; below 400°C, the cooling curve has a long tail. Therefore, the quenched specimens are aged in place for several seconds at a temperature which continuously approaches the ambient temperature of the system.

Sign in / Sign up

Export Citation Format

Share Document