Q2. What is the chemical treatment used in the textile industry?
Bleaching with hydrogen peroxide isanother chemical treatment widely used in the textile industry that provides surface modification of the fibers (Rout et al., 2001; Salam, 2006).
Q3. What is the effect of wetting on the thermal behavior of coir composites?
The wetting produced a stronger bond at the interface and reduced the available surface area for moisture desorption, resulting in a delay in moisture evaporation.
Q4. What is the effect of alkali treatment on the thermal stability of coir fibers?
3. Changes occurring in the fibers due to the treatments led to a positive effect on the thermal degradation behavior of the composites, as indicated by the higher thermal stability of the treated composites.
Q5. What was the effect of the alkali treatment on the fibers?
The alkali treatment changed the color of the fibers from brown to dark brown and the bleaching with H2O2 produced yellowish brown fibers, indicating that the expected modification (removal of wax, fatty substances and lignin) might have been achieved, as demonstrated in works of other research groups (Katz, 1977; Rout et al., 2001).
Q6. Why is starch a promising alternative to conventional polymers?
due to starch’s excessive hydrophilicity and brittleness, blending starch with conventional polymers is a promising approach to improve its drawbacks (Medeiros et al., 2008).
Q7. What is the reason for the tendency to release moisture at higher temperatures?
According to these authors, the tendency to release moisture at a higher temperature in the treated composites could be due to the improved wetting of the finely separated fibers by the matrix.
Q8. How many g of coir fibers were added to a solution of 320?
Coconut fibers (200 g) were added to a 2 L solution containing 320 mL (30%; w/w) hydrogen peroxide and 1 g sodium hydroxide at 85 C and stirred for 1 h.
Q9. How long did the specimens be coated with gold?
All specimens were coated with Gold–Palladium for 45 s in a Denton Desk II sputter coating unit (Denton Vacuum USA, Moorestown, NJ).
Q10. What is the effect of the treatment on the mechanical properties of coir fibers?
All the treatments removed surface impurities on fibers, producing modifications on the surface and improving thermal stability of both fibers and fiber-reinforced composites.
Q11. What is the effect of alkali on the elongation of the composites?
as reported by Mohanty et al. (2001), alkali treatment reduces fiber diameter and thereby increases the aspect ratio, improving mechanical characteristics of the composites.
Q12. What is the effect of alkali on the tensile strength of composites?
Prasad et al. (1983) studying composites made of polyester resin and coir fibers, obtained a 15% increase in tensile strength when fibers were soaked in a 5% NaOH aqueous solution at 28 C for 72–76 h.
Q13. What is the potential of starch in biocomposites?
derivate from variety of botanical sources (cereals, legumes, and tubers), is widely available raw material for use in bioplastics (Bastioli et al., 1995; Kumar and Singh, 2008).
Q14. What is the effect of alkali on the elongation of the fibers?
As shown in Table 1, the elongation at break (e) of the starch/ EVOH blends decreased and tensile modulus (E) increased considerably by approximately 74% with the incorporation of fibers, due to the rigid nature of the fibers reducing the ductile behavior of the composites.
Q15. What is the percentage of crystallinity of coir fibers affected by alkal?
According to Varma et al. (1986), upon alkali treatment, there was a partial loss of cementing material via the rupture of ester linkages between polyuronic acid and lignin, increasing the percentage of crystallinity index of alkali-treated fibers.
Q16. What is the effect of the treatment on the hemicellulose degradation temperature?
The hemicellulose degradation temperature increased slightly with treatment from 314 C for untreated fiber-composite to 318, 317, 317, and 315 C for washed, mercerized and blenched fiber-reinforced composites, respectively.
Q17. What is the common modification of starch?
One of most used modifications is the treatment with an alkali solution (Corradini et al., 2006; Prasad et al., 1983; Ray et al., 2001).
Q18. What is the effect of alkali on the coir fibers?
Interfacial adhesion between coir and natural rubber was increased by treatment of the coir fibers with alkali (Geethamma, 1998).
Q19. What is the effect of alkali treatment on cellulose?
some authors (Sreenivasan et al., 1996; Varma et al., 1986) reported that coir fibers changed their crystallinity through alkali treatment.