Dimitrina Atanasova Todorova

Prof. Dr. Dimitrina Atanasova Todorova

Pulp, Paper and Printing arts, University of Chemical Technology and Metallurgy, Sofia, Sofia-Grad, Bulgaria
orcid

Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
25 April 2023 in Coatings
Verified
Journal Article
Open access
PDF file
Urška Vrabič-BrodnjakUrška Vrabič-Brodnjak
Urška Vrabič-Brodnjak
Nikolay YavorovNikolay Yavorov
Nikolay Yavorov
VLVeska Lasheva
Veska Lasheva
Dimitrina Atanasova TodorovaDimitrina Atanasova Todorova
Dimitrina Atanasova Todorova
The aging of paper depends on various factors, including environmental conditions, microbiological factors and chemical composition. Chitosan-coated paper is an eco-friendly material that has potential use in various packaging applications due to its mechanical, barrier and antibacterial properties. In this study, the aging stability of chitosan-coated wood-free wrapping paper was evaluated by examining pulp and four paper samples with different quantities of chitosan. Accelerated thermal aging and dynamic thermogravimetric analysis were used to assess the aging stability, while color changes were examined to understand the impact of chitosan coating. The study found that increasing chitosan coating led to improved aging stability due to the improved crosslinking process between chitosan and paper. The coated paper samples displayed a yellowish hue after 72 h of aging, with increased strength and resistance to weight loss. TGA results indicated that the temperature of complete burning of the sample increased with increasing chitosan coating. Additionally, coated paper samples exhibited a more even surface and improved barrier properties. Overall, chitosan-coated paper is a promising material for sustainable and eco-friendly packaging, printing and wrapping applications. This study’s findings have important implications for the development of environmentally-friendly packaging materials that possess desirable mechanical and barrier properties.

24 December 2022 in Coatings
Verified
Journal Article
Open access
PDF file
Dimitrina Atanasova TodorovaDimitrina Atanasova Todorova
Dimitrina Atanasova Todorova
Nikolay YavorovNikolay Yavorov
Nikolay Yavorov
VLVeska Lasheva
Veska Lasheva
SDStanka Todorova Damyanova
Stanka Todorova Damyanova
IKIliana Kostova
Iliana Kostova
Based on many years of experience, packaging is considered as an inactive barrier that protects materials and goods from environmental factors. The applicability of native chemical additive such as essential oils in wrapping papers can be used in the forms of films, treatments, coatings or others. Essential oils or extracts from different aromatic plants are used as bioactive substances for antimicrobial activity. In this research, lavender essential oil treatment of packaging papers is examined for its inhibition activity under nine microorganisms—two Gram-positive bacteria, three Gram-negative bacteria, two yeast and two fungal strains. The effectiveness of the treatment on the structural and strength indicators of the obtained paper samples is monitored. In detail, a five-day examination is conducted on the antibacterial effectiveness of lavender essential oil treatment. Results indicate that the lavender treatment of the obtained packaging paper is successful and the antifungal effect is more pronounced. The antimicrobial efficiency of paper treated with lavender essential oil is between 60 and 90% in the first two hours after treatment and gradually decreases to 40%–50% at the end of the 120 h period. The lavender essential oil treatment of wrapping paper has a promising perspective for preserving products from microbial spoilage and extending their shelf life.

30 March 2022 in Sustainable Chemistry and Pharmacy
Verified
Journal Article
Closed access
Dimitrina Atanasova TodorovaDimitrina Atanasova Todorova
Dimitrina Atanasova Todorova
Nikolay YavorovNikolay Yavorov
Nikolay Yavorov
VLVeska Lasheva
Veska Lasheva

26 July 2024 in Polymers
Verified
Journal Article
Open access
PDF file
Dimitrina Atanasova TodorovaDimitrina Atanasova Todorova
Dimitrina Atanasova Todorova
Nikolay YavorovNikolay Yavorov
Nikolay Yavorov
Urška Vrabič-BrodnjakUrška Vrabič-Brodnjak
Urška Vrabič-Brodnjak
In this study, a comparative analysis of silver nanoparticles treatment and chitosan coating on packaging paper barrier properties was carried out. In order to examine the water, grease, and antibacterial barrier properties of silver nanoparticle-treated and chitosan-coated laboratory-obtained paper samples, a mixture of bleached softwood and hardwood celluloses was used. In order to conduct the comparative analysis SEM, water contact angle, Cobb60, and Kit tests were carried out on a cellulose sample, and four paper samples (three of them treated with silver nanoparticles—1, 2, and 3 mL/20 cm2 or chitosan coated—0.5, 1, and 2 g/m2) together with the inhibition activity against nine Gram-positive and Gram-negative bacteria, yeast, and fungal strains. The study found out that increasing the silver nanoparticle treatment and chitosan coating led to improved water resistance, while grease resistance was improved only for chitosan coated paper samples. Additionally, paper treated with 3 mL/20 cm2 of silver nanoparticles had the highest antibacterial protection (81.6%) against the Gram-positive bacterium Staphylococcus aureus, followed by Gram-negative Escherichia coli (75.8%). For the rest of the studied microorganisms, the average efficiency of the treated paper was 40.79%. The treatment of the paper with 1 and 2 mL/20 cm2 of silver nanoparticles was less effective—27.13 and 39.83%, respectively. The antibacterial protection of 2 g/m2 chitosan-coated paper samples was the most effective (average 79%) against the tested bacterial, yeast, and fungal strains. At 1 and 0.5 g/m2 chitosan coatings, the efficiency was 72.38% and 54.67%, respectively. Gram-positive bacteria, yeasts, and fungal strains were more sensitive to chitosan supplementation.

1 December 2021 in Sustainable Chemistry and Pharmacy
Verified
Journal Article
Closed access
Dimitrina Atanasova TodorovaDimitrina Atanasova Todorova
Dimitrina Atanasova Todorova
KDKiril Dimitrov
Kiril Dimitrov
MHMichael Herzog
Michael Herzog

1 November 2018
Verified
Conference Paper
Closed access
UBUrška Vrabič Brodnjak
Urška Vrabič Brodnjak
Dimitrina Atanasova TodorovaDimitrina Atanasova Todorova
Dimitrina Atanasova Todorova