Polypropylene- nanocomposite maleic anhydride-grafted

As the hydrophilic clay is incompatible with polypropylene, compatibilization between the clay and PP is necessary to form stable PP nanocomposites. There are two ways to compatibilize the clay and PP. In the first approach, the enthalpy of the interaction between the surfactant and the clay is reduced. In the second approach, a compatibilizer, such as maleic anhydride grafted PP (PPgMA) can be used( Manias et al.,2001). The clay is melt compounded with the more polar compatibilizer to form an intercalated master batch. The master batch is then compounded with the neat PP to form the PP nanocomposite. 

Layered siUcate/polypropylene nanocomposites were prepared by melt intercalation method. Homopolymers PP alone and maleic anhydride-grafted polypropylene (PPgMA) as a compatibiUzer were used as the matrix. Clay (Na montmorillonite, MMT) particles were used to obtain silicate nano-layers within the PP matrix. Structural modification of MMT... 

The compatibilizer as such may be compatible with the clay surfaces and hence easily intercalates into the interlayer spacing of the clay platelets and separates the clay platelets, and with bulk polymer it leads to the formation of well-dispersed nanocomposites. The compatibilizer widely used for polypropylene (PP) is maleic anhydride grafted PP (PP-g-MA) [15-16], Other compatibilizers used are diethyl maleate (DEM-g-PP) and polyolefin elastomer grafted maleic anhydride (POE-g-MA),... 

Dubnikova, I. L., Berezina, S. M., Korolev, Y. M., Kim, G. M., and Lomakin, S. M. 2007. Morphology, deformation behavior and thermomechanical properties of polypropylene/maleic anhydride grafted polypropylene/layered silicate nanocomposites. 

Shen et al. [130] prepared maleic anhydride grafted polypropylene (PP)/ expanded graphite nanocomposites by solution blending. The conductive performance of PP was improved significantly. 

Mirzazadeb et al. [152] prepared master batches of maleic anhydride-grafted polypropylene with different loadings of organoclay in an internal mixer and then added polypropylene to give polypropylene nanocomposites with different degrees of intercalation. The polypropylene nanocomposites prepared were melt-blended with ethylene-propylene-diene rnbber in the presence of a vulcanizing system. 

Chow WS, Abu Bakar A, Mohd Ishak ZA, Karger-Kocsis J, Ishiaku US. Effect of maleic anhydride-grafted ethylene-propylene rubber on the mechanical, rheological and morphological properties of organoclay reinforced polyamide 6/polypropylene nanocomposites. Eur Polym J 2005 41 687-96. 

Melt intercalation of the polymer into previously organo-modified silicates. It is a very effective method when polymers, such as polyamide-6, polysiloxane and even polystyrene are intercalated. For the formation of PP-based nanocomposites, a compatibilizer such as maleic anhydride grafted polypropylene (PP-MA) or acrylic acid grafted PP is involved, which improves the polyolefin-filler interactions. ... 

Li, J., Zhou, C., Gang, W. (2003), Study on nonisothermal crystallization of maleic anhydride grafted polypropylene/montmorillonite nanocomposite , Polym Testing, 22 (2), 217-223. 

A multilayer coextrusion die was used to create polypropylene (PP) / organoclay nanocomposites and to study the stress effects on clay dispersion. Nanocomposites contained 5 wt% maleic anhydride grafted PP compafibilizer and 1-5 wt% organoclay. Nanocomposite layers were extruded opposite talc fill PS before being separated. Individual PP nanoconposite layers were tested for improvements in mechanical, thermal and barrier properties and were compared to theoretical predictions in order to determine an aspect ratio for the organoclay. Aspect ratios from theory were compared to those measured directly through TEM. A PP nanocomposite / elastomer system was also considered. 

Tidjani, A., Wald, O., Pohl, M. M., Hentschel, M. P., and Schartel, B. 2003. Polypropylene-graft-maleic anhydride-nanocomposites. I. Characterization and thermal stability of nanocomposites produced under nitrogen and in air. Polymer Degradation and Stability 82 133M0. 

Jang, L. W., Kim, E. S., Kim, H. S., and Yoon, J.-S. 2005. Preparation and characterization of polypropylene/ clay nanocomposites with polypropylene-graft-maleic anhydride. Journal of Applied Polymer Science 98 1229-1234. 

N. Dayma, B.K. Satapathy, Morphological interpretations and micromechanical properties of polyamide-6/polypropylene-grafted-maleic anhydride/nanoclay ternary nanocomposites, Materials and Design 31 (10) (2010) 4693-4703. 

On the other hand, Chen and showed that in polypropylene-graft-maleic anhydride (PE-g-MA) nanocomposite based on a dodecyl sidfate-modified LDH, thermal stability is depressed bnt charring of the polymer is enhanced. So it seems that the intercalated anion, in particular its acidity, are main factors that influence the degradation pathway by a charring mechanism. 

Diagne, M. Gueye, M. Vidal, L. Tidjani, A. Thermal stability and fire retardant performance of photo-oxidized nanocomposites of polypropylene-graft-maleic anhydride/clay. Polym. Degrad. Stab. 2005, 89, 418-426. 

Hemmati M, Narimani A, Shariatpanahi H (2011) Study on morphology, rheology and mechanical properties of thermoplastic elastomer polyolefin (TPO)/carbon nanotube nanocomposites with reference to the effect of polypropylene-grafted-maleic anhydride (PP-g-MA) as a compatibilizer. Int J Polym Mater 60 384—397... 

Cengiz [53] studied a recycled polypropylene (rPP)/organoclay nanocomposite containing ethylene-methyl acrylate-glycidyl methacrylate (E-MA-GMA) and polypropylene-grafted-maleic anhydride (PP-g-MA) compatibilisers. The rPP/ Cloisite 15A nanocomposite provided the highest improvement in mechanical properties. PP-g-MA was indicated as a better compatibiliser and furthermore, the improvement of both tensile and impact properties were better at a compatibiliser to clay ratio of 3. In addition, a significant enhancement of dispersion level as well... 

---