Preparation And Characterization Of Functional Gelatin Composite Films

Gelatin is a kind of natural biological macromolecule material derived from the hydrolysis of collagen in the skin,bones and other connective tissues of an animal.It has the characteristics of easy moldability,biodegradable entry,Year research hot spots.However,its poor toughness,easy to break,which seriously hampered its application,so the modification of gelatin is the current research direction.At present,gelatin modification methods are mainly added plasticizers,cross-linking agents,biological macromolecules.In this thesis,gelatin matrix composite membrane was prepared by solution casting method,and its structure,thermal stability,mechanical properties,optical and water absorption properties were characterized.The main research contents and results are as follows:1.Microfibrillated cellulose(Microfibrillated,MFC)as the reinforcing phase,glycerol as a plasticizer,the effect of microfibrillated cellulose content on the properties of gelatin/microfibrillated cellulose composite membrane can be SEM image Gelatin and microfibrillated cellulose have good compatibility;the effect of microfibrillated cellulose on the mechanical properties of the gelatin/microfibrillated cellulose composite membrane was studied.The results show that with the microfibrillated cellulose content,The tensile strength of gelatin/microfibrillated cellulose composite films tended to increase,the elongation at break showed a downward trend,and the gelatin film had a better toughness.The effects of microfibrillated cellulose on gelatin/micro The results showed that the melting transition temperature of the gelatin/microfibrillated cellulose composite membrane increased with the increase of the content of the microfibrillated cellulose.Compared with pure gelatin,the melting temperature increased 44.1?,the thermal stability of the composite film is improved,indicating that microfibrillated cellulose can enhance the thermal stability of the composite film;the effect of microfibrillated cellulose on the transparency of the gelatin/microfibrillated cellulose composite film Impact,The results showed that the transmittance of gelatin/microfibrillated cellulose composite membrane remained at least 80% at the visible light central point of 600 nm,which was a transparent material.The effect of microfibrillated cellulose on gelatin/ microfibrillated cellulose The results showed that with the increase of microfibrillated cellulose content,the water absorption of gelatin/microfibrillated cellulose composite membrane showed a downward trend.When the content of microfibrillated cellulose was 1.0%,the water absorption Was 391.1%,microfibrillated cellulose to a greater extent to improve the water absorption of gelatin film.2.The effect of nanocrystalline cellulose content on the properties of gelatin/nanocrystalline cellulose composite membranes was studied with nanocrystalline cellulose(NCC)as reinforcing phase and glycerol as plasticizer.SEM images It can be seen that when the nanocrystalline cellulose content is 0.2% and 0.4%,the surface of the composite film is relatively smooth.When the mass concentration of the nanocrystalline cellulose is 0.6%,the surface of the composite film can be seen uniformly dispersed fibrous,When the mass concentration was 0.8%,agglomeration occurred.When the mass concentration was 1.0%,the surface of the composite film was accompanied by the presence of agglomeration and the occurrence of cracks.The effect of nanocrystalline cellulose on the mechanical properties of gelatin/nanocrystalline microcrystalline cellulose composite membranes was studied.The results show that the tensile strength of gelatin/nanocrystalline microcrystalline cellulose composite membranes increases with the increase of nanocrystalline cellulose content Increase and then decrease,the elongation at break shows a downward trend.When the content of nanocrystalline cellulose is 0.6%,the turning point of tensile strength(13.56MPa)has a great improvement on the poor toughness of gelatin film.The effect of nanocrystalline microcrystalline cellulose on the thermal stability of gelatin/nanocrystalline cellulose composite films was studied.The results show that the melting temperature of gelatin/nanocrystalline cellulose composite films increases with the increase of nanocrystalline cellulose content Compared with the pure gelatin,increased by 69.5?,indicating that nanocrystalline cellulose can enhance the thermal stability of the composite film;studied the effect of nanocrystalline cellulose on the transparency of the gelatin/nanocrystalline cellulose composite film The results showed that the light transmittance of gelatin/ nanocrystalline cellulose composite was 81.2% when the amount of microcrystalline cellulose was 0.6%,which was a transparent material,and the addition of small amount 80%.The effect of nanocrystalline cellulose on the water absorption of gelatin/nanocrystalline cellulose composite membranes was studied.The results showed that with the increase of nanocrystalline cellulose content,the water absorption of gelatin/nanocrystalline cellulose composite membranes When the content of nanocrystalline cellulose was 1.0%,the water absorption rate was 271.1%.Nanocrystalline cellulose improved the water absorption of gelatin film to a great extent.3.The effect of chitosan content on the properties of gelatin/chitosan composite membrane was studied by using chitosan(CS)as reinforcing phase and glycerol as plasticizer.SEM images showed that gelatin and chitosan The effect of chitosan on the mechanical properties of gelatin/chitosan composite films was studied.The results showed that with the increase of chitosan content,the tensile strength of gelatin/chitosan composite films was When the content of chitosan was 30%,the tensile strength and elongation at break were 11.25 MPa and 108.9%,respectively,which greatly improved the inferior toughness of gelatin film.The effect of chitosan on the thermal stability of gelatin/chitosan composite films was studied.The results showed that the melting transition temperature of gelatin/chitosan composite films increased with the increase of chitosan content,Ratio,increased 16.3 ?,the thermal stability of the composite film is improved,indicating that nanocrystalline cellulose can improve the thermal stability of the composite film;chitosan on the transparency of the gelatin/chitosan composite membrane,the results It shows that the center of visible light is 600 nm,The light transmittance of the gelatin/chitosan composite membrane basically maintained more than 80%,belonging to the transparent material;the effect of the chitosan on the water absorption capacity of the gelatin/chitosan composite membrane was studied.The results showed that with the chitosan content,The water absorption of gelatin/chitosan composite membrane showed a downward trend.When the content of chitosan was 30%,the water absorption was 251.1%.Chitosan improved the water absorption of gelatin membrane to a great extent.