Mechano-sorptive creep of Portuguese pinewood chemically modified

Autorzy

• Duarte Barroso Lopes School of Engineering – Polytechnic of Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal
  phone: +351228340500, fax: +351228321159, e-mail: dbl@isep.ipp.pt
  Wood Biology and Wood Products, Büsgenweg 4 - 37077, Germany
• Carsten Mai Wood Biology and Wood Products, Büsgenweg 4 - 37077, Germany

Abstract

The effect of chemical modification on mechano-sorptive creep in bending was studied by experimental work. Stakes with 20 × 20 × 400 mm RTL of Portuguese wood species (Pinus pinaster Aiton) modified with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU), m-methylated melamine resin (MMF), tetraethoxysilane (TEOS) and amid wax (WA) were measured under asymmetric moistening conditions over a period of 42 days (app. 1000 hours) with stress level (SL) of 12 MPa, according to ENV 1156.
The cell wall treatments (DMDHEU and MMF resins) had shown significant reduction of creep (creep factors, kc) when compared to untreated wood under similar conditions. Both types of resins and levels of treatments (different WPG) did not shown significant effects.
In the lumen fill treatments, deposit material of TEOS did not affected the creep behaviour (kc); Wax treatment was shown a particular compliance of creep due to avoid exchange moisture (by the hydrophobic effect of wax).
The anti-creep efficiency (ACE) correlated better than other mechanical or physical properties imparted by the modification process.

Keywords

• admid wax
• bending creep
• creep factor
• mechano-sorptive effect
• Pinus pinaster
• resins