Bioplastic Nanocomposites Based on Polybutylene Succinate Adipate (PBSA)/Aminosilane Modified Nonocrystalline Cellulose: Structural, Thermal and Physical Properties

Nanocrystalline cellulose (NCC) has received much attention to be used as nanofiller in bioplastics due to its biodegradability, renewability and fantastic mechanical properties. The well distribution of NCC is a key factor in determining the enhanced properties of bioplastics/NCC nanocomposites. Surface modification of NCC using aminosilanes can improve its dispersion in a polymer matrix.

N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane was used for surface modification of nanocrystalline cellulose (NCC) to improve its affinity to polybutylene succinate adipate (PBSA). PBSA-based nanocomposites, containing 0, 0.1, 0.3, 0.5, 1 and 2 phr modified, NCC were prepared by solution mixing. The structural, thermal and physical properties of the prepared samples were characterized using FTIR, RMS, SEM, TGA, DSC and water absorption techniques.

The chemical modification of NCC was confirmed by FTIR, TGA and EDX. Linear viscoelastic measurements show that the incorporation of NCC in PBSA resulted in a non-terminal behavior and viscosity up-turn in the low frequency range, which are pronounced in high loadings of NCCs. The enhanced affinity of NCC toward PBSA, obtained by surface modification, resulted in hydrodynamic interactions between them, leading to the formation of a 3D network structure in the matrix. The SEM results showed well distribution of modified NCC in the PBSA matrix. The TGA results showed that the thermal stability of PBSA increases in the presence of silane-modified NCC. This can be attributed to the interactions formed between the components of nanocomposite, needing higher energy for thermal degradation. Study on DCS results indicated that the crystallization temperature of the nanocomposites containing modified NCC increases as a consequence of well distributed modified NCC. The water absorption results demonstrated that the water uptake of the samples containing modified NCC increases as compared to virgin PBSA...