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 ◽  
...  

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.

2020 ◽  
Vol 15 (2) ◽  
pp. 290-303
Author(s):  
Nadia Embarek ◽  
Nabahat Sahli

The present work focuses on the preparation and characterization of poly(3-Glycidoxypropyltrimethoxysilane) (PGPTMS) under mild conditions. Ring-opening polymerization of the 3-Glycidoxypropyltrimethoxysilane (GPTMS) is initiated with the bentonite of Maghnite-H+ (Mag-H+), an ecologic and low-cost catalyst. The evolution of epoxy ring-opening was studied in bulk and in solution using CH2Cl2 as solvent, as well as the influences of several factors such as the amount of Mag-H+, polymerization time and temperature on the yield of polymer were investigated. The best polymer yield (30 %) was obtained in bulk polymerization at room temperature (20 °C) for a reaction time 8 h, and it’s increases with time and reaches 68 % for 7 days. The structures of the obtained polymers (PGPTMS) were confirmed respectively by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR). The thermal properties of the prepared polymers were given by Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA), the Tg of PGPTMS is recorded at -31.27 °C, and it is thermally stable with a degradation start temperature greater than 300 °C, all  decomposition stopped at 600 °C. Copyright © 2020 BCREC Group. All rights reserved


Author(s):  
Abbas Hassan Faris

In this work, appropriate alternative for diglycidyl ether bisphenol A (DGEBA) was found to avoid the destructive effects of bisphenol A. Lignin, an aromatic compound from palm tree leaves, was used as a renewable material to synthesize a bio-based epoxy resin. Lignin extracted using Kraft pulping process. Kraft Lignin was epoxidized with epichlorohydrin in alkaline medium. Nano-titanium dioxide was used as filler with ratio of 10% to prepare the green epoxy composite. The structure of the Kraft lignin and lignin-based epoxy resin was proven via Infrared spectra (FT-IR) were recorded using solid KBr disk by testing Shimadzu (FT-IR-8300) spectrophotometer. The thermal properties of the curing process of lignin-based epoxy resin and composite were investigate using Differential scanning calorimetry (DSC) analysis. Potentiodynamic measurements data revealed that the anti-corrosion performance of the lignin based epoxy resin. The study demonstrates successful of epoxidation of Kraft lignin. In addition, lignin based eopxy resin showed effective inhibitor for carbon steel in 3.5 wt. % NaCl electrolyte solutions


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Jing Zhang ◽  
Ji Jun Tang ◽  
Jiao Xia Zhang

Several biorenewable vegetable oil-based polyols with different molecular weights and various hydroxyl functionalities were successfully prepared by ring-opening epoxidized soybean oil with a castor oil-based fatty diol. It was found that several factors, including reaction time, reaction temperature, and molar ratios between epoxidized soybean oil and castor oil diol, affect structures and rheology behaviors of the final polyols. Proton NMR, FT-IR, GPC, and rheometry results revealed that the hydroxyl functionalities, molecular weight, and viscosity of the polyols could be tailored by controlling the above-mentioned factors. Besides, the role of solvents in the epoxy ring-opening process was investigated as well.


Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5184
Author(s):  
Mariusz Tryznowski ◽  
Zuzanna Żołek-Tryznowska

Poly(hydroxyurethane)s (PHU) are alternatives for conventional polyurethanes due to the use of bis-cyclic dicarbonates and diamines instead of harmful and toxic isocyanates. However, the surface properties of poly(hydroxyurethane)s are not well known. In this work, we focus on the analysis of the surface properties of poly(hydroxyurethane) coatings. Poly(hydroxyurethane)s were obtained by a catalyst-free method from commercially available carbonated diglycidyl ether of bisphenol A (Epidian 6 epoxy resins) and various diamines: ethylenediamine, trimethylenediamine, putrescine, hexamethylenediamine, 2,2,4(2,4,4)-trimethyl-1,6-hexanediamine, m-xylylenediamine, 1,8-diamino-3,6-dioxaoctane, 4,7,10-trioxa-1,13-tridecanediamine, and isophorone diamine, using a non-isocyanate route. The structures of the obtained polymers were confirmed by FT-IR, 1H NMR and 13C NMR spectroscopy, and thermogravimetric (TGA) and differential scanning calorimetry (DSC) analyses were performed. The rheological characteristic of the obtained polymers is presented. The static contact angles of water, diidomethane, and formamide, deposited on PHU coatings, were measured. From the measured contact angles, the surface free energy was calculated using two different approaches: Owens–Wendt and van Oss–Chaudhury–Good. Moreover, the wetting envelopes of PHU coatings were plotted, which enables the prediction of the wetting effect of various solvents. The results show that in the investigated coatings, a mainly dispersive interaction occurs.


Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1184 ◽  
Author(s):  
Sandra Castillejos ◽  
Jorge Cerna ◽  
Francisco Meléndez ◽  
María Castro ◽  
Rocío Aguilar ◽  
...  

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.


