scholarly journals Bulk Modification of Poly(lactide) (PLA) via Copolymerization with Poly(propylene glycol) Diglycidylether (PPGDGE)

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1184 ◽  
Author(s):  
Sandra Castillejos ◽  
Jorge Cerna ◽  
Francisco Meléndez ◽  
María Castro ◽  
Rocío Aguilar ◽  
...  
Keyword(s):  
Propylene Glycol ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Diglycidyl Ether ◽  
Scanning Calorimetry ◽  
Monomer Ratio ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Poly Propylene ◽  
Made In

Copolymers of l-lactide and poly(propylene glycol) diglycidyl ether (PPGDGE380) were synthesized by ring opening polymerization (ROP). Stannous octoate was used as the catalyst and 1-dodecanol as the initiator. The effect of the variables on the thermal properties of the copolymers was investigated by differential scanning calorimetry (DSC). Contact angle measurements were made in order to study the wettability of the synthesized copolymers. The copolymers differed widely in their physical characteristics, ranging from weak elastomers to tougher thermoplastics, according to the ratio of l-lactide and PPGDGE380. The results showed that the copolymers were more hydrophilic than neat Poly(lactide) (PLA) and the monomer ratio had a strong influence on the hydrophilic properties.

Synthesis, characterization, and structures of zircona- and boracyclosiloxanes with ferrocenyl substituents

2002 ◽  
Vol 80 (11) ◽  
pp. 1469-1480 ◽  
Author(s):  
Karena Thieme ◽  
Sara C Bourke ◽  
Juan Zheng ◽  
Mark J MacLachlan ◽  
Fojan Zamanian ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
The Novel ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Multinuclear Nmr Spectroscopy

The novel zirconatetraferrocenylcyclotrisiloxane Cp2Zr(OSiFc2)2O (6), dizirconatetraferrocenylcyclotetrasiloxane [Cp2Zr(OSiFc2)O]2 (7), boratetraferrocenylcyclotrisiloxane (C6H5)B(OSiFc2)2O (8), and diboratetraferrocenylcyclotetrasiloxane [(C6H5)B(OSiFc2)O]2 (9) with ferrocenyl (Fc = Fe(η-C5H4)(η-C5H5)) substituents at silicon have been prepared from the reactions of Cp2Zr(NMe2)2 and PhBCl2 with diferrocenylsilanediol Fc2Si(OH)2 (3) and tetraferrocenyldisiloxanediol [Fc2SiOH]2O (5). The compounds were characterized by mass spectrometry, elemental analysis, UV–vis, IR, Raman, and multinuclear NMR spectroscopy, as well as single crystal X-ray diffraction. Thermogravimetric analysis and differential scanning calorimetry investigation of 6–9 showed that the cycles decompose before they can undergo any thermal ring-opening polymerization. In addition, no polymerization was detected in the presence of either KOSiMe3 or HOTf. The bulky ferrocenyl substituents on the Si atoms are likely to be at least partially responsible for the inability of these heterocycles to undergo ring-opening polymerization. Key words: heterocyclosiloxanes, ferrocenyl.

Preparation and Characterization of Multiwalled Carbon Nanotubes-Reinforced pCBT by Ring-Opening Polymerization of Cyclic Butylene Terephthalate

2016 ◽  
Vol 848 ◽  
pp. 125-131
Author(s):  
Yin He Su ◽  
Jun Rong Yu
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Scanning Calorimetry ◽  
Multiwalled Carbon ◽  
Butylene Terephthalate ◽  
Cyclic Butylene Terephthalate ◽  
The Matrix ◽  
Higher Temperature

Multiwalled carbon nanotubes (MWCNT)-reinforced polymerized cyclic butylene terephthalate (pCBT) nanocomposites were prepared by in situ ring opening polymerization of cyclic butylene terephthalate oligomers (CBT). The results of differential scanning calorimetry (DSC) indicated that the melting peak located at the low temperature (Tm1) increased and that at higher temperature (Tm2) decreased with the increasing of content of the MWCNT. During the cooling the MWCNT served as nucleation points from where crystallization can start. The more the MWCNT in the system the earlier the crystallization starts. The Morphological investigations performed by scanning electron microscopy (SEM) shown that the MWCNT were embedded in the matrix and held tightly by the matrix. The modulus and strength increased with MWCNT concentration in the nanocomposites, however, the elongation at break, absorbed energy at break and impact strength were decreased with the increasing of MWCNT content.

