An Effective Way to Prepare High Performance Biomass-Based Fatliquoring Agent Bromination Modification of Rapeseed Oil and Its Fatliquoring and Flame-Retardant Properties

Abstract

With the implementation of Carbon Neutralization strategy, it is urgently needed to develop low-carbon leather chemicals through replacing petrochemicals with biomass-based raw materials in leather industry. To solve the problems existing in the leather fatliquored by the biomass-based fatliquoring agents made from vegetable oils with high unsaturation, such as poor storability, unpleasant odor, yellowing and possible formation of hexavalent chromium, the strategy was put forward, improving the oil saturation through the double bonds addition reaction with halogen to solve the abovementioned problems resulting from the poor oxidation resistance of oil, and increase the binding ability of the oil with leather fibers and endow the leather with flame-retardant simultaneously. In this paper, the methods of modified rapeseed oil by bromine addition and its fatliquoring and flame-retardant properties were studied. The results showed that the bromine addition reaction of rapeseed oil was easy to proceed and the iodine value of the modified oil decreased almost linearly with the added amount of bromine. The binding and antioxidant properties of the oil and the physical properties of the fatliquored leather were significantly improved with the increase degree of bromination modification. Furthermore, above mentioned unpleasant odor, yellowing and hexavalent chromium formation problems were effectively solved when the iodine value of modified fatliquors was reduced to 31 g I2/100 g. Additionally, brominemodified rapeseed oil could endow leather with good flame-retardant properties and the fatliquored leather was changed from combustible to flame-retardant material with the increasing amount of bromine in the oil. The limit oxygen index (LOI) increased from 24% to 31%, the flame combustion time decreased from 127.0 s to 4.3 s, and the flameless combustion time decreased from 28.5 s to 0.0 s. This study provided an effective way to develop biomass-based and low-carbon fatliquors based on natural unsaturated oils.