Rheological behavior of lubricating systems in polypropylene/seaweed composites

Mechanical and Dynamic Mechanical Behavior of the Lignocellulosic Pine Needle Fiber-Reinforced SEBS Composites

Aiming to generate wealth from waste and due to their significant fire threats to forests and their rich cellulose content, lignocellulosic pine needle fibers (PNFs) are utilized in this study as a reinforcement of the thermoplastic elastomer styrene ethylene butylene styrene (SEBS) matrix to create environmentally friendly and economical PNF/SEBS composites using a maleic anhydride-grafted SEBS compatibilizer. The chemical interaction in the composites studied by FTIR shows that strong ester bonds are formed between reinforcing PNF, the compatibilizer, and the SEBS polymer, leading to strong interfacial adhesion between the PNF and SEBS in the composites. This strong adhesion in the composite exhibits higher mechanical properties than the matrix polymer indicating a 1150 % higher modulus and a 50 % higher strength relative to the matrix. Further, the SEM pictures of the tensile-fractured samples of the composites validate this strong interface. Finally, the prepared composites show better dynamic mechanical behavior indicating higher storage and loss moduli and T_g than the matrix polymer suggesting their potential for engineering applications.

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

The paper describes the preparation and characterization of rigid polyurethane-polyisocyanurate (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 (I_ISO = 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 I_ISO 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 I_ISO, a slight decrease in processing times and mechanical properties was observed. As expected, foams with higher I_ISO exhibited a higher relative concentration of polyisocyanurate groups in their chemical structure, which was confirmed using principal component analysis (PCA).