Study On Blending,Oxygen Barrier And Active Packaging Properties Of Polyamide 610/poly(vinyl Alcohol)Bio-based Blends

The oxygen permeation rates,average volumes of free-volume-cavities(Vf)and fractional free volume(Fv)values of polyamide 6,10(PA610)/poly(vinyl alcohol)(PVA)(i.e.PA610xPVA05y,PA610xPVA08y and PA610xPVA14y)bio-based blend films reduced to a minimal value,when their PVA contents reached a corresponding optimal value,respectively.The minimal oxygen permeation rate,Vf and Fv values obtained for the optimal PA610xPVAzy blown films were reduced considerably with decreasing PVA degrees of polymerization.The oxygen permeation rate of the optimal bio-based PA61080PVA0520 blown film was only 2.4 cm3/m2.day.atm,which is about the same as those of the most often used high barrier polymers ethylene-vinyl alcohol copolymer(EVOH).Experimental findings from dynamic mechanical analysis,differential scanning calorimetry,wide angle X-ray diffraction and Fourier transform infrared spectroscopy of the PA610XPVAzy blend series suggest that PA610 and PVA in PA610xPVAzy are miscible to some extent at the molecular level when their PVA contents are ? the corresponding optimal values.The considerably enhanced oxygen barrier properties of the PA610xPVAzy blend films with optimized compositions are attributed to the significantly reduced local free-volume characteristics.The oxygen scavenger compound was prepared by mixing modified iron(MFe),anhydrous calcium chloride with zeolite and its oxygen depletion properties were systematically investigated.The optimal compound was obtained by adjusting the compositions of each scavenger component.The peroxide value(POV)with/without optimal oxygen scavenger compound in a modeled sample were compared to prove the effect of the compound.The experimental results clearly suggested that the oxygen depletion rates of the oxygen scavenger compound with MFe powders were much faster than those with pure iron powders in the same weight.With the proper amounts of sodium chloride in MFe powders,anhydrous calcium chloride and zeolite in the oxygen scavenger compound,the residual oxygen content in the sealed bottle after a specific period was reduced to a minimum value.The minimal residual oxygen content reduced to around 3.0%after 108 days in a sealed bottle at 25°C and 100%relative humidity,when the oxygen scavenger compound used in the active packaging system was prepared by mixing 2g modified iron powder with 2g zeolite and 0.75g anhydrous calcium chloride.The optimal oxygen scavenger compounds were placed in polyethylene,PA610 and PA61O80PVA0520 packagings to form an active packaging systems,respectively.The minimal POV reduced to around 1.3 after maintaining 144 hours in the best active packaging system at 25°C.These results clearly indicated that the optimal oxygen scavenger compound effectively inhibited the lipid oxidation in the active packaging system.