Synthesis of Plastic Films from Inulin by Acylation

An Empirical Model for Predicting Biodegradation Profiles of Glycopolymers

Pollution caused by plastic materials has a great impact on the environment. The biodegradation process is a good treatment solution for common polymers and biodegradation susceptible ones. The present work introduces new insight into the biodegradation process from a mathematical point of view, as it envisions a new empirical model for this complex process. The model is an exponential function with two different time constants and a time delay, which follows the weight loss profile of the polymer during the biodegradation process. Moreover, this function can be generated as the output variable of a dynamic exogenous system described through state equations. The newly developed models displayed a good fit against the experimental data, as shown by statistical indicators. In addition, the new empirical model was compared to kinetics models available in the literature and the correlation coefficients were closest to 1 for the new empirical model in all discussed cases. The mathematical operations were performed in the MATLAB Simulink environment.

Biodegradation Pattern of Glycopolymer Based on D-Mannose Oligomer and Hydroxypropyl Acrylate

Glycopolymers are polymers with sugar moieties which display biodegradable and/or biocompatible character. They have emerged as an environmentally-friendly solution to classical synthetic polymers and have attracted significant research interest in the past years. Herein, we present the synthesis of a D-mannose based glycopolymer with biodegradable features. The glycopolymer was synthesized by radical copolymerization between a D-mannose oligomer bearing polymerizable double bonds and 2-hydroxypropyl acrylate, in a weight ratio of 1:2. The copolymerization kinetics was investigated by differential scanning calorimetry (DSC) and the activation energy of the process was comparatively assessed by Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa methods. The obtained glycopolymer displayed good thermal behavior, fact proven by thermogravimetrical (TG) analysis and it was submitted to biodegradation inside a bioreactor fed with water from the Bega River as the source of microbial inoculum. The glycopolymer sample degraded by approximately 60% in just 23 days. The biodegradation pattern of the glycopolymer was successfully fitted against a modified sigmoidal exponential function. The kinetic model coefficients and its accuracy were calculated using Matlab and the correlation coefficient is more than promising. The changes inside glycopolymer structure after biodegradation were studied using TG and FTIR analyses, which revealed that the sugar moiety is firstly attacked by the microbial consortia as nutrient source for proliferation.

Reducing the brittleness of zein films through chemical modification

Zein protein is a major coproduct of biofuel from corn. To reduce the brittleness of zein films, a new type of zein-based biomaterial, was synthesized by chemical modification of zein with lauryl chloride through an acylation reaction. The final products were confirmed by (1)H NMR, FT-IR analysis, and SDS-PAGE. Thermal analysis detected no microphase separation in the synthesized polymer matrix. As the content of lauryl moiety increased, the glass transition temperatures of modified zein decreased by as large as 25.8 °C due to the plasticization effect of the lauryl moiety. In addition, mechanical and surface properties of cast films from acylated zein were also investigated. The elongation at break of modified zein sheet was increased by about 7-fold at the high modification level with some loss of mechanical strength. The surfaces of modified zein films were as uniform as unmodified zein film but more hydrophobic, further suggesting that no microphase separation happened during the film formation process. This work indicated the potential of these new biomaterials in the development of biodegradable food packaging materials and delivery systems.

Highly stable foams from block oligomers synthesized by enzymatic reactions

We have synthesized a new amphiphilic block oligomer by the enzymatic linking of a fatty acid (lauric acid) to a fructan oligomer (inulin) and tested the functionality of this carbohydrate derivative in foam stabilization. The structure of the modified oligosaccharide was found to be (Fruc)n(Glc)1CO-C11H23, which implies that on average one lauric acid molecule was linked to one inulin molecule. The new component produces foams with exceptional stability. Our results show that enzymatic acylation can produce an entirely new class of amphiphilic materials, with functionality comparable to that of synthetic block copolymers.