Preparation And Properties Of Starch/PBAT/Cellulose Films

Starch/Poly(butylene adipate-co-terephthalate)(PBAT)composite films are a kind of starch-based biodegradable materials with great potential for commercial application,but their excellent performance depends on the addition of high proportion of PBAT.PBAT is a biodegradable material from the polymerization of petrochemical monomers,which is costly and continuously depleting non-renewable crude oil resources.When the proportion of starch adding in starch/PBAT composite film is increased,the overall performance of the material would deteriorate,which leads to the properties of starch/PBAT composite film with high starch content far from meeting the conditions of application,especially its poor mechanical,barrier performance and strong moisture sensitivity.Thus,in this study starch and PBAT were used as film-forming matrix,and the effects of modified cellulose types,adding methods,adding states,viscosity types and emulsifier types on the structure and properties of the films were studied.The main findings were as follows:1.The types and adding methods of modified cellulose had a significant impact on the performances of composite films.Cellulose interacts with starch through hydrogen bonding,and the addition of cellulose in emulsion made the composite film more uniform and compact.The addition of MCC by adding emulsion enhanced the mechanical properties of the composite film most significantly(TS 40%,YM 149%),while HPMC added by adding emulsion improved the performance of the composite film the most comprehensively,improving the mechanical properties of the composite film(TS 30%,EAB 26%,YM 92%),water resistance(20%),oxygen barrier(93%),surface hydrophobicity(20%),water resistance and thermal stability.2.HPMC viscosity types and adding states have a significant impact on performances of the composite film.Entanglement build-up within/between molecular chains through hydrogen bonding exists in the HPMC powders.HPMC interacts with the composite films through hydrogen bonds,and HPMC in the emulsion state made the composite film more uniform and dense,especially HPMC-10 c P.HPMC-10 c P(emulsion state)enhanced the mechanical properties of the composite film by the largest(TS 32%,EAB 20%,YM 135%),while improving the water barrier(23%),oxygen barrier(94%),visible light transmittance(55%)and surface hydrophobicity(8%)of the composite film.It also improved the thermal stability,water solubility of the composite films and reduced the swelling degree.The addition of HPMC in a gel state gave the composite films a UV barrier.3.The length of the emulsifier-side chain has a significant effect on the performances of the composite films.The phenolic hydroxyl group of the emulsifier mainly interacts with HPMC-10 c P through hydrogen bonds,and the steric hindrance effect of its benzene ring molecular structure promoted the stretching and uniform dispersion of HPMC-10 c P molecular chain.The emulsifier interacted with the composite films through hydrogen bonds,and its amphiphilic properties improved the compatibility and stability of the film-forming matrix.Adding HPMC-10 c P with emulsifier made the films more uniform and dense,and significantly reinforced the mechanical properties,surface hydrophobicity,water barrier,visible light transmittance and water resistance of the films,especially propyl p-hydroxybenzoate.