Volume expansion of polyethylene with various degrees of crystallinity over a wide range of temperatures

Бартенев, Г. М.; Ремизова, А. А.; Kuleshov, I.V.; Martynov, M.A.

doi:10.1016/0032-3950(73)90337-7

Cited by 3 publications

(1 citation statement)

References 9 publications

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“…An earlier study shown that T g increased as a function of crystallinity in the case of branched PE. 39 One can thus conclude that particle size is taking a dominating factor with change in crystallinity of PP nanoparticles to affect the T g . Hence, PP particles with size ranging from several nanometers to several micrometers are spherical in nature with different T g values.…”

Section: Resultsmentioning

confidence: 98%

High molecular weight polypropylene nanospheres: Synthesis and characterization

Paik

Kar

2007

J of Applied Polymer Sci

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The high molecular weight (MW) polypropylene with average particle size of 60 nm was synthesized by controlled growth mechanism using ZieglerNatta catalyst. The atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies showed that PP nanoparticles were spherical in shape. Structure and crystallinity were concomitantly studied through Fourier transform infrared spectroscopy and X-ray diffraction, respectively. It shows nanospherical PP particles with more crystallinity ($ 75%) compared with macrosized PP ($ 59%). In addition, differential scanning calorimetry studies revealed the finite particle size effect on T g and the scale dependence T g followed a first order exponential trend. As particle size goes down to nano-scale from macrosize, continuous elevation of T g 's were observed from À25 to À118C. This phenomenon was directed to configuration entropy of single spherical nanoparticles of PP. The mechanical properties and surface roughness were also evaluated through AFM. At last, the properties of nanosized PP were compared with micron and macrosized particles.

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Section: Resultsmentioning

confidence: 98%