scholarly journals Chemical bonding of polycaprolactone on the surface of hydroxyapatite via silanization and ring opening polymerization

2020 ◽  
Vol 19 (2) ◽  
pp. 154-164
Author(s):  
Nadir Slimani ◽  
Giovanni Dal Poggetto ◽  
Paola Laurienzo ◽  
Dalila Ksouri ◽  
Hafit Khireddine
Keyword(s):  
Surface Modification ◽  
Reaction Time ◽  
Ring Opening ◽  
Secondary Phase ◽  
Ring Opening Polymerization ◽  
Tem Analysis ◽  
No Formation ◽  
Waxs Pattern ◽  
The Impact ◽  
Effect Of Surface

In this study, surface modification of hydroxyapatite (HAp) by grafting polycaprolactone (PCL) is described. This method is carried out into two steps: (1) A treatment of HAp powder with a mixture of tetraorthosilicate (TEOS) and 3-aminopropyl-etriethoxysilane (APTES) to introduce amine groups and enhance nucleophilicity of surface functionalities; (2) Initiation of the Ring Opening Polymerization (ROP) of the ε-caprolactone (CL) in the presence of the silanized HAp. Moreover, the impact of the reaction time (24, 48 and 72 h) on the grafting amount of PCL is performed. The results of FTIR analysis confirmed the presence of carbonyl groups on the silanized HAp, providing evidence of grafting of PCL on the HAp surface. WAXS pattern showed no formation of a secondary phase after surface modification and the crystallinity is preserved. SEM/TEM analysis revealed a homogenous surface powder composed of irregular nanoscale crystals. TGA analysis indicated the dependence of PCL graft amount on the reaction time. Finally, the effect of surface modification on HAp/PCL nanocomposites morphology was investigated.

Ring-Opening Polymerization of Lactide Using Aluminum Salen-Type Initiators

2014 ◽  
Vol 915-916 ◽  
pp. 713-716
Author(s):  
Qing Zhang ◽  
Jing Tian ◽  
Zhi Qi Cao ◽  
Ru Xia Xu ◽  
Zhen Zhen Sun ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Infrared Spectroscopy ◽  
Reaction Time ◽  
Magnetic Resonance ◽  
Schiff Bases ◽  
Reaction Temperature ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Resonance Spectroscopy ◽  
Aluminum Complex

In this investigation, Schiff bases aluminum complex was synthesized and used as the initiator in the polymerization of D,L-lactide. The aluminum complex was characterized by infrared spectroscopy (IR), and nuclear magnetic resonance spectroscopy (NMR). The influences of different factors, including reaction time, reaction temperature, and the ratio of D, L-lactide/Al3+ on the synthesis of polylactide were described. The results showed that Schiff bases aluminum complex could be successfully applied in the ring opening polymerization. The optimum condition of the ring opening polymerization of D,L-lactide, which included D,L-lactide/Al3+ (mol/mol) ratio of 250, reaction temperature of 120 °C, and reaction time of 16 hours.

Optimization of Polydimethylsiloxane Synthesized Parameters as Vitreous Humour Substitutes

2019 ◽  
Vol 966 ◽  
pp. 189-193 ◽  
Author(s):  
Soni Setiadji ◽  
Fitrilawati ◽  
Anna Niska Fauza ◽  
Atikah Ardi ◽  
Ressa Muhrifah Novianti ◽  
...  
Keyword(s):  
Reaction Time ◽  
Ring Opening ◽  
Vitreoretinal Surgery ◽  
Ring Opening Polymerization ◽  
Vitreous Humour ◽  
Commercial Product ◽  
Chain Terminator

Polydimethylsiloxane (PDMS) with two type viscosity that commonly used as vitreous humour substitutes in vitreoretinal surgery has been successfully synthesized by ring-opening polymerization. Optimization of synthesized parameters such as ratio of monomer and chain terminator, the amount of initiator, mixing temperature and reaction time was carried out to obtain PDMS materials having similar properties with commercial product. PDMS with viscosity of 1.17 Pas that very close to viscosity of commercial PDMS of 1.08 Pas, was successfully synthesized with a ratio of 26:10 monomer and terminator chain, 0.58 M of initiator KOH, 170 oC of mixing temperature and 35 minutes of reaction time. By changing reaction time to 40 minutes, PDMS was successfully synthesized with viscosity of 3.42 that similar to that of commercial one.

