The Role of Birch Tar in Changing the Physicochemical and Biocidal Properties of Polylactide-Based Films

Abstract

The objective of this study was to produce bactericidal polymer films containing birch tar (BT). The produced polymer films contain PLA, plasticiser PEG (5% wt.) and birch tar (1, 5 and 10% wt.). Compared to plasticised PLA, films with BT were characterised by reduced elongation at break and reduced water vapour permeability, which was the lowest in the case of film with 10% wt. BT content. Changes in the morphology of the produced materials were observed by performing scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis; the addition of BT caused the surface of the film to be non-uniform and to contain recesses. FTIR analysis of plasticised PLA/BT films showed that the addition of birch tar did not change the crystallinity of the obtained materials. According to ISO 22196: 2011, the PLA film with 10% wt. BT content showed the highest antibacterial effect against the plant pathogens A. tumefaciens, X. campestris, P. brassicacearum, P. corrugata, P. syringae. It was found that the introduction of birch tar to plasticised PLA leads to a material with biocidal effect and favourable physicochemical and structural properties, which classifies this material for agricultural and horticultural applications.

Birch Tar Introduced into Polylactide and Its Influence on the Barrier, Thermal, Functional and Biological Properties of the Film Obtained by Industrial Extrusion

“…These results show that the 10% addition of an oily substance in the form of tar significantly changed the barrier properties, resulting in the possibility of using the obtained films. Richert et al [ 9 ] presented the results of water vapor permeability tests for a PLA sample with 10% tar content; however, the tested foil was obtained by the laboratory solvent method, with a difference of 1.5% between their reported results and those obtained in the present study.…”

“…Some strains of microorganisms, such as Staphylococcus , Escherichia and Pseudomonas , are responsible for serious disease infections that affect millions of people around the world [ 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. The problem of contamination does not only concern humans or animals but also plants, the growth, development and yield of which are limited due to the influence of pathogens, both bacterial ( A. tumefaciens , X. campestris , P. brassicacearum , P. corrugate and P. syringae ) [ 9 ] and fungal ( A. niger , A. flavus and A. versicolor ) [ 10 , 11 ]. When deposited on the surface of tissues or objects, many microbes can form a protective matrix made of DNA, proteins and polysaccharides called the exopolysaccharide matrix (EPS).…”

“…Owing to the need to protect the environment and reduce waste, an increasing amount of research and development has been conducted with respect to degradable plastics. In recent studies, we presented test results of a plasticized polylactide film containing tar produced in the laboratory using the solvent method [ 9 , 23 , 24 ].…”

Biopolymer Composites: Synthesis, Properties, and Applications

“…This Special Issue, with a collection of eight research articles, offers representative examples of the most recent advances in the synthesis, properties and applications of biodegradable biopolymer composites. Attention has been focused on production, processing, and application of biodegradable composites prepared from polymers such as polylactic acid (PLA) [6], chitosan [7], alginate [8], natural rubber [9], and so forth, which are amongst the most promising matrices for green composites in the future.…”

“…The chemical components of BT are mostly phenol derivatives (guaiacol, creosote, and pyrocatechin), organic acids, and resin substances. Thus, biopolymer composites including PLA, poly(ethylene glycol) (PEG) as plastizer (5 wt%), and BT (1, 5 and 10 wt%) have been developed and characterized [6]. PLA film with 10 wt% BT displayed the best antibacterial effect against plant pathogens, i.e., X. campestris, A. tumefaciens, P. corrugata, and P. syringae.…”