The Performance And Interface Characterization Of Bamboo Flour/PP Composites

The interfacial structure and property between bamboo flour and thermoplastic matrix is one of the most basic and important science issues of the bamboo fiber /thermoplastics composites. Revealing its microstrcuture and mechanism of interface formation can be of important significance both in theoretical and practical apllication aspects. Bamboo flour / polypropylene thermoplastics composites were prepared by molding with injection machine.Before composites fabricating , bamboo flour was treated by different coupling agents including maleic anhydride grafted polypropylene(MAPP), silane, aluminum coupling agent respectively.By means of micro-scanning and computer imaging processing system, the micro-morphology of the explosive bamboo flour reinforced polypropylene thermoplastics composite was detected. Effects of different particle sizes of bamboo flour on mechanical, thermotic and prcessing properties of composites were studied. Effects of modified bamboo flour treated with different coupling agents on properties of composites were compared as well .Through orthogonal experiments,effects of different factors, including bamboo flour dosage ,coupling agent dosage , brabender rotating speed of rheometer , and lubricant dosage on the mechanical performance of bamboo flour/polypropylene thermoplastics composites were studied. Through analyzing the relationship between the interface properties and interface morphology of composites, the strcuture and composition of interface layer was also analyzed.By computer imaging ,the interface micro-morphology of bamboo flourr/polypropylene thermoplastics composite was analyzed ,the relationship between the macroscopical mechanics performance and the interface micro-morphology of bamboo flour/ polypropylene thermoplastics composite was modeled.Based on the studies above ,the conclusions were shown as follow:1. Compared with particle sizes of bamboo flour between 20meshes and 200meshes, the ratio of length to width of 40meshes, particle is more stable than that of other sizes due to its smaller variation coefficient. With the particle size reducing, the amount of parenchyma cells of bamboo flour gradually decreased. With decreasing of bamboo particle sizes,fibers tend to thinner and longer ,and fiber surface tends to smoother.2. With particle sizes of bamboo flour ranging from 40meshes to120meshes, with the particle size decreasing, the tensile strength, fractural strength, impact strength of compsite showed general decrease. Compared with that of composite of 120meshes particle size ,the tensile strength ,fractural strength and impact strength of that of 40meshes increased by 9.8%,10.5%,27% respectively. Scaning electron microscopy(SEM) of fractures of composites ,showed that for those with longer bamboo fiber ,more interfacial diffusion and mutual lock be in the interface of fiber and matrix.3. The results of analysis of variance(ANOVA) of experiment data showed that: the amounts of bamboo flour in composite has significant effect on tensile strength, modulus of rupture(MOR), breaking elongation rate ,and impact strength. The content of coupling agent, brabender rotational speed, also has an effect on mechanical properties of composite .But the content of lubricants did not affects the mechanical properties of composite so much.4. The SEM images of fractured surface of composites showed that the contour of images of unmodified bamboo fibre control is much more clear than that of modified bamboo fibre ,which suggests ,a more clear separation interphase between fiber and matrix .And fiber agglomeration can be seen in the fracture surface ,and matrix particles were sticked to the pulled out bamboo fiber .This may suggest that bamboo fibre be well infiltrated by MAPP.Fourier transform infrared(FTIR) spectroscopy showed that for the composite prepared by MAPP modified bamboo fiber, hydroxyl groups stretching vibration peak of spectra was not so strong as that of control .An absorption peak around 1733 cm -1indicated that anhydride groups of maleated polypropylene reacted with hydroxyl groups of bamboo fiber leading to an esterification .Also the winding vibration peak of FTIR of symmetry methylic around 1380 cm -1could be found in the spectra.5. Through the computer imaging processing method based on the means of principle component Analysis (PCA), the relationship between macro-mechanical properties of composites and micro-morphology of the compsite was modeled.