Viscoelastic Properties of Epoxidized Natural Rubber/Poly(lactic acid) PLA/ENR Blends Containing Glycidyl-POSS and Trisilanolisooctyl-POSS as Functional Additives

Magdalena Lipińska; Klaudia Toczek; Magdalena Stefaniak

doi:10.3390/ma14102686

Viscoelastic Properties of Epoxidized Natural Rubber/Poly(lactic acid) PLA/ENR Blends Containing Glycidyl-POSS and Trisilanolisooctyl-POSS as Functional Additives

Materials (Basel). 2021 May 20;14(10):2686. doi: 10.3390/ma14102686.

Authors

Magdalena Lipińska¹, Klaudia Toczek¹, Magdalena Stefaniak¹

Affiliation

¹ Institute of Polymer and Dye Technology, Lodz University of Technology, 90-924 Lodz, Poland.

Abstract

The glycidyl-POSS (Polyhedral Oligomeric Silsesquioxanes, Polysilsesquioxane, POSS) (Gly-POSS) and trisilanolisooctyl-POSS (HO-POSS) were applied as functional additives influencing on the viscoelastic properties of the dynamic vulcanized PLA/ENR (poly(lactic acid)/epoxidized natural rubber) blends. The plasticizing effect of HO-POSS on PLA/ENR melt, leading to the decrease of complex viscosity at 160 °C, was observed. After the incorporation of Gly-POSS into PLA/ENR blends the complex viscosity increased confirming that the epoxy groups of Gly-POSS were able to react with the functional groups of ENR and the groups present at the end of PLA chains. The incorporation of Gly-POSS into 40:60 PLA/ENR blend provided significant enhancement of the storage shear modulus G' at 30 °C. Furthermore, the glass transition temperatures T_g of ENR phase for PLA/ENR/Gly-POSS blends were shifted to higher values of temperature as compared with blends modified by HO-POSS. Strong reduction of the elongation at break E_b for 40:60 PLA/ENR/Gly-POSS blend indicated that Gly-POSS particles acted as multifunctional cross-links reducing elasticity of the material. The modification of 40:60 PLA/ENR blend by HO-POSS molecules led to lower values of composting coefficient K_C indicating stronger deterioration of the mechanical properties that resulted from more intense degradation processes occurring during disposal in soil.

Keywords: poly(lactic acid)/epoxidized natural rubber blends; polyhedral oligomeric silsesquioxanes POSS; thermoplastic vulcanizates; viscoelastic properties.