Interaction between Polyaramidic Electrospun Nanofibers and Epoxy Resin for Composite Materials Reinforcement

2017 ◽  
Vol 748 ◽  
pp. 39-44 ◽  
Author(s):  
Stefano Merighi ◽  
Emanuele Maccaferri ◽  
Juri Belcari ◽  
Andrea Zucchelli ◽  
Tiziana Benelli ◽  
...  
Keyword(s):  
Composite Materials ◽  
Epoxy Resin ◽  
Electrospun Nanofibers ◽  
Cross Linking ◽  
Curing Process ◽  
Electrospinning Technique ◽  
Epoxy Matrix Composite ◽  
The Cross ◽  
Kinetics Of ◽  
Composite Properties

Interaction between poly (m-phenylene isophtalamide) (PMIA) electrospun nanofibers and commercial epoxy resin precursor during the cross-linking process was investigated, in order to use such polyaramidic nanofibers for composite materials reinforcement. Hence nanofibrous PMIA mats were produced via electrospinning technique to be used for the functional modification of the epoxy matrix composite properties. When adding such fibers to an epoxy resin precursor, it was observed a strong influence on the kinetics of its curing process. The final results, however, demonstrates that boosting the reaction condition (raising the temperature and the reaction time) the curing is pushed to completion, indicating that the cross-linking process of the resin is just delayed and not completely hampered. It will be therefore necessary to rethink the composite cure cycle when PMIA nanofibers are added to the composite material, in order to attain significant improvement of the final composite performance.

Cure Monitoring of Epoxy Resin by Simultaneous DSC/FTIR

2014 ◽  
Vol 881-883 ◽  
pp. 905-908
Author(s):  
Li Wei Wang ◽  
Gerard F. Fernando
Keyword(s):  
Cross Linking ◽  
Resin System ◽  
Fibre Optic ◽  
Cure Monitoring ◽  
Epoxy Amine ◽  
Fibre Optic Probe ◽  
The Cross ◽  
Optic Probe ◽  
Conventional Dsc ◽  
Kinetics Of

The cross-linking kinetics of an epoxy/amine resin system was studied using the conventional DSC and FTIR spectroscopy, respectively. Conventional DSC was modified to accommodate two fibre optic probes which could be used to monitor the spectra of epoxy/amine resin system during cure. The cross-linking kinetics for the epoxy/amine resin system obtained via the conventional DSC and FTIR and simultaneous DSC/FTIR were similar. The feasibility of using a simple bifurcated fibre optic probe to link the DSC to the FTIR spectrometer was demonstrated.

Dilatometric Measurement of the Rate of Vulcanization of Crepe Rubber by Sulfur Monochloride

1952 ◽  
Vol 25 (1) ◽  
pp. 48-49
Author(s):  
J. Glazer
Keyword(s):  
Chemical Analysis ◽  
Cross Linking ◽  
Mustard Gas ◽  
Dilatometric Measurement ◽  
Sulfur Monochloride ◽  
Dilatometric Method ◽  
The Cross ◽  
Kinetics Of ◽  
Vulcanization Process

Abstract The cold vulcanization of rubber by sulfur monochloride is believed to consist essentially of the cross-linking of adjacent polyisoprene units by a series of sulfide bonds. Chemical analysis of the product suggests that the cross-linking process is analogous to the mustard gas reaction of ethylene with sulfur monochloride, thus: (see PDF for diagram) Nothing is known, however, about the kinetics of this vulcanization process. General considerations lead one to expect that such a reaction, involving polymer aggregation, should be accompanied by an increase in the density of the rubber; moreover, by choosing a suitably delicate technique, it should be possible to utilize such density changes for rate determinations. A dilatometric method seemed most suitable, and the experiments described here show that the vulcanization process is, indeed, accompanied by a decrease in volume of the reaction mixture, and that the reaction may be followed quantitatively using a tap dilatometer.

Cell adhesion and proliferation enhancement by gelatin nanofiber scaffolds

2011 ◽  
Vol 26 (6) ◽  
pp. 565-577 ◽  
Author(s):  
Shih-Ching Wu ◽  
Wei-Hong Chang ◽  
Guo-Chung Dong ◽  
Kuo-Yu Chen ◽  
Yueh-Sheng Chen ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Cost Effective ◽  
Average Diameter ◽  
Gelatin Film ◽  
Cross Linking ◽  
Electrospinning Technique ◽  
Cell Compatibility ◽  
The Cross ◽  
Electrospun Gelatin ◽  
Cell Adhesion And Proliferation

Gelatin nanofibers (GNs) prepared by electrospinning were cross-linked with glutaraldehyde vapor to improve their water-resistant ability. After cross-linking treatment, the form of the fibers expressed no substantial change, but the average diameter of the fibers increased with increasing cross-linking time. The swelling induced by the moisture during the cross-linking process was moderated when the cross-linking time reached 45 min. The contact angle measurements confirmed that the electrospun gelatin fibers were more hydrophilic than the gelatin film (GF). Increasing the cross-linking time did not alter the hydrophilic properties of the gelatin fibers. The cell compatibility was evaluated based on 3-(4,5-dimethylthiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay, scanning electron microscope and confocal microscope observations, and Western blot analysis by culturing MG-63 cells on the GFs and GNs. The nanofibrous structure fabricated by an electrospinning technique was found to enhance cell adhesion and proliferation. This process is a cost-effective simulation of GN structures’ promising applications on scaffold preparation for tissue engineering.

