Results 1 Tensile Test

In evaluating of experiments was compared the influence of a dose of gamma radiation on the mechanical properties of materials.

The graphic dependence of the measured average values of the tensile test of test samples - yield strength σY of test samples in a standard ambient and degradation in UV chambers Figure 7.

81

Fig. 7. Tensile strength of test samples with different irradiation dose

The graphic dependence of the measured average values of relativeelongation of test samples in a standard ambient and degradation in UV chamber (Fig. 8).

Fig. 8. Relative elongation of test samples with different irradiation dose 3.2 Charpy Impact test

The test samples were controlled after injection molding process and after the conditioning time. It was tested in 10 samples of each type of materials in standard ambient and after UV exposure chamber. The test samples were subjected to the tests without notch. The graphic dependence of the impact resistance acU of test samples with different irradiation dose (Fig. 9).

82

Fig. 9. Impact resistance of test samples with different irradiation dose

The fracture areas of test samples after tensile test without exposure and were observed on scanning electron microscope JEOL JSM - 7000F, Japan.The fracture areas of test samples of non-irradiated and irradiated materials with different of radiation dose in standard ambient after tensile test were compared, Figure 10.

Fig. 10. The fracture areas of test samples irradiated by different radiation dose: a) test sample non irradiated, b) test sample – 15 kGy, c) test sample – 50 kGy

a) b)

c)

83

By the influence of cross-linking was observed increasing density of cross-linking, It was created a sufficient number of networked sites. For all test samples there has been a brittle fracture of testing samples. The spectrum of the chemical composition is shown in Figure 11 confirmed on scanning images of test samples in standard ambient the presence of chemical elements. These were the elements of the polymer – A label, the elements of filler – B label and the elements of cross-linking agent (TAIC) – label C.

Fig. 11. The spectrum of the chemical composition of tested material in standard ambient:

a) test sample non irradiated, b) test sample – 15 kGy, c) test sample – 50 kGy 4. Conclusions

On the basis of the experimental results of mechanical tests the following conclusions could be formulated:

• After tensile test with material Hostacom CR G61330 250 F G61330 by test samples in standard ambient was found increasing tendency of tensile strength and relation elongation.

We can state, that the values of tensile strength and relation elongation were influenced by irradiation dose – Figure 9, 10.

• The value of tensile strength achieved increasing tendency by irradiated test samples in standard ambient against the base material about 10%. By irradiated test samples after degradation in UV chamber were achieved the values of tensile strength decreasing tendency. These values were influenced by irradiation dose about 10–15%.

Irradiated test samples in standard ambient had against non-irradiated material progressive tendency of relative elongation. These values were influenced by

84

irradiation dose about 25–50%. Irradiated test samples after degradation in UV chamber had against non-irradiated material decreasing tendency of relative elongation. These values were influenced by irradiation dose about 25–75%.

On the basis of the experimental results of mechanical tests the following conclusions could be formulated:

• At the material Hostacom CR G61330 250 F G61330 is not explicit influence of radiation dose to the impact resistance.

• The increasing tendency of value acU was recorded in irradiated test samples after degradation in UV chamber.

• By non – irradiated and irradiated test samples in standard ambient was recorded decreasing tendency by irradiation dose 15 and 33 kGy and marginal increase by irradiation dose 50 kGy.

• The highest values of parameter acU of irradiated test samples were evaluated at 50 kGy radiation dose.

Acknowledgement

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 734205-H2020-MSCA-RISE-2016.

References

[1] Manas, D., et all., The High-Density Polyethylene Composite with Recycled Radiation Cross-Linked Filler of rHDPEx, Polymers 2018, 10, 12, 1361.

[2] Hubo S., Leite L., Martins C., Ragaert K., Evaluation of industrial and post-consumer polyolefin-based polymer waste streams for injection moulding;

Proceedings of the 6th Polymers & Mould Innovations International Conference;

University of Minho, Guimarães, Portugal. 10–12 September 2014; pp. 201–206.

[3] Khonakdar, H.A., Jafari, S.H., Wagenkecht, U., Jehnichen, D., Effect of electron-irradiation on cross-link density and crystalline structure of low- and high-density polyethylene. Radiat. Phys. Chem. 2006, 75, 78–86.

[4] Manas, D. et all.,The Effect of Irradiation on Mechanical and Thermal Properties of Selected Types of Polymers, Polymers 2018, 10, 2, 158–166.

[5] Mizera, A. et all., Properties of Polymers after Radiation Cross-linking, International journal of mathematics and computers in simulation 2012, 6, 592–

599.

[6] Yoshii, F., Radiation Crosslinking of Polymer Materials, Takasaki Radiation Chemistry Research Establishment, JAERI, Jaeri – Conf 2004-007, 83–91.

[7] Ionisos, Z.I., Radiation cross-linked plastics: a versatile material solution for packaging, automotive, Electrotechnic and Electronics, Radiation Physics and Chemistry, Volume 71, Issues 1–2, September–October 2004, 527–530.

85

[8] Brocka, Z., Strahlenvernetzte Kunstoffe Verarbeitung, Eigenschaften, Anwendung, Springer VDI Verlag, Düsseldorf. 2006, pp. 1–30.

[9] Ortiz, J., Lima, E., Handbook of Polymer Synthesis, Characterization, and Processing, February 2013, ISBN: 9781118480793.

[10] http://www.marmon-ad.com/polymer-cross-linking, cit.

[11] Greškovič, F., Varga, J., Dulebová, Ľ., The utilize of gamma radiation in the examination of mechanical properties of polymeric materials. Metalurgija 2012, 51, 2, 245–248.

[12] Drobny, J.G., Radiation Technology for Polymers, Boca Raton: CRC Press, 2003.

[13] BGS – Beta Gama Service. [online]. www: http://bgs.eu.

[14] Bussink J., Engineering Plastics. In: Lemstra P.J., Kleintjens L.A. (eds) Integration of Fundamental Polymer Science and Technology-3. Springer, Dordrecht, (1989), 43-50.

[15] Shukushima, H., Radiation Physics and Chemistry, 2001, 60, 4–5, 489–493. [16] Varga, J., The influence of radiation crosslinking on mechanical properties of

plastic parts, PhD thesis, Košice, 2009, pp. 100–140.

86

António Gaspar-Cunha¹

COMPUTATIONAL ASSESSMENT OF THE