scholarly journals Living Chain-Walking (Co)Polymerization of Propylene and 1-Decene by Nickel α-Diimine Catalysts

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1988
Author(s):  
Pei Li ◽  
Xiaotian Li ◽  
Shabnam Behzadi ◽  
Mengli Xu ◽  
Fan Yu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Room Temperature ◽  
Nickel Complexes ◽  
Polymerization Temperature ◽  
Narrow Molecular Weight Distribution ◽  
Structure Control ◽  
Living Nature ◽  
Branched Structure ◽  
Chain Walking

Homo- and copolymers of propylene and 1-decene were synthesized by controlled chain-walking (co)polymerization using phenyl substituted α-diimine nickel complexes activated with modified methylaluminoxane (MMAO). This catalytic system was found to polymerize propylene in a living fashion to furnish high molecular weight ethylene-propylene (EP) copolymers. The copolymerizations proceeded to give high molecular weight P/1-decene copolymers with narrow molecular weight distribution (Mw/Mn ≈ 1.2), which indicated a living nature of copolymerization at room temperature. The random copolymerization results indicated the possibility of precise branched structure control, depending on the polymerization temperature and time.

Organocatalytic Ring-Opening Polymerization Strategies for Synthesis of Poly(phosphothioesters) with a Pendent Phenyl Group

Synlett ◽  
2020 ◽  
Vol 31 (12) ◽  
pp. 1167-1171 ◽  
Author(s):  
Guangqiang Xu ◽  
Xin-Qi Hao ◽  
Qinggang Wang ◽  
Huating Yan ◽  
Rulin Yang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Weight Distribution ◽  
Ring Opening ◽  
Diblock Copolymers ◽  
Phenyl Group ◽  
Ring Opening Polymerization ◽  
Polymerization Process ◽  
Narrow Molecular Weight Distribution ◽  
Living Nature

A novel type of phosphothioester substrate, 2-phenyl-1,3,2-dioxaphospholane 2-sulfide (PTP), has been synthesized and subjected to ring-opening polymerization. DBU/thiourea served as an efficient cooperative organocatalyst for the synthesis of poly(PTP), delivering the polymer with a well-defined structure, a relatively narrow molecular-weight distribution (1.14–1.20), and high molecular weight (up to 45.2 kg/mol). The ring-opening polymerization process showed a controlled/living nature. In addition, diblock copolymers of PTP with rac-lactide with well-defined structures were also synthesized.

scholarly journals A Complexed Initiating System AlCl3·Phenetole/TiCl4·H2O with Dominant Synergistic Effect for Efficient Synthesis of High Molecular Weight Polyisobutylene

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2121
Author(s):  
Yulong Jin ◽  
Liang Chen ◽  
Xing Guo ◽  
Linfeng Xu ◽  
Zhihua Zhu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Synergistic Effect ◽  
High Molecular Weight ◽  
Monomer Concentration ◽  
Catalyst System ◽  
Polymerization Temperature ◽  
Simple Preparation ◽  
Order Of Magnitude ◽  
Unique Approach ◽  
High Molecular Weight Polyisobutylene

A complexed initiating system AlCl3·phenetole/TiCl4·H2O was prepared by simply compounding AlCl3/phenetole and TiCl4/H2O and used for cationic polymerization of isobutylene. It was found AlCl3·phenetole/TiCl4·H2O exhibited activities 1.2–3 times higher than those of AlCl3/phenetole, and more than an order of magnitude higher than those of TiCl4/H2O, which indicated a notable synergistic effect produced in the complexed system. In addition, due to the higher activity of AlCl3·phenetole/TiCl4·H2O, lower coinitiator concentration and polymerization temperature, as well as higher monomer concentration were more favored for this complexed initiating system to produce polyisobutylene (PIB) with reasonable molecular weight (Mw) and molecular weight distribution (MWD). Furthermore, high molecular weight polyisobutylene (HPIB) with Mw = 1–3 × 105 g·mol−1 could be successfully produced by the complexed catalyst system at Tp = −60 to −40 °C. As a whole, the high activity as well as the simple preparation procedures of the complexed initiating system offer us a unique approach for the production of HPIB with improved efficiency.

