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Poly vinyl alcohol (PVA)/Zinc acetate (ZnAc) Solid Polymer Electrolytes (SPEs) of different ZnAc weight percentage (5%, 10%, 15%, 20%) were prepared. Positron Lifetime Spectroscopy (PLS) studies reveal the increased fractional free volume (Fv) from 1.93% to 2.16% for 20 wt% of ZnAc loading. The increased ionic conductivity of PVA/ZnAc SPEs for 20 wt% of ZnAc loading suggests the increased concentration of Zn2+ cations and acetate anions. The ionic conductivity of PVA/ZnAc SPEs increases at higher frequencies of the applied electric field due to the increased polarization of dipoles. The increased ionic conductivity of PVA/ZnAc SPEs with increased fractional free volume suggests that the mobility of Zn2+ and acetate ions is favored by the amorphous phase of the SPEs. The XRD results justify the increased amorphousness of PVA/ZnAc SPEs. FTIR studies confirm the formation of polymer salt complexes due to chemical bonding between C–H group of PVA and carbonyl group of (C=O) of ZnAc salt.

A series of high‐density polyethylene (HDPE) – chitosan (CS) composites with varying concentrations of chitosan have been prepared using a peroxide‐initiated melt mixing process with maleic anhydride as compatibilizer. Palm oil has been added as a plasticizer to the optimized HDPE/CS5 composite. The variation in the free hole volume, microstructure, and crystallinity of the prepared composites has been studied using Positron annihilation lifetime spectroscopy (PALS), dynamic mechanical analysis (DMA), and X‐ray diffractometry (XRD) respectively. The interaction between HDPE and chitosan is evidenced from the FTIR spectroscopic studies. The addition of palm oil to optimized HDPE‐CS composite increased the crystallinity upto 41.3%. A shift as well as a decrease in loss modulus was obtained for 5 wt% chitosan added HDPE sample which can be ascribed to the better crosslinking observed in the composite. The increased amorphization of HDPE‐chitosan composites with a higher concentration of chitosan beyond the optimized concentration is observed from the tan delta values. Free‐hole value is reduced by 20 Å3 with the addition of 5 wt% palm oil to HDPE/CS5 composite system. The microstructural analysis shows evidence of efficient interaction of HDPE‐chitosan system that can be used for further applications in medical field and food packaging industry.