Peláez Samaniego, Manuel Raúl2018-01-112018-01-112013-02-01183830https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873896858&doi=10.1515%2fhf-2012-0071&partnerID=40&md5=3d5473bde4c3ec4bca91a1fd7aab3b09http://dspace.ucuenca.edu.ec/handle/123456789/22081Undebarked ponderosa pine chips were treated by hot water extraction to modify the chemical composition. In the treated pine (TP), the mass was reduced by approximately 20 %, and the extract was composed mainly of degradation products of hemicelluloses. Wood flour produced from TP and unextracted chips (untreated pine, UP) was blended with high-density polyethylene (HDPE) and polypropylene (PP) and was extruded into wood plastic composites (WPCs). Formulations for WPCs consisted of 58 % pine, 32 % plastic, and 10 % other additives. WPC based on HDPE? + ?TP and PP? +?TP absorbed 46-45% less water than did WPC based on HDPE? +?UP and PP? + ?UP, respectively. Thickness swelling was reduced by 45-59%, respectively, after 2520 h of immersion. The diffusion constant decreased by approximately 36 %. Evaluation of mechanical properties in flexure and tension mode indicated improvements in TP-WPC properties, although the data were not statistically significant in all cases. Results showed that debarking of ponderosa pine is not required for WPC production.en-USExtrusionHot Water ExtractionHygroscopicityWood Plastic Composites (Wpc)Article10.1515/hf-2012-0071