The Effect of Surface Modification of Polytetrafluoroethylene (PTFE) on the Properties of POM/PTFE Fiber Composites

2015 ◽  
Vol 642 ◽  
pp. 253-258 ◽  
Author(s):  
Chi Yuan Huang ◽  
Mei Chuan Kuo ◽  
Min Lih Roan
Keyword(s):  
Surface Modification ◽  
Plasma Polymerization ◽  
Frictional Coefficient ◽  
Fiber Composites ◽  
Wear Factor ◽  
Grafting Polymerization ◽  
Plasma Grafting ◽  
Ptfe Composites ◽  
The Impact ◽  
Effect Of Surface

Surface modification of polytetrafluoroethylene (PTFE) fiber by plasma grafting polymerization with acrylamide (AAm) was studied to improve the compatibility between polyacetal (POM) and PTFE. The best modified PTFE manufactured by self-designed plasma polymerization was investigated and denoted as AAm (20wt%)-g (plasma 30min)-PTFE. The grafting polymerization is successful and shown by ESCA spectra of modified PTFE fibers. It is also proved by SEM photographs and the improvement of properties of the POM/PTFE composites. As a result, the friction coefficients, Taber wear factors, and impact strengths of composites with 85wt% of POM and 15wt% of a variety of PTFEs were investigated. The frictional coefficient of POM/ AAm (20wt%)-g (plasma 30min)-PTFE deceased to 0.162; while that of POM/PTFE was 0.174. Taber wear factor of the composite significantly decreased from 5.2 to 1.5 when the PTFE was replaced by AAm-g (plasma)-PTFE. Meanwhile, the impact strength increased from 6.1 kg-cm/cm (POM/PTFE) to 9.3kg-cm/cm (POM/ AAm-g (plasma)-PTFE). Besides, the multi-yield behaviors were found in the Stress-Strain curves of composites with modified PTFE fibers.

scholarly journals Amphiphilic Nucleobase-Containing Polypeptide Copolymers—Synthesis and Self-Assembly

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1357
Author(s):  
Michel Nguyen ◽  
Khalid Ferji ◽  
Sébastien Lecommandoux ◽  
Colin Bonduelle
Keyword(s):  
Self Assembly ◽  
Ring Opening ◽  
Building Blocks ◽  
Ring Opening Polymerization ◽  
The Self ◽  
Amphiphilic Copolymers ◽  
Transmission Electron ◽  
Scattering Measurements ◽  
Thymidine Monophosphate ◽  
The Impact

Nucleobase-containing polymers are an emerging class of building blocks for the self-assembly of nanoobjects with promising applications in nanomedicine and biology. Here we present a macromolecular engineering approach to design nucleobase-containing polypeptide polymers incorporating thymine that further self-assemble in nanomaterials. Diblock and triblock copolypeptide polymers were prepared using sequential ring-opening polymerization of γ-Benzyl-l-glutamate N-carboxyanhydride (BLG-NCA) and γ-Propargyl-l-glutamate N-carboxyanhydride (PLG-NCA), followed by an efficient copper(I)-catalyzed azide alkyne cycloaddition (CuAAc) functionalization with thymidine monophosphate. Resulting amphiphilic copolymers were able to spontaneously form nanoobjects in aqueous solutions avoiding a pre-solubilization step with an organic solvent. Upon self-assembly, light scattering measurements and transmission electron microscopy (TEM) revealed the impact of the architecture (diblock versus triblock) on the morphology of the resulted nanoassemblies. Interestingly, the nucleobase-containing nanoobjects displayed free thymine units in the shell that were found available for further DNA-binding.