2011 ◽  
Vol 236-238 ◽  
pp. 1692-1696
Author(s):  
Xiao Jing Zhang ◽  
Chao Jun Wang ◽  
Jia Shu Sun ◽  
Xi Niu Han

A series of hybrid materials involving cage-like octaaminopropyl polyhedral oligomeric silsesquioxane and Polyvinyl alcohol(OAPS/PVA) were prepared via solution blending method. The hybrid systems were characterized by FT-IR, scanning electronic microscopy(SEM), energy dispersive X-ray(EDS), differential scanning calorimetry(DSC), thermogravimetry analysis(TGA) and tensile test. The results show that hydrogen bond interactions are formed between OAPS and PVA and OAPS has a good dispersion in PVA matrix. The glass transition temperature(Tg) of OAPS/PVA increases from 53°C to 61°C, while the melting temperature(Tm) decreases from 180°C to 173°C with increasing OAPS content from 0% to 12%. The thermal stability of PVA main chain is improved by the addition of OAPS and the residue ratio also increases. The tensile strength of OAPS/PVA decreases from 39MPa to 16MPa, while the elongation at break of hybrid films increases from 148% to 351%.


2009 ◽  
Vol 620-622 ◽  
pp. 595-598
Author(s):  
Yu Shun Jin ◽  
Fei Xiao ◽  
Wen Li Guo

Functional poly(L-lactide) (PLLA-OH) containing vinyl groups as well as hydroxyl end groups was synthesized by ring-opening polymerization (ROP), using stannous octanoate as the catalyst and 2-hydroxyethyl methacrylate (HEMA) as the initiator. The structure of the obtained PLLA-OH was characterized using both Fourier Transform Infrared (FT-IR) spectroscopy and 1H nuclear magnetic resonance (1H-NMR) spectroscopy, while their crystallinities and thermo behavior were studied by differential scanning calorimetry (DSC), separately. The best condition for the ROP of the studied PLLA-OH was found with the polymerization temperature of T= 145 °C, the weight percent of the catalyst of 0.03 wt%, the ROP duration of 48 h and the L-lactide/initiator molar ratio of 100/1.


2021 ◽  
Vol 2 (4) ◽  
pp. 244-250
Author(s):  
L Zhang ◽  
S Zhang ◽  
C Wang ◽  
J Hu ◽  
W Li ◽  
...  

A hypoxanthine modified polyethylene glycol diglycidyl ether gel was prepared by the ring opening polymerization of polyethylene glycol diglycidyl ether with hypoxanthine in a simple sol-gel method. The structure and composition were characterized by SEM, FT-IR, BET and XRD. The adsorption experiments of ciprofloxacin at different pH, temperature, contact time and initial concentration were studied. The results show that the gel is porous with the average pore size of 5.2 nm, the optimum adsorption pH is 5 and the saturated adsorption time is 240 minutes. The maximum equilibrium adsorption capacity of ciprofloxacin is 56.1 mg/g at 308 K according to the Langmuir model. The repeated adsorption experiments show that the gel could still adsorb 80% of the first adsorbed ciprofloxacin after 5 times of elution. These results indicate that the gel can be used as a practical adsorbent for ciprofloxacin in aqueous solution.


Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 240
Author(s):  
Iuliana Bejenari ◽  
Roxana Dinu ◽  
Sarah Montes ◽  
Irina Volf ◽  
Alice Mija

Thiswork is focused on the development of sustainable biocomposites based on epoxy bioresin reinforced with a natural porous material (hydrochar, HC) that is the product of spruce bark wastes subjected to hydrothermal decomposition. To identify the influence of hydrochar as a reinforcing material on the designed composites, seven formulations were prepared and tested. An aromatic epoxy monomer derived from wood biomass was used to generate the polymeric matrix, and the formulations were prepared varying the filler concentration from 0 to 30 wt %. The reactivity of these formulations, together with the structural, thermal, and mechanical properties of bio-based resin and biocomposites, are investigated. Surprisingly, the reactivity study performed by differential scanning calorimetry (DSC) revealed that HC has a strong impact on polymerization, leading to an important increase in reaction enthalpy and to a decrease of temperature range. The Fourier Transform Infrared Spectroscopy (FT-IR) investigations confirmed the chemical bonding between the resin and the HC, while the dynamic mechanical analysis (DMA) showed increased values of crosslink density and of storage moduli in the biocomposites products compared to the neat bioresin. Thermogravimetric analysis (TGA) points out that the addition of hydrochar led to an improvement of the thermal stability of the biocomposites compared with the neat resorcinol diglycidyl ether (RDGE)-based resin (T5% = 337 °C) by ≈2–7 °C. Significantly, the biocomposites with 15–20 wt % hydrochar showed a higher stiffness value compared to neat epoxy resin, 92SD vs. 82SD, respectively.


2017 ◽  
Vol 68 (8) ◽  
pp. 1895-1902
Author(s):  
Ioana Cristina Tita ◽  
Eleonora Marian ◽  
Bogdan Tita ◽  
Claudia Crina Toma ◽  
Laura Vicas

Thermal analysis is one of the most frequently used instrumental techniques in the pharmaceutical research, for the thermal characterization of different materials from solids to semi-solids, which are of pharmaceutical relevance. In this paper, simultaneous thermogravimetry/derivative thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC) were used for characterization of the thermal behaviour of candesartan cilexetil � active substance (C-AS) under dynamic nitrogen atmosphere and nonisothermal conditions, in comparison with pharmaceutical product containing the corresponding active substance. It was observed that the commercial samples showed a different thermal profile than the standard sample, caused by the presence of excipients in the pharmaceutical product and to possible interaction of these with the active substance. The Fourier transformed infrared spectroscopy (FT-IR) and X-ray powder diffraction (XRPD) were used as complementary techniques adequately implement and assist in interpretation of the thermal results. The main conclusion of this comparative study was that the TG/DTG and DSC curves, together with the FT-IR spectra, respectively X-ray difractograms constitute believe data for the discrimination between the pure substance and pharmaceutical forms.


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