کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
820626 | 906712 | 2012 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Hydro and thermal stability of die drawn wood polymer composites in comparison to solid wood Hydro and thermal stability of die drawn wood polymer composites in comparison to solid wood](/preview/png/820626.png)
Both isotropic and oriented wood polymer composites (WPC) based on 40% w/w of a softwood powder/hardwood powder and polypropylene (PP), together with solid pieces of wood, were subjected to water immersion and thermal expansion tests. Although generally die drawing increased the amount of water absorbed by the WPC by about 2-fold when compare to isotropic WPC, the oriented WPC exhibited extremely high hydro-dimensional stability. The values of the longitudinal and transverse swelling/shrinkage of the WPC oscillated only between 0 and −2.3% compared to values of between 4 and 14% for the solid woods. Incorporation of soft/hard wood powders into PP also substantially decreased its thermal expansion coefficient α in both the isotropic and the oriented states. This extremely positive effect was enhanced by increasing the draw ratio. In the longitudinal direction, α decreased from about 80 × 10−6 °C−1 (for the isotropic PP) to 5 × 10−6 °C−1 for the highly drawn PP filled with softwood.
Journal: Composites Science and Technology - Volume 72, Issue 12, 23 July 2012, Pages 1436–1442