V. A. Szabó

57204632786

Publications - 7

Automotive Application of Chemically Foamed rPET

András Kovács V. A. Szabó Sándor K. Jakab Tamara Zsuzsanna Böcz G. Dogossy

Publication Name: Polymers

Publication Date: 2025-05-01

Volume: 17

Issue: 9

Page Range: Unknown

Description:

This study investigated the automotive applicability of parts produced from a newly developed foamed recycled polyethylene terephthalate (rPET). The injection molded part contained a combination of both endothermic and exothermic foaming agents and phosphorus (Exolit OP 1240) (OP)- and melamine polyphosphate (MPP)-based flame retardant agents. The parts were produced using a breathing mold technique to achieve a suitable level of foaming. The aim was to produce lighter parts made of recycled material that also complied with the fire safety automotive industry standards. Computer tomographic scans revealed the foam structure formed successfully, which contributed to an improved strength-to-weight ratio. The scans further showcased that larger cells tended to form in the thicker areas within the part, while smaller cells generally formed in the thinner areas. Finite element simulations showed that the large cell formation in the thicker parts had no effect on the part’s load bearing property, and there were not stress concentration points after the boundary conditions were defined. The sample produced from the material was determined to be a possible replacement of small-sized automotive components.

Open Access: Yes

DOI: 10.3390/polym17091251

Use of Hybrid Flame Retardants in Chemically Foamed rPET Blends

András Kovács V. A. Szabó Sándor K. Jakab Tamara Zsuzsanna Böcz G. Dogossy

Publication Name: Crystals

Publication Date: 2025-01-01

Volume: 15

Issue: 1

Page Range: Unknown

Description:

The foamed structure of recycled polyethylene-terephthalate (rPET) is a promising solution for industrial applications; however, the remedy for its inherent melt-dripping property is still a challenging topic. In our research, we were able to improve the flame retardancy of the endothermic–exothermic hybrid rPET foam by adding a different mixture of flame retardants to the formula. Three different kinds of halogen-free flame retardant agents were used: ammonium polyphosphate-based Exolit AP 422 (AP), organic aluminum phosphate in the form of Exolit OP 1240 (OP), and Budit 342 containing melamine polyphosphate (MPP). The hybrid flame retardant mixture, by combining the swelling and charring mechanism, increased the flame retardancy of the samples. The sample made with 15 phr OP and 5 phr MPP displayed outstanding performance, where five samples were capable of self-extinguishing in 5 s, while only slightly decreasing the tensile and flexural strength properties and simultaneously increasing the Young and flexural modulus compared to the reference sample. The addition of MPP reduced the porosity in many cases, while preventing cell coalescence. Our results prove that the hybrid flame retardant agent frameworks efficiently increase the flame retardancy of rPET foams, facilitating their application in industrial sectors such as the aerospace, packaging, renewable energy, and automotive industries to realize sustainability goals. The utilization of halogen-free flame retardants is beneficial for better air quality, reducing toxic gas and smoke emissions.

Open Access: Yes

DOI: 10.3390/cryst15010080

Endothermic–Exothermic Hybrid Foaming of Recycled PET Blends

Gusztáv Fekete V. A. Szabó G. Dogossy

Publication Name: Journal of Composites Science

Publication Date: 2024-10-01

Volume: 8

Issue: 10

Page Range: Unknown

Description:

Over the past decades, the use of polyethylene terephthalate (PET) has seen significant growth, particularly in the packaging industry. However, its long decomposition time poses serious environmental challenges. The aim of this research was to develop a process for the foaming of large quantities of recycled PET (rPET) using endothermic and exothermic foaming agents. Various formulations with different ratios of endothermic and exothermic foaming agents were prepared, as well as their mixtures. The study found that the endothermic–exothermic hybrid foaming process resulted in a finer cell-size distribution and enhanced mechanical properties, making the foams highly suitable for widespread applications. The results support the potential use of exothermic foaming agents as nucleating agents in a hybrid foaming system. In particular, the ratio of 3% endothermic and 1% exothermic foaming agents proved optimal in terms of achieving a balance between porosity and mechanical strength, thereby enabling broad industrial applicability.

