Study On Preparation And Properties Of Zein Composite Materials

Oil pollution is an important category of environmental pollution.The effective solution of the oil pollution problem can not only prevent environmental pollution,but also enable the recycling of energy.Therefore,oil absorbing materials have attracted attention.At present,oil-absorbing materials are mainly composed of synthetic polymers,and the synthetic polymers are likely to cause secondary pollution due to they are degraded difficultly.As a rich and inexpensive natural polymer,Zein is an amino acid-based plant protein that has the advantages of biocompatibility and biodegradability.In this paper,Zein was used as raw material,which respectively combined the bio-compatible polyvinyl alcohol?PVA?and polysaccharide natural polymer sodium alginate?SA?to prepare porous oil-absorbing materials ZePSiFeGel and ZSSiOsp with special wetting properties.Besides,Zein was compounded with nano-silica?SiO₂?to obtain composite film?Z/nSi?.Further,the optimal preparation conditions were investigated.The structure and morphology of the three composites were characterized by Fourier transform infrared spectroscopy?FT-IR?,X-ray diffraction?XRD?,and thermogravimetric analysis?TG?and scanning electron microscopy?SEM?.The surface of the oil-absorbing material was tested by a contact angle tester,and the oil-absorbing properties of the oil-absorbing material and the drug releasing properties of the composite film were studied.Thesis mainly includes the following parts:Chapter 1,Firstly,the source and functional recycling of discarded natural polymers were introduced.Secondly,main types of polymer oil absorption materials were summarized from two aspects:synthetic polymers and natural polymers.Besides,the description of waste natural polymer oil absorption materials is also given.Now,most of the oil absorbing materials are synthetic polymers.Natural oil absorbent materials,including oil-absorbing materials prepared from waste natural polymers,have some reports,but they still have the issues such as low oil absorption efficiency and are difficult separation.So oil absorption materials prepared by natural polymer have a lot of research value and space.Chapter 2 is preparation of hydrophobic Zein-based composite gel and its oil absorption property,which via using zein and PVA as raw materials and adopting freeze-thaw technology,the ZePHGel with network structure was firstly prepared,and then Fe₃O₄ was introduced in ZePHGel by in-situ precipitation method.Finally,the magnetic ZePSiFeGel with hydrophobic was obtained after silane modification by low surface energy material KH570.The morphology and structure of the composite gel were characterized by FT-IR,XRD,SEM and TG.It was found that the gel had a multi-layered network structure and the contact angle was 132.8^o.The absorption of ZePSiFeGel for pure oil and separation performance of different oil-water mixtures were tested.It was found to have significant oil absorption and oil-water separation capabilities.Chapter 3 is preparation of porous hydrophobic Zein/SA sponge and its oil absorption property.Firstly,a composite sponge?ZSsp?with a porous structure was prepared using zein and SA as a raw material,glutaraldehyde?GA?and CaCl₂ as cross-linking agent and glycerin as a plasticizer.Further,a hydrophobic porous ZSSiOsp was obtained by soaking with a hydrophobic SiO₂ and a low surface energy material n-octadecanethiol?OCT?mixed solution.The morphology and structure of the ZSSiOsp were characterized by FT-IR,XRD,SEM and TG.It was found that the sponge had a multi-layered network structure and the contact angle was 135.1°.The absorption of ZSSiOsp for pure oil and separation performance of different oil-water mixtures were tested.It was found to have significant oil absorption and oil-water separation capabilities.Chapter 4 is preparation of pH sensitive Zein-based composite membrane and its drug release properties.Using Zein and SiO₂ as raw materials,glycerine and polyethylene glycol were mixed plasticizers,and the Z/nSi with certain mechanical properties was prepared by injection coating.The morphology and structure of Z/nSi were characterized by FT-IR,XRD,SEM and TG.The water absorption,salt absorption,and air permeability of Z/nSi were also investigated.The results show that the composite membrane can provide suitable wet microenvironment,which is conducive to wound healing.By loading the model drugs rhodamine B and vitamin B_2,the RB@Z/nSi and VB₂@Z/nSi drug-loaded membranes were prepared.Further,the release properties of two kinds of drug-loaded membranes in different buffers and different SiO₂ content were investigated.It was found that the release conditions of different SiO₂ were different and the release was different in the buffer with different pH.In summary,using inexpensive natural polymer Zein as the substrate,the two oil absorbing materials with the performance of oil absorption and oil-water separation was successfully prepared,which can be used for oil pollution treatment or oil-water separation area.And the resulting composite membrane has certain mechanical properties and pH sensitivity,which can be used in the field of external materials and is expected as a carrier for treating skin wounds and oral ulcers.