Study On Preparation Of Carboxymethyl Cellulose Composite Film And Its Antibacterial Performance

Environmental pollution caused by non-degradable synthetic polymer packaging is becoming more and more serious.Environmentally friendly biodegradable polymer packaging has gradually attracted people's attention.The carboxymethyl cellulose(CMC)has the advantages of good water solubility,non-toxicity,non-allergenicity,etc.,but CMC film shows lower mechanical property.Starch(SR)is a high molecular carbohydrate with good biodegradability and low price.It can be used to compound with CMC to prepare CMC/SR composite film with excellent mechanical properties.However,CMC/SR films have no antimicrobial activity and cannot meet the requirements of active packaging.Therefore,it is necessary to introduce functional materials into the CMC/SR composite film to provide antibacterial activity.Silver nanoparticles(Ag NPs)have good antibacterial properties and biocompatibility,and they can be introduced into CMC/SR composite films to prepare antibacterial Ag NPs/CMC/SR(ACS)composite films.In addition,commercial CMC is expensive due to the increasing demand for commercial CMC in recent years and the shortage of raw materials.In order to reduce the production cost of ACS composite films,the CMC is prepared from resource-rich waste disposable paper cups(WDPC)in this paper.The prepared CMC is expected to replace commercial CMC in ACS composite films.Using the commercial CMC and SR as reducing agent and stabilizer,Ag NPs/CMC/SR composite film was prepared by in-situ reduction method.The obtained Ag NPs were uniformly distributed in the CMC/SR network and its diameter was in the range of 8-16nm.In the ACS composite film,the SR to CMC ratio had an important effect on the tensile strength and elongation at break of the ACS film.When the ratio of SR to CMC is 4 to 0.6,the maximum tensile strength of the composite film reached 9.8 MPa and the elongation at break reached 63%.Moreover,the crystallization of as-prepared ACS films decreased with the increasing of SR content.All ACS films exhibited excellent antibacterial activity against S.aureus and E.coli.The inhibition effect of bacteria increased significantly with the increasing of the concentration of Ag NPs solution.Therefore,as-prepared ACS films in this paper can be considered as potential candidates for antimicrobial packaging.The Ag NPs/CMC/SR composite films prepared in this paper have good thermal stability,mechanical properties,and show good antibacterial properties against S.aureus and E.coli.They have potential applications in antibacterial packaging.The cellulose was extracted from WDPC in the alkaline cooking method.CMC with high degree of substitution(DS)was prepared by solvent method under the optimized conditions using cellulose as raw material.The results showed that when the etherification temperature was 70?,the etherification time was 1.5 h,and the amount of C2H3ClO2 was 7 g,the DS of CMC was as high as 1.21.Under optimal conditions,the CMC was band-shaped and rod-shaped with a diameter of 25-50?m.The FTIR results showed that the cellulose molecules reacted with the etherifying agent and the hydroxyl groups in the cellulose molecules were replaced by carboxymethyl groups.The XRD results showed that the diffraction peaks of CMC disappeared at 2?=16.17° and 22.77°,and new diffraction peaks appeared at 2?=27.46°,31.78° and 45.37°.In addition,CMC exhibited lower degradation temperature and higher residual weight after degradation.In this paper,The CMC with high degree of substitution was successfully prepared from discarded disposable paper cups,which reduced the investment cost of traditional raw materials and provided a new way for the recycling of discarded disposable paper cups.The prepared CMC is expected to replace commercial CMC for the preparation of CMC composite films.