Open Access: Yes

DOI: 10.3390/jcs8100383

Resistance to Tensile Stress and Foam Structure Formation in Chemically Foamed rPET Blends †

V. A. Szabó Gábor Böcz G. Dogossy

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

This research investigates the correlation between tensile strength, tensile strain, and porosity in chemically foamed recycled poly(ethylene-terephthalate) (rPET) samples. Tensile strength and strain were measured on non-foamed samples to predict the porosity of the foamed samples. Utilizing various flame retardants and additives, we analyzed their impact on mechanical properties and structures. However, neither tensile strength nor strain demonstrated a reliable correlation with the resulting porosity. Strain values did not consistently predict porosity, indicating the significant role of additive types and concentrations.

Open Access: Yes

DOI: 10.3390/engproc2024079070

Flame retardancy of recycled PET foam

V. A. Szabó G. Dogossy

Publication Name: Iop Conference Series Materials Science and Engineering

Publication Date: 2020-08-25

Volume: 903

Issue: 1

Page Range: Unknown

Description:

Although significant marketing efforts have been made in recent years to reduce polymer use, the number of plastic bottles being discarded is increasing worldwide. The global environmental-socio-economic problem posed by polyethylene terephthalate (PET) bottles can only be solved by expanding large-scale recycling opportunities, while reducing the use of pure raw materials. In this article on the large quantities product of PET was upcycled with chemical foaming. During the experiments 2 m% chain extender and 4 m% chemical blowing agent and different amount of brominated flame retardant was used. The invested materials were examined with standard mechanical tests, scanning electron microscopy and UL-94 standard flammability test. After the investigation it was found that the crystallized blue PET bottle re-granulate can be used forming a flame retardant closed cell foam structure.

Open Access: Yes

DOI: 10.1088/1757-899X/903/1/012048

Investigation of flame retardant RPET foam

V. A. Szabó G. Dogossy

Publication Name: Periodica Polytechnica Mechanical Engineering

Publication Date: 2020-01-01

Volume: 64

Issue: 1

Page Range: 81-87

Description:

The use of plastics in the food and the packaging industries continuously is increasing. In these areas of use the product's life cycle is short, therefore it quickly turns into waste. The polyethylene terephthalate (PET) - the material that is used as beverage containers - are the material with the greatest environmental load. The physical recycling of PET bottles in large quantities was the research goal. During the work with the help of chemical foaming a closed cell structural foam from PET bottle was produced. The research was carried out with upcycling using chain extender and impact modifier additives. For industrial use a bromine-based flame retardant was used and excellent flame retardancy was achieved. Based on the results obtained, the material previously managed as waste, with the appropriate treatment can be involved into the manufacturing of new products.

Open Access: Yes

DOI: 10.3311/PPme.14556

Structure and properties of closed-cell foam prepared from rPET

V. A. Szabó G. Dogossy

Publication Name: Iop Conference Series Materials Science and Engineering

Publication Date: 2018-10-18

Volume: 426

Issue: 1

Page Range: Unknown

Description:

Nowadays, in the field of packaging technology, one-way polymer packaging materials are increasingly used. Food and packaging industry uses the most, the life cycle of which becomes short, they become waste very quick. Also included are light weight bottles of polyethylene terephthalate (PET). Large amounts of waste can be handled with multiple options. The worst is their dumping on dump sites, as these materials do not compost. Their thermal recycling is more favorable due to their high calorific value, but a real cycle can only be achieved by their physical recycling. However, during the multiple re-purposing, PET's mechanical and processing properties are reduced. In our research, chemical foaming has been investigated, resulting in a smaller weight, better specific property, and fully reusable product. During our investigations, the structure and mechanical properties of recycled PET (rPET) specimens manufactured with different composition, chain and foam additives were analyzed.

Open Access: Yes

DOI: 10.1088/1757-899X/426/1/012043