scholarly journals Macromolecular Brushes Based on Poly(L-Lactide) and Poly(ε-Caprolactone) Single and Double Macromonomers via ROMP. Synthesis, Characterization and Thermal Properties

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1606 ◽  
Author(s):  
Nikovia ◽  
Sougioltzoupoulou ◽  
Rigas ◽  
Pitsikalis
Keyword(s):  
Thermal Properties ◽  
Polymer Brushes ◽  
Ring Opening ◽  
Size Exclusion ◽  
Molecular Characteristics ◽  
Scanning Calorimetry ◽  
Exclusion Chromatography ◽  
Copolymer Brush ◽  
Differential Thermogravimetry ◽  
Polymerizable Group

Single and double poly(L-lactide) (PLLA) and poly(ε-caprolactone) (PCL) macromonomers having a norbornenyl polymerizable group were prepared by conventional Ring Opening Polymerization (ROP). These macromonomers were further subjected to ring opening metathesis polymerization (ROMP) reactions in order to produce double polymer brushes consisting of PLLA or PCL side chains on a polynorbornene (PNBE) backbone. Statistical or block ring opening metathesis copolymerization of the PLLA and PCL macromonomers afforded the corresponding random and block double brushes. Sequential ROMP of the single PLLA, PCL and PLLA macromonomers resulted in the synthesis of the corresponding triblock copolymer brush. The molecular characteristics of the macromolecular brushes were obtained by 1H-NMR spectroscopy and Size Exclusion Chromatography. The thermal properties of the samples were studied by thermogravimetric analysis, TGA, Differential Thermogravimetry, DTG and Differential Scanning Calorimetry, DSC.

scholarly journals Supramolecular Triblock Copolymers Through the Formation of Hydrogen Bonds: Synthesis, Characterization, Association Effects in Solvents of Different Polarity

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 468
Author(s):  
Spyridoula-Lida Bitsi ◽  
Margarita Droulia ◽  
Marinos Pitsikalis
Keyword(s):  
Hydrogen Bonds ◽  
Triblock Copolymers ◽  
Size Exclusion ◽  
Hydroxyl Groups ◽  
Dilute Solution ◽  
Scanning Calorimetry ◽  
End Groups ◽  
Exclusion Chromatography ◽  
Dilute Solution Viscometry ◽  
Differential Thermogravimetry

Anionic polymerization techniques were employed for the synthesis of linear polystyrene (PS) and block copolymer of PS and polyisoprene (PI) PS-b-PI bearing end hydroxyl groups. Following suitable organic chemistry transformation, the –OH end groups were converted to moieties able to form complementary hydrogen bonds including 2,6-diaminopurine, Dap, thymine, Thy, and the so-called Hamilton receptor, Ham. The formation of hydrogen bonds was examined between the polymers PS-Dap and PS-b-PI-Thy, along with the polymers PS-Ham and PS-b-PI-Thy. The conditions under which supramolecular triblock copolymers are formed and the possibility to form aggregates were examined both in solution and in the solid state using a variety of techniques such as 1H-NMR spectroscopy, size exclusion chromatography (SEC), dilute solution viscometry, dynamic light scattering (DLS), thermogravimetric analysis (TGA), differential thermogravimetry (DTG), and differential scanning calorimetry (DSC).

Synthesis and thermal properties of poly(vinylcyclohexane)-b-poly(4-vinylpyridine) diblock copolymers prepared via RAFT polymerization

e-Polymers ◽  
2018 ◽  
Vol 18 (2) ◽  
pp. 197-203
Author(s):  
Yinghua Qi ◽  
Iryna I. Perepichka ◽  
Zhengji Song ◽  
Sunil K. Varshney
Keyword(s):  
Thermal Properties ◽  
Diblock Copolymers ◽  
Raft Polymerization ◽  
Size Exclusion ◽  
Esterification Reaction ◽  
Scanning Calorimetry ◽  
Raft Agent ◽  
Exclusion Chromatography ◽  
Ft Ir ◽  
Methylpropionic Acid

