Reversible Stepwise Condensation Polymerization with Cyclization: Strictly Alternating Co-polymerization and Homopolymerization Based upon Two Orthogonal Reactions

2021 ◽  
Author(s):  
Michael Lang ◽  
Kiran Suresh Kumar
Keyword(s):  
Condensation Polymerization

scholarly journals Responsive Polyesters with Alkene and Carboxylic Acid Side-Groups for Tissue Engineering Applications

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1636
Author(s):  
Stella Afroditi Mountaki ◽  
Maria Kaliva ◽  
Konstantinos Loukelis ◽  
Maria Chatzinikolaidou ◽  
Maria Vamvakaki
Keyword(s):  
Carboxylic Acid ◽  
Chain Length ◽  
Main Chain ◽  
Alkyl Chain ◽  
Click Reaction ◽  
Irradiation Time ◽  
Alkyl Chain Length ◽  
Polymer Chains ◽  
Condensation Polymerization ◽  
L929 Fibroblast

Main chain polyesters have been extensively used in the biomedical field. Despite their many advantages, including biocompatibility, biodegradability, and others, these materials are rather inert and lack specific functionalities which will endow them with additional biological and responsive properties. In this work, novel pH-responsive main chain polyesters have been prepared by a conventional condensation polymerization of a vinyl functionalized diol with a diacid chloride, followed by a photo-induced thiol-ene click reaction to attach functional carboxylic acid side-groups along the polymer chains. Two different mercaptocarboxylic acids were employed, allowing to vary the alkyl chain length of the polymer pendant groups. Moreover, the degree of modification, and as a result, the carboxylic acid content of the polymers, was easily tuned by varying the irradiation time during the click reaction. Both these parameters, were shown to strongly influence the responsive behavior of the polyesters, which presented adjustable pKα values and water solubilities. Finally, the difunctional polyesters bearing the alkene and carboxylic acid functionalities enabled the preparation of cross-linked polyester films by chemically linking the pendant vinyl bonds on the polymer side groups. The biocompatibility of the cross-linked polymers films was assessed in L929 fibroblast cultures and showed that the cell viability, proliferation, and attachment were greatly promoted on the polyester surface, bearing the shorter alkyl chain length side groups and the higher fraction of carboxylic acid functionalities.

scholarly journals Direct condensation polymerization of N-alkylated p-aminobenzoic acid and packing of rigid-rod main chains with flexible side chains

2010 ◽  
Vol 42 (1) ◽  
pp. 72-80 ◽  
Author(s):  
Yuji Shibasaki ◽  
Yoko Abe ◽  
Natsuki Sato ◽  
Atsuhiro Fujimori ◽  
Yoshiyuki Oishi
Keyword(s):  
Side Chains ◽  
Condensation Polymerization ◽  
Aminobenzoic Acid ◽  
Rigid Rod ◽  
Direct Condensation

scholarly journals Enzymatic synthesis and characterization of novel terpolymers from renewable sources

2019 ◽  
Vol 91 (3) ◽  
pp. 397-408
Author(s):  
Diana Aparaschivei ◽  
Anamaria Todea ◽  
August E. Frissen ◽  
Valentin Badea ◽  
Gerlinde Rusu ◽  
...  
Keyword(s):  
Polymerization Reaction ◽  
Molar Ratio ◽  
Condensation Polymerization ◽  
Average Molecular Mass ◽  
New Class ◽  
Platform Chemicals ◽  
Starting Point ◽  
Reaction Cycles ◽  
Methylene Group

Abstract 2,5-Furandicarboxylic acid and itaconic acid are both important biobased platform chemicals and their terpolymer with 1,6-hexanediol (HDO) can be the starting point for a new class of reactive polyesters, with important applications. The green synthetic route developed in this study involves a biocatalytic condensation polymerization reaction of dimethyl furan-2,5-dicarboxylate (DMFDC) and dimethyl itaconate (DMI) with HDO in toluene at 80°C, using commercial immobilized lipases from Candida antarctica B. In the best conditions, the formed polymer product was isolated with more than 80% yield, containing about 85% terpolymer with average molecular mass of about 1200 (Mn, calculated from MALDI-TOF MS data) and 15% DMFDC_HDO copolymer. Considering the higher reactivity of DMFDC, the composition of the synthesized polymer can be directed by adjusting the molar ratio of DMFDC and DMI, as well as by extending the reaction time. Structural analysis by NMR demonstrated the regioselective preference for the carbonyl group from DMI adjacent to the methylene group. The biocatalyst was successfully reused in multiple reaction cycles.

