Improved degradability and mechanical properties of bacterial cellulose grafted with PEG derivatives

Abstract

New functional materials based on bacterial cellulose (BC) grafted with poly(ethylene glycol) PEG derivatives for food packaging applications and a facile method for assessing the degradation rates of the final materials are presented. Two types of materials were obtained by grafting the BC films (BCF), respectively lyophilized BC pellicles (BCL) with three PEG derivatives of different molecular weights through radical polymerization. The BC based polymer materials were characterized by SEM, FT-IR, contact angle measurements, and TGA. Tensile tests and DMA analysis were used to compare the two types of materials in terms of shear-modulus, tensile strength and performance giving suitable information for food packaging applications. A new degradation evaluation method, that we propose herein, offers quantitative information about the degradation process in contrast with the SEM analysis, primarily used in literature, which is not decisive in all cases because it characterizes only small parts of the sample. The degradation rates evidenced that the PEG derivatives of higher molecular weight grafted on the surface of BCF led to an acceleration of the degradation process compared with the pristine samples. A good correlation was obtained between the samples analyzed by SEM after the degradation process and their degradation rates were mathematically determined.

Investigation of the Effect of Poly[poly(ethylene glycol) methyl ether methacrylate] Addition on the Electrochemical Performance of Cellulose-Based Solid- and Gel-Polymer Electrolytes in Lithium-Ion Batteries

“…Degradation between 300 and 450 °C is related to cellulose, and degradation between 220 and 330 °C is related to poly­(PEGMA) chains. , In SPE and GPE samples, another stage of destruction can be seen in the range of 100–200 °C, which is due to the presence of LiPF 6 salt in the structure of SPE and GPE . According to the results summarized in Table S2, PEGMA undergoes thermal degradation at lower temperatures compared to cellulose because the presence of ester moieties causes low thermal stability of this polymer. , According to DSC analysis of PEGMA-modified cellulose samples (Figure c,d), two glass-transition temperatures ( T g ’s) were observed, which were >0 °C related to cellulose and <0 °C related to poly­(PEGMA). The T g related to cellulose was not seen in some samples, which may be due to the high scan rate.…”

“…36 According to the results summarized in Table S2, PEGMA undergoes thermal degradation at lower temperatures compared to cellulose because the presence of ester moieties causes low thermal stability of this polymer. 37,38 According to DSC analysis of PEGMA-modified cellulose samples (Figure 2c,d), two glasstransition temperatures (T g 's) were observed, which were >0 °C related to cellulose and <0 °C related to poly(PEGMA). The T g related to cellulose was not seen in some samples, which may be due to the high scan rate.…”