AbstractA series of novel poly(vinylcyclohexane)-b-poly(4-vinylpyridine) (PVCH-b-P4VP) diblock copolymers have been synthesized through a combination of anionic and RAFT polymerization techniques. Using this approach, end functionalized ω-hydroxy-polystyrene was used to yield ω-hydroxy-PVCH by hydrogenation followed by end-functionalization via an esterification reaction with 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid to yield PVCH-RAFT agent. The crossover propagation from PVCH-RAFT to 4VP displays living character and allowed generating diblock copolymers with well-defined molecular compositions. The characterization of the resulted polymers was performed using 1H nuclear magnetic resonance (NMR) and Fourier-transform infra-red (FT-IR) spectroscopies, size-exclusion chromatography with light-scattering detector (SEC-LS), and the thermal properties were studied using differential scanning calorimetry (DSC).

A study on the kinetics and thermal properties of polystyrene/diatomite nanocomposites prepared via in situ ATRP

2018 ◽  
Vol 33 (2) ◽  
pp. 180-197 ◽  
Author(s):  
Khezrollah Khezri ◽  
Yousef Fazli
Keyword(s):  
Molecular Weight ◽  
In Situ Polymerization ◽  
Structural Characteristics ◽  
Nitrogen Adsorption ◽  
Linear Increase ◽  
Size Exclusion ◽  
Scanning Calorimetry ◽  
Morphological Studies ◽  
Exclusion Chromatography

Pristine mesoporous diatomite was employed to prepare polystyrene/diatomite composites. Diatomite platelets were used for in situ polymerization of styrene by atom transfer radical polymerization to synthesize tailor-made polystyrene nanocomposites. X-Ray fluorescence spectrometer analysis and thermogravimetric analysis (TGA) were employed for evaluating some inherent properties of pristine diatomite platelets. Nitrogen adsorption/desorption isotherm is applied to examine surface area and structural characteristics of the diatomite platelets. Evaluation of pore size distribution and morphological studies were also performed by scanning and transmission electron microscopy. Conversion and molecular weight determinations were carried out using gas and size exclusion chromatography, respectively. Linear increase of ln ( M0/M) with time for all the samples shows that polymerization proceeds in a living manner. Addition of 3 wt% pristine mesoporous diatomite leads to an increase of conversion from 72% to 89%. Molecular weight of polystyrene chains increases from 11,326 g mol−1 to 14134 g mol−1 with the addition of 3 wt% pristine mesoporous diatomite; however, polydispersity index values increases from 1.13 to 1.38. Increasing thermal stability of the nanocomposites is demonstrated by TGA. Differential scanning calorimetry shows an increase in glass transition temperature from 81.9°C to 87.1°C by adding 3 wt% of mesoporous diatomite platelets.

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 A Novel Synthesis of Poly(Ester-Alt-Selenide)s by Ring-Opening Copolymerization of γ-Selenobutyrolactone and Epoxy Monomer

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1203 ◽  
Author(s):  
Ya’nan Wang ◽  
Xiaofang Lin ◽  
Zhengbiao Zhang ◽  
Jian Zhu ◽  
Xiangqiang Pan ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Effective Means ◽  
Linear Structure ◽  
Size Exclusion ◽  
Ionization Time ◽  
Flight Mass Spectrometry ◽  
Epoxy Monomer ◽  
Polymerization System ◽  
Exclusion Chromatography

