Mechanical Properties of Green Composites Reinforced with Flaxseed Fiber Bundles.pdf

1、Green composites are currently the center of attention for most of the researchersworldwide due to the well-established mechanical properties, low density, cost effectivenessand biodegradability offered by natural fibers

2、.Flaxseed straws, which are currentlyconsidered as a waste, can be a valuable and abundant resource as reinforcement fibers ingreen composite materials.
　　This study involved two phases, in the first phase the alkalin

3、e treatment, chemicalcomposition analysis and tensile property of the flaxseed fiber bundles were investigated fortheir potential useful applications in green composites.Second phase included the compositefabrication fol

4、lowed by testing of tensile and bending properties of the composites.Twomethods were opted to treat flaxseed fiber bundles by using NaOH with the strengths of 10g/land 20g/l, resulting in 22.2％ and 45.2％ weight losses, r

5、espectively.The fibers were notseparated sufficiently despite the higher weight loss, which indicated flaxseed fiber bundleswere partially degummed.The SEM micrographs showed that alkali treatment resulted inimprovement

6、in the surface roughness and topography; with significantly better results in 20g/L NaOH treated samples.Quantitative composition analysis further proved the differentcomponents percentage in flaxseed as compared to the

7、common flax.The results showedWax 3.1％, Dissolvable Substances 7.14％, Pectin 6.3％, Lignin 15.08％, Hemi-Cellulose28.27％ and Cellulose 40.11％.In comparison with the fiber flax, the impurities in flaxseedwere found to be tw

8、ice or more, however, the Cellulose was almost 50％ less.Bundle fibertest method was used to determine the strengths of untreated fibers and NaOH treated fibers.Evaluation of tensile property revealed acceptable results s

9、howing samples treated with 10g/L NaOH (0.88cN/dtex) and 20 g/L NaOH (0.85cN/dtex) with almost 25％ decrease instrength as compared with the untreated samples (1.14 cN/dtex).Effects of temperature andpressure on fiber bun

10、dle strength showed that pressure had minimum effect (8％), however,the temperature had very significant effect (40％) on the fiber bundle strength.
　　These investigations provided the basis for choosing the appropriate

11、 matrix and methodto fabricate composites using both untreated and treated fiber bundles with evaluation andcomparison of their tensile, flexural and morphological properties.Polybutylene Succinate(PBS) with melting temp

12、erature of 113℃ was selected as a matrix.Compression moldingmethod was used in the fabrication of composites.Single layered lamina and three layered(laminae) composites were fabricated with 40％ fiber loading.It was obser

13、ved that untreatedthree layered laminae had higher average tensile strength (78MPa) as compared to untreatedsingle lamina (56 MPa) as well as three laminae NaOH 10g/L treated (53.85 MPa) and 20g/LNaOH treated (54.29 MPa)

14、.Outcomes of flexural property test were found to be foruntreated (26.69 MPa), NaOH10g/L (31.85 MPa) and NaOH 20g/L (42.69 MPa),respectively.This illustrated that the 20 g/L NaOH laminae had better bending propertiesrefe

15、rring to its improved surface topography and roughness that resulted in better mechanicalinterlocking and interfacial properties between the fiber and the matrix.Depending on thecriterion for the final composite applicat

16、ion, untreated fiber bundles with higher strength andalkali treated fiber bundles with better bending properties can both be used as reinforcementsin natural fiber composites.
　　This study provided significant fundame