Marta Musioł

Forensic engineering of advanced polymeric materials. Part III - Biodegradation of thermoformed rigid PLA packaging under industrial composting conditions

This paper presents a forensic engineering study on the biodegradation behaviour of prototype packaging thermoformed from PLA-extruded film and plain PLA film under industrial composting conditions. Hydrolytic degradation in water was conducted for reference. The effects of composting duration on changes in molar mass, glass transition temperature and degree of crystallinity of the polymeric material were monitored using gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). The chemical structure of water soluble degradation products of the polymeric material was determined using nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESI-MS). The results show that the biodegradation process is less dependent on the thermoforming process of PLA and more dependent on the composting/degradation conditions that are applied. The increase in the dispersity index, leading to the bimodal molar mass distribution profile, suggests an autocatalytic hydrolysis effect at the early stage of the composting process, during which the bulk hydrolysis mechanism dominantly operates. Both the prototype PLA-packaging and PLA rigid film samples were shown to have a gradual increase in opacity due to an increase in the degree of crystallinity.

A preliminary study of the degradation of selected commercial packaging materials in compost and aqueous environments

A preliminary study of the degradation of selected commercial packaging materials in compost and aqueous environments The paper presents the results of the degradation of two commercial packaging materials CONS-PET and BioPlaneta in the compost and distilled water at 70°C. The materials containing polylactide (PLA), CONS-PET 13% and BioPlaneta 20%, aliphatic-aromatic copolyester terephthalic acid/adipic acid/1,4-butanediol (BTA) and commercial additives degraded under the industrial composting conditions (composting pile or container) and in distilled water at 70°C in the laboratory holding oven. Distilled water provided the conditions for the hydrolytic (abiotic) degradation of the materials. Weight loss, changes of molecular weight, dispersity monitored via the GPC technique and the macroscopic surface changes of the tested materials were monitored during the experiments. The investigated systems show similar trends of degradation, however on the last day of the incubation the decrease of the molecular weight was higher in water than under the industrial composting conditions. The results indicate that commercial packaging materials can be degraded both while composting ((bio)degradation) and during the incubation in distilled water at 70°C (abiotic hydrolysis).

Forensic Engineering of Advanced Polymeric Materials. Part 1 –Degradation Studies of Polylactide Blends with Atactic Poly[(R,S)-3-hydroxybutyrate] in Paraffin

Classical forensic polymer engineering concerns a study of failure in polymer products. This area of science comprises fracture of plastic products, or any other reason why such a product fails in service, or fails to meet its specification.1 So far, most of the reported case studies concern ex-post investigations of traditional polymeric materials such as PE, PP, PS, PVC, ABS or their thermoplastic composites. Little is known about forensic engineering of novel and advanced polymeric materials. Thus, there is a real gap in this area of knowledge. Furthermore, the ex-ante studies are needed to define and minimise the potential failure of novel polymer products before specific applications. Environmental stress cracking (ESC) is one of the most common causes of unexpected brittle failure of thermoplastic (especially amorphous) polymers. The rate of ESC is dependent on many factors, including, for example, the polymer’s chemical composition, bonding, crystallinity, surface roughness, molar mass and residual stress. It also depends on the chemical nature of liquid media and the temperature of the system. Thus, evaluation and understanding of the structure, properties and behaviour of advanced polymer materials for perspective practical applications is needed, especially in the field of compostable polymer packages of long-life products, such as cosmetics or household chemicals. Because of the slow environmental degradation of traditional packaging, the use of conventional plastics is accompanied by significant ecological problems. To reduce plastic waste from the packaging industry, biodegradable polymers have become interesting alternatives, for packages with a long shelf life.2 The most important environmentally friendly plastics are generally based on aliphatic polyesters, such as poly(lactic acid), poly(3-hyForensic Engineering of Advanced Polymeric Materials. Part 1 – Degradation Studies of Polylactide Blends with Atactic Poly[(R,S)-3-hydroxybutyrate] in Paraffin

Oligo-3-hydroxybutyrate functionalised pyrroles for preparation of biodegradable conductive polymers

We report the synthesis and characterization of a novel polypyrrole material grafted with biodegradable oligo-3-hydroxybutyrate pendants. The polymer was prepared in a two-step process. Firstly, the potassium salt 1–(2-carboxyethyl)pyrrole was reacted with β-butyrolactone affording N-substituted macromonomer. Secondly, the macromonomer was oxidatively polymerised with FeCl3 Lewis acid. The reaction was carried out in solvents of assorted polarity: dimethylsulphoxide, acetonitrile, dimethylformamide and water. Obtained polymers have been characterised comprehensively using a suite of spectral techniques. The material was found to combine the well-known merits of 3-hydroxybutyrate polymers with the electrical conductivity imparted by polypyrrole units.

Bio)degradation studies of degradable polymer composites with jute in different environments

The introduction of new, environmentally friendly and sustainable plastics in the packaging and end-user industry is a solution to the problem of waste management. The degradation of polyesters in different environments could result from an enzymatic attack or simple hydrolysis, or both. The degree of degradation of blends containing polylactide and poly(3-hydroxybutyrate-co-4-hydroxybutyrate), PLA/P(3HB-co-4HB), and its composites with 20 %wt of jute incubated in distilled water at 70 ℃ (abiotic conditions) under industrial composting conditions (system KNEER) was investigated using a Zeiss optical microscope, an atomic force microscope, gel permeation chromatography, differential scanning calorimetry and thermal gravimetric analysis. PLA/P(3HB-co-4HB) was tested under laboratory composting conditions in order to verify whether biodegradation of this material occurs under industrial composting conditions. The addition of jute fibres did significantly reduce the disintegration of the composites during degradation.

