Effects of calcium carbonate and its purity on crystallization and melting behavior, mechanical properties, and processability of syndiotactic polypropylene

Supaphol, Pitt; Harnsiri, Wipasiri; Junkasem, Jirawut

doi:10.1002/app.13432

Cited by 80 publications

(78 citation statements)

References 29 publications

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“…It is well known that the commonly used reinforcing fillers for PP can also act as strong nucleating agents depending on the processing conditions used, degree of filler dispersion in the composite and filler surface coverage, thus, affecting the degree of crystallinity, rate of crystallization, crystal size and lamellae orientation and hence the composite properties [39][40][41][42]. Calorimetric studies reported on the composites investigated in the present study showed that under the processing conditions used in the study, the OMMT particles did not significantly affect the crystallinity of the polymer in the composites [21].…”

Section: Resultsmentioning

confidence: 99%

Polypropylene-Layered Silicate Nanocomposites: Filler Matrix Interactions and Mechanical Properties

Mittal

2007

Journal of Thermoplastic Composite Materials

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Various alkyl ammonium cations were ionically exchanged with the sodium cations of montmorillonites with two different cation exchange capacities (CECs). The organo-montmorillonites were compounded with polypropylene (PP) and the effect of filler-matrix interactions on the intercalation-exfoliation behavior and the mechanical properties of the composites were investigated. With increasing the chain packing density, an increase in the d-spacing was observed and for the same cation, the d-spacing of the OMMT was higher for the higher CEC clay. Covering the surface with molecules of higher cross-sectional area led to large basal plane spacing which was helpful in achieving the partial delamination of the filler in the PP matrix even without the use of conventional compatibilizers. The modulus of PP organo-montmorillonite composites was significantly enhanced, but the other tensile properties decreased indicating the increased brittleness and lack of stronger attraction forces at interface. Augmenting the filler volume fraction also led to a significant increase in the stiffness which was compared to the theoretical predictions using the Halpin Tsai model and its modified versions.

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Section: Resultsmentioning

confidence: 99%

Polypropylene-Layered Silicate Nanocomposites: Filler Matrix Interactions and Mechanical Properties

Mittal

2007

Journal of Thermoplastic Composite Materials

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“…As previously reported, 15 the presence of dolomite or CaMg(CO 3 ) 2 was postulated to be the reason for the observed increase in the nucleation ability of 10.5 m CaCO 3 particles. Figure 10 illustrates the variation of the t 0.5 on the choice of the T f for neat s-PP#8 and s-PP#8 filled with 40 wt % 1.9 m CaCO 3 particles of different surface modificiations (uncoated, stearic acid-coated, and paraffin-coated).…”

Section: Effect Of Melt-annealing Temperaturementioning

confidence: 60%

“…26 Interestingly, despite the different nature of the s-PP resin investigated here in comparison with other s-PP resins investigated in a previous report, similar results were obtained in that the critical T f that was needed for these s-PP resins to attain the complete molten state after 5 min of melt-annealing period (t h ) was essentially identical (160°C). 26 Moreover, the t 0.5 values for s-PP#8 filled with both 20 and 40 wt % 1.9 m uncoated CaCO 3 particles did not vary much with the T f , possibly a result of the enhanced nucleation rates attributable to the presence of the CaCO 3 particles 15 and that the t 0.5 values for s-PP#8 filled with 20 wt % CaCO 3 particles were systematically greater than those for s-PP#8 filled with 40 wt % CaCO 3 particles, suggested that an increase in the filler content enhanced the crystallization rates of the resulting compounds. Figure 9 shows dependence of the t 0.5 on the choice of the T f for neat s-PP#8 and s-PP#8 filled with 40 wt % CaCO 3 particles of varying size (1.9, 2.8, or 10.5 m).…”

Section: Isothermal Crystallization Behavior Of Neat Spp#8 and S-pp#8mentioning

confidence: 94%

“…In two related studies, Eckstein et al 18,19 studied oscillatory shear behavior of various s-PP samples in comparison with both i-PP and atactic polypropylene (a-PP) samples. The only available report on steady state shear behavior of neat and CaCO 3 -filled s-PP was by Supaphol et al, 15 who showed that, for a given shear rate, the steady-state shear viscosity increased with increasing CaCO 3 loading.…”