Redox-switchable ring-opening polymerization by tridentate ONN-type titanium and zirconium catalysts

2020 ◽  
Vol 10 (19) ◽  
pp. 6501-6510 ◽  
Author(s):  
Alicia M. Doerr ◽  
Justin M. Burroughs ◽  
Nicholas M. Legaux ◽  
Brian K. Long
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Metal Center ◽  
Redox Active ◽  
Active Metal ◽  
Zirconium Catalysts ◽  
Symmetry Number ◽  
The Impact

A study designed to ascertain the impact that ligand symmetry, number of redox-active moieties, and identity of the active metal center have on the catalytic ring-opening polymerization performance of redox-switchable catalysts.

Study of Salen(Al) Complex Catalytic System in Ring-Opening Polymerization of Lactide

2015 ◽  
Vol 1095 ◽  
pp. 407-410
Author(s):  
Yun Nie ◽  
Jing Tian ◽  
Qing Zhang ◽  
Meng Fei Du ◽  
Xiao Lun Hao ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Infrared Spectroscopy ◽  
Reaction Time ◽  
Magnetic Resonance ◽  
Optimum Condition ◽  
Catalytic System ◽  
Reaction Temperature ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Resonance Spectroscopy

In this paper, salen (Al) complex catalytic system was synthesized and used in the polymerization of lactide. The salen (Al) complex catalytic system was characterized by infrared spectroscopy (IR), and nuclear magnetic resonance spectroscopy (NMR). The influences of different factors, including reaction time, reaction temperature, and the ratio of lactide/Al3+ on the synthesis of polylactide were also described in the investigation. The results showed that the complex catalytic system could be successfully applied in the ring opening polymerization. The optimum condition of the ring opening polymerization of lactide, which included lactide/Al3+ (mol/mol) ratio of 300, reaction temperature of 140 °C, and reaction time of 12 hours.

scholarly journals Ring opening polymerization of glycidyl methacrylate by Maghnite-H+ a solid catalyst

2011 ◽  
Vol 1 (5) ◽  
pp. 196-202 ◽  
Keyword(s):  
Molecular Weight ◽  
Reaction Time ◽  
Ring Opening ◽  
Glycidyl Methacrylate ◽  
Average Molecular Weight ◽  
Weight Ratio ◽  
Ring Opening Polymerization ◽  
Montmorillonite Clay ◽  
Solid Catalyst

In the present work the ring-opening polymerization of glycidyl methacrylate (GMA) using Maghnite-H+, a proton exchanged montmorillonite clay as initiator is reported. The influences of solvent, weight ratio of initiator/monomer and reaction time on the conversion of monomer and on the molecular weight are investigated. Increasing Maghnite-H+ proportion increases (GMA) conversion and decreases the average molecular weight of resulted polymer. A cationic mechanism for the reaction was proposed.

scholarly journals Synthesis of bio-based poly limonene oxide with green catalyst

2021 ◽  
pp. 271-280 ◽  
Author(s):  
Chahrazed Bendiabdallah ◽  
Fatiha Reguieg ◽  
Mohammed Belbachir
Keyword(s):  
Reaction Time ◽  
1H Nmr ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Green Catalyst ◽  
Sheet Silicate ◽  
Silicate Clay ◽  
Limonene Oxide ◽  
Cationic Ring Opening Polymerization

In the present work, the polymerization of limonene oxide (LO) catalyzed by Maghnite H+ (Mag- H+) is investigated. Mag-H+ is Algerian montmorillonite sheet silicate clay exchanged with protons. The poly limonene oxide (PLO) is obtained by cationic ring opening polymerization in bulk and with solvent. The effect of the reaction time, the temperature and the amount of catalyst are studied and discussed in order to find the optimal reactions conditions. The polymerization in solution at 0 °C with 5% by weight of catalyst leads to the best yield 61.34% for a reaction time of 1h. The structure of the obtained products is characterized by XRD, 1H-NMR, 13C-RMN, ATR-FTIR, DSC and TGA.

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