Crystallinity as a tunable switch of poly(L-lactide) shape memory effects

Materials with shape memory effect (SME) have already been widely used in the medical field. The interesting part of this group is represented by double function materials. The bioresorption and SME ability are common in polyesters implants. The first information about vascular stent made of bioresorbable polyester with SME was published in 2000. However, there are not many investigations about SME control of elements in the aspect of material processing. In the present work, the ability to control the shape memory (SM) of bioresorbable and semicrystalline poly(L-lactide) (PLLA) is investigated. The studies are based on the unexpected effect of material orientation which was demonstrated even at low percentage deformation in crystallized mould injected material. The presented studies revealed that the different degrees of crystallinity obtained during processing might be a useful switch to create a tailored SME for a specific application. The prepared samples of variable morphology revealed a possibility to control the value of material stress during permanent shape recovery. The degree of shape recovery of the prepared samples was also controlable. The highest stress value observed during permanent shape recovery reached 10MPa for the sample annealed 60min at 115°C even when the sample was only deformed in 8%. The other significant aspect of this work is to present the problem of slow crystallization of the material during and after processing (cooling rate) as well as the possibility of negative SME change during the shelf life of the fabric.

Forensic engineering of advanced polymeric materials Part IV: Case study of oxo-biodegradable polyethylene commercial bag – Aging in biotic and abiotic environment

The public awareness of the quality of environment stimulates the endeavor to safe polymeric materials and their degradation products. The aim of the forensic engineering case study presented in this paper is to evaluate the aging process of commercial oxo-degradable polyethylene bag under real industrial composting conditions and in distilled water at 70°C, for comparison. Partial degradation of the investigated material was monitored by changes in molecular weight, thermal properties and Keto Carbonyl Bond Index and Vinyl Bond Index, which were calculated from the FTIR spectra. The results indicate that such an oxo-degradable product offered in markets degrades slowly under industrial composting conditions. Even fragmentation is slow, and it is dubious that biological mineralization of this material would occur within a year under industrial composting conditions. The slow degradation and fragmentation is most likely due to partially crosslinking after long time of degradation, which results in the limitation of low molecular weight residues for assimilation. The work suggests that these materials should not be labeled as biodegradable, and should be further analyzed in order to avoid the spread of persistent artificial materials in nature.

Forensic Engineering of Advanced Polymeric Materials—Part V: Prediction Studies of Aliphatic–Aromatic Copolyester and Polylactide Commercial Blends in View of Potential Applications as Compostable Cosmetic Packages

The main aim of the present study was to determine the behavior of the specimens from Ecovio, in the form of dumbbell-shaped samples and films, during degradation in selected cosmetic ingredients such as water and paraffin. The (bio)degradation test of the prototype cosmetic package (sachet) made from a PBAT (poly[(1,4-butylene adipate)–co–(1,4-butylene terephthalate)]) and PLA (polylactide) blend was investigated under industrial composting conditions, and compared with the sample behavior during incubation in cosmetic media at 70 °C. During the degradation tests, the changes of the samples were evaluated using optical microscopy, 1H NMR (proton nuclear magnetic resonance) and GPC (gel permeation chromatography) techniques. The structures of the degradation products were investigated using ESI-MSn (mass spectrometry with electrospray ionization on positive and negative ions) analysis. The thermal properties of selected materials were determined by DSC (differential scanning calorimetry) and TGA (thermogravimetric analysis) analysis. It was concluded that the PBAT and PLA blend studied had a good stability during aging in cosmetic media, and could be recommended for long-shelf-life compostable packaging of cosmetics, especially with oily ingredients.

Present and Future of Biodegradable Polymers for Food Packaging Applications

Abstract Using conventional nondegradable and noncompostable polymers has a significant negative impact on the environment, so biodegradable polymers can attract much attention in regards to the current interest in the field of sustainable development, recycling, or environmental protection. Morphological and structural transformations resulting from the degradation of the material have a significant impact on the polymer material properties. Thus, evaluation and understanding of the structure, properties, and behavior of advanced materials for perspective food packaging applications is important to avoid degradation during storage. This review focuses on biodegradable polymer materials with approved or potential applications in food packaging. The major groups of biodegradable natural, microbial, and synthetic polymers will briefly be discussed with regard to properties required for packaging materials, like permeability, physical and mechanical properties, antioxidative and antimicrobial additives, plasticization, and biodegradability, based on studies reported in the literature as well as future trends.

(Bio)degradable polymeric materials for a sustainable future – part 1. Organic recycling of PLA/PBAT blends in the form of prototype packages with long shelf-life

Prediction studies of advanced (bio)degradable polymeric materials are crucial when their potential applications as compostable products with long shelf-life is considered for todays market. The aim of this study was to determine the effect of the polylactide (PLA) content in the blends of PLA and poly(butylene adipate-co-terephthalate) (PBAT); specifically how the materials thickness corresponded to changes that occurred in products during the degradation process. Additionally, the influence of talc on the degradation profile of all samples in all environments was investigated. It was found that, differences in the degradation rate of materials tested with a similar content of the PLA component could be caused by differences in their thickness, the presence of commercial additives used during processing or a combination of both. The obtained results indicated that the presence of talc may interfere with materials behavior towards water and consequently alter their degradation profile.