scholarly journals Synthesis and Properties of Bioresorbable Block Copolymers of l-Lactide, Glycolide, Butyl Succinate and Butyl Citrate

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 214 ◽  
Author(s):  
Natalia Śmigiel-Gac ◽  
Elżbieta Pamuła ◽  
Małgorzata Krok-Borkowicz ◽  
Anna Smola-Dmochowska ◽  
Piotr Dobrzyński
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Biomedical Applications ◽  
Chain Growth ◽  
Hydroxyl Groups ◽  
Butylene Succinate ◽  
Branched Copolymers ◽  
Ultrahigh Molecular Weight ◽  
Biological Tests ◽  
Polymerization Mixture

The paper presents the course of synthesis and properties of a series of block copolymers intended for biomedical applications, mainly as a material for forming scaffolds for tissue engineering. These materials were obtained in the polymerization of l-lactide and copolymerization of l-lactide with glycolide carried out using a number of macroinitiators previously obtained in the reaction of polytransesterification of succinic diester, citric triester and 1,4-butanediol. NMR, FTIR and DSC were used to characterize the materials obtained; wettability and surface free energy were assessed too. Moreover, biological tests, i.e., viability and metabolic activity of MG-63 osteoblast-like cells in contact with synthesized polymers were performed. Properties of obtained block copolymers were controlled by the composition of the polymerization mixture and by the composition of the macroinitiator. The copolymers contained active side hydroxyl groups derived from citrate units present in the polymer chain. During the polymerization of l-lactide in the presence of polyesters with butylene citrate units in the chain, obtained products of the reaction held a fraction of highly branched copolymers with ultrahigh molecular weight. The reason for this observed phenomenon was strong intermolecular transesterification directed to lactidyl side chains, formed as a result of chain growth on hydroxyl groups related to the quaternary carbons of the citrate units. Based on the physicochemical properties and results of biological tests it was found that the most promising materials for scaffolds formation were poly(l-lactide–co–glycolide)–block–poly(butylene succinate–co–butylene citrate)s, especially those copolymers containing more than 60 mol % of lactidyl units.

New comonomer synthesis from thiophene-2-carbonyl chloride and cyclohexanone formaldehyde resin

2015 ◽  
Vol 44 (2) ◽  
pp. 79-86 ◽  
Author(s):  
Esin Ateş ◽  
Nilgün Kizilcan ◽  
Merve İstif
Keyword(s):  
Molecular Weight ◽  
Block Copolymer ◽  
Block Copolymers ◽  
Chemical Oxidation ◽  
Esterification Reaction ◽  
Formaldehyde Resin ◽  
Hydroxyl Groups ◽  
Content Type ◽  
Carbonyl Chloride ◽  
Oxidation System

