Physical Properties, Spectroscopic, Microscopic, X-ray, and Chemometric Analysis of Starch Films Enriched with Selected Functional Additives.

Maciej Combrzyński,Sławomir Kulesza,Tomasz Oniszczuk,Marek Milanowski,Marcin Mitrus,Kamila Kasprzak-Drozd,Karolina Wojtunik-Kulesza,Marek Gancarz,Daniel Kamiński,Dariusz Karcz,Jakub Soja,Agnieszka Wójtowicz,Iwona Budziak-Wieczorek,Lidia Ślusarczyk,Arkadiusz Matwijczuk,Iwona Kowalska,Karol Kupryaniuk

doi:10.3390/ma14102673

Abstract

Biodegradable materials are used in the manufacture of packaging and compostable films and various types of medical products. They have demonstrated a large number of potential practical applications in medicine and particularly in the treatment of various cardiac, vascular, and orthopedic conditions in adults as well in children. In our research, the extrusion-cooking technique was applied to prepare thermoplastic starch (TPS), which was then utilized to obtain environmentally friendly starch-based films. Potato starch was the basic raw material exploited. Polyvinyl alcohol and keratin were used as functional additives in amounts from 0.5 to 3%, while 20% of glycerol was harnessed as a plasticizer. The processing of the thermoplastic starch employed a single screw extruder-cooker with an L/D ratio of 16. The film blowing process was carried out using a film-blowing laboratory line with L/D = 36. FTIR Spectroscopy was applied for the assignment of the prominent functional groups. The results showed that the processing efficiency of thermoplastic starch with functional additives varied depending on the level of polyvinyl alcohol and keratin addition. Moreover, the FTIR data correlated with the changes in the physical properties of the tested films. The analysis of FTIR spectra revealed several changes in the intensity of bands originating from stretching vibrations characteristic of the –OH substituent. The changes observed depended on the presence/lack of the hydrogen bonding occurring upon interactions between the starch molecules and the various additives used. In addition, notable changes were observed in bands assigned to glycoside bonds in the starch.

Highlights

The bioplastics market, which started to emerge not even 20 years ago, is growing rapidly and has already reached impressive production volumes
It was observed that an increase in polyvinyl alcohol and keratin content resulted in increased efficiency of extrusion-cooking
The observed relationships resemble the results achieved during the extrusion-cooking of thermoplastic starch with functional additives, including polyvinyl alcohol (PVA) [26]

Summary

Introduction

The bioplastics market, which started to emerge not even 20 years ago, is growing rapidly and has already reached impressive production volumes. It is estimated that the global production of plastics reached over 400 million tons in 2015. In 2018, the global production of plastics totaled 359 million tons [1]. In 2017, it was estimated that the global bioplastics manufacturing capacity would increase from 2.05 million tons to approx. In a 2009 report, European Bioplastics envisaged the growth of the biopolymer market by an average of 19% yearon-year between 2007 and 2020. The use of polymers, such as PLA (polylactic acid) and PHAs (polyhydroxyalkanoates), has the greatest impact on the ever-higher supply of biodegradable plastics. The largest market for biodegradable polymers is Europe. Within the European continent, the greatest developments in biopolymers are seen in Germany, Austria, Benelux, and Scandinavia [2]

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Methods

Results