**Study on the Structure-Property Dependences of Rigid PUR-PIR Foams Obtained from Marine Biomass-Based Biopolyol**

**Paulina Kosmela 1,\*, Aleksander Hejna <sup>1</sup> , Jan Suchorzewski 2,3 , Łukasz Piszczyk <sup>1</sup> and Józef Tadeusz Haponiuk <sup>1</sup>**


Received: 23 January 2020; Accepted: 4 March 2020; Published: 10 March 2020

**Abstract:** The paper describes the preparation and characterization of rigid polyurethanepolyisocyanurate (PUR-PIR) foams obtained with biopolyol synthesized in the process of liquefaction of biomass from the Baltic Sea. The obtained foams differed in the content of biopolyol in polyol mixture (0–30 wt%) and the isocyanate index (IISO = 200, 250, and 300). The prepared foams were characterized in terms of processing parameters (processing times, synthesis temperature), physical (sol fraction content, apparent density) and chemical structure (Fourier transform infrared spectroscopy), microstructure (computer microtomography), as well as mechanical (compressive strength, dynamic mechanical analysis), and thermal properties (thermogravimetric analysis, thermal conductivity coefficient). The influence of biopolyol and IISO content on the above properties was determined. The addition of up to 30 wt% of biopolyol increased the reactivity of the polyol mixture, and the obtained foams showed enhanced mechanical, thermal, and insulating properties compared to foams prepared solely with petrochemical polyol. The addition of up to 30 wt% of biopolyol did not significantly affect the chemical structure and average cell size. With the increase in IISO, a slight decrease in processing times and mechanical properties was observed. As expected, foams with higher IISO exhibited a higher relative concentration of polyisocyanurate groups in their chemical structure, which was confirmed using principal component analysis (PCA).

**Keywords:** bio-based polyol; biomass liquefaction; rigid polyurethane-polyisocyanurate foams; structure-property relationship; isocyanate index
