Studies of vinyl ester resins and their urethanized derivatives

1993 ◽  
Vol 5 (3) ◽  
pp. 207-212 ◽  
Author(s):  
R R Pachha ◽  
J R Thakkar ◽  
R D Patel
Keyword(s):  
Vinyl Ester ◽  
Epoxy Resins ◽  
Average Molecular Weight ◽  
Diglycidyl Ether ◽  
Curing Temperature ◽  
Scanning Calorimetry ◽  
First Order ◽  
First Order Kinetics ◽  
Amino Phenol ◽  
Vinyl Ester Resins

The epoxy resins diglycidyl ether of bisphenol A and triglycidyl p-amino phenol were reacted with acrylic acid to afford the corresponding acrylated resins. These vinyl ester resins were then reacted with toluene di-isocyanate to procure their urethanized derivatives. All these resins were characterized by their viscosity, number average molecular weight and infrared spectrophotometry. Curingconditions for these resins were established by differential scanning calorimetry. The results indicated that the curing reaction follows first-order kinetics, with activation energy in the range 53-84 kJ mol-. Styrene monomer was observed to lower the curing temperature of all resin systems when incorporated prior to curing.

Curing Behavior of Siloxane-Containing Epoxy

2011 ◽  
Vol 233-235 ◽  
pp. 23-26 ◽  
Author(s):  
Wen Bing Sun ◽  
Ou Sheng Zhang
Keyword(s):  
Diglycidyl Ether ◽  
Curing Temperature ◽  
Order Kinetic ◽  
Scanning Calorimetry ◽  
Exponential Factor ◽  
Kinetic Reaction ◽  
First Order ◽  
Dynamic Methods ◽  
Bisphenol A Diglycidyl Ether ◽  
Lower Activation

The curing processes of a novelly synthesized siloxane-containing epoxy resin (SE) and bisphenol A diglycidyl ether (CYD-128) were investigated using dynamic differential scanning calorimetry (DSC), and analyzed by three different methods. The results show that while SE has a lower initial curing temperature and a smaller pre-exponential factor than CYD-128, their curing processes belong to first order kinetic reaction. All the three dynamic methods verified mutually reveal that SE with more catalytic hydroxyls possesses lower activation energy and exhibits a stronger curing reactivity than CYD-128.

scholarly journals New Biosourced Flame Retardant Agents Based on Gallic and Ellagic Acids for Epoxy Resins

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4305 ◽  
Author(s):  
Valeriia Karaseva ◽  
Anne Bergeret ◽  
Clément Lacoste ◽  
Hélène Fulcrand ◽  
Laurent Ferry
Keyword(s):  
Phenolic Compounds ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Flame Retardants ◽  
Fire Behavior ◽  
Diglycidyl Ether ◽  
Scanning Calorimetry ◽  
Burning Behavior ◽  
Borate Ester ◽  
Thermal Stability Of

The aim of this work was an investigation of the ability of gallic (GA) and ellagic (EA) acids, which are phenolic compounds encountered in various plants, to act as flame retardants (FRs) for epoxy resins. In order to improve their fireproofing properties, GA and EA were treated with boric acid (to obtain gallic acid derivatives (GAD) and ellagic acid derivatives (EAD)) to introduce borate ester moieties. Thermogravimetric analysis (TGA) highlighted the good charring ability of GA and EA, which was enhanced by boration. The grafting of borate groups was also shown to increase the thermal stability of GA and EA that goes up respectively from 269 to 528 °C and from 496 to 628 °C. The phenolic-based components were then incorporated into an epoxy resin formulated from diglycidyl ether of bisphenol A (DGEBA) and isophorone diamine (IPDA) (72, 18, and 10 wt.% of DGEBA, IPDA, and GA or EA, respectively). According to differential scanning calorimetry (DSC), the glass transition temperature (Tg) of the thermosets was decreased. Its values ranged from 137 up to 108 °C after adding the phenolic-based components. A cone calorimeter was used to evaluate the burning behavior of the formulated thermosets. A significant reduction of the peak of heat release rate (pHRR) for combustion was detected. Indeed, with 10 wt.% of GA and EA, pHRR was reduced by 12 and 44%, respectively, compared to that for neat epoxy resin. GAD and EAD also induced the decrease of pHRR values by 65 and 33%, respectively. In addition, a barrier effect was observed for the resin containing GAD. These results show the important influence of the biobased phenolic compounds and their boron derivatives on the fire behavior of a partially biobased epoxy resin.

