Study on the Utilization of Seed-Flax Stems as Reforcement for Green Composites.pdf

1、The present study on the use of flax stems as reinforcement for green composites has three
　　major objectives: 1) to use a variety of flax normally cultivated for its seeds, not for its fibers, in a textile-related ap

2、plication; 2) to avoid the wastage and pollution resulting from the traditional burning of these stems; and 3) to incorporate them almost directly in composites. First seed-flax stems were cut the same length and washed

3、with hot water.Their outer fibrous layer was sometimes peeled so that only the wooden inner part would remain.Two
　　types of reinforcement were thus prepared: wooden parts only (WOOD) and whole stems (STEM).Reinforcem

4、ent pieces were then aligned parallel to each other, maintained together by Kevlar threads, and hot pressed (sometimes in a frame) between polypropylene PP or low-density polyethylene LDPE films to make laminae and lamin

5、ates.The procedure followed was progressively improved by trying different processing settings such as temperature, pressure, and press time, and by changing such parameters as the arrangement of stems, the number of pol

6、ymer films, etc.
　　Finally samples were cut in the composites and subjected to tensile and bending tests.The results obtained showed that STEM composites exhibit higher mechanical properties due to the presence of fib

7、ers in the outer layer of the reinforcement pieces.Tensile strength and modulus are respectively comprised between 20-35 MPa and 3.2-6.7 GPa.The final behavior depends much on the orientation of reinforcement pieces in t

8、he composites, the relative quantity of polymer and the processing conditions, such as temperature and the use of a frame.For LDPE laminates made with a frame, the bending strength (60-70 MPa) was much increased compare