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Record W6990323447

Designing green plasticizers

2011· dissertation· en· W6990323447 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

aboutThe title or abstract carries a Canadian signal from the geographic lexicon.
no affNo Canadian affiliation: this work is invisible to an affiliation-only frame.
No Canadian affiliation. An affiliation-only frame, the usual design, would never have seen this work. It is one of the works that make the case for inverting the frame.

Bibliographic record

VenueeScholarship@McGill (McGill) · 2011
Typedissertation
Languageen
FieldMaterials Science
TopicPolymer Science and PVC
Canadian institutionsnot available
Fundersnot available
KeywordsPlasticizerPhthalateBiodegradationMaleic acidDibutyl phthalateSuccinic acidPolymer
DOInot available

Abstract

fetched live from OpenAlex

Plasticizers are additives in poly (vinyl chloride) (PVC) formulations that render the material flexible.This is important for many applications.Because these plasticizers are not bound to the polymer chemically, they will eventually leach out upon disposal.Considering also the widespread use of flexible PVC, it is not surprising that some plasticizers, such as di(2-ethylhexyl) phthalate (DEHP), are considered ubiquitous contaminants in the environment.Previous studies have shown that DEHP, upon degradation, forms stable, toxic metabolites.Because of this and other concerns, DEHP and other phthalates have already been banned in certain products in Canada and other countries.Hence, there is a strong incentive to develop new, green plasticizers.A series of diesters based on maleic acid, which resembles a part of the phthalate chemical structure, was tested, along with other series based on the structural isomer of maleic acid, fumaric acid, and the saturated analogue, succinic acid.The alcohols used to form the ester bonds varied in length from ethanol to octanol and, also, included the branched 2-ethyl hexanol.Each of these diesters was incorporated into unplasticized PVC at about 30 weight-percent and then evaluated for plasticizer properties such as glass transition temperature Tg and tensile strength.These data were compared to each other and to results with DEHP.Pure samples of the diesters were tested for their biodegradability by the common soil bacterium Rhodococcus rhodocrous (ATCC 13808) while it was growing on hexadecane as a primary carbon source.The results demonstrated that esters based on succinic and maleic acids performed at least as well as or were even superior to DEHP as plasticizers.In particular, the esters with the longer alcohols were very good plasticizers.There was little effect due iii to branching on the plasticizer properties.The experiments with Rhodococcus rhodocrous showed how important the structure of the central diacid is for the rate of biodegradation.In particular, the maleates, which have an orientation of the two ester groups very similar to that in DEHP, showed little to no susceptibility to biodegradation over the course of 30 days.The fumarates exhibited some degradation and the succinates were degraded very quickly.These results indicate that the orientation of the esters in DEHP, is responsible for the stability of this compound in the environment.The other factor in the rate of biodegradation was the length of the alcohol and the longest chains had the slowest rates.However, all straight-chained alcohols were biodegraded without the build-up of stable metabolites.The compounds made with the branched 2-ethyl hexanol did result in the formation of stable metabolites.Consequently, several of the tested diesters could be considered as "green".Yet, in terms of a middle molecule, the succinates should be considered as the best choice.As for side chain length, plasticizer properties improve with increasing alcohol length, and biodegradation properties improve with decreasing alcohol length.A potential candidate for a compromise would thus be dihexyl succinate.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesMeta-epidemiology (narrow), Science and technology studies, Insufficient payload (model declined to judge)
Consensus categoriesInsufficient payload (model declined to judge)
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.131
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0010.000
Meta-epidemiology (narrow)0.0010.001
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0000.001
Science and technology studies0.0020.000
Scholarly communication0.0000.001
Open science0.0020.000
Research integrity0.0010.001
Insufficient payload (model declined to judge)0.0020.005

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.

Opus teacher head0.027
GPT teacher head0.243
Teacher spread0.216 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it