Northampton Electronic Collection of Theses and Research

Extraction, characterisation and application of gelatin from chrome-tanned leather waste

Martínez de Luna, M. C. (2007) Extraction, characterisation and application of gelatin from chrome-tanned leather waste. Doctoral thesis. The University of Northampton.

Item Type: Thesis (Doctoral)
Abstract: The most significant problem of the tanning industry is waste generation. The presence of chromium in leather waste represents a potential hazard due to the possibility of Cr(III) being converted to its toxic state, Cr(VI). The treatment of chrome-tanned leather waste described in this research occurs in three phases: dechroming; isolation of gelatin, and application of the gelatin produced in the finishing of leather. Chrome-tanned shavings were dechromed and subsequently used for the production of gelatin. Gelatin was isolated from dechromed shavings in a one-step process, through thermal and chemical hydrolysis, using the hydrolytic agents ammonia, sodium hydroxide and acetic acid. The gelatin obtained through thermal hydrolysis exhibited better properties, in terms of gel strength, melting point, swelling and thermal properties, than the gelatin obtained through chemical hydrolysis and the former process was more cost-effective in terms of time, chemicals and waste production. The use of gelatin may be limited by its poor mechanical properties. The introduction of chemical modifications, using the crosslinking agents glutaraldehyde (GTA), oxazolidine II, ethylene glycol cliglycidyl ether (epoxy compound), hexamethylene dii socyanate (HMDC) and I -ethyl-3 -(3 -dimethylaminopropyl) carbodiimide (EDC), improved the performance in terms of strength and stability of the gelatin: oxazolidine and ethylene glycol diglycidyl ether are the most suitable since they confer plasticising properties in addition to stabilising the gelatin. A plasticiser (glycerol) was added into the matrix network of gelatin, increasing its flexibility. The isolated gelatin and a mixture of gelatinlglycerol were compared in use as a replacement for the commercial protein binder, casein, for glazed finishing. The finishing formulations were crosslinked with epoxy compound and oxazolidine. Physical tests carried out on the finished product showed promising results, with the gelatin/epoxy formulation showing potential for application. Ihe potential fbr gelatin isolated from chrome shavings to he produced as a high-added value material lor new applications in the future, such as a component tor finishing Formulations in the leather industry, was demonstrated
Subjects: T Technology > TS Manufactures > TS967 Chemistry and science of leather
T Technology > TS Manufactures > TS965 Leather technology > TS965.5 Tanning
T Technology > TD Environmental technology. Sanitary engineering > TD1020 Hazardous substances and their disposal
T Technology > TD Environmental technology. Sanitary engineering > TD794.5 Recycling
Creators: Martínez de Luna, Mercedes Catalina
Department: School of Applied Sciences (to 2009) > Theses (to 2009)
Faculties, Divisions and Institutes: University Faculties, Divisions and Research Centres - OLD > School of Applied Sciences (to 2009) > Theses (to 2009)
Date: 2007
Date Type: Completion
Number of Pages: 221
Language: English
Status: Unpublished
Institution: The University of Northampton

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