Thermally stable optically transparent copolymers of 2-methylene-1,3-dioxepane and N-phenyl maleimide with degradable ester linkages

e-Polymers ◽  
2015 ◽  
Vol 15 (4) ◽  
pp. 217-226 ◽  
Author(s):  
Yinfeng Shi ◽  
Seema Agarwal
Keyword(s):  
Ring Opening ◽  
Molar Mass ◽  
Charge Transfer Complex ◽  
Resonance Spectroscopy ◽  
Mechanistic Studies ◽  
Scanning Calorimetry ◽  
Reaction Conditions ◽  
Radical Ring ◽  
High Molar Mass

AbstractThe copolymers of 2-methylene-1,3-dioxepane (MDO) and N-phenyl maleimide (NPM) prepared by radical polymerization with high thermal stability, glass transition temperature and optical transparency are presented. The polymers made under specific reaction conditions, i.e., 120°C and high amounts of MDO, had degradable ester units, which were formed via radical ring-opening polymerization of MDO. The formation of charge-transfer complex between MDO and NPM also led to the formation of high-molar-mass copolymers by simple mixing and heating of monomers without the use of any initiator. Structural characterization of the copolymers including mechanistic studies was carried out using nuclear magnetic resonance spectroscopy, and their thermal properties were studied using differential scanning calorimetry and thermogravimetric analysis.

scholarly journals Synthesis of poly(γ-tert-butyl L-glutamate): influence of polymerization conditions

2019 ◽  
Vol 16 (3) ◽  
pp. 25
Author(s):  
Phung Thi Thuy Dung ◽  
Nguyen Thi Le Thu
Keyword(s):  
Ring Opening ◽  
Gel Permeation Chromatography ◽  
Attenuated Total Reflection ◽  
Resonance Spectroscopy ◽  
Reaction Conditions ◽  
Tert Butyl ◽  
Ft Ir ◽  
Hydrolysis Of ◽  
Polymerization Conditions

This work presents the synthesis and characterization of poly(γ-tert-butyl L-glutamate) (PtBuLG) via a living ring-opening polymerization procedure of γ-tert-butyl L-glutamate N-carboxyanhydride (tBuLG-NCA). The reaction conditions were investigated to optimize the polymerization yield and molecular weight polydispersity. The synthesized PtBuLG was characterized using nuclear magnetic resonance spectroscopy (NMR), gel permeation chromatography (GPC) and attenuated total reflection-Fourier transform infrared (ATR FT-IR. Finally, hydrolysis of PtBuLG resulted in poly(L-glutamic acid) (PLGA).

Thermal, Mechanical and Magneto-Mechanical Characterization of Liquid Crystalline Elastomers Loaded with Iron Oxide Nanoparticles

2015 ◽  
Vol 1718 ◽  
pp. 3-7
Author(s):  
Stephany Herrera-Posada ◽  
Barbara O. Calcagno ◽  
Aldo Acevedo
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Liquid Crystalline ◽  
Molar Mass ◽  
Oxide Nanoparticles ◽  
Magnetic Actuation ◽  
Scanning Calorimetry ◽  
Elastomeric Matrix ◽  
Alternating Magnetic Fields

ABSTRACTLiquid crystalline elastomers (LCEs) are materials that reveal unusual mechanical, optical and thermal properties due to their molecular orientability characteristic of low molar mass liquid crystals while maintaining the mechanical elasticity distinctive of rubbers. As such, they are considered smart shape-changing responsive systems. In this work, we report on the preparation of magnetic sensitized nematic LCEs using iron oxide nanoparticles with loadings of up to 0.7 wt%. The resultant thermal and mechanical properties were characterized by differential scanning calorimetry, expansion/contraction experiments and extensional tests. The magnetic actuation ability was also evaluated for the neat elastomer and the composite with 0.5 wt% magnetic content, finding reversible contractions of up to 23% with the application of alternating magnetic fields (AMFs) of up to 48 kA/m at 300 kHz. Thus, we were able to demonstrate that the inclusion of magnetic nanoparticles yields LCEs with adjustable properties that can be tailored by changing the amount of particles embedded in the elastomeric matrix, which can be suitable for applications in actuation, sensing, or as smart substrates.

scholarly journals Synthesis and Characterization of a Multifunctional Conjugated Polymer

