An Iterative Method for the Simulation of Rice Straw-Based Polyol Hydroxyl Moieties

Abstract

Bio-derived polyol products have gained global interest as a green and sustainable substitute for fossil-based polyols in a diverse range of polyurethane (PU) applications. According to previous studies, PU properties are highly influenced by the reaction kinetics during their formation. One major factor affecting this is the reactivity of their polyol’s functional hydroxyl moieties that are classified as primary, secondary, and hindered-secondary. However, experimental quantitative characterization of these polyol hydroxyl moieties remains a challenge in the field due to various factors affecting them, including extensive time requirements, the need for substantial and expensive resources, large potential errors, and the generation of wastes, as well as health and safety considerations. In this study, the molar fraction of primary, secondary, and hindered-secondary hydroxyl moieties of a petroleum-based polyol (V490) and a rice straw-based polyol were determined via an iterative computational method. The method employed a MATLAB script that can simultaneously solve multiple differential equations involving PU gelling reaction kinetics and thermodynamics. In this manner, numerical combinations of the fraction of each type of hydroxyl moiety are generated by looping together the respective numerical fractions for each moiety. The best-fit combinations of the fractions of the mixed polyol’s hydroxyl moieties were successfully found via curve fitting of the simulated and experimental gelling temperature profile with an average numerical deviation of less than 1%. Thus, the method presented in this study offers a faster and more reliable characterization of the polymeric reaction kinetics than the experimental and conventional computational methods for product property enhancement and development in the field.

Valorization of Agricultural Rice Straw as a Sustainable Feedstock for Rigid Polyurethane/Polyisocyanurate Foam Production

“…The data presented in Table 3 show the impact of substituting V490 with RS-based polyol within the 0–50% range on the foaming reactions kinetics of RPUFs. This analysis highlights key parameters such as cream time, gel time, and maximum temperature ( T max ), 30 , 35 and has been conducted with three replicates, providing insights into the thermodynamic aspects of the foaming process. Significantly, both cream and gel times exhibit a consistent incremental increase as the proportion of RS-based polyol increases.…”

“…The polyol types significantly influence the resulting PU properties. 28 , 31 − 35 Traditionally, polyols used in PU production are primarily derived from petroleum feedstocks. However, industrial-scale petroleum-based PU production is associated with substantial adverse environmental impacts, contributing to global environmental hazards.…”