Ring-opening copolymerization (ROCOP) is an effective means to prepare functionalized polyester. In this work, a type of selenide-containing polyesters with controllable structure, molecular weight, and molecular weight distribution was successfully prepared by ROCOP of γ-selenobutyrolactone and epoxy compounds. The influence of the catalyst, solvent, and reaction temperature on the reaction efficiency was examined. Then, kinetic study was investigated under an optimized condition. The structure of the copolymers was carefully characterized by nuclear magnetic resonance (NMR), 1H NMR, 13C NMR, and 77Se NMR, Matrix-assisted laser-desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and size exclusion chromatography (SEC). The resulting polymers showed a linear structure with a sequence regulated backbone repeating unit of ester-selenide. On this basis, some typical epoxides were investigated to verify the scope of the polymerization system. Due to the “living”/controlled characteristics of this ROCOP, multiblock, amphiphilic, and stereotactic copolymers could be prepared with a pre-designed structure. As expected, the selenide-containing amphiphilic copolymer could self-assemble to micelles and showed an oxidative response.

Combined Main- and Side-Chain Azobenzene Polyesters: A Potential For Photoinduced Nonlinear Waveguides

1999 ◽  
Vol 561 ◽  
Author(s):  
F. Sahlén ◽  
T. Geisler ◽  
S. Hvilsted ◽  
N. C. R. Holme ◽  
P. S. Ramanujam ◽  
...  
Keyword(s):  
Refractive Index ◽  
Third Harmonic Generation ◽  
Size Exclusion ◽  
Side Chain ◽  
Visible Spectroscopy ◽  
Scanning Calorimetry ◽  
Nonlinear Waveguides ◽  
Third Harmonic ◽  
Exclusion Chromatography ◽  
Uv Visible

ABSTRACTNew combined main- and side-chain azobenzene polyesters, which exhibit an intensity dependent refractive index, have been prepared in order to optically fabricate nonlinear waveguides. Novel sulfone azobenzenes, a diester, (4-[[5-(ethoxycarbonyl)pentyl]sulfonyl]-4'-[[5-(ethoxycarbonyl)pentyl]methylamino] azobenzene, and a diol, 4-[[(8-hydroxy-7-methylhydroxy)-octyl]sulfonyl]-4'-N, N-dimethylamino azobenzene, have been used to prepare new polyesters by transesterification in the molten state. The polyesters have been characterized by UV-visible spectroscopy, differential scanning calorimetry (DSC), size exclusion chromatography (SEC), third harmonic generation (THG) and optical anisotropy measurements. The molar masses of the polyesters were in the range of 5000-10000 g mol−1, which was sufficient in order to spin coat thin films. From THG measurements the polymers are shown to possess an offresonance electronic X(3) of the order 10−12 esu corresponding to a nonlinear refractive index of 2.3×10−14 cm2/W.

scholarly journals Synthesis and characterization of poly(1-methyltrimethylene carbonate) (PMTMC) by mean ring-opening polymerization

2020 ◽  
Vol 5 (3) ◽  
pp. 21
Author(s):  
Jesús Miguel Contreras Ramírez ◽  
Meribary Monsalve
Keyword(s):  
Ring Opening ◽  
Molar Mass ◽  
Thermal Polymerization ◽  
Ring Opening Polymerization ◽  
Active Species ◽  
Size Exclusion ◽  
Polymerization Process ◽  
Molar Ratio ◽  
Molecular Characteristics ◽  
Ft Ir