scholarly journals Tailored Crosslinking Process and Protective Efficiency of Epoxy Coatings Containing Glycidyl-POSS

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 591 ◽  
Author(s):  
Mirjana Rodošek ◽  
Mohor Mihelčič ◽  
Marija Čolović ◽  
Ervin Šest ◽  
Matic Šobak ◽  
...  
Keyword(s):  
Ring Opening ◽  
Protective Coatings ◽  
Diglycidyl Ether ◽  
Scanning Calorimetry ◽  
Protective Efficiency ◽  
Crosslinking Process ◽  
Operational Temperature ◽  
Epoxy Ring Opening ◽  
Ft Ir ◽  
Oligomeric Silsesquioxane

Versatile product protective coatings that deliver faster drying times and shorter minimum overcoat intervals that enable curing at faster line speeds and though lower energy consumption are often desired by coating manufacturers. Product protective coatings, based on silsesquioxane-modified diglycidyl ether of bisphenol-A (DGEBA) epoxy resin, are prepared through a glycidyl ring-opening polymerization using dicyandiamide (DICY) as a curing agent. As silsesquioxane modifier serves the octaglycidyl-polyhedral oligomeric silsesquioxane (GlyPOSS). To decrease the operational temperature of the curing processes, three different accelerators for crosslinking are tested, i.e., N,N-benzyl dimethylamine, 2-methylimidazole, and commercial Curezol 2MZ-A. Differential scanning calorimetry, temperature-dependent FT-IR spectroscopy, and rheology allow differentiation among accelerators’ effectiveness according to their structure. The former only contributed to epoxy ring-opening, while the latter two, besides participate in crosslinking. The surface roughness of the protective coatings on aluminum alloy substrate decreases when the accelerators are applied. The scanning electron microscopy (SEM) confirms that coatings with accelerators are more homogeneous. The protective efficiency is tested with a potentiodynamic polarization technique in 0.5 M NaCl electrolyte. All coatings containing GlyPOSS, either without or with accelerators, reveal superior protective efficiency compared to neat DGEBA/DICY coating.

scholarly journals 1-n-Butyl-3-methylimidazolium-2-carboxylate: a versatile precatalyst for the ring-opening polymerization of ε-caprolactone and rac-lactide under solvent-free conditions

2013 ◽  
Vol 9 ◽  
pp. 647-654 ◽  
Author(s):  
Astrid Hoppe ◽  
Faten Sadaka ◽  
Claire-Hélène Brachais ◽  
Gilles Boni ◽  
Jean-Pierre Couvercelle ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Ring Opening ◽  
Gel Permeation Chromatography ◽  
Ring Opening Polymerization ◽  
Solvent Free ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Solvent Free Conditions ◽  
Gel Permeation

The ring-opening polymerization of ε-caprolactone (ε-CL) and rac-lactide (rac-LA) under solvent-free conditions and using 1-n-butyl-3-methylimidazolium-2-carboxylate (BMIM-2-CO2) as precatalyst is described. Linear and star-branched polyesters were synthesized by successive use of benzyl alcohol, ethylene glycol, glycerol and pentaerythritol as initiator alcohols, and the products were fully characterized by 1H and 13C{1H} NMR spectroscopy, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). BMIM-2-CO2 acts as an N-heterocyclic carbene precursor, resulting from in situ decarboxylation, either by heating under vacuo (method A) or by addition of NaBPh4 (method B). Possible catalytic and deactivation mechanisms are proposed.

Analysis of the Mechanical Properties of Solvent Cast Blends of PLA/PCL

2014 ◽  
Vol 679 ◽  
pp. 50-56 ◽  
Author(s):  
Yuan Yuan Chen ◽  
Luke M. Geever ◽  
Clement L. Higginbotham ◽  
Declan M. Devine
Keyword(s):  
Mechanical Properties ◽  
Contact Angle ◽  
Tensile Test ◽  
Ductile Material ◽  
Infrared Spectrometry ◽  
Significant Shift ◽  
Scanning Calorimetry ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Mass Fractions

