Location: Functional Foods Research Unit
Title: Properties of high density polyethylene – Paulownia wood flour composites via injection molding Authors
Submitted to: BioResources
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 10, 2013
Publication Date: July 17, 2013
Citation: Tisserat, B., Reifschneider, L., Joshee, N., Finkenstadt, V.L. 2013. Properties of high density polyethylene – Paulownia wood flour composites via injection molding. BioResources. 8(3):4440-4458. Interpretive Summary: Waste wood and sawdust generated by the lumber industry provides the filler material utilized in the wood plastic composites (WPC) whose markets increases ~12% annually and is currently valued at $5.6 billion. However, increasing competition with the bio-energy market is raising the price for waste wood making the need to develop new wood fillers impetrative in order to satisfy demands. Fast-growing, coppicing, hardwood “weed” trees produce biomass that far exceed that obtained from ag-waste gleanings and can be employed for both WPC and bio-energy markets. Paulownia, an extremely fast-growing tree is a excellent example of the type of future tree needed in the future. This study demonstrates the usefulness of employing Paulownia wood flour as a filler with high density polyethylene composite blends. Paulownia wood filler was found to be an excellent filler material for WPC.
Technical Abstract: Paulownia wood (PW) flour is evaluated as a bio-based fiber reinforcement. Composites of high density polyethylene (HDPE), 25% by weight of PW, and either 0% or 5% by weight of maleated polyethylene (MAPE) were produced by twin screw compounding followed by injection molding. Molded test composites were evaluated for their tensile, flexural, impact, and thermal properties. Composites made with PW and MAPE had significantly improved tensile and flexural properties compared to neat HDPE. The impact strength of all composites using MAPE was 30% improved over HDPE. Benchmarking PW composites to similar preparations of Pine wood flour composites demonstrated that PW can produce a comparable and in some cases a superior bio-fiber composite. The effect of environmental exposure was examined by soaking tensile bars of HDPE-PW blends in distilled water for 28 days to observe changes to their physical and mechanical properties. Finally, differential scanning calorimetery and thermogravimetric analysis were conducted on PW composites to evaluate their thermal properties and the implications these may have on selecting processing conditions for the bio-fiber reinforcements.