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篇目详细内容

【篇名】 Effect of unsaturated hydroxyl-fatty acid modified nano-CaCO3 on the morphological and rheological behavior of PP
【刊名】 Frontiers of Chemistry in China
【刊名缩写】 Front. Chem. China
【ISSN】 1673-3495
【EISSN】 1673-3614
【DOI】 10.1007/s11458-009-0013-z
【出版社】 Higher Education Press and Springer-Verlag
【出版年】 2009
【卷期】 4 卷1期
【页码】 75-82 页,共 8 页
【作者】 Ju GU; Qiang XIONG; Demin JIA; Yuanfang Luo; Rongshi Cheng;
【关键词】 modified nano-CaCO3; polypropylene; morphology; rheological behavior; mechanical properties

【摘要】
A modified nano-calcium carbonate (R-CCR) was prepared by coating a layer of unsaturated hydroxyl-fatty acid on the surface of CCR powders using a solid state method; the latter were commercial nano-CaCO3 modified with stearic acid. FTIR studies indicate that the modifier is combined on the surface of CaCO3. PP/EPDM/nano-CaCO3 ternary composites were prepared by a melt-mixing method. SEM and TEM were utilized to examine the morphology of the composites. The tensile fractured surface of PP/EPDM/R-CCR showed a fibroid morphology and large-scale yield deformation. The impact fractured surface showed that the amount of cavities in the PP/EPDM/R-CCR system was increased, however their size diminished obviously. R-CCR particles were dispersed uniformly in the PP matrix, and their compatibility was distinctly improved as compared to CCR when the amount of R-CCR was 15 h-1. The tensile strength remained nearly constant (reduced from 27.6 MPa to 27.5 MPa), while the impact strength increased from 9.6 kJ/m2 to 15.4 kJ/m2 as CCR was replaced by R-CCR. Meanwhile, the bending strength and bending modulus also increased correspondingly. Furthermore, the impact strength of PP/EPDM/R-CCR was maintained at a high level (15.4 kJ/m2), which was more than the sum of that of PP/EPDM and PP/R-CCR (6.6 kJ/m2 and 6.1 kJ/m2 respectively). This indicates that the R-CCR and EPDM have a significant synergistic toughening effect on PP while maintaining the strength and modulus of virgin PP. Both the storage modulus G¢ and loss modulus G¢¢ of PP/EPDM and PP/EPDM/R-CCR composites increase with increasing frequency, but the values of G¢ and G¢¢ of the tertiary composite are relatively higher than those of the binary system. The loss factor and viscosity decrease with increasing frequency, but there is little difference between tertiary and binary composites. The apparent viscosity η of the tertiary system containing R-CCR is lower than that of the tertiary system containing CCR and virgin PP. The viscosity of the composites significantly decreases with increasing shear rate. The measured mechanical properties of the composites indicate that replacing CCR with R-CCR for binary composites could simultaneously enhance the toughness and strength of PP.
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