Non-isothermal crystallization kinetics of calcium carbonate-filled β-crystalline phase polypropylene composites

Tjong, Sie Chin; Xu, Shiai

doi:10.1002/(sici)1097-0126(199709)44:1<95::aid-pi821>3.0.co;2-l

Cited by 80 publications

(49 citation statements)

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“…Pure HDPE cannot be used as a structural material for a variety of engineering applications because the mechanical strength and elastic modulus of HDPE are relatively low despite its good tensile ductility. The mechanical strength and modulus of polyolefins can be greatly improved by adding inorganic and synthetic fillers such as talc, [1] mica, [2] calcium carbonate, [3] glass beads, [4] and liquid crystalline polymer [5] of micrometer dimensions. However, it is necessary to add large volume fractions of these fillers to HDPE for achieving desired mechanical strength and stiffness.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and Thermal Performance of High-Density Polyethylene/Alumina Nanocomposites

Liao

Tjong

2012

Journal of Macromolecular Science, Part B

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High-density polyethylene (HDPE) nanocomposites reinforced with pristine and vinyltrimethoxysilane (VTMS)-treated alumina nanoparticles of 2, 4, and 6 wt% were melt-compounded in a twin-screw extruder followed by injection molding. Their structure, thermal and mechanical behaviors were studied. Fourier transform infrared (FTIR) spectra showed that VTMS was successfully covalently grafted to the alumina nanoparticles. The X-ray diffraction (XRD) patterns indicated that the alumina nanoparticle additions broadened the characteristic peak width of HDPE, indicating that they reduced the crystallite size of HDPE. The heat deflection temperature and thermogravimetric analyses demonstrated that the dimensional and thermal stability of HDPE were enhanced markedly by adding pristine and silane-treated alumina nanoparticles. The alumina nanoparticle additions were also beneficial in enhancing Young's modulus and yield strength of HDPE. The reinforcing effect was particularly apparent in the silane-treated nanocomposites due to improved filler-matrix interactions.

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Section: Introductionmentioning

confidence: 99%

Mechanical and Thermal Performance of High-Density Polyethylene/Alumina Nanocomposites

Liao

Tjong

2012

Journal of Macromolecular Science, Part B

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“…Used in low concentration, these agents, acting as heterogeneous nuclei, usually increase the rate of isothermal crystallization [3,6]. During nonisothermal crystallization from the melt, the temperature of crystallization of the nucleated polymer is shifted towards higher temperature [7,8]. For these reasons, nucleating agents are widely used in industry to reduce processing times and to improve the properties of iPP.…”

Section: Introductionmentioning

confidence: 99%

Characterization of a maleic anhydride-modified polypropylene as an adhesion promoter for glass fiber composites

Bogoeva‐Gaceva¹,

Janevski²,

Mäder³

2000

Journal of Adhesion Science and Technology

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Isothermal and nonisothermal crystallizationsof isotactic polypropylene(iPP), maleic anhydride (MAH)-grafted PP, and MAH-modi ed iPP were studied by differential scanning calorimetry (DSC), to evaluate the in uence of a small amount of MAH-grafted PP in iPP on its crystallization behavior. Isothermal crystallization was followed in the temperature range from 391 K to 403 K, and the rate constant and Avrami exponents were determined. Nonisothermal crystallization was carried out at different cooling rates (1-20 K/ min). It was found that the crystallization kinetics of iPP was signi cantly altered by modi cation with the MAH-grafted polymer. A decreased equilibrium melting temperature, as well as decreased surface energy of folding and critical dimensions of a growing nucleus, was determined for the MAH-modi ed iPP, indicating faster growth of lamellae and a higher rate of crystallization. The improved nucleation ability of the modi ed polymer was shown to cause a shift in the crystallization peak temperature towards higher values (from 393.7 K to 399.6 K, at a cooling rate of 1 K/ min), resulting in crystal structures less disposed to recrystallization. Model composites of iPP and MAH-modi ed iPP with glass bers were also analysed. The apparent shear strength of single-ber model composites with MAH-modi ed iPP was drastically increased compared with homo-iPP.

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“…The values of conditions and X-ray scattering has been used to identify and structurally characterize these. [9][10][11][12][13] The α-phase is the most predominant form of PP, wherein the chains crystallize into a monoclinic unit cell. This form has also been shown to be the most thermodynamically stable of all the crystalline polymorphs of PP.…”

Section: Methodsmentioning

confidence: 99%

Investigating the Morphological Variations Due to Processing and Thermomechanical Treatment of Poly(propylene) Using Raman Microscopy

Sanoria

Damodaran

Schuster

et al. 2016

Macro Chemistry & Physics

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Differences in the Raman spectrum of the α-and β-polymorph of poly(propylene) (PP) have been identifi ed in the form of band shifts distinct for the specifi c polymorph. A new method has been developed, which can ascertain the presence of the α-polymorph. These band shifts have been used to profi le both the polymorphs and variations in the crystallinity across the whole spherulite have been ascertained by carrying out a spatially resolved profi ling of the degree of crystallinity. The crystalline domains in PP have been qualitatively assessed using the band shifts in the Raman spectra. This approach has then been applied to study local variations in the morphology of welds between PP plates, wherein the complex interplay between the heating and cooling patterns as well as the mechanical forces due to shearing gives rise to the development of a different morphological structure in the weld. Using Raman microscopy, a reduction in the crystallinity (≈18%) in the region of the weld seams and sporadic formation of β-spherulites in the weld core is observed. The methodology developed has been applied to investigate a weld between PP-H and PP-R (PP with random ethylene copolymer), to ascertain the variations occurring upon welding in such materials. various components. [ 1,2 ] Processing PP into the fi nal product regularly infers anisotropies in the melt due to shear forces, which result in structural variations in the solidifi ed polymer. The latter embody themselves in the form of spatial variations in morphology, with their length scale and variance depending on the specifi c process and conditions. These in turn have a signifi cant impact on the macroscopic properties, such as mechanical properties and crack propagation. [3][4][5] Hence, spatially mapping the morphology in a comprehensive manner is an important task in order to establish process→structure→property relationships and use these to optimize manufacturing. [ 6 ] The morphology of PP has been well studied and it has been known that PP crystallizes in three different polymorphs, namely, the α-, β-and γ-form. [ 7,8 ] The crystallization into a specifi c form depends on the crystallization

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Non-isothermal crystallization kinetics of calcium carbonate-filled β-crystalline phase polypropylene composites

Cited by 80 publications

References 1 publication

Mechanical and Thermal Performance of High-Density Polyethylene/Alumina Nanocomposites

Mechanical and Thermal Performance of High-Density Polyethylene/Alumina Nanocomposites

Characterization of a maleic anhydride-modified polypropylene as an adhesion promoter for glass fiber composites

Investigating the Morphological Variations Due to Processing and Thermomechanical Treatment of Poly(propylene) Using Raman Microscopy

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