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Emerson C. G. Campos ◽  
Cristiano Zanlorenzi ◽  
Bruno F. Nowacki ◽  
Gabriela M. Miranda ◽  
Denis A. Turchetti ◽  
...  
Keyword(s):  
Conjugated Polymer ◽  
Molar Mass ◽  
Photophysical Properties ◽  
Gel Permeation Chromatography ◽  
Thermal Characterization ◽  
Polymer Structure ◽  
Synthesis And Characterization ◽  
Metallic Ions ◽  
Scanning Calorimetry

This work reports the synthesis and characterization of a conjugated polymer based on fluorene and terpyridine, namely, poly[(9,9-bis(3-((S)-2-methylbutylpropanoate))fluorene-alt-6,6′-(2,2′:6′,2′′-terpyridin-6-yl)] (LaPPS71). The structure was characterized by 1H and 13C nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectroscopy. The molar mass was measured by gel permeation chromatography (GPC). As thermal characterization, the glass transition temperature (Tg) was measured by differential scanning calorimetry (DSC). The polymer structure contains two sites capable of complexation with metallic ions, affording the possibility of obtainment of independent or electronically coupled properties, depending on the complexation site. The photophysical properties were fully explored in solution and solid state, presenting ideal results for the preparation of various metallopolymers, in addition to potential application as a metamaterial, due to the presence of the chiral center in the side chains of the polymer.

Characterization of bi-layered magnetic nanoparticles synthesized via two-step surface-initiated ring-opening polymerization

2015 ◽  
Vol 87 (11-12) ◽  
pp. 1085-1097 ◽  
Author(s):  
Li Wang ◽  
Stefan Baudis ◽  
Karl Kratz ◽  
Andreas Lendlein
Keyword(s):  
Magnetic Nanoparticles ◽  
Ring Opening ◽  
Average Molecular Weight ◽  
Polymer Networks ◽  
Gel Permeation Chromatography ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Transmission Electron

AbstractA versatile strategy to integrate multiple functions in a polymer based material is the formation of polymer networks with defined nanostructures. Here, we present synthesis and comprehensive characterization of covalently surface functionalized magnetic nanoparticles (MNPs) comprising a bi-layer oligomeric shell, using Sn(Oct)2 as catalyst for a two-step functionalization. These hydroxy-terminated precursors for degradable magneto- and thermo-sensitive polymer networks were prepared via two subsequent surface-initiated ring-opening polymerizations (ROPs) with ω-pentadecalactone and ε-caprolactone. A two-step mass loss obtained in thermogravimetric analysis and two distinct melting transitions around 50 and 85°C observed in differential scanning calorimetry experiments, which are attributed to the melting of OPDL and OCL crystallites, confirmed a successful preparation of the modified MNPs. The oligomeric coating of the nanoparticles could be visualized by transmission electron microscopy. The investigation of degrafted oligomeric coatings by gel permeation chromatography and 1H-NMR spectroscopy showed an increase in number average molecular weight as well as the presence of signals related to both of oligo(ω-pentadecalactone) (OPDL) and oligo(ε-caprolactone) (OCL) after the second ROP. A more detailed analysis of the NMR results revealed that only a few ω-pentadecalactone repeating units are present in the degrafted oligomeric bi-layers, whereby a considerable degree of transesterification could be observed when OPDL was polymerized in the 2nd ROP step. These findings are supported by a low degree of crystallinity for OPDL in the degrafted oligomeric bi-layers obtained in wide angle X-ray scattering experiments. Based on these findings it can be concluded that Sn(Oct)2 was suitable as catalyst for the preparation of nanosized bi-layered coated MNP precursors by a two-step ROP.

scholarly journals Synthesis and Self-Assembly of Poly(N-Vinylcaprolactam)-b-Poly(ε-Caprolactone) Block Copolymers via the Combination of RAFT/MADIX and Ring-Opening Polymerizations

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1252
Author(s):  
Rodolfo M. Moraes ◽  
Layde T. Carvalho ◽  
Gizelda M. Alves ◽  
Simone F. Medeiros ◽  
Elodie Bourgeat-Lami ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Ring Opening ◽  
Chain Transfer ◽  
Fluorescence Probe ◽  
Size Exclusion ◽  
Proton Nuclear Magnetic Resonance ◽  
Solution Temperature ◽  
Copolymer Composition ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry

