Tezislər / Theses

Supervisor: Dr. Amir Reza Vakhshouri 
Keywords:
polyurethane, foam, flexible, mechanical strength, polyols 
Polyurethanes (PUs), as an important family of polymers generated 
traditionally from petroleum fuels, finds its application in a wide range of 
areas. PUs can be manufactured as rigid or flexible foam and nonporous 
material in industries, depending on the use, such as adhesives, thermos-
plastics, coatings, etc. The automobile industry has benefited commercially 
from the development of flexible foam made from polyether polyols in the 
twenty-first century [1]. From 2021 to 2026, the worldwide polyurethane 
foams market is expected to increase at a CAGR of 7.5 percent, from USD 
42.8 billion in 2021 to USD 61.5 billion in 2026. Increased usage of 
polyurethane foams in a variety of industries, such as building insulation for 
energy conservation, as well as the adaptability and unique physical features 
of polyurethane foams, are driving factors for market expansion [2]. 
Polyurethane foam is a porous, cellularly organized synthetic substance 
created by combining diisocyanates and polyols. Its structure is made up of 
a mixture of solid and gas phases. The solid phase is constructed of 
polyurethane elastomer, whereas the gas phase is created by blowing 
agents and consists of air. Different types of oil can be used to synthesize 
polyols, but the distribution of hydroxyl groups in castor oil is homogeneous, 
resulting in a more uniform crosslinked structure in the final PUs and superior 
thermal stability and mechanical strength than other seed-oil-based PUs. 
Diisocyanates such as methylene diphenyl diisocyanate (MDI) and toluene 
diisocyanate (TDI) are mainly utilized during the production of respectively 
rigid and flexible polyurethane foams. Taking TDI as diisocyanate with polyol 
derived from the castor oil using water as a blowing agent, flexible 
polyurethane foam can be obtained through an exothermic reaction [3].
Changes in the foam raw material mix can be used to manage the foam 
production process. Besides polyol, isocyanate, and water needed to make 
foam, a range of additional chemicals and additives may be added to vary 
the final qualities of the foam based on client demands. For example, in order 
to prepare soft and lighter foams, carbon dioxide can be utilized to augment 
primary blowing agent. Also, catalysts participating in the reaction to speed 
up the reaction have a certain effect on the final properties of the foam. On 
the other hand, while fillers increase the weight of the foam and retardants 
significantly improve the resistance of the foam against fire and heat, they 

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