Reporter: Lin, An Advisor: Chen, Chuh-Yean Date: 6/11

Introduction Polypropylene (PP) is a thermoplastic being widely applied in the industry and is usually combined with inorganic particles or fibres aiming to improve its mechanical properties and reduce cost. Cork is a natural and complex polymeric composite material. Furthermore,cork is closed cell structure, viscoelastic properties, insulation properties, is chemically inert, fire resistance, microbial decay resistance. Polypropylene graft maleic anhydride (PP–g–MA)can overcome the problem of incompatibility, increasing the interfacial adhesion between both components and, the mechanical performance of the composites. coles open

cork granules Materials cork powder polypropylene (PP) homopolymer PP–g–MA Stearic acid average particle size 0.5–1 mm average particle size <500 m containing 0.5–1.0 wt.%

Coupling agent Methods PPCork powder Cork granule

Fig. 2. Representative micrographs from: (a) cork powder and (b) granulated cork. Image (c) shows the differences (for same weight) in volume between the three raw Materials used. Methods

CPC1~6,14,15 : without coupling agent CPC7~12 : with coupling agent Methods CPC13 : with stearic acid

Results and discussion

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Fig4. (b) effect of the coupling agent on the composites containing cork powder. Results and discussion

Powder 5 wt. % Powder 15wt. % Powder 30wt. % Granule 5wt. % Granule 15wt. % Granule 30wt. %

Results and discussion

The PP/cork composites exhibit reduced water uptake. The higher cork fraction, increases the water absorption up to 2.3 wt.% after a period of 1344 h. The tensile properties reveal that a 5 wt.% of cork provide a 10% stiffness increase. The addition of PP–g–MA enhanced the tensile strength and maximum strain, while the stearic acid promoted a slight increase on the maximum strain. Cork has an antioxidant effect to the PP, increasing the time to oxidation. Reducing the cork particle size and the composite density, contributes to a higher thermal-oxidative protection. Thermal analysis shows that PP/cork had higher crystallization temperatures than neat PP. Conclusions

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