Thermoreversible cross-linking of ethylene/propylene copolymers based on Diels–Alder chemistry: the cross-linking reaction kinetics

2020 ◽  
Vol 11 (36) ◽  
pp. 5851-5860
Author(s):  
Shuhui Liu ◽  
Xiaoyan Liu ◽  
Zongke He ◽  
Liying Liu ◽  
Hui Niu
Keyword(s):  
Reaction Kinetics ◽  
Diels Alder ◽  
Cross Linking ◽  
Ethylene Propylene ◽  
Rheological Method ◽  
The Cross ◽  
Kinetics Of

The kinetics of the cross-linking reaction of ethylene/propylene rubbers based on Diels–Alder chemistry was detected by the rheological method.

Mechanical Properties of Epoxidized Palm Oil/Epoxy Resin Blend

2014 ◽  
Vol 695 ◽  
pp. 655-658 ◽  
Author(s):  
Zyad Salem Alsagayar ◽  
Abdul Razak Rahmat ◽  
Agus Arsad ◽  
Alireza Fakhari ◽  
Wan Nurhayati binti Wan Tajulruddin
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Epoxy Resin ◽  
Palm Oil ◽  
Room Temperature ◽  
Flexural Properties ◽  
Cross Linking ◽  
Impact Tests ◽  
Epoxidized Palm Oil ◽  
The Cross

In this paper, a blend of epoxy resin and epoxidized palm oil (EPO) was prepared to investigate its mechanical properties. Epoxy and EPO were mixed for 20 minutes at room temperature before mixed with hardener and followed by curing for 2 hours at 100 °C. Tensile, flexural and impact tests were conducted to characterize the blend. In general, the tensile and flexural properties of epoxy resin/EPO decreased when the amount of EPO increased. However, strain at break, toughness and impact strength was slightly increased when the amount of EPO was increased up to 20%.The mechanical properties were reduced due to the reduction of the cross linking density and effect of plasticizer.

scholarly journals Volume growth, murein synthesis, and murein cross-linkage during the division cycle of Escherichia coli PA3092

1982 ◽  
Vol 152 (3) ◽  
pp. 1248-1254
Author(s):  
A J Olijhoek ◽  
S Klencke ◽  
E Pas ◽  
N Nanninga ◽  
U Schwarz
Keyword(s):  
Escherichia Coli ◽  
Sodium Dodecyl ◽  
Volume Growth ◽  
Diaminopimelic Acid ◽  
Cross Linking ◽  
Penicillin Binding Protein ◽  
Whole Cells ◽  
Cross Linkage ◽  
The Cross ◽  
Kinetics Of

Cells of Escherichia coli PA3092 were synchronized by centrifugal elutriation. The synchronously growing cells were double labeled with -3H or DL-[meso-2,6-14C]diaminopimelic acid (DAP) at different times. Cells incorporated [3H]DAP at a continuously increasing rate during their cycle, with a maximum occurring at about 30 min before division for trichloroacetic acid-precipitated cells (whole cells) and about 10 min before division for sodium dodecyl sulfate-treated cells (sacculi). This was in good agreement with the observed kinetics of volume growth under these conditions. Furazlocillin, which preferentially interacts with penicillin-binding protein 3, modified the pattern of incorporation of [3H]DAP. Electron microscopy indicated that furazlocillin did not inhibit the initiation of division but rather its completion. In addition, we measured the cross-linking of the murein inserted at different times during synchronous growth. The highest percentages were found to occur around division. At this same time, the cross-linking of old peptidoglycan was found to be decreased.

scholarly journals The Use of the ATD Technique to Measure the Gelation Time of Epoxy Resins

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6022
Author(s):  
Jakub Smoleń ◽  
Piotr Olesik ◽  
Paweł Gradoń ◽  
Mateusz Chudy ◽  
Bogusław Mendala ◽  
...  
Keyword(s):  
Carbon Fibers ◽  
Epoxy Resins ◽  
Gelation Time ◽  
Graphite Powder ◽  
Cross Linking ◽  
Gel Point ◽  
Curing Process ◽  
Carbon Particles ◽  
The Cross ◽  
The Stability

In this paper, we investigated the thermodynamics of the resin curing process, when it was a part of composition with graphite powder and cut carbon fibers, to precisely determine the time and temperature of gelation. The material for the research is a set of commercial epoxy resins with a gelation time not exceeding 100 min. The curing process was characterized for the neat resins and for resins with 10% by weight of flake graphite and cut carbon fibers. The results recorded in the analysis of temperature derivative (ATD) method unequivocally showed that the largest first derivative registered during the test is the gel point of the resin. The innovative approach to measuring the gelation time of resins facilitates the measurements while ensuring the stability of the curing process compared to the normative tests that introduce mechanical interaction. In addition, it was found during the research that the introduction of 10% by weight of carbon particles in the form of graphite and cut carbon fibers rather shortens the gelation time and lowers the temperature peak due to the effective absorption and storage of heat from the cross-linking system. The inhibiting (or accelerating) action of fillers is probably dependent on chemical activity of the cross-linking system.

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