1. Abrasive Wear of Salts Doped Epoxy Composites
International Scientific Conference BULTRIB '15
September 11-13, 2015, Sozopol, Bulgaria Society of Bulgarian Tribologists
Abrasive Wear of Salts Doped Epoxy Composites
Mihai BOȚAN1, Ioan BOSOANCĂ2, Radu BOSOANCĂ2, Iulia GRAUR1,2, Ionuț MIHALACHE1,2,
Marius BODOR1,2, Adrian CÎRCIUMARU1,2, Vasile BRIA1
1 - “Dunarea de Jos” University of Galati, Romania
2 - Diagnose and Measurement Group S.R.L., Galați, Romania

2. Introduction
The study was carried out in order to complete the characterization of ionic substances doped epoxy resin;
The doping method had been developed as part as research activity under the Project POSCCE 12P01.024/CD111 and was meant as an ease method to increase the electrical conductivity of polymers;
The abrasive wear analysis had been performed on the pin-on-disk geometry with composite pin and with the steel disk covered with abrasive paper.

3. Materials
Two types of ionic substances had been used namely Potassium dichromate and Sodium dichromate while the epoxy system was WWA and WWB from Resoltech;
Both salts were dehydrated by thermal cure to avoid the placement of water molecules into the polymer.
As solvent a commercial use nitro diluent named D209 had been used. It consists of a mixture of toluene, acetone, butyl acetate and butanol.

4. Materials
-The resin contains 75-78% bisfenol A according to the specification and the materials had been formed based on the lowest value such as at a given number of Bisfenol A molecules to correspond an alkaline ion.
-When the dispersion was uniform the conditions for solvent vaporization were set as follows: mechanical stirring at 200rot/min, temperature 70oC and continuous ventilation above the pot.
-The duration for solvent removal is about 150 minutes.

5. Materials
-The amounts of salts had been computed such as the doping levels to be of 1 alkaline ion at 5000 bisfenol A molecules. - As reference materials epoxy resin and diluted resin had been formed. -The resin-ions mixture was mixed with the required amount of hardener and samples were formed into cylindrical moulds of 11 mm diameter and 200 mm height.

6. Measurements and results
-The main goal of the test is to identify the effect of salts presence into the matrix on the basic properties of epoxy resin. -The second aim is to identify the effect of ultrasonic exposure on the properties of ions doped polymer.

7. Measurements and results
-In order to investigate probable formation of new chemical structures (for example by chelation of dichromate ions) Raman analysis was performed but, as it can be seen there are not important modifications.
Fig. 1. Raman spectrum of highest level of doping 1 Sodium ion at 100 bisfenol A molecules

8. Measurements and results
-The abrasive tests were performed on a Universal Testing Machine on the pin on disk geometry with the pin made of composite and the steel disk covered with abrasive paper P150. -Three regimes were set and the sliding distance was of 100m. -The three regimes were set such as the product sliding speed normal force to be constant and the values are given in the graphs below.

9. Measurements and results
Fig. 2. Abrasive wear resistance of epoxy and diluted epoxy
-The abrasive wear resistance of diluted epoxy resin is higher than the same parameter for epoxy resin but is decreasing with the duration of ultrasonic exposure while the abrasive wear resistance of epoxy resin is increasing with the duration of ultra-sonication.

10. Measurements and results
Fig. 3. Abrasive wear resistance of materials with lowest doping level

11. Measurements and results
Fig. 4. Abrasive wear resistance of materials with highest doping level

12. Measurements and results
Fig. 5. Abrasive wear resistance of materials with one alkaline ion at 400 bisphenol A molecules

13. Conclusions
-The diluted resin shows, generally, higher values of abrasive wear resistance, comparing with the epoxy resin, but these values are decreasing with the increase of ultrasonic exposure duration. - In the case of doped materials the Sodium dichromate doped materials seem to have higher values of abrasive wear resistance than the values showed by the Potassium dichromate doped materials at the same doping level and for the first regime of speed and loading (low speed, high load) and all the materials are showing same values of abrasive wear resistance for the other two regimes.

14. Conclusions
-The materials with one alkaline ion at 400 bisphenol A molecules are showing the same abrasive behaviour independent on the type of alkaline ion. -This result together with the fact that these materials are showing the highest values of specific weight leads to the conclusion that it is possible to appear some chemical structures determined by the presence of alkaline ions. - These structures cannot be identified by means of Raman spectrophotometry because they are packed in polymer and their signal is very low due to the low concentration of alkaline ions relative to the amount of resin.

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