scholarly journals [Rh(L-alaninate)(1,5-Cyclooctadiene)] Catalyzed Helix-Sense-Selective Polymerizations of Achiral Phenylacetylenes

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1223 ◽  
Author(s):  
Qingyu Wang ◽  
Hongge Jia ◽  
Yongqiang Shi ◽  
Liqun Ma ◽  
Guoxing Yang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Main Chain ◽  
Helical Structure ◽  
Active Species ◽  
Rhodium Complex ◽  
High Yield ◽  
Hydroxyl Groups ◽  
High Catalytic Activity ◽  
Chiral Amine ◽  
Polymer Main Chain

The [Rh(L-alaninate)(cod)] (cod = 1,5-Cyclooctadiene) complex was synthesized and characterized. Asymmetric polymerizations of achiral phenylacetylene with two hydroxyl groups and a dodecyl group (DoDHPA) were performed by using the rhodium complex as the catalyst to provide polymers with a higher molecular weight (>105) than the polymers obtained using the [Rh(cod)Cl]2 initiator systems. The resulting polymers showed circular dichroism (CD) signals at approximately 310 and 470 nm, indicating that they have a preferential one-handed helical structure. The helix sense in the polymer main chain was controlled by the sign of the catalyst chirality. These findings suggest that the rhodium complex with a chiral amine is the true active species for the helix-sense-selective polymerization of DoDHPA. The [Rh(L-alaninate)(cod)] complex also exhibits high catalytic activity in the polymerization of phenylacetylene (PA) to give a high yield and molecular weight. All these results demonstrate that this Rh complex is an excellent catalyst for the polymerization of phenylacetylene monomers.

New Host-Guest Polymeric System for Thermal Stability Enhancement of Electro Optic Effect

2002 ◽  
Vol 725 ◽  
Author(s):  
Seung Koo Park ◽  
Jung Yun Do ◽  
Jung-Jin Ju ◽  
Suntak Park ◽  
Myung-Hyun Lee
Keyword(s):  
Thermal Stability ◽  
Model Compound ◽  
Main Chain ◽  
Side Chain ◽  
Hydroxyl Groups ◽  
New Host ◽  
Polymer Main Chain ◽  
Electro Optic ◽  
Chromophore Concentration ◽  
Stability Enhancement

AbstractA new host-guest electro optic (EO) polymer, in which a chromophore can be reacted with the polymer main chain during poling to give the corresponding side-chain EO polymer, has been prepared for improving EO effect and its thermal stability. Polyisoimide (PII) synthesized from 2, 2-bis (4-aminophenyl) hexafluoropropane and oxydiphthalic anhydride and Disperse Red 1 (DR1) were used as a host and a guest, respectively. A model compound reaction and Infrared spectra of the host-guest film after annealing at various temperatures show that the reaction between the isoimide groups in PII and the hydroxyl groups in DR1 occurs around 140 °C. The glass transition temperatures of the resulting EO polyamic aicd ester-imide copolymer with 0, 10, 20 and 30 wt. % of chromophore concentration were 275, 219, 160, and 124 °C, respectively. The EO coefficient obtained at a wavelength of 1.55 νm was 5.3 and 10.5 pm/V from the EO polymer film with 20 and 30 wt. % DR1. The EO signals exhibited only a slight decay at high temperature due to the chemical reaction between the host and guest during poling.

Changes in Molecular Weight of Poly(Styrenesulfonate) Initiated by Thioxanthone: Photolysis and Photo-Oxidation

2016 ◽  
Vol 869 ◽  
pp. 346-349
Author(s):  
Josy Anteveli Osajima ◽  
Carla Cristina Schmitt Cavalheiro ◽  
Miguel Guillermo Neumann
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
Main Chain ◽  
Inert Atmosphere ◽  
Kinetic Behavior ◽  
Photo Oxidation ◽  
Polymer Main Chain ◽  
Air Atmosphere ◽  
Atmosphere System ◽  
Kinetics Of

The presence of dyes in colored polymers can cause a series of reactions that promote their photodegradation under irradiation. The aim of this study was to investigate the kinetic behavior of the photodegradation of poly (sodium 4-styrenesulfonate) (PSS) in aqueous solution or in the presence of thioxanthone (TX) under UV radiation in different atmospheres. These systems were monitored by SEC. The polydispersity decreased in all systems studied indicating that there was a breach of the polymer main chain. Only the PSS / TX / air atmosphere system peaked, which occured at 43h of irradiation. However, this system showed slower kinetics of polymeric scission due to the dye suppressing a transfer of energy from the triplet state to the polymer. The photodegradation of solutions of PSS / air atmosphere showed higher efficiency under ultraviolet radiation in relation to the PSS in the presence or absence of the dye under an inert atmosphere.

