Waste Wool, Poultry, Wool Keratin Degradation And Resource Utilization

Nowadays, studies on recycling wastes are gaining increasing attention because of the shortage of resources, particularly petroleum, and the more serious environmental problems. The large scale leather industry and poultry farming in our country produce great quantities of solid wastes each year from waste wool and feather. However, these reproducible keratin resources haven't yet got reasonable exploitation currently, with the most being treated by filling and burying. This result in impropriate land occupation, and brings serious pollution to atmosphere, water and soil environment. Meanwhile, the chemical products which have the petroleum as raw material, such as synthesized tan agent and plastic materials, produce serious environmental pollution that is difficult to degrade, such as the "white pollution" that we all know. Therefore, to reuse these natural resources of wool and feather, which otherwise will produce harm when abandand, in the produce of tanning agent and degradable film to substitute for petroleum-based synthesized tan agent and plastic film is of important scientific value, great economic significance and social benefit.The applied base, resources condition and studies progress at home and broad of keratin are reviewed in chapter 1.The prospects of recycling waste wool and feather keratin and the main problem in the research are put forward. At the same time, the aim of research, instruction thought and research content are ascertained.The preparation of keratin hydrolysate from waste wool by ultrasonic, the graft modification and its application in tan leather are illustrated in chapter 2. The use of pretreatment agent and ultrasonic in the preparation keratin by acid hydrolysis of waste wool has not been reported yet. The advantages of this method include:firstly, the hydrolysis rate is enhanced effectively; secondly, the dosage of acid is decreased greatly; thirdly, the molecular weight uniformity of keratin is improved evidently. The use of keratin hydrolysate in chrome tan has obvious incrassation effects on crust, and can raise the tensile strength and tearing strength, increase the water vapor of leather, and reduce the chrome content in the tanning waste.The application of keratin modification product that is prepared by graft copolymerization of ultrasonic keratin and acrylamide in chrome tan, can replace half chrome tanning agent, reduce the dosage of chrome tanning agent effectively, has good choice filling property and could raise quality of leather. Moreover, it not only treats waste wool reasonably but also has great significance to leather industry and environment protection. This method develops a novel route for the leather industrial cleaning production.The reaction condition and preparation method of keratin based film from waste wool and feather are explained in chapter 3.The preparation condition of keratin by reduction and alkali oxidization is optimized. The application of ultrasonic in the reaction can shorten hydrolysis time and raise hydrolytic efficiency. The molecular size and structure are analyzed by the GPC and XRD. The result of DSC-TG indicates that the prepared keratin has good thermal stability.The preparation conditions of composite films from keratin hydrolysate and polyvinyl alcohol (PVA) are explored and optimized. The analysis of XRD shows that the structure of the thin films is affected by keratin molecule size, the mass ratio of keratin and PVA, blend temperature, cross linker and plasticizer. The film has compact structure, smooth and neat surface, and there was good compatibility between keratin and PVA, which can be concluded from the AFM analysis. The result of DSC-TG shows that the blend of PVA and keratin from different methods under high temperature can improve the thermal property of film. The result of measurement displayed that the tensile strengthen of prepared film can reach the China standard (GB4455-94).The degradation experiments of the film show that the film has good property to naturally degrade. The germination experiment of the rapeseed shows the films have good properties to protect the water and preserve heat functions.The technology of extracting cystine from the waste wool that was from leather making industry is studied in chapter 4. The optimum condition for the hydrolysis is the mixture of acid and wool in a mass ratio of 1.8:1,120℃temperature and 8h for reaction.The content of cystine is 98.56%.The development of keratin tanning agent and keratin composite film, which has potential application foreground, provides the theoretical basis for the exploitation of keratin, makes these precious keratin resources of wool and feather going to reasonable utilization, and offer new ideals and a new approach to the exploitation of keratin and modified preparation novel materials.