  In this work, the activity of samarium (III) acetate (Sm(OAc)3) was evaluated as a possible initiator in the ring opening polymerization (ROP) of 1-methyltrimethylene carbonate (MTMC). The effects of temperature (Tr) and monomer-initiator molar ratio (M/I) on the molecular characteristics (conversion, dispersity, and molar mass) of the polymers obtained were analyzed. The reaction temperature was varied between 90 and 160 °C and the molar ratio M/I between 200 and 1000. The molar mass of the products was obtained by size exclusion chromatography (SEC), while its structure was analyzed using FT-IR and 1H-NMR spectroscopy. Thermal polymerization experiments (in the absence of an initiator) were performed in order to evaluate the effectiveness of the initiator. The comparison between the thermal polymerization of MTMC and its polymerization in the presence of Sm(OAc)3, suggests that acetate has very low catalytic activity as the initiator of the ROP of PMTMC. The molar masses of the polymers obtained ranged between 6000 and 10000 Dalton, and the monomer to polymer conversions varied between 9 and 30 %. SEC chromatograms showed monomodal and symmetric curves, suggesting that only one type of active species participates in the polymerization process. Based on the structural analysis, a polymerization mechanism was proposed in which the water possibly acts as the only active species that initiates the reaction.   Palabra clave: Samarium (III) acetate, ring-opening polymerization, 1-methyltrimethylenecarbonate, poly(1-methyltrimethylenecarbonate).   Abstract En este trabajo se evaluó la actividad del acetato de samario (III) (Sm(OAc)3) como posible iniciador en la polimerización de apertura de anillo (PAA) del carbonato de 1-metiltrimetileno (MTMC). Se analizaron los efectos de la temperatura (Tr) y relación molar monómero-iniciador (M/I) sobre las características moleculares (conversión, dispersidad y masa molar) de los polímeros obtenidos. La temperatura de reacción se varió entre 90 y 160 °C y la relación molar M/I entre 200 y 1000. La masa molar de los productos se obtuvo mediante cromatografía de exclusión por tamaño, mientras que su estructura fue analizada mediante espectroscopia FT-IR y 1H-RMN. Además, se realizaron algunos experimentos de polimerización térmica (en ausencia de iniciador) que sirvieron de referencia para evaluar la efectividad del iniciador. La comparación de los resultados obtenidos en la polimerización térmica y en presencia del Sm(OAc)3 indicó que este último presenta muy poca actividad catalítica como iniciador de la PAA de PMTMC. Las masas molares de los polímeros obtenidos oscilaron entre 6000 y 10000 Dalton, mientras que las conversiones de monómero a polímero variaron entre 9 y 30%. Los cromatogramas SEC mostraron curvas mono-modales y simétricas, indicando que en el proceso de polimerización participa un solo tipo de especie activa. En base al análisis estructural, mediante técnicas espectroscópicas, se propuso un mecanismo de reacción para la polimerización en la que el agua posiblemente actúa como la única especie activa iniciadora de la reacción.   Keywords: Acetato de samario (III), polimerización por apertura de anillo, 1-metiltrimetilencarbonato, poli(1-metiltrimetilencarbonato).  

scholarly journals Towards Novel Fluorinated Methacrylic Coatings for Cultural Heritage: A Combined Polymers and Surfaces Chemistry Study

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1190 ◽  
Author(s):  
Valentina Sabatini ◽  
Eleonora Pargoletti ◽  
Valeria Comite ◽  
Marco Aldo Ortenzi ◽  
Paola Fermo ◽  
...  
Keyword(s):  
Prolonged Exposure ◽  
Accelerated Aging ◽  
Water Repellency ◽  
Size Exclusion ◽  
Butyl Methacrylate ◽  
Capillary Absorption ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Coated Materials ◽  
Exclusion Chromatography

In this work, new co- and ter-polymers of methyl methacrylate (MMA), ethyl methacrylate (EMA), and N-butyl methacrylate (nBuMA), containing just 1% mol × mol−1 of a fluorinated co-monomer, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-octyl methacrylate (POMA), were synthesized. After an UV accelerated aging test, the photo-chemical stability of the polymers prepared was determined by 1H NMR and FT-IR spectroscopy, size exclusion chromatography, differential scanning calorimetry and wettability measurements. The polymers were applied to Botticino tiles to achieve better performances in terms of water repellency and consequently deterioration resistance. One-year prolonged exposure to a real environment was conducted and the properties of the coated materials and their performances were studied using different surface techniques such as water contact angle (WCA) and colorimetric measurements (CIELaB), capillary absorption, permeability (RVP) tests and soluble salts determination. The effectiveness of the fluorinated methacrylic coatings was clearly demonstrated; among all the resins, the co-polymer MMA_POMA seems to be the most performing one. Furthermore, both the UV photo-chemical resistance and the easiness of removal was successfully studied.

