Study of adhesive-particle interaction in OSB (Oriented Strand Board)
Notice bibliographique
Résumé
The market of OSB panels has enhanced and the production of high quality products requires satisfactory adhesion. This work aimed to evaluate the interaction between strand particles and phenol-formaldehyde adhesive in order to relate this interaction with the final quality of the panel. Pinus oocarpa and Eucalyptus grandis trees were used and had their basic density, chemical composition and anatomical properties determined. Strand particles were obtained in disc mill and. The following chemical treatments were applied to the particles: sodium hydroxide at 1,5%, acetic acid at 1,5% distilled water during 24 hours. Moreover, non-treated particles were evaluated as control. Contact angles measurements with particle surfaces were preceded by selecting particles from heartwood and sapwood for Eucalyptus oocarpa and spring wood and late wood for Pinus oocarpa. The adhesive amount per particles values were obtained by measuring dimensions and mass before and after gluing. To allow the analyses, the particles were divided into groups which corresponded to adhesive proportion. OSB panels were produced with phenol-formaldehyde adhesive at 6, 9 and 12% for both species. The pressing cycle variables were: pressure of 3,92 MPa and temperature of 150°C during 8 minutes. After the production, the panels were transformed in samples which were acclimatized until constant mass for perpendicular traction. Average results for basic density were 0,456 g/cm³ for Pinus oocarpa and 0,510 g/cm³ for Eucalyptus grandis. Adhesive contents did not significantly influenced effective amount of adhesive applied, but they were significant for glue amount. Adhesive application groups were significant for both variables. For Pinus oocarpa species, spring wood presented lower contact angle, while lower angles were observed for sapwood of Eucalyptus grandis. Chemical treatments applied to the particles of both species caused changed in the particle surfaces and decreased the contact angle possibly due to extraction of a portion of extractives. Acetic acid and sodium hydroxide were more efficient in reducing contact angle. Panels made from Eucalyptus grandis and adhesive at 9 and 12% and panels made from Pinus oocarpa and adhesive at 12% presented perpendicular traction values that met CSA 0437-0 (CANADIAN STANDARDAS ASSOCIATION - CSA, 1993) standard requirement. Pinus oocarpa had lower basic density and lower perpendicular traction. The interaction between particle and adhesive was very complex, mostly due to need to control homogeneity of adhesive application. More details about the modifications suffered by the extractives due to chemical treatment of the particles are needed.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».