Novel Bismaleimide–Epoxy Resin System: II

1996 ◽  
Vol 8 (2) ◽  
pp. 233-242
Author(s):  
Hasmukh S Patel ◽  
Sanket N Shah
Keyword(s):  
Epoxy Resin ◽  
Average Molecular Weight ◽  
Conductometric Titration ◽  
Diglycidyl Ether ◽  
Spectral Studies ◽  
Reinforced Composites ◽  
Resin System ◽  
Number Average Molecular Weight ◽  
Scanning Calorimetry ◽  
Epoxy Resin System

Novel diamines, namely N, N′-bis[1-(2-methyl-4-aminophenyl)ethanonyl]-1,4- benzenediamine (BMAED 1) and N, N′-bis[1-(4-methyl-3-animophenyl)ethanonyl]-1,4-benzenediamine (BMAED 2), have been prepared and reacted with various bismaleimides (BM) at a BM:diamine ratio of 1:2. The resulting oligoimides have been characterized by elemental analysis, IR spectral studies and the number average molecular weight ( Mn) estimated by non-aqueous conductometric titration and thermogravimetry. Some of the oligomides have been modified by addition (i.e. curing reaction) of epoxy resin, namely the diglycidyl ether of bisphenol-A, and studied by differential scanning calorimetry (DSC). The glass- and carbon-reinforced composites have also been prepared and characterized by their mechanical properties.

ATRP of MMA initiated by 2-bromoisobutyric acid 4-(2- benzothiazole-2-yl-vinyl)-phenyl ester (BPBVE) and its fluorescent property in the presence of metal ions

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Pei-Yang Gu ◽  
Qing-Feng Xu ◽  
Jian-Feng Ge ◽  
Zhang Liang ◽  
Jian-Mei Lu ◽  
...  
Keyword(s):  
Average Molecular Weight ◽  
Monomer Conversion ◽  
Linear Increase ◽  
Number Average Molecular Weight ◽  
Phenyl Ester ◽  
Strong Emission ◽  
First Order ◽  
First Order Kinetics ◽  
Light Area ◽  
End Group

Abstract2-Bromoisobutyric acid 4-(2-benzothiazole-2-yl-vinyl)-phenyl ester (BPBVE) was used for the heterogeneous atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) with a copper(I)bromide/2,2’-bipyridine catalytic system. Factors such as the reaction temperature and mole ratio of catalyst to initiator, which could affect the ATRP system, were discussed in the paper. The functional end group was characterized via UV-vis and 1H NMR spectroscopy. The rates of polymerizations exhibited first-order kinetics with respect to the monomer, and a linear increase in the number-average molecular weight with increasing monomer conversion was observed for these initiation systems. The polydispersity indices (PDI) of the polymer were relatively low (1.07- 1.23) up to high conversions. This PMMA with BPBVE as end group shows strong emission at blue-light area whether in solution or in solid. In particularly, emission was decreased (or quenched) with appearance of metal cations (Zn2+, Co2+, Ni2+, Pb2+, Mn2+, Cu2+, Fe3+, Ag+) in DMF solution.

Poly(Amido-Imide)s Based on Amino-Terminated Oligoimides

1997 ◽  
Vol 9 (1) ◽  
pp. 33-39 ◽  
Author(s):  
Hasmukh S Patel ◽  
Nilesh P Patel
Keyword(s):  
Epoxy Resin ◽  
Addition Reaction ◽  
Average Molecular Weight ◽  
Conductometric Titration ◽  
Diglycidyl Ether ◽  
Spectral Studies ◽  
Michael Addition Reaction ◽  
Scanning Calorimetry ◽  
Epoxy Resin System ◽  
Cure Temperature

An amino-terminated oligoimide was prepared by Michael addition reaction of N, N′-1, 4-phenylene bismaleimide (PBM) and 4, 4′-diamino-diphenyl methane (DDM) at a PBM–DDM ratio of 1:2. The poly(amido-imide)s (PAIs) were prepared by condensation of this PBM–DDM oligoimide with various aliphatic bisesters. The resultant PAIs were characterized by elemental analysis, IR spectral studies, number-average molecular weight ( Mn), estimated by nonaqueous conductometric titration, and thermogravimetry. The curing reaction of the epoxy resin–, namely diglycidyl ether of bisphenol-A (DGEBA)–, PAI system was monitored by differential scanning calorimetry (DSC). Based on cure temperature, the glass- and carbon-fibrereinforced composites (i.e. laminates) of the PAI–epoxy resin system have also been prepared and characterized.

