Effect of Composting on the Behavior of Polyolefin Films - A True-to-Life Experiment
Bibliographic record
Abstract
Commercial polypropylene (PP), high-, medium- and low density polyethylene (HDPE, MDPE, LDPE) films, as well as MDPE films containing pro-oxidative additives and thermoplastic starch (TPS) were composted for six weeks together with biologically degradable films, such as poly (lactic acid) (PLA), Ecovio (BASF), Mater Bi(Novamont) and cellophane. Visual appearance of the polyolefin-based films did not change significantly, while the biologically degradable films fell apart. Thickness and mechanical properties of the polyolefin-based films also did not vary significantly after composting. The thickness of the degradable films however increased due to biofilm formation and finally decreased due to biodegradation, and their mechanical properties drastically dropped. FTIR proved the formation of carbonyl absorption of commercial and of the additive-containing films respectively) after composting due to oxidation. The FTIR-spectrum of the biodegradable films showed drastic change after composting. Formation of free radicals was detectable by ESR-spectroscopy, if pro-oxidative additive containing MDPE film was exposed for one week to sunlight, and the intensity of free radical formation increased after composting. The number-average molecular mass of MDPE films containing pro-oxidative additives decreased, low molecular mass fractions appeared and polydispersity increased after composting. Commercial polyolefin films were covered by microorganisms much more densly than films containing pro-oxidative additives detected by SEM. Even TPS did not increase the quantity of microorganisms. Biodegradable films were densly covered by microorganisms of different types and they became porous and holes were observable on their surface. It can be concluded that composting had no significant effect on the behaviour of the commercial PP and PE films. Signs of initial degradation were observable on MDPE films with pro-oxidative additives and TPS after 6 weeks composting, although it cannot be considered as biological degradation. Non of the tested polyolefin films suffered such degree of degradation in compost, as the biologically degradable films. It may be concluded that polyolefin films neither degrade in compost nor they undergo biodegradation.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".