Purpose – The purpose of this paper is to synthesise an electro-active monomer containing ketonic resins and then to investigate the redox reaction between Fe+3 and bound thiophene in comonomer. First, thiophene-functionalised ketonic resins were synthesised by esterification reaction of thiophene-2-carbonyl chloride (ThCCl) and hydroxyl groups of cyclohexanone formaldehyde resin (CFR). Thiophene-containing cyclohexanone formaldehyde resin (Th-CFR) was then polymerised by ferric salt. The structures of the specimens were characterised by means of Fourier transform infrared and Proton – Nuclear Magnetic Resonanse (1H-NMR) spectroscopy. Thermal properties of the samples were determined with differential scanning calorimeter. Molecular weights of the specimens were determined by gel permeation chromatography. The obtained samples were also characterised morphologically by scanning electron microscope. Design/methodology/approach – Synthesis of Th-CFR comonomers by a combination of condensation polymerization and chemical oxidation polymerisation processes is described. First, Th-CFR units were prepared by direct condensation reaction of thiophene-2-carbonyl chloride (ThCCl) and hydroxyl groups of CFR. Then, the chemical oxidation (CO) of Th-CFR in the presence of anhydrous iron (III) chloride salt (FeCl3) was performed in chloroform (CHCl3)/acetonitrile mixture solutions at room temperature. Findings – The important structural factor determined quantitatively for Th-CFR is the CFR/ThCCl ratio after reaction. The effect of the mole ratio effect of ThCCl and ketonic resin on the solubility, molecular weight, Tm and Tg values of the comonomers (Th-CFRs) were investigated. Research limitations/implications – The ferric ion (Fe+3) has a standard oxidation potential. Furthermore, FeCl3 can react with thiophene to produce a cation radical. FeCl3 cannot react with hydroxyl groups of ketonic resins. When ferric is used for in situ chemical oxidation application at relatively low temperatures (e.g. < 20°C), the oxidation reactions are usually less aggressive. Practical implications – This work provides technical information for the synthesis of conducting block copolymer and for the synthesis of chain-extended resins. The modified resins contain electro-active monomer as thiophene. The chemical oxidation system has been used to polymerise these thiophene groups and resins with much higher molecular weight might be produced. These resins may also promote the adhesive strength of a coating and corrosion inhibition to metal surfaces of a coating. Social implications – This will be used for the preparation of AB- and ABA-type block copolymers. These block copolymers may exhibit different properties due to incorporation of monomer into the block copolymer structure. Originality/value – Novel Th-CFR comonomers were synthesised. These comonomers have higher glass transition temperature (Tg) and melting temperature (Tm) value than CFR alone. The chemical oxidation system has been used to polymerise these thiophene-functionalised ketonic resins.

scholarly journals Porous Ultrahigh Molecular Weight Polyethylene/Functionalized Activated Nanocarbon Composites with Improved Biocompatibility

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6065
Author(s):  
Wangxi Fan ◽  
Xiuqin Fu ◽  
Zefang Li ◽  
Junfei Ou ◽  
Zhou Yang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Contact Angle ◽  
Tensile Strength ◽  
Wear Resistance ◽  
Biomedical Applications ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
In Vitro Experiments ◽  
Ultrahigh Molecular Weight ◽  
Uhmwpe Composite

Ultrahigh molecular weight polyethylene (UHMWPE) materials have been prevalent joint replacement materials for more than 45 years because of their excellent biocompatibility and wear resistance. In this study, functionalized activated nanocarbon (FANC) was prepared by grafting maleic anhydride polyethylene onto acid-treated activated nanocarbon. A novel porous UHMWPE composite was prepared by incorporating the appropriate amount of FANC and pore-forming agents during the hot-pressing process for medical UHMWPE powder. The experimental results showed that the best prepared porous UHMWPE/FANC exhibited appropriate tensile strength, porosity, and excellent hydrophilicity, with a contact angle of 65.9°. In vitro experiments showed that the porous UHMWPE/FANC had excellent biocompatibility, which is due to its porous structure and hydrophilicity caused by FANC. This study demonstrates the potential viability for our porous UHMWPE/FANC to be used as cartilage replacement material for biomedical applications.

Synthesis of ultrahigh molecular weight bottlebrush block copolymers of ω-end-norbornyl polystyrene and polymethacrylate macromonomers

Polymer ◽  
2019 ◽  
Vol 177 ◽  
pp. 241-249 ◽  
Author(s):  
Ho-Bin Seo ◽  
Yong-Guen Yu ◽  
Chang-Geun Chae ◽  
Myung-Jin Kim ◽  
Jae-Suk Lee
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Ultrahigh Molecular Weight

Preparation of ultrahigh molecular weight ethylene/1-octene block copolymers using ethylene pressure pulse feeding policies

2015 ◽  
Vol 6 (20) ◽  
pp. 3800-3806 ◽  
Author(s):  
Weifeng Liu ◽  
Andrew Toye Ojo ◽  
Wen-Jun Wang ◽  
Hong Fan ◽  
Bo-Geng Li ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Pressure Pulse ◽  
Coordination Polymerization ◽  
Ethylene Pressure ◽  
Ultrahigh Molecular Weight

Ultrahigh molecular weight ethylene/1-octene block copolymers were prepared from ethylene pressure pulse feeding policies in living coordination polymerization.

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