Polyisoprene Nanoparticles Prepared by Polymerization in Microemulsion

Abstract

Batch polymerization of isoprene was carried out at25∘Cin a normal microemulsion stabilized with sodium dodecyl sulfate and initiated with the redox coupletert-butyl hydroperoxide/tetraethylene-pentamine. Characterization by transmission electronic microscopy showed that polyisoprene nanoparticles with number-average diameter close to 20 nm were obtained. The low molecular weights obtained, as determined by gel permeation chromatography, were probably due to chain scission as inferred from the oxidative ambient at which polymerization was carried out. Microstructure calculated from infrared spectroscopy data indicates that the obtained polyisoprene contains around 80% total 1,4 units, which is in accordance with its glass transition temperature (-60.8∘C) determined by differential scanning calorimetry.

Molecular and Structure–Properties Comparison of an Anionically Synthesized Diblock Copolymer of the PS-b-PI Sequence and Its Hydrogenated or Sulfonated Derivatives

“…In the case of complete hydrogenation, the carbon double bonds were eliminated. The different microstructures of the PI (−1,4: 839 cm −1 /−3,4: 890 cm −1 and −1,2:910 cm −1 ) [ 17 , 49 , 50 ] showcased a similar behavior. Therefore, the band intensities in the modified materials were either decreased (after partial sulfonation) or completely disappeared (after full hydrogentation).…”

“…The >C=C< bond as well as the >C-H bond on the aromatic ring can be clearly identified at 1500 cm −1 , 1600 cm −1 and 760 cm −1 , respectively [ 18 ], whereas after 3000 cm −1 , the C-H vibrations are evident [ 18 ]. The characteristic stretching of the double bond of the PI block at 1664 cm −1 [ 18 ] as well as the characteristic peaks for the different microstructures (−1,4, −1,2 and −3,4) at the regime of 839–910 cm −1 [ 49 ] are evident. Furthermore, the presence of fewer peaks in the area of 800–1000 cm −1 after hydrogenation, are observed [ 19 ], whereas for the SI/sulf sample, new intense peaks emerged due to the sulfonation.…”

Effect of Impact Modifiers on Strength and Fracture Toughness of CFRPs

“…The size of these particles can be adjusted from their formulation due to emulsion polymerisation. Recent advances have proved that these particles exhibit good dispersion in the epoxy matrices, increase fracture properties while maintaining glass transition temperature and viscosity [7]. This study aims to investigate the effect of core-shell rubbers on the mechanical properties of CFRPs.…”