Synthesis of sulfonated Sesamum indicum L.seed oil and its application as a fatliquor in leather processing

Fatliquor is an oil-in-water emulsion that improves the physical properties of leather such as tensile strength,flexibility,and softness by lubricating the leather fibres.Sulfonated Sesamum indicum oil was synthesized,characterized,and examined for consideration as a substitute for imported fatliquor in Nigeria.The sulfonation of the oil was confirmed by the significant observations made in the FTIR,1 H NMR,13 C NMR,and 13 C NMR DEPT analysis results.A remarkable difference was observed in the physicochemical properties results of both unsulfonated and sulfonated oils.The sulfonated sesame fatliquor was applied onto goatskin and compared with a commercial sulfated fatliquor in the processing of shoe upper leather using standard methods.The average results for tensile strength,double edge tear,elongation,and softness results for the commercial and synthesized fatliquors are as follows:14.27 N/mm^(2);13.77 N/mm^(2),50.61N;60.11 N,38.06%;54.28%,25.2;25.0.A comparable level of lubrication of the leather treated with the sulfonated Sesamum indicum oil and that treated with the commercial leather fatliquor was revealed by the Sudan IV stain test as well as scanning electron microscopy analysis results.Experimental analyses,therefore,show that the as-synthesized sulfonated Sesamum indicum oil could be considered as a substitute for imported fatliquor in the leather industry.

Diagnosing the environmental impacts of typical fatliquors in leather manufacture from life cycle assessment perspective

The environmental impacts of typical fatliquors were diagnosed by the life cycle assessment of industrial production and use(post-tanning)processes.Life cycle impact assessment and sensitivity analysis showed that fatliquor and fatliquoring operation were the major contributors to the environmental impacts of post-tanning because a large amount of fatliquors was consumed during fatliquoring operation.The environmental impacts of fatliquors decreased in the following order:chlorinated paraffin(CP)>sulfonated rape oil(SNR)>sulfated rape oil(SR)>phosphated rape oil(PR)>oxidized-sulfited rape oil(OSR).Sulfuric acid,fuming sulfuric acid,and chlorine used for fatliquor modification gave the main contribution to most impact categories for SR,SNR,and CP production,whereas rape oil contributed the most for PR and OSR production.OSR use process reduced the primary energy demand,abiotic depletion potential,and global warming potential by 38.5%,56.0%,and 48.5%,respectively,compared with CP use process.These results suggested that biomass-derived fatliquors,especially oxidized-sulfited and phosphate modified fatiliquors,helped reduce the environmental burdens in leather manufacturing.

Evaluation and improvement of the oxidative stability of leather fatliquors

Fatliquor oxidation may give leather unpleasant odor,and excessive amounts of Cr(VI)and volatile organic com-pounds.The accurate evaluation and improvement of the oxidative stability of fatliquors are of great significance to high-quality leather manufacturing.We proposed a set of practical methods for evaluating the oxidative stability of fatliquors on the basis of oxidation induction time,change in iodine value(∆IV),and change in acid value(∆AV)under accelerated oxidation conditions(at 100°C with 10 L/h of air).Oxidation induction time is a highly sensitive marker for quantifying the oxidative stability of fatliquors,and∆IV and∆AV that are low cost and easy to operate are useful in evaluating the oxidative stability of fatliquors when the oxidation induction time is less than 22 h.The number of double bonds in fatliquors is an important factor affecting oxidative stability.The sulfation modification of fatliquors that greatly reduces double bonds and the addition of antioxidants,especially butylated hydroxyanisole and butylated hydroxytoluene,markedly improve oxidative stability of fatliquors.