scholarly journals Evaluation of Novel Bio-Based Amino Curing Agent Systems for Epoxy Resins: Effect of Tryptophan and Guanine

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 42
Author(s):  
Stefano Merighi ◽  
Laura Mazzocchetti ◽  
Tiziana Benelli ◽  
Loris Giorgini
Keyword(s):  
Epoxy Resin ◽  
Reaction Temperature ◽  
Epoxy Resins ◽  
Diglycidyl Ether ◽  
Crosslinking Reaction ◽  
Curing Agent ◽  
Scanning Calorimetry ◽  
Agent Systems ◽  
New Class ◽  
System L

In order to obtain an environmentally friendly epoxy system, L-tryptophan and guanine were investigated as novel green curing agents for the cross-link of diglycidyl ether of Bisphenol A (DGEBA) as a generic epoxy resin model of synthetic and analogous bio-based precursors. In particular, L-tryptophan, which displays high reaction temperature with DGEBA, was used in combination with various bio-based molecules such as urea, theobromine, theophylline, and melamine in order to increase the thermal properties of the epoxy resin and to reduce the crosslinking reaction temperature. Later, in order to obtain similar properties using a single product, guanine, a totally heterocyclic molecule displaying amine functional groups, was tested as hardener for DGEBA. The thermal behavior of the precursor mixtures was evaluated by dynamic differential scanning calorimetry (DSC) leading to a preliminary screening of different hardening systems which offered a number of interesting hints in terms of bio-based compounds able to provide high Tg resins. These encouraging results pave the way for a further study of a new class of renewable, low-toxic, and sustainable curing agent systems for the production of fully bio-based epoxy resins.

scholarly journals Kinetic Analysis of the Curing of a Partially Biobased Epoxy Resin Using Dynamic Differential Scanning Calorimetry

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 391 ◽  
Author(s):  
Diego Lascano ◽  
Luis Quiles-Carrillo ◽  
Rafael Balart ◽  
Teodomiro Boronat ◽  
Nestor Montanes
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Epoxy Resins ◽  
Curing Kinetics ◽  
Reaction Model ◽  
Diglycidyl Ether ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Model Free

This research presents a cure kinetics study of an epoxy system consisting of a partially bio-sourced resin based on diglycidyl ether of bisphenol A (DGEBA) with amine hardener and a biobased reactive diluent from plants representing 31 wt %. The kinetic study has been carried out using differential scanning calorimetry (DSC) under non-isothermal conditions at different heating rates. Integral and derivative isoconversional methods or model free kinetics (MFK) have been applied to the experimental data in order to evaluate the apparent activation energy, Ea, followed by the application of the appropriate reaction model. The bio-sourced system showed activation energy that is independent of the extent of conversion, with Ea values between 57 and 62 kJ·mol−1, corresponding to typical activation energies of conventional epoxy resins. The reaction model was studied by comparing the calculated y(α) and z(α) functions with standard master plot curves. A two-parameter autocatalytic kinetic model of Šesták–Berggren [SB(m,n)] was assessed as the most suitable reaction model to describe the curing kinetics of the epoxy resins studied since it showed an excellent agreement with the experimental data.

Fracture Toughening of Epoxy Resins by Addition of a Novel Thermoplastic PPAEs

2012 ◽  
Vol 161 ◽  
pp. 153-156 ◽  
Author(s):  
Ya Juan Xu ◽  
Si Kai Zhou ◽  
Xi Gao Jian
Keyword(s):  
Fracture Toughness ◽  
Epoxy Resins ◽  
Diglycidyl Ether ◽  
Fracture Mechanisms ◽  
Moderate Increase ◽  
Aryl Ether ◽  
Scanning Calorimetry ◽  
Fracture Toughening ◽  
The Matrix ◽  
Unmodified Epoxy

A series of blends have been prepared by adding a novel thermoplastic Poly (aryl ether) s containing phthalazinone moiety (PPAEs) in varying proportions to diglycidyl ether of bisphenol A epoxy resin (DGEBA) cured with p-diaminodiphenylsulfone (DDS). The glass transition temperature (Tg) of DGEBA /PPAEs blends were performed using differential scanning calorimetry (DSC) technique. It is proved that the addition of PPAEs resulted in enhancement of thermal properties of the blends, especially PPENK. There was moderate increase in the fracture toughness as estimated by notched impact strength. Compared to that of unmodified epoxy, the maximum toughness of the modified blends had increased 44% by addition of 15 phr PPENK. Fracture mechanisms such as plastic deformation and the ductile nature of the crack of the matrix were responsible for the increase in the fracture toughness of the blends.

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