The mechanical properties of wood polymer composites consisting of polypropylene and mixed sawdust of meranti shorea spp. dominant and rice husk filler have been studied. Three different filler loadings of 50, 60, and 70 wt% were used and the process of compounding and extrusion was carried out using a twin-screw extruder. Increase in flexural modulus and tensile modulus are observed while tensile strength, elongation at break, flexural strength, and Izod impact decrease with increasing filler loading. Poor interaction between wood filler and the plastics is believed to be the main reason for the decreasing trend. Maleic anhydride grafted polypropylene (MAPP) was used in the formulation to improve the interfacial adhesion between the two components. Addition of the MAPP shows some improvement, particularly at 1%, and further increment of the MAPP did not show any significant impact on the properties tested.
ABSTRACT:The blends of Polypropylene (PP), that is a semicrystalline and nonpolar thermoplastic polymer with a polar and amorphous polymer such as Polystyrene (PS), are known to be immiscible. This article investigates the use of an aromatic vinyl monomer (AVM)-grafted PP (PPA) as a potential compatibilizer for such an immiscible blend system (PP/PS blend). PPA was prepared by grafting a monofunctional aromatic vinyl monomer onto PP using an organic peroxide at 180°C for 10 min in a Brabender mixer. Using a twin-screw extruder, blends of PP/PS in various composition containing different amount of PPA were prepared. Results obtained from tensile and impact strength, heat deflection, and melt flow index measurements shows some improvement in the properties of the blends indicating some compatibilization effects in the blend system. However, the scanning electron microscopy (SEM) micrographs strongly suggested a significant compatibilization between PP and PS.
This paper presents the moisture absorption and shock cushioning properties of flexible polyurethane foams (PU) filled with saw dust fibers at 10, 15 and 20wt%. The compositeswere fabricated using open molded method from a two-part liquid foamsystem consisting of part-A (Isocyanate) and part-B (Polyol).The diffusion rates from the moisture absorption test is calculated using Ficks second law equation. Thesample with 10 wt% filler shows the highest diffusion ratewhile the lowest rateis sample with15wt% filler. The shock cushioning properties was determined via drop test where an 11.48-kg weight is dropped, from a height of 610 cm on the composites. The average Gvalue that represents product fragility was found to be 55.45.
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