Section: Introductionmentioning

confidence: 98%

“…Typically, CaCO 3 is added to i-PP to reduce the cost of the final product, to improve mechanical properties (e.g., modulus and heat stability), and to enhance the crystallization rate. Available reports on filled systems of s-PP have been concerned with their mechanical and thermal properties, including the phase behavior of s-PP filled with glass beads and talcum, [12][13][14] effects of CaCO 3 of varying size and surface modification on thermal and mechanical properties of s-PP/CaCO 3 compounds, 15 and effects of various organic and inorganic nucleating agents on crystallization and mechanical properties of nucleated s-PP systems.…”

Section: Introductionmentioning

confidence: 99%

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Rheological and isothermal crystallization characteristics of neat and calcium carbonate‐filled syndiotactic polypropylene

Supaphol

Harnsiri

2006

J of Applied Polymer Sci

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Steady-state and oscillatory shear behavior of three neat syndiotactic polypropylene (s-PP) resins and a s-PP resin (s-PP#8) filled with CaCO 3 particles of varying content, size, and type of surface modification were investigated. All of the neat s-PP resins investigated exhibited the expected shear-thinning behavior. Both the storage and loss moduli increased with decreasing temperature. The shift factors used to construct the master curves were fitted well with both the Arrhenius and the Williams-Landel-Ferry (WLF) equations. The inclusion of CaCO 3 particles of varying content, size, and type of surface modification, to a large extent, affected both the steady-state and oscillatory shear behavior of s-PP/CaCO 3 compounds, with the property values being found to increase with increasing content, decreasing size, and surface coating of the CaCO 3 particles. Lastly, the effects of melt-annealing and crystallization temperatures on isothermal crystallization behavior of s-PP#8 filled with CaCO 3 particles of varying content, size, and type of surface modification were also investigated. The half-time of crystallization of neat s-PP#8 exhibited a strong correlation with the choice of the melt-annealing temperature (T f ) when T f was less than about 160°C, while it became independent of T f when T f was greater than about 160°C. On the other hand, the half-time of crystallization of s-PP#8/CaCO 3 compounds did not vary much with the T f . Generally, the observed half-time of crystallization decreased with increasing CaCO 3 content and increased with increasing CaCO 3 particle size. Finally, coating the surface of CaCO 3 particles with either stearic acid or paraffin reduced the ability of the particles to effectively nucleate s-PP#8.

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Viscoelastic properties of nanosilica‐filled polypropylene in the molten state: Effect of particle size

Haghtalab¹,

Marzban²

2011

Adv Polym Technol

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ABSTRACT:Composites of polypropylene (PP) with nontreated nanosilica at different particle sizes are prepared, and their viscoelastic properties are studied by dynamic strain-and frequency-sweep experiments. It is clear that incorporation of nanoparticles in a polymer matrix due to the huge specific surface area enhances both moduli so that the storage modulus is intensified more than loss modulus. The specific surface area of a particles increases as a particle size decreases, leading to a stronger tendency to form reinforcing structures. In nanocomposites of smaller particles due to existence of a larger contact area between particles, more and stronger filler clusters are formed. Thus, a stronger filler-filler network is formed by decreasing the particle size so that both storage and loss moduli present higher values. The slope of dynamic moduli as a function of frequency decreases with filler loading augmentation in a low-frequency region, and this solid-like behavior becomes more significant with particle size reduction. The PP composites in high filler loadings exhibit a yield stress, and weight fraction corresponds to the onset of this well-defined yield stress and is lower in the case of smaller filler particles. In addition, the polymer chains adsorption on the particles and/or clusters surface and formation of filler-polymer network increases with filler loading augmentation. The influence of these two reinforcing mechanisms leads to a gradual enhancement of the Payne

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Effects of calcium carbonate and its purity on crystallization and melting behavior, mechanical properties, and processability of syndiotactic polypropylene

Cited by 80 publications

References 29 publications

Polypropylene-Layered Silicate Nanocomposites: Filler Matrix Interactions and Mechanical Properties

Polypropylene-Layered Silicate Nanocomposites: Filler Matrix Interactions and Mechanical Properties

Rheological and isothermal crystallization characteristics of neat and calcium carbonate‐filled syndiotactic polypropylene

Viscoelastic properties of nanosilica‐filled polypropylene in the molten state: Effect of particle size

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