An Easy Route for the Preparation of Soluble High Molecular Weight Polymer Under Friedel-Crafts Conditions

2014 ◽  
Vol 887-888 ◽  
pp. 989-992 ◽  
Author(s):  
Cong Qi Li ◽  
Bo Yu ◽  
Cheng Wang ◽  
Yong Xi Li ◽  
Yu Chen
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
High Yield ◽  
Hydroxyl Groups ◽  
Synthetic Method ◽  
Polycondensation Reaction ◽  
Hydrogen Atoms ◽  
High Molecular Weight Polymer ◽  
Molecular Weight Polymer ◽  
Short Reaction Time

A facile synthetic method that would be applied to polycondensation reaction between monomer A with bifunctional hydroxyl groups and monomer B with bifunctional reactive hydrogen atoms under Friedel-Crafts conditions was described. This approach, which has the advantage of short reaction time, high yield and simple synthesis operation, opens a way to prepare soluble high molecular weight polymers by the polycondensation reaction between monomer A with bifunctional hydroxyl groups and monomer B with bifunctional reactive hydrogen atoms under Friedel-Crafts conditions.

Poly(para-phenylene) ionomer membranes: effect of methyl and trifluoromethyl substituents

2021 ◽  
Author(s):  
Fanghua Liu ◽  
Jinju Ann ◽  
Junpei Miyake ◽  
Kenji Miyatake
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Main Chain ◽  
Polymer Main Chain ◽  
Ionomer Membranes ◽  
Sulfonated Poly

Sulfonated poly(para-phenylene)s with high molecular weight and membrane forming capability were obtained by use of the effect of methyl and trifluoromethyl substituents. The linearity of the polymer main chain decreased...

Synthesis and Properties of Polyamide-Imide Based on 2, 2-Bis[4-(4-Aminophenoxy)Phenyl]Hexafluoropropane and 2, 2-Bis[4-(4-Aminophenoxy)Phenyl]Propane

1998 ◽  
Vol 10 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Yuvraj Singh Negi ◽  
Yoshi-Ichi Suzuki ◽  
Ichiro Kawamura ◽  
Masa-Aki Kakimoto ◽  
Yoshio Imai
Keyword(s):  
Molecular Weight ◽  
Thermal Decomposition ◽  
Main Chain ◽  
Aromatic Polyamide ◽  
Decomposition Temperature ◽  
High Yield ◽  
Absorption Analysis ◽  
Thermal Decomposition Temperature ◽  
Glass Transition Temperatures ◽  
Transparent Films

Aromatic polyamide-imides having hexafluoroisopropylidene and isopropylidene groups in the main chain of the polymer were prepared by reacting 4-chloroformylphthalic anhydride (CPA) and fluorine or non-fluorine containing diamines using low-temperature polycondensation. Polyamide-imides were obtained with high molecular weight and high yield. Thermal decomposition temperature and glass transition temperatures of polymers were above 460 °C and 275 °C respectively. Fluorine and non-fluorine containing polyamide-imides were cast into transparent films which were characterized by mechanical and water absorption analysis.

scholarly journals Synthesis of Soluble Novel Polyacetylenes Containing Carbamate and Eugenol Moieties

2020 ◽  
Vol 20 (4) ◽  
pp. 818
Author(s):  
Erwin Abdul Rahim
Keyword(s):  
Molecular Weight ◽  
Organic Solvents ◽  
Helical Structure ◽  
High Yield

This study was aimed to synthesize a series of novel polyacetylenes containing carbamate and eugenol moieties. The polymerization of 1-(3,4-dimethoxyphenyl) propane-2-yl prop-2-ynylcarbamate (1), 1-(3,4-dimethoxyphenyl)propane-2-yl 3-ethynyl phenylcarbamate (2), 1-(3,4-dimethoxyphenyl)propane-2-yl 4-ethynylphenylcarbamate (3), (2S)-1-(3,4-dimethoxyphenyl)propane-2-yl 2-((prop-2ynyloxy)carbonylamino)propanoate (4) in the presence of (nbd)Rh+[ɳ6-C6H5B–(C6H5)3] as catalyst have successfully produced corresponding polyacetylenes [poly(1)–poly(4)] in high yield. The molecular weight of the synthesized polyacetylenes ranged between 13,900–18,400 g/mol. In particular, the molecular weight of poly(1) could be increased by the addition of menthol. Practically, these polymers were found to have a stable helical structure and soluble in common organic solvents.

Composition of low molecular weight impurities in dimethylmethylpheylsiloxane rubbers with terminal hydroxyl groups

2020 ◽  
Vol 86 (11) ◽  
pp. 20-27
Author(s):  
A. M. Filippov ◽  
N. Yu. Semenkova ◽  
S. M. Gorelov ◽  
T. I. Shulyatieva ◽  
P. A. Storozhenko
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Hydroxyl Groups
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