Biodegradable Starch/Chitosan Foam via Microwave Assisted Preparation: Morphology and Performance Properties

Abstract

The effects of chitosan (CTS) as the reinforcing phase on the properties of potato starch (PS)-based foams were studied in this work. The formic acid solutions of CTS and PS were uniformly mixed in a particular ratio by blending and then placed in a mold made of polytetrafluoroethylene for microwave treatment to form starch foam. The results showed that the molecular weight and concentration of CTS could effectively improve the density and compressive properties of starch-based foams. Furthermore, orthogonal experiments were designed, and the results showed that when the molecular weight of CTS in foams is 4.4 × 10⁵, the mass fraction is 4 wt%, and the mass ratio of CTS-PS is 3/4.2; the compressive strength of foams is the highest at approximately 1.077 mPa. Furthermore, Fourier transform infrared spectroscopy analysis demonstrated the interaction between starch and CTS, which confirmed that the compatibility between CTS and PS is excellent.

Keywords: chitosan; foam; microwave; orthogonal experiments; potato starch.

Figure 1

Schematic diagram of preparation of CTS-starch foams.

Figure 2

Intrinsic viscosity of CTS in 0.2 M HAc/0.1 M NaAc at 30 °C.

Figure 3

The surface morphologies of foams made from low (a), medium (c), and high (e) viscosity CTS and the corresponding inner morphologies (b,d,f). Scale bar = 500 μm

Figure 4

The density of foams with CTS solution for 4.2 wt%.

Figure 5

Compressive strength of foams with chitosan solution for 4.2 wt%.

Figure 6

Infrared spectrogram of materials.

Figure 7

Thermal decomposition process of materials (a): raw materials, (b): CTS–PS foams.

Figure 8

DSC diagrams of raw materials and CTS/PS foams.

Figure 9

The morphology of CTS-starch-based foams in deionized water (a): start time, (b): 3 days later, (c): 10 days later, (d): 18 days later, (e): 24 days later, (f): 30 days later.