Effects of Polyol-Based Plasticizer Types and Concentration on the Properties of Polyvinyl Alcohol and Casein Blend Films


Ucpinar Durmaz B., AYTAÇ A.

JOURNAL OF POLYMERS AND THE ENVIRONMENT, 2020 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası:
  • Basım Tarihi: 2020
  • Doi Numarası: 10.1007/s10924-020-01881-x
  • Dergi Adı: JOURNAL OF POLYMERS AND THE ENVIRONMENT

Özet

This study aimed to examine the structural, mechanical, thermal and barrier properties of the polyvinyl alcohol/casein (PVA/CA) films plasticized with poly(ethylene glycol) (PEG) and sorbitol (SOR). The films were prepared by solution casting technique at different loading levels of plasticizers (10-15-20-25%). The mechanical results indicated that PEG and SOR effectively plasticize the PVA/CA film while SOR efficiency was higher than PEG. The addition of plasticizers decreased the tensile strength while the increased elongation at break value of PVA/CA film. The maximum tensile strength was observed in 10% PEG addition as 37.5 MPa. On the other hand, maximum elongation at break value was observed in 15% SOR at 369% that was higher than the un-plasticized film about 58%. The water contact angle measurements showed that all films were hydrophilic structures (32-75 degrees). Also, the water vapour permeability of the un-plasticized film was measured as 6.4 g m(-1) s(-1) Pa-1 x 10(-11). This value decreased with the addition of PEG (5.5 g m(-1) s(-1) Pa-1 x 10(-11)) while increasing SOR addition (12.2 g m(-1) s(-1) Pa-1 x 10(-11)). The thermal degradation temperature of un-plasticized PVA/CA film was decreased with plasticization. The residual weight of un-plasticized PVA/CA was 12.5 wt. %, which decreased at 4.5 wt. % for PEG-25 and 4.8 wt. % for SOR-20 films. Also, the melting temperature of the films decreased by increasing the content of plasticizers. Melting temperatures of SOR containing films were lower than PEG containing the films. Consequently, un-plasticized and plasticized PVA/CA-based films successfully prepared and analyzed to determine the appropriate plasticizer. All prepared films exhibited acceptable properties for use as food packaging or biobased materials.