Selective or living organopolymerization of a six-five bicyclic lactone to produce fully recyclable polyesters

2019 ◽  
Vol 10 (23) ◽  
pp. 3097-3106 ◽  
Author(s):  
Robin M. Cywar ◽  
Jian-Bo Zhu ◽  
Eugene Y.-X. Chen
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Room Temperature ◽  
Heterocyclic Carbenes ◽  
Base Pairs ◽  
Ring Open ◽  
Bicyclic Lactone

A ring-fused γ-butyrolactone can be selectively ring-open polymerized at room temperature by N-heterocyclic carbenes to cyclic polyester or by bifunctional (thio)urea and base pairs in a living fashion to high molecular weight linear polyester that can be organocatalytically and quantitatively recycled at 120 °C.

Formation of high-molecular weight polyaminoborane by Fe hydride catalysed dehydrocoupling of methylamine borane

2017 ◽  
Vol 46 (21) ◽  
pp. 6843-6847 ◽  
Author(s):  
F. Anke ◽  
D. Han ◽  
M. Klahn ◽  
A. Spannenberg ◽  
T. Beweries
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Room Temperature ◽  
Catalyst Precursor

The complex [(PNHP)Fe(H)(CO)(HBH3)] (PNHP = HN(CH2CH2Pi-Pr2)2) serves as a catalyst precursor for the selective dehydrocoupling of methylamine borane at room temperature, tentatively via an off-metal polymerisation pathway.

Bis(phenolate) N-heterocyclic carbene rare earth metal complexes: synthesis, characterization and applications in the polymerization of n-hexyl isocyanate

RSC Advances ◽  
2015 ◽  
Vol 5 (101) ◽  
pp. 83295-83303 ◽  
Author(s):  
Min Zhang ◽  
Jingjing Zhang ◽  
Xufeng Ni ◽  
Zhiquan Shen
Keyword(s):  
Molecular Weight ◽  
Rare Earth ◽  
Metal Complexes ◽  
High Molecular Weight ◽  
Molecular Weight Distribution ◽  
Rare Earth Metal ◽  
Weight Distribution ◽  
Earth Metal ◽  
Narrow Molecular Weight Distribution ◽  
Rare Earth Metal Complexes

Polyhexyl isocyanantes catalyzed by N-heterocyclic carbene rare earth metal complexes show high molecular weight with narrow molecular weight distribution.

scholarly journals Kinetic analysis of mechanoradical formation during the mechanolysis of dextran and glycogen

2017 ◽  
Vol 13 ◽  
pp. 1174-1183 ◽  
Author(s):  
Naoki Doi ◽  
Yasushi Sasai ◽  
Yukinori Yamauchi ◽  
Tetsuo Adachi ◽  
Masayuki Kuzuya ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Electron Spin Resonance ◽  
Room Temperature ◽  
Particle Diameter ◽  
Helical Structure ◽  
Esr Spectra ◽  
Radical Concentration ◽  
Maximum Value ◽  
Spin Resonance ◽  
Branched Structure

A detailed electron spin resonance (ESR) analysis of mechanically induced free radicals (mechanoradicals) formation of glucose-based polysaccharides, dextran (Dx) and glycogen (Gly) was performed in comparison with amylose mechanoradicals. The ESR spectra of the samples mechanically fractured at room temperature were multicomponent. The radical concentration of Dx and Gly mechanoradicals gradually decreased during vibratory milling after reaching the maximum value. Although the molecular weight of Dx or the particle diameter of Gly steeply diminished until reaching the each maximum value of radical concentration, after that the molecular weight or the particle diameter slowly decreased. These results suggested that Dx and Gly mechanoradicals might be more unstable than amylose radicals possessing an intramolecular helical structure due to the branched structure.

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