Performance of Nano-Silica Insulation Material Enhanced by High Humidity-Reinforcement Method

2016 ◽  
Vol 697 ◽  
pp. 433-436
Author(s):  
Shi Chao Zhang ◽  
Yu Feng Chen ◽  
Wei Wu ◽  
Hao Ran Sun ◽  
Guang Hai Wang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Raw Material ◽  
High Humidity ◽  
Insulation Material ◽  
Condensation Polymerization ◽  
Drying Process ◽  
Nano Silica ◽  
Insulation Materials ◽  
The One ◽  
Strength Improvement

In this paper, fumed nano-silica as the main raw material, nano-silica insulation materials were prepared by the dry processing. Research on humidity-reinforcement of nano-Silica insulation materials has been carried out and analyzed. When hygroscopicity of samples reach to 23%, the compressive strength 1.65MPa is at twice the one without high humidity-reinforcement, while the thermal conductivities are almost the same. Then, the action mechanism of high humidity-reinforcement method was analyzed. In humidity-reinforcement method, as vapor enters, silica sol is formed in the gap between one aggregate particle and another, and various condensation polymerization occurred in the drying process, which lead to aggregates connection and compressive strength improvement.

scholarly journals The assembly of microtubule protein in vitro. The kinetic role in microtubule elongation of oligomeric fragments containing microtubule-associated proteins

1985 ◽  
Vol 227 (2) ◽  
pp. 439-455 ◽  
Author(s):  
P M Bayley ◽  
F M M Butler ◽  
D C Clark ◽  
E J Manser ◽  
S R Martin
Keyword(s):  
Self Assembly ◽  
Protein Concentration ◽  
Wavelength Dependence ◽  
Electrophoretic Analysis ◽  
Slow Phase ◽  
Condensation Polymerization ◽  
Fast Phase ◽  
Microtubule Protein ◽  
Kinetics Of

The kinetics of assembly were studied for bovine and pig microtubule protein in vitro over a range of conditions of pH, temperature, nucleotide and protein concentration. The kinetics are in general biphasic with two major processes of similar amplitude but separated in rate by one order of magnitude. Rates and amplitudes are complex functions of solution conditions. The rates of the fast phase and the slow phase attain limiting values as a function of increasing protein concentration, and are more stringently limited at pH 6.5 than pH 6.95. Such behaviour indicates that mechanisms other than the condensation polymerization of tubulin dimer become rate-limiting at higher protein concentration. The constancy of the wavelength-dependence of light-scattering and ultrastructural criteria indicate that microtubules of normal morphology are formed in both phases of the assembly process. Electrophoretic analysis of assembling microtubule protein shows that MAP- (microtubule-associated-protein-)rich microtubules are formed during the fast phase. The rate of dissociation of oligomeric species on dilution of microtubule protein closely parallels the fast-phase rate in magnitude and temperature-dependence. We propose that the rate of this process constitutes an upper limit to the rate of the fast phase of assembly. The kinetics of redistribution of MAPs from MAP-rich microtubules may be a factor limiting the slow-phase rate. A working model is derived for the self-assembly of microtubule protein incorporating the dissociation and redistribution mechanisms that impose upper limits to the rates of assembly attainable by bimolecular addition reactions. Key roles are assigned to MAP-containing fragments in both phases of microtubule elongation. Variations in kinetic behaviour with solution conditions are inferred to derive from the nature and properties of fragments formed from oligomeric species after the rapid temperature jump. The model accounts for the limiting rate behaviour and indicates experimental criteria to be applied in evaluating the relative contributions of alternative pathways.

Fundamental Principles of Condensation Polymerization.

1946 ◽  
Vol 39 (1) ◽  
pp. 137-197 ◽  
Author(s):  
Paul J. Flory
Keyword(s):  
Condensation Polymerization

Synthesis, Characterization and Thermooxidative Properties of Hybrid Block Poly(silane-b-arylacetylene)

2014 ◽  
Vol 1004-1005 ◽  
pp. 527-532
Author(s):  
Ying Jie Xu ◽  
Hui Min Qi ◽  
Ya Ping Zhu ◽  
Fan Wang
Keyword(s):  
Weight Loss ◽  
Oxidative Stability ◽  
Lewis Acid ◽  
Grignard Reagent ◽  
Room Temperature ◽  
Condensation Polymerization ◽  
Thermooxidative Stability ◽  
Thermal Cure ◽  
Inorganic Hybrid ◽  
Thermal And Oxidative Stability

Organic-inorganic hybrid block Poly (silane-b-arylacetylene) (PSbA) have been synthesized through condensation polymerization between chloro-terminated polysilane and diethynylbenzene Grignard reagent, and chloro-terminated polysilane was synthesized through condensation polymerization of dichloromethylvinylsilane in the presence of Mg metal and Lewis acid (ZnCl2, LiCl). The structures of PSbAs were characterized by FTIR, 1H, 13C, 29Si NMR, and GPC. The PSbAs are orange viscous liquid and can be soluble in common organic solvents at room temperature. The thermal cure behavior of PSbAs was determined by DSC, and the thermal and oxidative stability of the cured PSbAs were investigated using TGA. The results showed that the cured PSbAs exhibit high thermal and thermooxidative stability. The degradation temperatures at 5% weight loss for the cured PSbAs are 470-533°C under N2 and 378-456°C under air, and the residue yields at 1000°C are 77.9-82.8% under N2 and 40.4-50.5% under air.

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