| The attapulgite (ATT) clay is a linear hydrated magnesium aluminum silicate. It is easy to aggregate and fracture during the mechanical mixing, which limites its application in polymer composition. In the present work, two approaches were applied for improving the compatibility between ATT and polymer matrix: firstly, a polyolefin elastomer (POE)/ATT masterbach for polypropylene matrix was prepared, and silane coupling agent KH570 was selected for ATT modification; secondly, an in situ modification of ATT clay by toluene-2,4-di-isocyanate (TDI) was employed, therefore polymethylmethacrylate (PMMA)/ATT nanocomposites were prepared by mechanical mixing.Polypropylene(PP)/ATT-KH570/POE ternary composites and PP/ATT-KH570 binary composites were prepared by melt blending method, and were systemically investigated, in particular for its mechanical properties, rheological and crystallizing behavior. It was found that both of ATT-KH570 and ATT without modification were able to significantly the tensile strength (σt) of PP, and ATT-KH570 exhibited a higher reinforcement efficiency due to the better dispersion and interfacial bonding. The impact strength of PP/ATT-KH570 was higher than that of neat PP and increased with the addition of ATT-KH570 content from 0 to 1 wt%. However, ATT without modification had a negative effect on the impact strength. For the PP/POE/ATT-KH570 ternary composites, The mechanical property characterization showed that at a fixed weight ratio of ATT-KH570 and PP (5/100), the content of POE dominantly affected the impact strength of the composites. When the content of POE was 5%, the impact strength of composites reached 8.91KJ/m~2 which has around 21.10% enhancement over that of the composites wihtout POE. When the content of POE was increased to 15% , a 44.8% enhancement for the impact strength was observed. More importantly, no tensile strength of PP was sacrificed with the addtion of ATT and POE, which might be attributed to the synergistic effect of these two modifiers. From the rheological curves, we found that the addition of ATT-KH570 obviously decreased the melt fluidity of composites at low shear rate. In addition, POE and ATT-KH570 were effective in promoting the crystallization of PP by the analysis of DSC.A novel in-situ modification of ATT by toluene-2,4-di-isocyanate using mechanical mixing with polymethylmethacrylate (PMMA) was exploited. As a consequence, PMMA/organo-modified ATT nanocomposites were prepared, which provided prominent improvements in strength, toughness and thermal stability. High grafting efficiency of TDI on ATT surface was confirmed by FTIR spectra and SEM observations. The uniform dispersion and rod-like texture of in-situ modified ATT nanorods in the PMMA which was clearly visible in the TEM micrographes, influenced the mechanical and thermal properties of the nanocomposites. The tensile strength of nanocomposites first increased and then decreased with the in-situ modified ATT concentration ranging from 0 to 6.0%, and reached the maximum value at 3.0%. For the impact strengh, PMMA/in-situ modified ATT with 2.0% ATT had the maximum value which showed around 31% enhancement than that of pure PMMA. The chain mobility of PMMA was significantly inhibited by the uniformly dispersed fibrous nanoparticles, leading a 13.20℃increase in the glass transition temperature of PMMA/in-situ modified ATT nanocomposite containing 2.0% ATT. The thermal stability of the nanocomposites was enhanced by the presence of ATT. For example, 10% mass loss temperature of PMMA/in-situ modified ATT was 73.47℃higher than that of pristine PMMA.
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