1. Faculty of Material Science and Applied Chemistry, Institute of Polymer Materials, Riga Technical University, 3/7 Paula Valdena St., LV 1048, Riga, Latvia
2. Faculty of Material Science and Applied Chemistry, Institute of Applied Chemistry, Riga Technical University, 3/7 Paula Valdena St., LV 1048, Riga, Latvia
3. Latvian State Institute of Wood Chemistry, 27 Dzerbenes St., LV-1006, Riga, Latvia