Rigid Polyurethane Foams Reinforced with POSS-Impregnated Sugar Beet Pulp Filler

Abstract

Rigid polyurethane (PUR) foams were reinforced with sugar beet pulp (BP) impregnated with Aminopropylisobutyl-polyhedral oligomeric silsesquioxanes (APIB-POSS). BP filler was incorporated into PUR at different percentages—1, 2, and 5 wt.%. The impact of BP filler on morphology features, mechanical performances, and thermal stability of PUR was examined. The results revealed that the greatest improvement in physico-mechanical properties was observed at lower concentrations (1 and 2 wt.%) of BP filler. For example, when compared with neat PUR foams, the addition of 2 wt.% of BP resulted in the formation of PUR composite foams with increased compressive strength (~12%), greater flexural strength (~12%), and better impact strength (~6%). The results of thermogravimetric analysis (TGA) revealed that, due to the good thermal stability of POSS-impregnated BP filler, the reinforced PUR composite foams were characterized by better thermal stability—for example, by increasing the content of BP filler up to 5 wt.%, the mass residue measured at 600 °C increased from 29.0 to 31.9%. Moreover, the addition of each amount of filler resulted in the improvement of fire resistance of PUR composite foams, which was determined by measuring the value of heat peak release (pHRR), total heat release (THR), total smoke release (TSR), limiting oxygen index (LOI), and the amount of carbon monoxide (CO) and carbon dioxide (CO2) released during the combustion. The greatest improvement was observed for PUR composite foams with 2 wt.% of BP filler. The results presented in the current study indicate that the addition of a proper amount of POSS-impregnated BP filler may be an effective approach to the synthesis of PUR composites with improved physico-mechanical properties. Due to the outstanding properties of PUR composite foams reinforced with POSS-impregnated BP, such developed materials may be successfully used as thermal insulation materials in the building and construction industry.

Effects of Physical and Chemical Modification of Sunflower Cake on Polyurethane Composite Foam Properties

“…This, in turn, may be related to the fact that, on its surface, there are the most active cellulosic and lignin groups (e.g., hydroxyl groups), which, through interaction with polyester polyol, best disperse in polyol premixes. Similar results can also be found in earlier studies [ 21 , 22 ].…”

“…Previous studies confirmed that the chemical treatments, especially alkalization, remove the waxy substances, which are responsible for the smooth surface of the filler. Due to this, the structure of the treated fillers becomes rough, which, in turn, may result in the better interlocking of the filler in the polymeric matrix [ 21 , 22 ].…”

“…Similar dependence was found in previous studies. It was reported that the deterioration of PUR structures may be connected with the attachment of filler particles to the cell struts, which results in weakening of the PUR foam morphology and cell coalescence [ 7 , 21 , 22 ].…”

“…PUR composite foams were produced following the method reported in the previous works [ 7 , 21 , 22 ]. In brief, the synthesis of PUR composite foams modified with the addition of SC was as follows: The previously modified SC fillers were added to the polyol premix and mixed for 60 s to obtain a homogeneous dispersion.…”

Coir Fibers Treated with Henna as a Potential Reinforcing Filler in the Synthesis of Polyurethane Composites

“…Thus, the surface modification of the cellulosic filler seems to be necessary. Previous studies have reported different methods of filler modification, which include silane treatment [ 30 ], acetylation [ 31 ], or physical impregnation with selected flame-retardant compounds [ 32 ] or polysilsesquioxanes [ 33 ].…”