Banana fibers received four treatments, namely squeezing, alkali and hydrogen peroxide treatment, washing with water, and drying. Thermoplastic starch composites was prepared with glycerol as the plasticizer, banana fiber as reinforcement and thermoplastic cassava starch as matrix. The banana fiber could increase processing torque highly, while the effects of fiber contents on peak torque at 3min was so obvious. X-ray diffractograms illustrated that with increasing fiber content, cellulose crystallinity at 22.5° gradually got stronger but starch crystallinity at 20° almost didn’t. SEM micrographs showed good dispersion and adhesion between starch and fiber. Studies in the dependence of mechanical properties of reinforced TPS on the contents of fiber that with increasing fiber content from 0 to 20phr, the initial tensile strength was trebled up to 14.46 MPa, while the elongation at break was reduced from 68 to 13%. TG mass loss curves showed that thermal stability of this composites had great improved under 500°C.

Flame retardation of banana fiber reinforced epoxy composites using melamine pyrophosphate and pentaerythritol as intumescent flame retardants and the influence of mechanical properties were investigated. The effects of IFR contents and the ratio of MPP and PER on limiting oxygen index (LOI) and UL94 rating of banana fiber reinforced epoxy composites has been studied. It was found that the combustion performance of the composites increases with increasing IFR contents,and the composites at the ratio of MPP/PER=2:1(weight ratio) at the same loading 40% showed the best combustion performance with IFR contents increasing,the limiting oxygen index (LOI) increased and UL94 rating reached, but the mechanical properties of composites significantly decreased. In order to increase the comprehensive properties, the flame retarded fiber was used to prepared the composites,the limiting oxygen index (LOI) of the composites significantly increased. the best complex properties were the IFR contents was 40%, the ratio of MPP/PER=2:1 (weight ratio), by the spraying method with 20g the fire retardant liquid of every 30g banana fiber.

As the matrix of sisal fiber, thermoplastic tapioca starch(TPS) was prepared with the mixed plasticizer, formamide and urea (mass ratio 2:1). X-ray diffractograms showed that with increasing fiber content(below 30phr), cellulose crystallinity at 22.5° gradually got stronger but starch crystallinity at 15.3°, 17.1°, 18.2°, 23.5° already disappeared, showed that this matrix still restrained the retrogradation of starch. SEM micrographs showed good dispersion and adhesion between starch and fiber. Studies in the dependence of mechanical properties of reinforced TPS on the fiber content from 0 to 30phr, the initial tensile strength was quadrupled up to the maximum 21.83MPa at 20phr fiber content, while the elongation at break was reduced from 72% to 0.44%. TG mass loss curves showed that thermal stability of this composites had great improved under 500°C.

Banana fiber/tapioca starch (BFRTPS) composites modified by magnesium hydroxide (Mg(OH)2) were prepared with glycerin as the plasticizer, banana fiber as reinforcement and thermoplastic tapioca starch as matrix. Rheological properties testing showed that Mg(OH)2take a strong effect to the preparation processing and made it hard to mix while the content increasing. Mechanical properties testing revealed that at the range of the Mg(OH)2content from 5 to 20phr, the tensile strength of the composites increased from 12.8MPa to 24.8MPa at 15phr Mg(OH)2content, but its elastic modulus was increased with the increasing of Mg(OH)2, reached the maximum of 3100MPa at 20phr Mg(OH)2content. Obviously, Mg(OH)2has an enforced effect to the composites. Combustion performances of the composites was improved by Mg(OH)2, the limited oxygen index(LOI) of the composites reached to 31% while the content of Mg(OH)2was 20phr, and then the result of flammability testing achieved UL94HF-1 and UL94 V-0 level.

The starch-based foam was preprared by moulding process and studied the effects on the density, mechanical properties, hardness and water absorption capacity of the foams with different polyvinyl alcohol (PVA) contents. The microstructure and crystallization of the foam was observed through the scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the addition of PVA could better improve the material mechanical properties, the elongation at break was increased from 15.72% to 113.86% while the hardness was reduced from 37.3 to 16.7. The density of foam reached to the minimum value of 0.261 g/cm3, attaining to the maximum tensile strength of 1.08 Mpa. SEM and XRD showed that the compatility of starch and PVA was very good and the addition of PVA helped to improve the bubble distribution of foam and inhibit the retrogradation of starch granules.