Well-defined amphiphilic, biocompatible and partially biodegradable, thermo-responsive poly(N-vinylcaprolactam)-b-poly(ε-caprolactone) (PNVCL-b-PCL) block copolymers were synthesized by combining reversible addition-fragmentation chain transfer (RAFT) and ring-opening polymerizations (ROP). Poly(N-vinylcaprolactam) containing xanthate and hydroxyl end groups (X–PNVCL–OH) was first synthesized by RAFT/macromolecular design by the interchange of xanthates (RAFT/MADIX) polymerization of NVCL mediated by a chain transfer agent containing a hydroxyl function. The xanthate-end group was then removed from PNVCL by a radical-induced process. Finally, the hydroxyl end-capped PNVCL homopolymer was used as a macroinitiator in the ROP of ε-caprolactone (ε-CL) to obtain PNVCL-b-PCL block copolymers. These (co)polymers were characterized by Size Exclusion Chromatography (SEC), Fourier-Transform Infrared spectroscopy (FTIR), Proton Nuclear Magnetic Resonance spectroscopy (1H NMR), UV–vis and Differential Scanning Calorimetry (DSC) measurements. The critical micelle concentration (CMC) of the block copolymers in aqueous solution measured by the fluorescence probe technique decreased with increasing the length of the hydrophobic block. However, dynamic light scattering (DLS) demonstrated that the size of the micelles increased with increasing the proportion of hydrophobic segments. The morphology observed by cryo-TEM demonstrated that the micelles have a pointed-oval-shape. UV–vis and DLS analyses showed that these block copolymers have a temperature-responsive behavior with a lower critical solution temperature (LCST) that could be tuned by varying the block copolymer composition.

scholarly journals Synthesis and Characterization of Low-Cost Cresol-Based Benzoxazine Resins as Potential Binders in Abrasive Composites

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2995
Author(s):  
Artur Jamrozik ◽  
Mateusz Barczewski ◽  
Grzegorz Framski ◽  
Daniel Baranowski ◽  
Paulina Jakubowska ◽  
...  
Keyword(s):  
Low Cost ◽  
2D Nmr ◽  
Additional Analysis ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Voc Emission ◽  
Chemical Structures ◽  
Oxazine Ring ◽  
Nmr Techniques

A series of cresol-based benzoxazines were synthesized for potential application as a polymer matrix in abrasive composites. The chemical structures of the obtained benzoxazine resins were investigated in detail using Fourier transform infrared spectroscopy (FTIR) and hydrogen-1 as well as carbon-13 nuclear magnetic resonance spectroscopy (1H NMR, 13C NMR) with an additional analysis using two-dimensional NMR techniques (2D NMR 1H-1H COSY, 1H-13C gHSQC and gHMBC). Structural analysis confirmed the presence of vibrations of -O-C-N- at ~950 cm−1 wavenumber, characteristic for an oxazine ring. The thermal properties of benzoxazine monomers were examined using differential scanning calorimetry (DSC) analysis. The polymerization enthalpy varied from 143.2 J/g to 287.8 J/g. Thermal stability of cresol-based benzoxazines was determined using thermogravimetry (TGA) analysis with additional analysis of the amount of volatile organic compounds (VOC) emitted from the synthesized benzoxazines during their crosslinking by static headspace coupled with gas chromatography technique (HS-GC). The amount of residual mass significantly differed between all synthesized polybenzoxazines in the range from 8.4% to 21.2%. The total VOC emission for benzoxazines decreased by 46–77% in reference to a conventional phenolic binder. The efficiency of abrasive composites with the benzoxazine matrix was evaluated based on abrasion tests. Performed analyses confirmed successful synthesis and proper chemical structure of cresol-based benzoxazines. All the experiments indicated that benzoxazines based on different cresol isomers significantly differ from each other. Good thermal performance and stability of the abrasive composites with the polybenzoxazine matrix and significantly lower VOC emission allow us to state that benzoxazines can be a promising and valuable alternative to the phenolics and a new path for the development of modern, eco-friendly abrasives.

scholarly journals Keggin-Type Heteropolyacid for Ring-Opening Polymerization of Cyclohexene Oxide: Molecular Weight Control

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Ahmed Aouissi ◽  
Zeid Abdullah Al-Othman ◽  
Abdurrahman Salhabi
Keyword(s):  
Molecular Weight ◽  
Reaction Time ◽  
Acetic Anhydride ◽  
Ring Opening ◽  
Weight Control ◽  
Reaction Medium ◽  
Resonance Spectroscopy ◽  
Cyclohexene Oxide ◽  
Scanning Calorimetry ◽  
Catalyst Amount