Monitoring the chemical heterogeneity of metallocenecatalysed copolymers of ethylene and higher 1-olefins using CRYSTAF and SEC-FTIR

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Sven M. Graef ◽  
Robert Brüll ◽  
Harald Pasch ◽  
Udo M. Wahner
Keyword(s):  
Differential Scanning Calorimetry ◽  
Size Exclusion Chromatography ◽  
Catalyst System ◽  
Size Exclusion ◽  
Side Chain ◽  
Chemical Heterogeneity ◽  
Scanning Calorimetry ◽  
Crystallisation Temperature ◽  
Exclusion Chromatography

Abstract Copolymers of ethylene with 1-decene, 1-tetradecene and 1-octadecene were prepared using the catalyst system racEt[Ind]2ZrCl2/MAO and were analysed with regard to chemical heterogeneity using crystallisation analysis fractionation (CRYSTAF), differential scanning calorimetry (DSC) and size exclusion chromatography coupled to FTIR (SEC-FTIR). The melting and crystallisation temperatures from DSC decrease linearly with increasing amount of comonomer, independently of the nature thereof. The decrease in crystallisation temperature from CRYSTAF of copolymers with higher 1-olefin content indicates a small dependence on the length of the side chain. The chemical heterogeneity of the copolymers as analysed by DSC and CRYSTAF broadens with increasing comonomer concentration.

INTRODUCTION OF A DOUBLE BOND CONTAINING MODIFIER ON THE SURFACE OF MCM-41 NANOPARTICLES: APPLICATION FOR SR&NI ATRP OF STYRENE

NANO ◽  
2014 ◽  
Vol 09 (02) ◽  
pp. 1450023 ◽  
Author(s):  
KHEZROLLAH KHEZRI ◽  
VAHID HADDADI-ASL ◽  
HOSSEIN ROGHANI-MAMAQANI
Keyword(s):  
Molecular Weight ◽  
Double Bond ◽  
Mesoporous Silica Nanoparticles ◽  
Nitrogen Adsorption ◽  
Size Exclusion ◽  
Proton Nuclear Magnetic Resonance ◽  
Scanning Calorimetry ◽  
Morphological Studies ◽  
Exclusion Chromatography ◽  
Mcm 41

Mesoporous silica nanoparticles (MCM-41) surface was functionalized with 3-(trimethoxysilyl)propyl methacrylate (MPS). Then, the resultant double bond containing nanoparticles were used in grafting through simultaneous reverse and normal initiation technique for atom transfer radical polymerization (SR&NI ATRP) of styrene to synthesize well-defined polystyrene nanocomposites with twofold chains. Nitrogen adsorption/desorption isotherm and X-ray diffraction analysis were used to evaluate characteristics of spherical MCM-41 nanoparticles. Morphological studies were also performed by scanning and transmission electron microscopy. Conversion and molecular weight determinations were carried out using gas and size exclusion chromatography respectively. Addition of MCM-41 nanoparticles by 3 wt.% results in a decrease of conversion from 93% to 82%. Molecular weight of the free and attached polystyrene chains decreases by adding 3 wt.% MCM-41 nanoparticles; however, PDI values increases from 1.27 to 1.78 for free chains and 1.87 to 2.48 for attached chains. A peak around 4.1 ppm which originates from hydrogen atom of terminal units of polystyrene chains in proton nuclear magnetic resonance spectra in combination with low PDI values can appropriately demonstrate the living nature of the polymerization. Increasing thermal stability of the nanocomposites is demonstrated by Thermogravimetric analysis. Differential scanning calorimetry also shows a decrease in glass transition temperature by increasing MCM-41 nanoparticles.

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