Polylactic acid (PLA) is the most promising material in the biodegradable category. However, brittleness and poor thermal stability restrict its application. To overcome this limitation, PLA may be blended with other biodegradable materials to tailor its properties while maintain biodegradability. In this study a series of blends of PLA and poly (ε-caprolactone) (PCL) with various mass fractions were prepared by solution method and solvent casting. Films of each blend were formed when the solvent evaporated. Subsequently, tensile test samples were punched out of the film for testing and tensile testing, Fourier transform infrared spectrometry (FTIR), Differential scanning Calorimetry (DSC) and contact angle measurements were carried out. Since PCL is a ductile material, the two materials were blended together in an effort to improve the mechanical properties. However, on thermal analysis of the blends, two individual melting peaks were observed in the DSC thermograms. Furthermore, no significant shift in peaks was observed on the FTIR spectra, and clear droplets and boundaries between two components of the blend can be observed in morphology study, all indicated the immiscibility of PLA and PCL. Tensile test showed poor mechanical properties due to the poor adhesion of the two immiscible components of the blend, and the addition of PCL did not influence the wettability of the surface of the blends as there were no significant differences in contact angle measurements.

CARBON NANOTUBE-GRAFT-BLOCK COPOLYMERS CONTAINING SILVER NANOPARTICLES

2009 ◽  
Vol 08 (06) ◽  
pp. 533-541 ◽  
Author(s):  
MOHSEN ADELI ◽  
REZA SEPAHVAND ◽  
ALI BAHARI ◽  
BANDAR ASTINCHAP
Keyword(s):  
Carbon Nanotubes ◽  
Silver Nanoparticles ◽  
Carbon Nanotube ◽  
Block Copolymers ◽  
Functional Groups ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Multi Wall Carbon Nanotubes ◽  
Grafted Copolymer ◽  
Monomer Ratio

Polycaprolactone-polylactide block copolymers (PCL-block-PLA) were grafted onto filled multi-wall carbon nanotubes (MWCNT) successfully. In this synthesis, MWCNTs were opened and functionalized, and then they were filled by silver nanoparticles. The filled MWCNT were used as macroinitiator for ring opening polymerization of ε-caprolactone and L-lactide. Then the end hydroxyl functional groups of MWCNT-graft-PCL or MWCNT-graft-PLA were used as initiator for ring opening polymerization of lactide and ε-caprolactone and MWCNT-graft-PCL-block-PLA or MWCNT-graft-PLA-block-PCL were obtained, respectively. Length of grafted copolymer chains onto the MWCNT was controlled using CNT/monomer ratio. Nanocomposites' properties depend on the length of polymer blocks strongly. Structure of nanocomposites was evaluated by TEM and spectroscopy methods.

SYNTHESIS OF POLY[(ε-CL)-co-(GA-alt-L-Asp)] COPOLYMER AND EFFECTS ON CELLS AFTER COUPLING WITH SMALL PEPTIDE

2015 ◽  
Vol 27 (06) ◽  
pp. 1550053
Author(s):  
Na Qiang ◽  
Fang Xie ◽  
Hao Liang ◽  
Xian-Feng Li ◽  
Shuo Tang ◽  
...  
Keyword(s):  
Ring Opening ◽  
Gel Permeation Chromatography ◽  
Ring Opening Polymerization ◽  
Carboxyl Groups ◽  
Structure And Properties ◽  
Small Peptide ◽  
Scanning Calorimetry ◽  
Beneficial Effects ◽  
Structural Regularity ◽  
Gel Permeation

A novel poly[([Formula: see text]-CL)-co-(GA-alt-L-Asp)] with improved hydrophilicity was prepared. The monomer 3(S)-[(benzyloxycarbony)methyl]-1,4-dioxane-2,5-dione (BMD) was prepared from aspartic acid. The polymer was obtained by ring-opening polymerization of [Formula: see text]-caprolactone ([Formula: see text]-CL) and BMD. Poly[([Formula: see text]-CL)-co-(GA-alt-L-Asp)] was synthesized by deprotection. The structure and properties of the polymer were characterized using 1H nuclear magnetic resonance, gel permeation chromatography, and differential scanning calorimetry. The melting point and melting enthalpy of the polymer decreased with the increase of BMD. The structural regularity of polycaprolactone was destroyed by the BMD. A laminin-derived peptide [i.e., Arg-Gly-Asp (RGD)] was covalently tethered to the carboxyl groups and the peptide-grafted films. Results indicated that the addition of RGD had beneficial effects for cell growth, as shown by scanning electron microscopy.

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