Polymerization of 1,2-cyclohexene oxide (CHO) in dichloromethane was catalyzed by 12-tungstophosphoric acid (H3PW12O40·13H2O) as a super solid acid. The effect of polymerization parameters such as reaction time, temperature, and catalyst amount was investigated. The effect of acetic anhydride as a ring-opening agent was also investigated. The resulting poly(1,2-cyclohexene oxide) (PCHO) was characterized by Fourier transform infrared (FTIR), nuclear magnetic resonance spectroscopy (1HNMR), gel-permeation chromatography (GPC), and differential scanning calorimetry (DSC). It has been found that the PCHO prepared over H3PW12O40·13H2O has a stereoregularity higher than that prepared over clay and Aluminium alkoxide catalysts. TheTgvalue obtained is due to the microstructure but not to molecular weight. The yield and the molecular weight of the polymer depend strongly on the reaction conditions. Molecular weights can be readily controlled by changing reaction temperature, reaction time, and catalyst amount. Contrary to most polymerization reactions, the molecular weight increases with the temperature increase. Addition of acetic anhydride to the reaction medium increased the yield threefold.

The synthesis and characterization of liquid crystalline oligoimides and polyimides

1995 ◽  
Vol 7 (4) ◽  
pp. 421-431 ◽  
Author(s):  
P Alder ◽  
J G Dolden ◽  
P Smith
Keyword(s):  
Liquid Crystalline ◽  
Solution Method ◽  
Molar Mass ◽  
Building Blocks ◽  
Decomposition Temperature ◽  
Synthesis And Characterization ◽  
Scanning Calorimetry ◽  
Nematic Phases ◽  
Optical Polarizing Microscopy

There are few examples of thermotropic polyimides reported in the literature. In the present article the authors report the synthesis and characterization of some novel oligoand poly-imides which exhibit mesogenic behaviour. The solution method of Yamazaki et al (Yamazaki N, Higashi F and Kawasaki J 1974 J. Polym. Sci., Polym. Chem. Ed. 12 2149) for the preparation of polyamides was successfully applied to the formation of imide compounds and oligomers. Liquid crystal phases were characterized by optical polarizing microscopy and by differential scanning calorimetry. Two anhydrides were employed which were considered to be suitable building blocks for preparing potentially mesogenic polyimides, namely biphenyl tetracarboxytic dianhydride and pyromellitic dianhydride. Low-molar-mass materials were first synthesized with monoanhydride units to endcap the chains. using nadic and maleic anhydrides. Nematic phases Awere observed in several nadic diimide compounds containing multicyclic cores and in some low-molar-mass diimides and polyimides which contained a biphenylene unit in conjunction with at least one other unsaturated ring When the nadlmldes were heated above 220 C cross-linking and decomposition occurred with loss of mesogenic properties. A fusible polyimide was synthesized containing a flexible chain which exhibited thermotropic behaviour below its decomposition temperature.

scholarly journals A Greener Enzymatic Oligoesterification of Biobased Renewable Synthons

2021 ◽  
Author(s):  
Juan Villavicencio ◽  
Ferley Orozco ◽  
Ricardo Benitez ◽  
Jaime Martin ◽  
Giovanni Rojas
Keyword(s):  
Molecular Weight ◽  
Molar Mass ◽  
Gel Permeation Chromatography ◽  
Scanning Calorimetry ◽  
Reaction Conditions ◽  
Step Process ◽  
Gel Permeation ◽  
One Step ◽  
First Time ◽  
Temperature Time

Polyesters of xylitol and succinic acid were prepared yielding from 70 to 75% by enzymecatalyzed esterification using a molar mass from 1:1 to 2:5 at 120 and 140 °C employing from 1 to 10% m/m of enzyme. Control over branching degree was achieved by tuning the reaction conditions (temperature, time, comonomer ratio, enzyme content). This one-step process from renewable starting materials avoids protection-deprotection techniques, as well as the use of toxic solvents by introducing limonene as solvent for polyesterification for the first time. All materials were structurally characterized by infrared (IR) and nuclear magnetic resonance (NMR)spectroscopy, their thermal properties were studied by differential scanning calorimetry (DSC)and thermogravimetric analysis (TGA), and the molecular weight of samples were obtained by gel-permeation chromatography (GPC).

Sign in / Sign up

Export Citation Format

Share Document